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F5 Signaling Delivery Controller Product Description Software Version: 4.0.5 Publication Date: March 2014 Catalog Number: GD-014-405-4 Ver.2 Proprietary and Confidential Information of F5 Networks 1 LEGAL NOTICES ......................................................................................................................... 6 Copyright .......................................................................................................................................................... 6 Trademarks ...................................................................................................................................................... 6 1 ABOUT THIS DOCUMENT .......................................................................................................................... 7 1.1 DOCUMENT OBJECTIVES ................................................................................................ 7 1.1 CONVENTIONS ............................................................................................................. 7 1.2 GLOSSARY OF TERMS AND ABBREVIATIONS ....................................................................... 8 1.3 DOCUMENT VERSION HISTORY ....................................................................................... 9 2 INTRODUCTION TO SDC .......................................................................................................................... 10 3 DEPLOYMENT ARCHITECTURES ............................................................................................................... 13 3.1 4 5 6 DEPLOYMENT MODES: ................................................................................................. 13 3.1.1 Core network deployment ............................................................................................................... 14 3.1.2 Edge deployment ............................................................................................................................. 16 3.1.3 Dual mode deployment.................................................................................................................... 17 3.1.4 Multi-site deployment...................................................................................................................... 18 DIAMETER AND LEGACY PROTOCOLS SUPPORT ...................................................................................... 19 4.1 DIAMETER AND 3GPP REFERENCE POINTS SUPPORT ......................................................... 19 4.2 LEGACY PROTOCOLS SUPPORT ....................................................................................... 19 4.3 NETWORK AND TRANSPORT SUPPORT ............................................................................ 20 SDC PLATFORM ARCHITECTURE .............................................................................................................. 21 5.1 CONFIGURATION MANAGER ......................................................................................... 21 5.2 WEB UI AND SOAP .................................................................................................... 22 5.3 CONTROL PLANE FUNCTION (CPF) ................................................................................ 22 5.4 FRONT-END PROXY (FEP) ............................................................................................ 22 5.5 TRIPO ....................................................................................................................... 24 5.6 FILE SERVER ............................................................................................................... 24 5.7 NMS AGENT ............................................................................................................. 24 THE SDC PIPELINE ................................................................................................................................... 25 6.1 SECURITY ENFORCEMENT ............................................................................................. 26 Proprietary and Confidential Information of F5 Networks 2 6.2 PRE-ROUTING TRANSFORMATION ................................................................................. 26 6.3 ROUTING................................................................................................................... 27 6.3.1 Basic Routing ................................................................................................................................... 28 6.3.2 Routing using external location functions ....................................................................................... 29 6.3.3 Routing decision binding between different Diameter reference points ......................................... 30 6.3.4 Multi-Protocol Session Binding ........................................................................................................ 32 6.3.5 Bi-directional routing ....................................................................................................................... 33 6.3.6 Redirection ....................................................................................................................................... 36 6.3.7 Routing example .............................................................................................................................. 36 6.4 6.4.1 By Precedence .................................................................................................................................. 39 6.4.2 Round Robin..................................................................................................................................... 39 6.4.3 Weighted Round Robin .................................................................................................................... 40 6.4.4 Fastest Response Time ..................................................................................................................... 41 6.4.5 Queue Size Ratio .............................................................................................................................. 42 6.4.6 Load Based ....................................................................................................................................... 43 6.4.7 Contextual........................................................................................................................................ 44 6.4.8 Weighted Contextual ....................................................................................................................... 45 6.4.9 External ............................................................................................................................................ 45 6.5 7 LOAD BALANCING ....................................................................................................... 38 OUTGOING MESSAGE TRANSFORMATION ....................................................................... 47 OVERLOAD AND CONGESTION CONTROL ................................................................................................ 50 7.1 7.1.1 7.2 THROTTLING AND RATE LIMITING .................................................................................. 51 Token bucket algorithm ................................................................................................................... 52 OVERLOAD CONTROL MECHANISM ................................................................................ 52 7.2.1 Peer Rate Limit Definition ................................................................................................................ 53 7.2.2 Global Rate Limiter .......................................................................................................................... 53 7.2.3 Resource Monitoring ....................................................................................................................... 53 7.2.4 Rejection .......................................................................................................................................... 53 7.3 HEALTH MONITORING ................................................................................................. 54 7.4 IN SESSION MONITORING ............................................................................................ 54 7.5 EXTERNAL MONITORING .............................................................................................. 55 7.6 CONNECTIVITY MONITORING ........................................................................................ 55 Proprietary and Confidential Information of F5 Networks 3 8 9 OAM SUPPORT ....................................................................................................................................... 57 8.1 ALARMS .................................................................................................................... 58 8.2 TRACING AND LOGGING ............................................................................................... 58 8.3 MONITORING............................................................................................................. 59 8.4 PERFORMANCE MANAGEMENT ..................................................................................... 59 8.5 SECURITY MANAGEMENT ............................................................................................. 59 8.6 LICENSING MANAGEMENT ........................................................................................... 59 8.7 LIFECYCLE MANAGEMENT ............................................................................................ 59 8.8 SOAP API................................................................................................................. 59 8.9 SNMP AGENT ........................................................................................................... 60 8.10 CLUSTER MANAGEMENT .............................................................................................. 60 8.11 AUDITING .................................................................................................................. 60 8.12 BACKUP & RESTORE .................................................................................................... 60 HIGH AVAILABILITY AND SCALABILITY .................................................................................................... 61 9.1 SCALABILITY ............................................................................................................... 61 9.2 LOCAL REDUNDANCY AND SCALABILITY .......................................................................... 63 9.2.1 Hot/Standby deployment................................................................................................................. 64 9.2.2 N+K Scalable service deployment .................................................................................................... 65 9.2.3 Virtual IP, Failure detection and recovery ........................................................................................ 69 9.3 9.3.1 10 11 GEOGRAPHICAL REDUNDANCY ...................................................................................... 71 Site Replication ................................................................................................................................ 74 SECURITY ................................................................................................................................................ 76 10.1 DIAMETER TOPOLOGY HIDING ...................................................................................... 76 10.2 DIAMETER CONNECTION SECURITY ................................................................................. 76 10.3 DIAMETER MESSAGE SECURITY ...................................................................................... 76 10.4 OS/SYSTEM SECURITY ................................................................................................. 77 10.5 NETWORK LEVEL SECURITY........................................................................................... 77 NETWORKING ......................................................................................................................................... 78 11.1 NETWORK REDUNDANCY .............................................................................................. 78 11.2 PHYSICAL INTERFACES.................................................................................................. 79 Proprietary and Confidential Information of F5 Networks 4 11.3 12 ADDRESSING SCHEME.................................................................................................. 80 HW ARCHITECTURE ................................................................................................................................. 81 12.1 SUPPORTED HW ........................................................................................................ 81 13 APPENDIX A – OAM SNAPSHOTS ............................................................................................................ 82 14 APPENDIX B – ACCESS LEVEL SECURITY ................................................................................................... 87 15 APPENDIX C – LOW LEVEL SDC PIPELINE ................................................................................................. 89 ABOUT F5 NETWORKS...................................................................................................................................... 90 Proprietary and Confidential Information of F5 Networks 5 Legal Notices Document Name: F5 Signaling Delivery Controller 4.0.5 Product Description Catalog Number: GD-014-405-4 Ver.1 Publication Date: January 2014 Copyright © 2005-2014 F5 Networks, Inc. All rights reserved. F5 Networks, Inc. (F5) believes the information it furnishes to be accurate and reliable. However, F5 assumes no responsibility for the use of this information, nor any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent, copyright, or other intellectual property right of F5 except as specifically described by applicable user licenses. F5 reserves the right to change specifications at any time without notice. Trademarks F5 Networks, F5, F5 (design), OpenBloX, OpenBloX (design), Rosetta Diameter Gateway, Signaling Delivery Controller and SDC, are trademarks or service marks of F5 Networks, Inc., in the U.S. and other countries, and may not be used without The F5 express written consent. All other product and company names herein may be trademarks of their respective owners. Confidential and Proprietary The information contained in this document is confidential and proprietary to F5 Networks. The information in this document may be changed at any time without notice. Proprietary and Confidential Information of F5 Networks 6 F5 Signaling Delivery Controller Product Description 1 About this Document 1.1 Document Objectives This document provides an overview and a high level functionality description of the F5 Signaling Deliver Controller (SDC). The target audience of this document includes Network and Solution Architects and Program and Product Managers. 1.1 Conventions The style conventions used in this document are detailed in Table 1. Table 1: Conventions Convention Use Times New Roman Regular text Times New Roman Names of menus, commands, buttons, and other elements of the user interface Bold Times New Roman Links to figures, tables, and sections in the document, as well as Italic references to other documents Courier New Language scripts Calibri File names Notes which offer an additional explanation or a hint on how to Note: overcome a common problem Warnings which indicate potentially damaging user operations and explain how to avoid them An example 7 F5 Signaling Delivery Controller Product Description 1.2 Glossary of Terms and Abbreviations Table 2: Glossary of Terms and Abbreviations Term Definition AAA Authentication, Authorization and Accounting. AF Application Function Cluster Group of nodes used to provide services as a single unit. Cluster Node A node in the Cluster. CPF Control Plane Function Data Dictionary Defines the format of a protocol’s message and its validation parameters: structure, number of fields, data format, etc. DRA Diameter Routing Agent DRT Data Transfer Request (GTP term) EMS Element Management System FEP Front End Proxy HTTP Hypertext Transfer Protocol HSS Home Subscriber Server IMS IP Multimedia Subsystem JMS Java Message Service LDAP Lightweight Directory Access Protocol Link The connection joint between the Cluster and Remote Nodes. LTE Long Term Evolution MME Mobile Management Entity NGN Next Generation Networking. Node Physical or virtual addressable entity PCEF Policy and Charging Enforcement Function PCRF Policy and Charging Rules Function, acts as decision point and enforces policy usage for a subscribers Peer Physical or virtual addressable entity. A Client or Server Peer in the NGN network that provides or consumes AAA services Pool A group of server remote nodes. RADIUS Remote Authentication Dial In User Service 8 F5 Signaling Delivery Controller Product Description Term Definition Remote Node A client or server node in the network that provides or consumes AAA services. Scenario Logical policies of translation flow. SDC Signaling Delivery Controller SNMP Simple Network Management Protocol SS7 Signaling System No. 7 TCP Transmission Control Protocol TLS Transport Layer Security UDP User Datagram Protocol URI Universal Resource Identification. 1.3 Document Version History Date – Version Change Reference March 2014-2 Licensing Management See Licensing Management text 9 F5 Signaling Delivery Controller Product Description 2 Introduction to SDC The F5 Signaling Delivery Controller (SDC) is a modular signaling platform that provides a flexible and robust solution for the emerging control plane connectivity challenges. The SDC is shown in Figure 1. The SDC was designed to meet the demanding requirements posed by the growing volume of signaling traffic and the complexity of connectivity and signaling in LTE and IMS networks with advanced Diameter Gateway, Diameter Load Balancer, and Diameter Router solutions, consolidated on a single, unified platform. The SDC enables service providers to scale and manage services and applications in LTE and IMS networks, supporting millions of concurrent sessions and hundreds of millions of subscribers. The SDC solution centralizes signaling and Diameter routing, traffic management, and load balancing tasks to scale and grow IMS and LTE networks incrementally and cost effectively, while increasing resiliency and reliability to support the subscriber’s ever increasing service and broadband demands. Figure 1: Signaling Delivery Controller 10 F5 Signaling Delivery Controller Product Description The core functionality of SDC is based on a powerful contextual routing engine which allows definition and execution of different routing policies that simplify the control plane network management. The routing engine, together with advanced load balancing algorithms, fast failback detection, failover mechanisms, and congestion control, provide unprecedented scalability and high-availability of Diameter and other nodes. When deploying the SDC between LTE, IMS, and legacy network elements, service providers gain multiple added-value benefits such as: Simple and transparent Diameter network configuration, administration, and maintenance. Easy installation procedures with a user friendly GUI makes SDC fast to deploy and easy to maintain. Its capabilities are extremely powerful, yet simple to configure and modify. Automatic cluster detection and a secure configuration replication among parallel cluster nodes reduce the administrator’s efforts to minimum. Comprehensive network management using Diameter contextual routing engine that reduces and centralizes the routing logic and reliefs Diameter nodes from handling this logic. Congestion control for Diameter servers using advanced in-band health monitoring, overload detection and throttling mechanisms. Using the health monitoring mechanisms, SDC manages back-end failures and reduces the risk of unintentionally sending traffic to overloaded or unavailable servers. Scalability of Diameter server nodes (such as PCRF, HSS, OCS) using Layer 4-7 load balancing algorithms, and fast failover detection and failback mechanisms. Combined with congestion control mechanisms, SDC assures that signaling traffic is sent to healthy servers and that after unhealthy server recovery, it is automatically and gradually reintroduced to the network. SDC provides flexibility, scripting and customization. SDC provides full user control for definition for routing and transformation script rules using the Java-based Groovy scripting language. Using this flexible scripting, SDC can detect errors in messages or perform interaction with external systems while executing routing 11 F5 Signaling Delivery Controller Product Description decision. When interaction with external systems is required, SDC can be integrated with 3rd party, Java-based libraries. LTE to legacy interoperability interconnectivity between new Diameter-based functionalities and legacy infrastructure using legacy signaling protocols. Service level security and authorization for Diameter. To avoid Denial of Service and Distributed Denial of Service attacks, SDC runs different heuristics to protect the system from overrun attempts and invalid requests. It also controls and fine-tunes Denial of Service protection through ACLs. Visibility into Diameter level performance. The management console allows real time performance visualization and monitoring of SDC internals and back-end servers. The performance counters are also available through multiple methods that allow import to external monitoring systems. Carrier grade product using off the shelf hardware. SDC supports front-end failover using multiple Virtual IPs. Using multi-threading and internal load balancing, the SDC performance scales linearly with the number of cores/processors and the number of SDC blades. The scale out ability protects SDC and the signaling network from multiple compound failures. Centralized Management. In multi-site deployments, the Element Management System (EMS) receives data (counters, states, alarms) from each SDC site, and enables global configuration of many aspects of the SDC sites in the deployment. The SDC provides Diameter protocol routing, mediation and interworking functions, allowing service providers to manage legacy to LTE and LTE to LTE roaming seamlessly. By avoiding the need of complex integration and customization projects, SDC provides a simple, reliable, and easy to deploy solution to the most challenging control plane connectivity issues. The SDC is the market's only fully native Diameter solution and can be deployed as an IETF Diameter Agent (relay, proxy, redirect and translation), 3GPP Diameter Routing Agent (DRA), GSMA Diameter Edge Agent (DEA) and 3GPP Interworking Function (IWF). 12 F5 Signaling Delivery Controller Product Description 3 Deployment Architectures SDC’s deployment modes are depicted in Figure 2. HSS DEA MME SGSN S6a/d, Sh, Proxy PLMN-C AF DRA DEA DEA DEA DEA GGSN PLMN-B Gy, Ro Proxy PCRF DEA SDC MVNO-B-A OCS DEA PLMN-A IPX-A IPX-B MVNO-B-B Figure 2: End to end Diameter Architecture Multiple types of service and network providers can benefit from SDC capabilities. The actual deployment mode depends on the provider’s needs. 3.1 Deployment modes: Core Network: SDC is deployed in the PLMN and enables management and scaling of the internal network. Figure 2 depicts an internal network deployment for PLMN-A. In this deployment, SDC is used (1) S6a/d and Sh Proxy for HSS; (2) Gy/Ro Proxy for OCS; (3) Gx/Rx DRA between GGSN/AF and PCRF. SDC in PLMN-A provides the routing and load-balancing functionalities for Diameter nodes, and gateway/mediation functionalities with non-Diameter nodes. The 13 F5 Signaling Delivery Controller Product Description functionality split is logical and all the functionalities are served by a single SDC deployment. Edge: The SDC is deployed at the edge of administrative domains, e.g. PLMN or IPX, and enables secure and interoperable roaming and single point of attachment between the partners. In Figure 2, edge network deployment is shown. In this deployment, SDC is used (1) between PLMN and IPX; (2) IPX to IPX (3) PLMN to PLMN (4) PLMN to MVNO/ISP/OTT service provider. SDC provides the security enforcement and border control functionalities between the domains. It hides the internal PLMN topology of Diameter nodes and provides interworking function with non-Diameter nodes. In this mode SDC incorporates an IWF function as defined by 3GPP and supports DEA (Diameter Edge Agent) guidelines recommended by GSMA. IPX: SDC is deployed in IPX provider and performs traffic steering between domains based on the supported roaming agreements. When deployed in IPX carrier/wholesale carrier/roaming hubs, it provides a secure platform to protect the network and properly route Diameter traffic at ingress and egress points. 3.1.1 Core network deployment The SDC can be deployed in the core network of the service provider. When deployed in the core network, it reduces the operational burden posed by the peer-to-peer connectivity architecture defined between the different Diameter based network elements. In core network deployment, the SDC provides: Centralized management of Diameter signaling routing and flexibility in network configuration Native means for scaling up of the Diameter based servers by using Diameter based, message oriented load-balancing mechanisms Native methods for overload and failover management by using Diameter based, message oriented, congestion control mechanisms 14 F5 Signaling Delivery Controller Product Description Mechanisms for message normalization and adaptation between Diameter variants and between Diameter and legacy protocols In core network deployment, SDC can serve as a Proxy (Figure 3) or Redirect (Figure 4) routing agent: In proxy mode, all Diameter transactions between two Diameter nodes are transferred through SDC. In redirect mode, SDC participates in session establishment between two Diameter nodes, but it does not handle the Diameter transactions. To leverage the benefit of Diameter message normalization or modification, the SDC should be deployed in proxy mode. Figure 3: SDC deployment as proxy in local mode 15 F5 Signaling Delivery Controller Product Description Figure 4: SDC deployment in local mode using redirect 3.1.2 Edge deployment SDC can be deployed at the border of the service provider or IPX network. When deployed at the edge of the network, SDC serves as single point of attachment for roaming partners, other service providers or IPX network. Edge deployment of SDC is shown in Figure 5. In this deployment, SDC: hides the Diameter network topology and performs Diameter traffic steering and routing based on predefined rules and roaming policies; Enforces Diameter security policies incoming Diameter connection and applies message normalization and adaptation. Does message normalization and adaptation between Diameter variants and between Diameter and legacy protocols. SDC serves as an IWF function defined by 3GPP standards (29.805 and 29.305). In edge deployment, SDC works as Diameter Proxy agent. 16 F5 Signaling Delivery Controller Product Description Figure 5: SDC roaming deployment 3.1.3 Dual mode deployment In dual mode deployment, SDC serves as an internal network router and load-balancer. Dual mode deployment of SDC is shown in Figure 6. SDC routes traffic between different Diameter-enabled network nodes within the operator's network and provides roaming connectivity with partner service provider networks and MVNO/ISP networks using Diameter, SS7 and other protocols. The SDC can work in dual mode, Proxy for roaming connection and Relay for the local PLMN. 17 F5 Signaling Delivery Controller Product Description Figure 6: SDC dual mode 3.1.4 Multi-site deployment The SDC Element Management System (EMS) supports multi-site deployments by providing a centralized point of control. When using EMS, each site is installed with an EMS agent, used to collect key performance indicators from the site and communicate with the EMS manager in the EMS to relay and receive global configuration parameters. There are two types of EMS multi-site deployments: 1. Centralized – each site is installed with an EMS agent and Splunk Forwarder component. These components respectively forward information to and receive information from the EMS manager and Splunk components in the management site to create an overview of the deployment’s performance and support shared configuration across multiple sites. 2. Distributed – in addition to the EMS agent and Splunk Forwarder components, each site is installed with their own Splunk component. The Splunk component for each site communicates directly with the Splunk component in the management site. For more information about the Element Management System, see the F5 SDC Element Management System. 18 F5 Signaling Delivery Controller Product Description 4 Diameter and Legacy Protocols Support 4.1 Diameter and 3GPP reference points support SDC provides native Diameter support for IETF RFCs 3588, 6733, and related IETF RFC and for all reference points defined by 3GPP, e.g. Gx, Gxx, Rx, S6a, S6d, S9, S13, Sh, Ro, Rf, Gy, SWx. SDC also complies with GSMA and MSF guidelines. SDC provides a flexible and simple mechanism for adding support for new Diameter interfaces, which is achieved by uploading the relevant Diameter data dictionaries. Uploading new data dictionaries is done in runtime and does not require software upgrade or maintenance downtime. The dictionaries are XML based. The SDC solution provides seamless and transparent support for any vendor specific AVP. Multiple different versions of the same AVP, optionally, encoded differently, are transparently handled by the system. If AVP modification is required, the AVPs are added to the dictionary file with different names, allowing user access and modification. 4.2 Legacy protocols support The solution supports simultaneous usage of multiple dictionaries, enabling SDC to interconnect with multiple Diameter nodes over multiple different reference points. For the roaming or legacy connectivity, the SDC supports the following protocols: Telecom protocols, like RADIUS, GTP’, SS7: MAP, Camel. Support for the SS7 protocols – MAP and CAMEL – is provided by the SDC in a few ways. The implementation of the SDC as an IWF provides a variety of support scenarios between Diameter and MAP, including the following: o Mobility management – an S6a/S6d - Rel8 Gr interworking scenario In this interworking scenario, the SDC acts as an IWF directly connecting between a Diameter based MME or SGSN using S6a/S6d and a MAP based Rel8 HLR using Gr. 19 F5 Signaling Delivery Controller Product Description o Mobility management – an S6a/S6d - S6a/S6d interworking scenario with two IWFs In this interworking scenario, the Traffic SDC acts as an IWF that works with an additional 3rd party IWF to connect between a Diameter based MME or SGSN using S6a/S6d, a Diameter based Rel8 HSS-MME or Rel8 HSS-SGSN using S6a/S6d, and an SS7/MAP based roaming agreement. o IMEI check – an S13/S13' - Gf interworking scenario with one IWF In this interworking scenario, the SDC acts as an IWF directly connecting between a Diameter based MME or SGSN using S13/S13’ and a MAP based Pre Rel8 EIR using Gf. IT protocols, like LDAP, HTTP, JMS, SQL (as shown in Figure 7) Figure 7: Protocol Interconnectivity 4.3 Network and Transport support At the network layer, SDC provides support for IPv6 and IPv4. At the transport layer TCP, UDP and SCTP are supported. SDC supports simultaneous use of SCTP and TCP transport protocols. It allows interconnecting between two peers that use different transport protocols; one peer can use SCTP, while the other is using TCP. It also supports interconnecting between two peers that use different network protocols, IPv4 and IPv6 protocols. 20 F5 Signaling Delivery Controller Product Description 5 SDC Platform Architecture SDC is a modular platform that allows easy integration of new services, providing flexible mechanisms for adding new external components. As shown in Figure 8, external components can easily be added to the SDC by creating one point of contact between the component and a FEP or the component and a CPF. The architecture also allows CPFs to be added without affecting other system components. Client Server Server Client HA Cluster FEP-O FEP-O (SCTP) (TCP) Config Mgr Web UI Shared Memory CPF CPF CPF CPF SOAP FEP-I FEP-I (IPSEC) (TCP) Client Client Client Client Figure 8: SDC Platform Architecture 5.1 Configuration Manager The Configuration Manager serves as the system configuration repository, enabling configuration management and distribution between the nodes. This module manages the 21 F5 Signaling Delivery Controller Product Description configuration information for interconnected peers, as well as their status, protocol dictionaries, and deployed business rules. The Element Management System (EMS), an optional add-on for multi-site deployments, manages the configuration information for certain components of the installed SDC sites. 5.2 Web UI and SOAP The SDC provides both a web-based interactive GUI and a SOAP-based programmatic system configuration and provisioning interface. It is responsible for performance statistics collection and presentation. 5.3 Control Plane Function (CPF) The Control Plane function is the core component in the SDC architecture, providing Session management, Routing, Load Balancing, and messages manipulation services. CPF provides replication, alarms, and logging support, as well as basic functionalities required for integrating new services and modules that are not part of the standard deployment, enabling customization of the solution. An example of such customization is adding support for SLF (Service Location Function) as an external application loaded by the solution. This SLF function is called within the solution rules management, and on its backplane it communicates with proprietary interfaces as supported by the Java application. 5.4 Front-End Proxy (FEP) The Front-End Proxy is a network distribution point in SDC. It is built on top of the CPF framework to take advantage of the CPF management, pipeline and other infrastructures. FEP maintains a steady single connection of TCP with the multiple CPF nodes. For each Remote 22 F5 Signaling Delivery Controller Product Description Node, it manages the connection and state machine, providing statistics and management capabilities for the connections and the traffic. The FEP and CPF nodes, as aforesaid, share the same framework. Both nodes construct a transport pipeline with each of its peers. The FEP node is responsible for managing the peers’ state machines, maintain and configure the connections. As FEP is the connection point, and there usually is a single FEP in SDC, all Remote Servers are connecting to a single connection point, therefore the requirement to maintain a complex network with multiple links becomes redundant. Each Remote Server is now connected to the FEP while the FEP is automatically connected to all CPF nodes. Moreover, and as a byproduct, the topology is transparent to the user. The following image depicts the basic network architecture: Figure 9: FEP Network Architecture The FEP nodes are bi-directional: FEP-I: A single network distribution point, hides the internal network architecture from external clients and performs Peer management FEP-O: A single network aggregation, hides the internal network architecture from external servers and performs Peer management 23 F5 Signaling Delivery Controller Product Description All FEP nodes are connected to all CPF nodes. When a new CPF node joins the cluster, all FEP nodes connect to it. When a new FEP node joins the cluster it automatically connects to all CPF nodes. 5.5 Tripo SDC supports dynamic routing based on stateful session management. The SDC session repository – the Tripo – manages the destination of the ongoing transactions per session. The session repository includes session replication between mated SDC sites. 5.6 File Server In some routing scenarios when the online transaction processing cannot be performed, the not routed transactions should be persisted for later offline processing. The SDC File server is used to persist those messages. 5.7 NMS Agent The NMS Agent is an SDC site central component that collects information about system performance and forwards it to the EMS. The NMS Agent is also used to inform the northbound about unusual SDC system behavior. 24 F5 Signaling Delivery Controller Product Description 6 The SDC Pipeline SDC processes Diameter and other protocols by applying a pipeline of functionalities. The pipeline consists of a chain of processing elements arranged so that the output of each element is the input of the next. The SDC pipeline flow is shown in Figure 10. Figure 10: SDC pipeline flow The pipeline consists of the following processing elements: Security Enforcement manages access permissions with the client peers. Validation is done at the IP and Diameter (Application) levels. Pre-Routing Transformation adapts the incoming message to the SDC format needed to perform effective routing Routing makes a routing decision based on the message content. The Routing decision results in the selection of a destination pool for the session. A pool must contain at least one server peer. Load Balancing chooses the peer from the pool to handle the transaction. Post-Routing Transformation adapts the outgoing messages to match the destination’s format. Selection of the applied processing elements depends on the connection type, signaling protocol, and configured rules. 25 F5 Signaling Delivery Controller Product Description It is possible to define multiple processing flows which are selected based on matching conditions and priorities. The Routing and Load Balancing decisions are applied only at session establishment. The decisions are persistent for the entire duration of the stateful session between the client and server peers. 6.1 Security enforcement SDC enables service providers to apply policy control and different security methods on the peer nodes. This allows control of roaming connections with multiple roaming partners and protection of the signaling network from unexpected traffic. The security enforcement is done by setting and applying security rules on both the IP and the application levels. The Security rules at the IP level are defined in ACL format, with support for wildcards. At the application level, the rules are defined according to fields that are contained in the first request of a specific protocol, e.g. capabilities exchange in Diameter. Fine-grained policy control can be applied for routing by performing deep inspection of the messages for specific values. 6.2 Pre-Routing Transformation The message transformation mechanism implemented by SDC overcomes interoperability issues between different Diameter vendors and allows the translation from one Diameter protocol to another signaling protocol and vice versa. SDC provides full support for adding, modifying and/or removing AVPs based on user configurable rules. The rules are implemented using smart decision grids and Groovy scripting language, which provides configuration flexibility and simple management. The solution enables bi-directional Diameter message modification and provides the ability to create different rules of message modification according to the direction of the message flow and/or message type, for example: 26 F5 Signaling Delivery Controller Product Description Modification of Client initiated messages Client->Server Request (such as CCR) Client->Server Answer (such as RAA) The message transformation process is shown in Figure 31. Client à Server Request Response Request Transformation Engine Response Peer v Peer Request Request Response Response Server Client Client ßServer Figure 11: A 4 Way Message Transformation As seen in the above figure, SDC provides the flexibility by defining transformations of Client Requests and Client Responses. SDC supports message transformation between Diameter, LDAP, RADIUS, and HTTP nodes, and between nodes of the same type. SDC also supports transformation of generic Diameter sessions to TCAP dialogues, for example, Diameter to CAMEL. In the same way, SDC supports transformation of generic Diameter sessions to SS7 dialogues. For more information about SS7-Diameter interworking, see the SS7 Diameter Interworking Function Feature Description. 6.3 Routing 27 F5 Signaling Delivery Controller Product Description SDC implements an advanced routing management engine which provides service providers with flexibility to implement different routing rules and policies required to satisfy their business requirements. Routing rules apply different criteria using combinations of Diameter AVP's, request source, and other properties to make decisions. The routing engine natively works with the load balancing (Section 7.4) and the transformation (Section 7.5) engines to provide a harmonized solution for the most demanding and highly complex deployments. The SDC routing management also supports routing resolution using external systems or service location functions such as SLF, DNS, LDAP or SQL. These routing scenarios can be applied separately or together. 6.3.1 Basic Routing Basic routing decisions result in the selection of a destination pool for the established Diameter session. Pool selection is done using a combination of different AVPs such as Subscription-Id, APN from Called-Station-ID, Application-ID, Source-Peer, etc. The values of the AVPs of the incoming requests are matched with condition sets defined for SDC routing rules or by resolution against external service location functions. After the basic routing decisions are completed, the load balancing algorithm is applied. The supported load balancing algorithms are described in section 7.4. The flow of actions is shown in Figure 12. After the destination peer is selected, all messages for the appropriate Diameter session are sent to the selected node. For failover scenarios, where errors are detected in the remote nodes or they are disconnected, please refer to Chapter 8. 28 F5 Signaling Delivery Controller Product Description Figure 12: Routing flow using defined criteria in the SDC 6.3.2 Routing using external location functions In some deployments, routing decisions should be retrieved from an external system. SDC supports several methods of retrieving the routing decisions. 1. Using internally provisioned routing rules, the routing rules are provisioned using SOAP API to the SDC internal provisioning database. When a new Diameter session is established, SDC fetches the destination from its provisioning database. When provisioning routing entries, expiry time can be set for the provisioned entries, or they can be kept on a permanent basis. In addition to provisioning, SDC can calculate routing decisions, or apply default decisions if routing decisions can be fetched from the internal database. 2. Using the retrieval function, which implements LDAP, SQL or SOAP. After a new Diameter session’s establishment, SDC will send a request to the location function. The request will include the query parameters, and the response will contain the appropriate pool for the specific request. The query parameters are extracted from the Diameter request’s AVPs or calculated by the routing engine. 3. Using a 3rd party library integrated with SDC. The following method implements the same logic as described above, but instead of sending requests to an external system, SDC performs programmatic call to an external library integrated within it. The rules can be broad, e.g. using MCC/MNC, or fine-grained, using IMSI, or other combination of values. SDC provides a caching functionality for the routing policies. Caching can be used in scenarios 2-4. The fetched information is cached for a pre-defined duration. If caching is enabled, SDC first checks if a routing entry for a specific set of AVPs is present in the cache 29 F5 Signaling Delivery Controller Product Description before sending the request to an external location function. The use of internal caching for routing decisions reduces the overall response time for the Diameter transactions. 6.3.3 Routing decision binding between different Diameter reference points For some Diameter reference points, there is a need to bind sessions originating from different network elements and share common attributes. Bound sessions are handled as a session bundle composed of several sub-sessions. One of such scenarios is IP-CAN session binding, as described in 3GPP 29.213. IP-CAN session binding is required to associate between Rx and Gx session for the same UE. After PCEF establishes a Gx session with the selected PCRF for some UE, all Rx sessions associated with the same UE should be routed to the same PCRF. The process of IP-CAN session binding is shown in Figure 14. SDC supports this binding functionality using sets of common AVPs that are available for both reference points. The functionality is available out-of-the-box. For example, for Gx and Rx it can be "Framed-IPAddress" or a combination of "Called-Station-ID" and "Framed-IP-Address". 30 F5 Signaling Delivery Controller Product Description Figure 13: GX and RX session binding 31 F5 Signaling Delivery Controller Product Description Bound sessions are related to as Slave Sessions subject to their Master Sessions. The Master Session is the session for which the routing selection is performed based on the routing rules. Slave Sessions are applied with routing rules inherited from the Master Session. The session binding is done using one of several session binding methods and based on binding keys. Binding Keys are sets of values extracted from different attributes (e.g. AVPs or XML attributes) of the Master Session and used to bind several session identities. Figure 14: Session Binding in the SDC Management Console 6.3.4 Multi-Protocol Session Binding Multiple-protocol session binding is applied by linking Destination Server Peers, in addition to the routine client session binding. When two destination servers share a Binding Name they act as a cluster of servers in which each server handles its corresponding sessions, when handling sessions originating from multiple-protocol Clients. For example, when a Slave Session originates from an HTTP Client Peer and the Master Session originates from a Diameter Client Peer, two Destination Server Peers are required to handle the bound sessions: an HTTP Server and a Diameter Server, respectively. Each time the Diameter Server is selected to handle a Diameter Master session, the Master Session’s Slave Sessions are directed to the HTTP Server subjected to the Diameter Server, as depicted in the following image: 32 F5 Signaling Delivery Controller Product Description Figure 15: Multi-Protocol Session Binding 6.3.5 Bi-directional routing Bi-Directional routing is natively supported by SDC. Two scenarios of bi-directional routing are handled by the system, 1. In session routing In this scenario, the Diameter server peer sends the request (e.g. RAR) to the Diameter client peer using the same Diameter Session-ID that was previously established by the Diameter client side. SDC routes the request to the client that established the session as shown in the call flow depicted in Figure 16. 33 F5 Signaling Delivery Controller Product Description Figure 16: In session call flow of server initiated Diameter request SDC accepts requests from different server peers as long as the requests share a Session-ID that was established by the client peer, as shown in the call flow depicted in Figure 17. 34 F5 Signaling Delivery Controller Product Description Figure 17: Call flow of Diameter server request, where the server peer is changed 2. Out of session routing In some cases the communication between the Diameter client and server peers is stateless, meaning that SDC does not maintain a reverse path for the Session-ID. To allow proper handling of out of session server initiated Diameter request, SDC implements advanced routing rules that can be used by the user to define the required behavior. In case no rule is set, SDC sends the request to a client based on the request’s "Destination-Host" AVP. This behavior is shown inFigure 18. 35 F5 Signaling Delivery Controller Product Description Figure 18: Out of Session call flow of server initiated Diameter request 6.3.6 Redirection The SDC routing engine supports working in redirect mode. In this mode SDC acts as a Diameter DNS and leases routing decisions to the clients for a predefined and configurable amount of time. 6.3.7 Routing example An example of a complex routing rule that can be implemented in SDC is shown in the following figures: 36 F5 Signaling Delivery Controller Product Description Figure 19: Routing Rule Attributes Figure 20: Routing Rule The routing rule shown in Figure 20 is applied on the Gx Interface. The rules selects which PCRF pool to route a particular session, - The selection is based on IMSI range. - The IMSI value is retrieved from "Subscription-ID-Data" AVP, which is part of grouped AVP called "Subscription-ID" and compared to two ranges of IMSIs. o The first range is routed to “pcrf-cluster-a”, o The second range is routed to “pcrf-cluster-b”. - If the Subscription-ID-Data AVP is missing or IMSI is not in range, the system routes the traffic to the “default” pool. Alternatively, the Routing Rule can query an external data source – as shown in Figure 21 - to obtain the routing decision. 37 F5 Signaling Delivery Controller Product Description Figure 21: Sample routing script using external data source The routing decision is made upon Diameter Session establishment. The decision persists for the duration of the Diameter session. 6.4 Load Balancing SDC offers several load balancing policies. Load balancing policies define the pattern according to which the system decides how to distribute control plane traffic across the peer nodes in the pool. This section details the different policies according to which the load balancing mechanism may operate, explains the differences between them and describes the conditions under which each policy should be used. 38 F5 Signaling Delivery Controller Product Description 6.4.1 By Precedence In this policy, Diameter messages are sent to the first peer in the pool. The messages are sent until health monitoring and overload detection mechanisms decide that the peer is out-ofservice. When the peer is declared as out-of-service, Diameter messages are sent to the next Remote Node in the pool, etc. When the peer recovers it is brought back to the pool, and Diameter message routing to this peer is resumed. Incoming requests distribution is depicted in Figure 22. Internet Clients Router SDC Traffic is distributed consistently to the same Remote Peer, until a connection channel is blocked: 1 2 Remote Peers 3 4 5 Figure 22: By Precedence Policy 6.4.2 Round Robin When selecting the Round Robin load balancing policy, traffic is evenly distributed across the pool’s available Diameter peers and the Diameter peer to which the new request is delivered is the next available in row. Round Robin is a static algorithm. It has no external parameters taken into account upon request distribution. Incoming requests distribution is depicted in Figure 23. 39 F5 Signaling Delivery Controller Product Description Figure 23: Round Robin Policy 6.4.3 Weighted Round Robin When selecting the Weighted Round Robin policy, traffic is distributed across the pool’s available Diameter peers according to a predefined proportion defined by a peer’s weight. The weight of each Diameter peer in the pool is set according to its capacity and ability to handle incoming Diameter messages. Weighted Round Robin is a static algorithm. It has no external parameters taken into account upon request distribution. Using Weighted Round Robin algorithm, new messages are distributed in the Round Robin pattern, but instead of sending the request to the next available Diameter peer in row, messages are sent to the Diameter peer that has not yet reached its quota. Sample request distribution with weight set to 3:2:1:1 is depicted in Figure 24. 40 F5 Signaling Delivery Controller Product Description Figure 24: Weighted Round Robin Policy 6.4.4 Fastest Response Time When selecting the Fastest Response Time load balancing policy, the incoming Diameter traffic is distributed across the pool’s available Diameter peers according to the respective response time of the peer. The response time is measured for a predefined duration of time using real time statistics. Fastest Response Time is a dynamic algorithm that tries to achieve equal load distribution between available Diameter peers. When Fastest Response Time policy is used, new Diameter sessions are distributed to the Remote Node which has the fastest average response time measured during last measurement period. Incoming requests distribution is depicted in Figure 25. 41 F5 Signaling Delivery Controller Product Description Figure 25: Fastest Response Time Policy 6.4.5 Queue Size Ratio SDC distributes the requests to the Remote Servers according to the weight/queue length ratio. If Server A’s weight is higher than Server B’s weight, the policy assumes Server A’s higher traffic handling capacity and maintains a longer queue of pending requests, compared to other Servers in the Pool. That is, the higher the server’s weight, the greater the number of pending requests it will handle. After getting the performance figures from the active peers (RTT or the number of pending requests), they are normalized between the value 1 and the maximal ratio (the default value is 100): The highest value is 1 while the lowest value is the max ratio value. Queue Size Ratio policy is a dynamic algorithm and responds to external fluctuations upon request distribution. 42 F5 Signaling Delivery Controller Product Description Figure 26: Queue Size Ratio Policy 6.4.6 Load Based Load Based load balancing distributes the requests between servers based on the real-time performance and load experienced by the servers in the pool. Servers with the least load will be the first to receive requests. Internet Clients Router SDC Traffic is distributed between peers based on their real-time load, distributing to the peer with the highest availability. 1 2 3 Remote Peers 4 5 Figure 27: Load Based Policy 43 F5 Signaling Delivery Controller Product Description 6.4.7 Contextual Contextual load balancing policy maps the messages to a list of available peers in the pool using a “Context ID”. The Context ID is a key that can be defined by a user upon session creation. For example: a Context ID can be a set of AVPs that are hashed to a specific key. Using this method, messages are sent to a specific Diameter peer according to their Context ID. In addition to the Context ID parameter, traffic distribution is also controlled by a predefined proportion. If not set by the user, the default Context ID key is set to Diameter Session ID. The weight of each Diameter peer in the pool is set according to its capacity and ability to handle incoming Diameter messages. Incoming requests distribution is depicted in Figure 28. Internet Clients Router Traffic is contextually distributed, according to session ID SDC 1 1 2 2 2 2 3 3 4 4 4 5 5 5 5 Remote Peers Figure 28: Contextual Policy 44 F5 Signaling Delivery Controller Product Description 6.4.8 Weighted Contextual Weighted Contextual load balancing policy maps the clients’ session ID’s to a list of available Server Peers. This way messages are sent to a specific Server Peer according to the session they belong to. In addition to the session ID parameter, traffic distribution is also controlled by a predefined proportion. The weight of each Server Peer is set when establishing it and should be based upon its ability to handle incoming requests. Note: Messages sharing the same session ID will always be sent to the same server within a specific Session Timeout, regardless of the amount of messages handled within the session, and regardless of the SDC instance handling them, as depicted in the following image: Figure 29: Weighted Contextual Policy 6.4.9 External The request’s destination Server Peer is selected according to an external script’s rule. External load balance policy may use a peer selector which its policy is set as a value of the Peer Selection script’s argument (the policy may be used, for example, as a default policy when no server meets the specified script. This must be defined by the script). 45 F5 Signaling Delivery Controller Product Description <ExternalSelectors> <ExternalSelector policyName="Hash" poolName="zone-b"> <SelectionScript><![CDATA[ /* * Looking for the peer in the UserTable, * If it is not in the pool table, using peerSelector */ def peer = null; def key=session.getSessionId(); if (key != null) { userTraceLogger.debug("looking for peer with key: " + key); // getting the reference for the UserStorage def provider = UserStorageFactory.getProvider(); def routingTable = provider.getUserTable("RoutingTable"); // getting "peer Identity" (peer name) String peerIdentity = routingTable.get(key); userTraceLogger.debug("found for a key: " + key + " the following peer: " + peerIdentity); if (peerIdentity != null) { userTraceLogger.debug("getting peer " + peerIdentity + " from peer table for key:" + key + ", provider " + provider); // getting the "peer" object peer = peerTable.getPeer(peerIdentity); } // if the destination is not in the table, should add an option to decide that the message is not routable, if destinations are not provisioned if (peer == null && activePeerList.size() > 0) { // if the above was not found, using peerSelector, according to its policy peer = peerSelector.select(request, activePeerList, session, sourcePeer); userTraceLogger.debug("allocating peer " + peer.getName() +" 46 F5 Signaling Delivery Controller Product Description for key:" + key + ", provider " + provider); routingTable.put(key, [peer.getName(), "zone-b", session.getSessionId()]); } } else { userTraceLogger.log(Level.WARN, "failed to lookup, Framed-IPAddress is missing for " + request); } return peer; ]]></SelectionScript> </ExternalSelector> </ExternalSelectors> Incoming requests are distributed as depicted in the following image: Figure 30: External Policy 6.5 Outgoing Message Transformation 47 F5 Signaling Delivery Controller Product Description The message transformation mechanism implemented by SDC overcomes interoperability issues between different Diameter vendors and allows the translation from one Diameter protocol to another signaling protocol and vice versa. SDC provides full support for adding, modifying and/or removing AVPs based on user configurable rules. The rules are implemented using smart decision grids and Groovy scripting language, which provides configuration flexibility and simple management. The solution enables bi-directional Diameter message modification and provides the ability to create different rules of message modification according to the direction of the message flow and/or message type, for example: Modification of Server initiated messages Server->Client Request (such as RAR) Server->Client Answer (such as CCA) The message transformation process is shown in Figure 31. Client à Server Request Response Request Transformation Engine Response Peer v Peer Request Request Response Response Server Client Client ßServer Figure 31: A 4 Way Message Transformation As seen in the above figure, SDC provides the flexibility by defining Server Responses and Server Requests. SDC supports message transformation between Diameter, LDAP, RADIUS, and HTTP nodes, and between nodes of the same type. 48 F5 Signaling Delivery Controller Product Description A sample modification script is shown in Figure 32. Figure 32: Sample transformation grid 49 F5 Signaling Delivery Controller Product Description 7 Overload and Congestion Control SDC provides multiple mechanisms for resource management and congestion control that protect SDC and the connected Peer nodes from overload conditions, by controlling and limiting the resources usage and allocation, e.g. controlling the incoming/outgoing message/traffic rate. The implemented methods are based on message oriented flow control, traffic shaping algorithms and load shedding algorithms. There are multiple possible reasons for overload, like signaling storms caused by faulty Peers or unexpected memory, CPU high usage or other resource utilization that exceeds the engineered capacity of SDC. The implemented overload control mechanisms assure that the service continues with minimal degradation. The overload control mechanisms: Protect Peer nodes (e.g. PCRF, HSS) from overload by controlling and limiting the resource usage and allocation, e.g. controlling the outgoing message/traffic rate, or limiting the number of requests pending answers per destination peer or group of destination peers Protect the SDC node from overload by controlling and limiting resource usage and allocation, e.g. controlling the incoming message/traffic rate, or by bounding incoming requests queue/ write buffer allocations or the number of connections. The diagram below describes the architecture of the rate control and the overload health monitoring. 50 F5 Signaling Delivery Controller Product Description Figure 33: Rate Control and the Overload Health Monitoring Architecture 7.1 Throttling and Rate Limiting The throttling and flow control mechanisms implemented in SDC are based on token bucket algorithm. The token bucket algorithm is used to check that data transmissions conform to defined limits on bandwidth and burstiness 1. 0F SDC implements two types of throttling: Message rate limiter Byte rate limiter The limiters control the reading rate per channel (between SDC and a Peer) or globally (between SDC and all Peers). The message and byte rate limiters operation is similar. The only difference is that the message rate limiter counts and limits the number of incoming messages, and the byte rate limiter calculates traffic estimation and limits it to a total rate in bytes. 1 A measure of the unevenness or variations in the traffic flow 51 F5 Signaling Delivery Controller Product Description 7.1.1 Token bucket algorithm The token bucket algorithm is based on an analogy of a bucket that contains tokens, each of which can represent a unit of bytes or a single packet of predetermined size. When a packet is to be checked for conformance to the defined limits, the bucket is inspected to see if it contains sufficient tokens at that time. If so, the appropriate number of tokens, e.g. equivalent to the length of the packet in bytes, are removed ("cashed in"), and the packet is passed, e.g., for transmission. If the number of tokens in the bucket is insufficient the packet does not conform and the contents of the bucket are not changed. The mechanism controls the volume of traffic being sent in a specified time interval (bandwidth throttling), or the maximum rate at which the traffic is sent (rate limiting). The mechanism puts a hard limit and caps the number of messages sent (and pending answers) to a certain Peer or a group of Peers to avoid flooding. Similarly, throttling and hard limits are applied to the received messages. The parameters that control throttling are user configurable. Figure 34: Token Bucket Algorithm 7.2 Overload Control Mechanism The overload conditions are determined using multiple resource monitors described in Health Monitoring. Under normal conditions, all messages are processed. When an overload condition is detected, the SDC limits (either partially or fully) processing of incoming messages. 52 F5 Signaling Delivery Controller Product Description 7.2.1 Peer Rate Limit Definition The Peer Rate Limiter is used to prevent a single client from flooding the SDC components (CPFs and FEPs) with a large amount of traffic. The limiter estimates the incoming traffic rate for each Peer (channel) separately. Then the estimated traffic receive rate is compared to the maximum allowed Peer rate. If the actual rate supersedes the allowed rate, the limiter stops reading from the Peer for a user configurable amount of time. In case the rate limiter fails to reduce the rate, and the Peer continues with the flooding, the overload protection mechanism described in the section is activated. 7.2.2 Global Rate Limiter The Global Rate Limiter is used to prevent all clients from flooding the SDC components (CPF’s and FEPs) with a large amount of traffic that might cause denial of service. The limiter estimates the total incoming traffic rate for all Peers (channels). Then the estimated traffic receive rate is compared to the Total allowed rate for all Peers. If the actual rate supersedes the allowed rate, the limiter stops reading from all Peers for a user configurable amount of time. In case the rate limiter fails to reduce the rate, and the amount of traffic grows above the global limit, the overload protection mechanism described in the section is activated. 7.2.3 Resource Monitoring The solution monitors local resources to protect itself from overload conditions. When local resources are exhausted, incoming messages are selectively rejected until resources are available. Local resources mainly include memory consumption and the size of the queues of incoming messages, as well as system wide resources, such as CPU and networking. 7.2.4 Rejection When a message is marked for rejection, SDC sends a busy response to the requesting peer. The response is sent for each message, until the condition changes. For example, a full 53 F5 Signaling Delivery Controller Product Description response that includes the “DIAMETER_TOO_BUSY” Result-Code is depicted in the following snapshot. Figure 35: “DIAMETER_TOO_BUSY” Result-Code 7.3 Health Monitoring SDC provides built in health monitoring mechanisms that are used to identify overload condition or other abnormal behavior of the remote Diameter peers and act accordingly. Two health monitoring mechanisms are available: In Session Monitoring and External Health Monitoring. When overload or abnormal behavior is detected, proper alarms are sent to the OSS and traffic is routed to an alternative Diameter peer or is gracefully rejected according to the defined policy. The alarms triggered by the system contain sufficient information to describe the type of overload. 7.4 In Session Monitoring In Session Monitoring is based on a mechanism that performs health monitoring and detects overload conditions for remote peers. It is based on instantly monitoring error events in Diameter traffic from Diameter Peer such as: Timeouts Response time per peer Busy answers Other Diameter error codes 54 F5 Signaling Delivery Controller Product Description If the rate of the errors events exceeds the user configurable threshold, the Diameter peer server is considered “out of service” for a certain time interval. The time interval duration is user configurable. During the “out of service” period the server does not handle new Diameter sessions. The Diameter peer can also be defined as “partially out of service”, continuing to handle existing sessions but not accepting new sessions 7.5 External Monitoring SDC provides the ability to add custom and proactive service monitoring mechanism that can perform a wide range of tests: from simple tests, such as pinging each connected peer, to more sophisticated tests, such as assuring that the connected peers are able to serve specific requests. It is possible to have multiple monitors perform any test that is required in order to assure service availability. These health monitoring tests are performed in addition to the other SDC tests when it attempts to send requests to Remote Nodes and analyze responses received from them. External Monitoring is based on active, script-based, custom health monitors that can be used to augment the statistical information collected by In Session monitoring, e.g. by probing external counters such as CPU and Server Utilization, using protocols such as SNMP and JMX or using synthetic transactions. The External Monitoring is integrated with a threshold mechanism where the user can use statistics collected by scripts and set the same thresholds as explained in In Session monitoring. 7.6 Connectivity Monitoring In addition to the error and traffic rate monitoring, SDC uses Diameter DWR/DWA Mechanisms to verify the availability of the remote peers. For Diameter clients, SDC replies with a DWA to each DWR sent from the client side, while for Diameter servers, the system sends a DWR if no traffic is received during a predefined time interval. The time interval is user configurable. If, after sending DWR, SDC does not receive a 55 F5 Signaling Delivery Controller Product Description DWA, SDC declares the peer as disconnected and tries to re-establish the Diameter connection by sending a CER to the disconnected peer. 56 F5 Signaling Delivery Controller Product Description 8 OAM Support The SDC provides support for Operation, Administration, and Maintenance (OAM) using its Management function. The Management function of the platform is comprised of the modules shown in Figure 36: Configuration Manager is the configuration repository and configuration distribution service that is responsible for the distribution of the configuration to all SDC nodes within the cluster. It also provides auditing, backup and restore functions, as well as server for performance statistics collection. Management Console is a Web based client GUI that enables, configures and manages SDC. Sample snapshots of the GUI are shown in Appendix A. Provisioning Interface (SOAP API) provides programmatic interface that enables automatic configuration and management of SDC. SDC Node OAM Security and Administration Manager SDC SDCCore SDC Core Blade/Server Configuration Manager CLI Web Service Provisioning Interface (SOAP) Web Service SOAP XML Management Console HTTP/S WEB Access Fault and Performance Manager AMM SNMP/Syslog Figure 36: SDC OAM Function architecture 57 F5 Signaling Delivery Controller Product Description The Management function provides the following capabilities. SDC Cluster node Configuration and management Remote Peer Configuration and management Flow and routing configuration Translation configuration Remote Provisioning Alarm Dilution management Tracing and Logging management Monitoring and Performance management License management Backup and Restore activation The Element Management System (EMS) provides a single, centralized system that helps manage OAM for multi-site deployments. In standalone deployments, the configuration management is performed locally. In multisite deployments with the EMS, some configuration is performed globally. 8.1 Alarms The OAM constitutes a collection and aggregation point for all alarms and events issued by the platform components and the deployed applications. Fault management capabilities such as alarm clearing, alarm filtering, alarm flood suppression and alarm forwarding are provided. All fault situations are notified with an appropriate alarm. Recovery from a fault situation is also notified with the associated clearance alarm. 8.2 Tracing and Logging The OAM ensures management of component-based tracing, logging and statistics reports. The platform provides OAM with configured traces on per-component basis. It also updates the configured statistic counters in real-time so that SNMP can generate the required statistic reports. 58 F5 Signaling Delivery Controller Product Description 8.3 Monitoring The OAM ensures monitoring of manageable components providing real-time information about the status of cluster, nodes, application, service enablers, and protocol stacks. Monitoring of resource usage such as memory and CPU is also provided. 8.4 Performance Management The OAM supports a predefined set of performance counters and allows for definition of custom performance counters. Monitoring, and scheduling of performance counter as well as statistic collection related to performance counters are supported. The OAM supports the compression of performance reports since those may have a very large size. 8.5 Security Management This includes access rights management, communication links protection and management operation logging. 8.6 Licensing Management The OAM supports the functions related to licensing and licensing issues notification. License keys, as well as counter reports related to licensing (i.e. reports of number of Sessions per Second during a predefined period) are monitored by OAM, which acts according to the observed state and counter values. The OAM sends a notification when the SDC license is about to expire, as well as, a notification upon extending the license expiration date. 8.7 Lifecycle Management The OAM supports lifecycle management of the platform’s components and services. It also supports dynamic configuration of parameters related to the platform’s components and services. Graceful Software and Hardware upgrade (i.e. without service interruption) are part of the OAM configuration management functions. 8.8 SOAP API 59 F5 Signaling Delivery Controller Product Description SOAP API is a programmatic interface that allows users to automate commands as well as integrate OAM with umbrella management systems or Network Management Centers for functionalities such as automatic provisioning, queries, lookups and more. 8.9 SNMP Agent The OAM uses SNMP to deliver traps to Network Managements Centers. This is done via an SNMP Agent that delivers traps to SNMP managers connected to it. The OAM supports SNMP v2c 8.10Cluster management The Cluster management process is constantly monitoring platform instances and can take appropriate actions in case of fatal fault situation (for example, restart the Diameter Router instance in case the latter is not responding for a certain period of time). 8.11Auditing The OAM documents each of the actions taken in the auditing list. If needed, the audited actions can be used to restore the documented configuration of the exact point in time in which the action was performed. 8.12Backup & Restore The OAM provides support for backup and restore of the configuration backup. Using this feature, it is possible to restore the configuration back to a working configuration set. 60 F5 Signaling Delivery Controller Product Description 9 High Availability and Scalability 9.1 Scalability The SDC solution provides a vertical and horizontal scalability. Both options are standard, and provided out-of-the-box. For vertical scalability, it implements a message driven component, optimized for low latency processing and multi-core architecture, e.g. SPARC. It relies heavily on multithreading and asynchronous network I/O processing. For horizontal scalability, it allows use of multiple servers in two modes; “hot standby deployment” and “scalable deployment”. Horizontal scalability in SDC is achieved using built-in cluster management software. Typical “scalable deployment” is shown in Figure 37 and Figure 38. The clustering software: - Hides the internal structure of the node - Presents VIP(s) for clients and servers - Distributes the load between the blades - Aggregates blade connections to Diameter peers - Manages the different processes and services For each of the deployed blades, the main software processes are shown in Figure 39. - VIP is the clustering component, responsible for load sharing and resources management in the solution - SDC core process is responsible for processing of Diameter or other message oriented protocols, e.g. security, routing, load balancing and message transformation; - Config Manager Process is responsible for configuration, distribution and storage; - Distributed Storage is responsible for the management of static and dynamic routing tables; 61 F5 Signaling Delivery Controller Product Description - The Web Console process provides a WEB interface for interactive system configuration and communicates with the Config Manager processes. - The EMS agent process communicates with the EMS system and performs OAM tasks. Client1 ClientK Backbone Clients “Scalable Mode” - SDC Node Network External SDC Blade 1 SDC Blade 2 SDC Blade 3 VIP (Active) VIP (Standby) VIP (Standby) SDC Engine SDC Engine SDC Engine Distributed Storage Distributed Storage Config Mgr Config Mgr Web Interface Web Interface SDC Blade 12 Scalable (blades 12) VIP (Standby) SDC Engine Interconnect Management Network Backbone Servers Server1 ServerM Figure 37: Scalable Deployment, Physical View 62 F5 Signaling Delivery Controller Product Description Client Server Server Client HA Cluster FEP-O FEP-O (SCTP) (TCP) Config Mgr Web UI Shared Memory SDC Engine SDC Engine SDC Engine SDC Engine SOAP FEP-I FEP-I (IPSEC) (TCP) Client Client Client Client Figure 38: Scalable Deployment, Logical View SDC Blade X VIP (Active) SDC Engine Distributed Storage Config Mgr Web Interface EMS Agent Figure 39: Main Software Processes 9.2 Local Redundancy and Scalability 63 F5 Signaling Delivery Controller Product Description The SDC solution supports Hot/Standby and N+1 redundancy models. In both models, any failure on the SDC side is transparent to both client and server peers and does not require any manual intervention or reconfiguration of the nodes. 9.2.1 Hot/Standby deployment In Hot/Standby model, shown in Figure 40, SDC is deployed using two servers, in a standard clustering solution. The Clustering solution provides Virtual IP (VIP) support. All Diameter Clients connect to a Virtual IP address of the cluster, which resides in the active node. All Diameter traffic is handled by the active node, and the data required for maintenance of sessions and state persistence is replicated to the standby node. The components of the local redundancy mode deployment are shown in the figure below. In case of an active node failure, the Virtual IP fails over to the Standby Node and from this point all traffic is handled by the standby node. The failover is transparent to both clients and servers. Once the failed node is restored, the traffic remains on the active node, while the node returning to operation acts as a backup node. Automatic failback is also supported. The session data required for maintenance of the session persistence is automatically replicated to the backup node. 64 F5 Signaling Delivery Controller Product Description Client Peer Server Peer Node 1 Node 2 Diameter VIP Diameter VIP SDC Core SDC Core Session Replication Configuration Manager Configuration Manager Web UI / WS Web UI / WS Management VIP Management VIP Management Workstation Figure 40: Hot-Standby HA architecture 9.2.2 N+K Scalable service deployment In Scalable Active-Active (N+K) deployment mode, as shown in Figure 41, SDC utilizes the Linux IPVS to distribute incoming traffic among available SDC nodes, and to provide service redundancy. 65 F5 Signaling Delivery Controller Product Description Client1 3 1 Node 1 Node 2 Diameter VIP Node 2 Diameter VIP Diameter VIP 3 2 Physical IP SDC 3 Physical IP Physical IP 2 SDC SDC Session Replicattion Configuration Manager Configuration Manager Web UI / WS Web UI / WS Physical IP Physical IP Physical IP Management VIP Management VIP Management VIP Management Workstation Figure 41: Scalable N+K HA architecture. Normal operation 66 F5 Signaling Delivery Controller Product Description Normal Operation, Scalable and Highly-Available Request Processing Flow: 1) Incoming Request: a. Incoming client requests are directed to a single floating IP Address. b. The floating IP Address is assigned to a “Global Interface” (“GIF”). The Global Interface and floating IP Address are managed by the Cluster software. The “Global Interface” is held by one system node (server) at one time. c. The request is received by the system node currently holding the “Global Interface”. 2) The request is redirected: a. The request is redirected to the least loaded, available node using Round-Robin load-balancing policy. b. Weighted Round-Robin and Sticky Round-Robin load-balancing policies are available for the selection of a suitable node. c. If no suitable node is currently available - the original node which received the incoming request - may also handle the request. 3) The request is handled and a Reply is sent to the Client a. The request is handled by the node to which it was redirected, and a reply is sent to the client. The source address in the reply packet is set to the floating IP Address of the Global Interface. In case of a system failure in the server holding the “Global Interface”, the interface automatically relocates to the next available server. This is managed by the cluster software. Operation during Node Failure: 67 F5 Signaling Delivery Controller Product Description Client1 1 3 Node 2 Node 1 Diameter VIP Node 2 Diameter VIP Diameter VIP 3 Physical IP Physical IP SDC SDC 2 Physical IP SDC Session Replicattion Configuration Manager Configuration Manager Web UI / WS Web UI / WS Physical IP Physical IP Physical IP Management VIP Management VIP Management VIP Management Workstation Figure 42: Scalable N+K HA architecture. Failure operation For ease of the network integration types, the system may be configured to issue outgoing Diameter connections from the floating address of the Global Interface Note: In Active/Active mode, the load is distributed among all available system nodes. 68 F5 Signaling Delivery Controller Product Description 9.2.3 Virtual IP, Failure detection and recovery In local (non-geographical) redundant configuration, SDC exposes the Virtual IP address – VIP - toward Diameter clients. Additional VIPs can be configured if required. On the server side the solution maintains peering connection between all cluster nodes of the solution and the server peers. The above architecture provides fast response upon any failure event that occurs within the system. It is also possible to aggregate the connections to servers, having a peer to peer connection from the solution cluster to each of the Diameter servers. SDC relies on standard, commercial availability management mechanisms, which enable it to execute failovers from one functional unit to the other in a very short time, measured in milliseconds. The following table summarizes the different mechanisms used for the solutions components, “scalable deployment” is assumed. Component H/A Model Service Maximum Comments Concurrent Active Instances SDC Configuration Manager Distributed Store Web UI / WS Service and VIP CPF VIP Active/Active Active/Active with Multi-Master Replication Active/Active Failover (Active/Multiple standbys) Failover (Active/Multiple standbys) N 2 One instance per node Installed on two nodes, performing mutual updates on configuration changes N 1 One instance per node Runs on one system node, failover in case of node failure 1 Virtual IP Address will be active on one node at a time, with multiple nodes (1 in failover architecture) serving as hot standbys In the geographic deployment, each SDC cluster provides one VIP per-site towards Diameter clients. Additional VIPs can be configured if required. In order to support high availability, a system is required to utilize reliable processes and hardware, that is, to extend the mean time between failures (MTBF) and shorten the recovery 69 F5 Signaling Delivery Controller Product Description time (MTTR). Extending MTBF is achieved by duplicating SDC nodes and using redundant hardware. SDC nodes can assume each other’s load. These duplicate nodes are also called redundant components. For further analysis on failure detection and recovery, please refer to the following tables: Hardware Redundancy: Failure Type Failure Detection Method Automatic Remedy Action Non-redundant HW (Server Cluster heartbeat Node failover / Traffic shift to other motherboard) node PSU (Power Supply Unit) Built-in Hardware Failover to Redundant PSU Monitoring Network Interface Network Link monitoring Node traffic failover to secondary (OS) NIC Disk failure Hardware – RAID controller RAID failover to 2nd disk Network switch Switch Redundancy Network Switch Failover mechanisms Node traffic failover to secondary Network Link monitoring NIC (OS) Network Redundancy: Failure Type Failure Detection Method Automatic Remedy Action Network link failure Network Link monitoring (OS) Node traffic failover to secondary NIC Upstream network Linux Bonding ARP Probe Address (Network Switch Redundancy) failure monitoring Node traffic failover to secondary NIC Node Redundancy: Failure Type FailurelDetection Method Automatic Remedy Action Scheduled shutdown / Cluster resource mgmt and/or Service Node failover / Reboot Monitor Traffic shift to other node Critical hardware Cluster heartbeat Node failover / failure Traffic shift to other node 70 F5 Signaling Delivery Controller Product Description Failure Type FailurelDetection Method Automatic Remedy Action Irreversible hardware Cluster heartbeat Node failover / failure Traffic shift to other node OS Crash Low Memory Low Free Disk Space CPU Overload Cluster resource mgmt and/or Node failover / Service Monitor Traffic shift to other node Resource Monitor utility or SNMP Monitor Send Notification to Operator (Low from external system Memory) Resource Monitor utility or SNMP Monitor Send Notification to Operator (Low from external system Free Disk space) Resource Monitor utility (in scalable architecture) Lower percentage of requests directed to system node Process Redundancy: Failure Type Failure Detection Method Automatic Remedy Action Crash Process watchdog Automatic Persistent data store recovery “is running” check Process start service monitor Lockup Service monitor Process forced termination Automatic Persistent data store recovery Process start Partial lockup Service monitor Process forced termination Automatic Persistent data store recovery Process start Cannot start SDC Overload Cluster resource mgmt and/or Node failover / Service Monitor Traffic shift to other node Service monitor (in scalable architecture) Lower percentage of requests directed to system node 9.3 Geographical redundancy 71 F5 Signaling Delivery Controller Product Description SDC supports geographical redundancy by deploying locally redundant SDC clusters (as described in section 10.2) in each geographical location site. Each of the locally redundant SDC clusters exposes one or more VIP address(es), as depicted in the following figure. Figure 43: Geographical redundancy, Active-Standby deployment mode The solution supports multiple geo-redundancy deployment configurations, such as ActiveActive or Active-Standby. Replication of routing and session tables is supported in both modes. Active-Standby and Active-Active deployments are shown in Figure 44 and Figure 45, respectively. 72 F5 Signaling Delivery Controller Product Description Figure 44: Geographical redundancy, Active-Standby deployment mode Figure 45: Geographical redundancy, Active-Active deployment mode 73 F5 Signaling Delivery Controller Product Description 9.3.1 Site Replication Site replication allows geographically distributed SDC clusters to synchronize Diameter session data amongst sites. Diameter session data includes the following: Destination Peer Pool name Origin Peer Session Binding data Session data is distributed by one SDC node (the origin node) to Remote Servers (the target nodes) configured to receive and handle the replicated data. An SDC node which receives a request may handle the request or proxy the request to a remote site. Proxying the request is performed when the session is unknown to the local site and the remote site has the required data to handle the incoming request, as depicted below: Figure 46: Site Replication This functionality is activated using a new proxy API in a pre-routing script. The network used for replication between sites must have sufficient capacity to carry the replication data traffic. Updates are streamed to the receiving system without expecting acknowledgment. In 74 F5 Signaling Delivery Controller Product Description asynchronous mode, the replication latency has no impact on the system latency, but it does affect the eventual consistency. For example: when the replication latency is 10ms, and each site handles 30K TPS where 5K TPS is a new session, and there are up to 100 TPS of routing updates, the following calculation is performed: "Lost updates"= 10/1000 * (5000 + 500) =~ 55 updates. 75 F5 Signaling Delivery Controller Product Description 10 Security F5 realizes that security is vital to assure availability, integrity and confidentiality of the operator’s signaling network. SDC provides multi-level security features that are described in the following sections 10.1Diameter Topology Hiding The SDC solution supports topology hiding by exposing one or more VIP (Virtual IP) in the direction of the peers. The VIP is used as a single point of attachment for all peers connected to the SDC node. To prevent DOS attack, the solution limit external networks’ access to port 3868 and other agreed ports. The solution uses IPTABLES to protect the network from intrusion attempts. 10.2Diameter connection security The SDC solution limits the number of incoming clients and network sources. The SDC solution provides Diameter level access control lists (ACLs) to ACCEPT or REJECT peers by their IP address, host name/subnet, application-id, product-type, etc. Additionally, the solution provides the user with the ability to implement a custom access policy. The user can inspect any combination of AVPs in a CER message and ACCEPT or REJECT the connection establishment based on custom policy criteria. SDC ensures idle connection termination after a user configurable timeout period, for both Diameter and management traffic. The solution uses IPSEC, TLS and DTLS to implement transport level security 10.3Diameter message security SDC limits and enforces maximal Diameter message length and for Diameter message screening. The SDC solution allows: 76 F5 Signaling Delivery Controller Product Description - removing certain AVP(s) than can unveil the internal structure of the network - Rewriting AVP(s) using certain anonymization techniques to protect data and mitigate privacy and security concerns to comply with legal requirements of the network and to avoid exposing of information contained in the AVP(s) like Session-Id, Origin-Host, Origin-Realm, etc. - using encryption mechanism for encoding/decoding of payload of AVP(s) 10.4OS/System security SDC uses commercially available RHEL distribution. During system installation, unused modules are removed or disabled and ports’ usage is restricted. The deployment of the solution complies with CIS (Center for Internet Security) and NSA (National Security Agency) recommendation for OS and application hardening as described in the following documentation: - CIS_RHEL5_Benchmark_v1.1 - CIS_Apache_Tomcat_Benchmark_v1.0.0 - NSA, Guide to the Secure Configuration of Red Hat Enterprise Linux 5, Revision 4.1, February 28, 2011 10.5Network Level Security SDC applies the following network level security: - IPTABLES are used to protect the system, e.g. to block non-Diameter traffic on Inland interfaces - signaling and OAM networks are separated, as well as internal and external signaling networks - SSH daemon and WEB GUI listen only on OAM network - Idle OAM connections are terminated 77 F5 Signaling Delivery Controller Product Description 11 Networking 11.1Network redundancy SDC applies the networking redundancy scheme for both TCP and SCTP transport protocols. The network redundancy is achieved using redundant pairs of Switch modules (one pair for Signaling traffic and another pair for O&AM) and NIC bonding for TCP or multi-homing SCTP. The local redundancy architecture, as shown in Figure 47, is achieved in the following way: - TCP VIP and SCTP VIP can be resident on the same or different SDC blades. - The traffic is distributed to all available SDC nodes within the cluster - The TCP and SCTP traffic distribution will be done based on Diameter messages using round-robin or other load balancing algorithm - TCP and SCTP VIP's will not be dependent on each other EXT-SCTP-A EXT-TCP-A INT-SCTP-A EXT-TCP INT-TCP EXT-SCTP-B INBAND: Connections to upstream Routers INT-SCTP-B Blade Chassis [Virtual Fabric Switch 1] External Ports:10 x 10GbE + 1 x 1GB port [Virtual Fabric Switch 2] External Ports:10 x 10GbE + 1 x 1GB port S Virtual IP For SCTP and TCP (all VIPs are doubled per Internal and External Networks T S S SDC Worker Node TCP Vs S S T S SDC Worker Node TCP Vs Interswitch Link S S SDC Worker Node TCP Vs S S [L2/3 1GB Copper Switch A] [L2/3 1GB Copper Switch B] MGMT-A Interswitch Link MGMT-B 78 F5 Signaling Delivery Controller Product Description Figure 47: Local Network redundancy architecture 11.2Physical Interfaces The default physical interfaces and cabling of the SDC for HP and IBM infrastructures are detailed in the following tables: HP BladeSystem c7000 Chassis Network Data Signaling Switch Interface Port Connector Speed Count type HP Virtual 10GbE (or 6 10GbE Fiber Data Signaling (Diameter, Connect Flex-10 1GbE) 850mns or SIP, etc.) Module Description 1GbE Copper (RJ45) Ethernet 2 N/A HP VC Flex-10 Stacking Links (no cables required) HP Virtual 10GbE (or Connect Flex-10 1GbE) 6 Module 10GbE Fiber Data Signaling (Diameter, 850mns or SIP, etc.) 1GbE Copper (RJ45) Ethernet 2 N/A HP VC Flex-10 Stacking Links (no cables required) OAM-OS: HP/BNT GbE2c Management and L2/3 Switch 1 Backup Network HP/BNT GbE2c Connection L2/3 Switch 1 OAM-LOM: HP Onboard Chassis Administrator Hardware and Module 1 1GbE 1GbE 1GbE 5 5 1 Ethernet Connection to Management Copper RJ45 and/or Backup Networks Ethernet Connection to Management Copper RJ45 and/or Backup Networks Ethernet Connection to Management Copper RJ45 Network, for Chassis Hardware and Switch Switch (“Lights- (“Lights-Out”) Management Out”) and Monitoring 79 F5 Signaling Delivery Controller Product Description Management and HP Onboard Monitoring Administrator 1GbE 1 Ethernet Connection to Management Copper RJ45 Network, for Chassis Module 2 Hardware and Switch (“Lights-Out”) Management and Monitoring 11.3Addressing Scheme SDC supports the following default scheme of IP addressing. Detailed networking design is done after Site Survey and Customer Workshop. Failure Type Automatic Remedy Action Data Signaling 4 IP Addresses per Signaling Interface (e.g.: Diameter). Note: Additional addresses per signaling interfaces are supported Multiple signaling interfaces are supported Multiple Networks and/or VLANs supported IPv4 and IPv6 are supported SCTP Multi-Homing Supported If Solution is required to perform L3 routing 3 addresses per subnet will be required for (for VRRP Switch Redundancy) OAM: Management and Backup Network One IP Address per hardware blade, plus one Management VIP (4 addresses in the baseline chassis configuration) Additional Management VIPs are supported Multiple addresses per blade are supported Multiple Networks and/or VLANs supported, e.g.: dedicated Management and Backup Interface Additional addresses will be required for a dedicated Backup Network connection Connection OAM-LOM: Chassis Hardware and Switch (“Lights-Out”) Management and Six (6) IP Addresses: 2 for Advanced Management Modules 4 for Switch Management Monitoring 80 F5 Signaling Delivery Controller Product Description 12 HW Architecture 12.1Supported HW SDC runs on standard off-the-shelf HW such as: HP Blade System with Bl460c Gen8 Blades HP DL380p Gen8 Rackmount Servers IBM BladeCenter with HS22 Blades For a scalable deployment, it is recommended to use a blade-based solution that provides chassis-based high capacity HW architecture with inherent manageability, reliability, and redundancy. 81 F5 Signaling Delivery Controller Product Description 13 Appendix A – OAM Snapshots Figure 48: Internal Cluster node status Figure 49: Remote Peer Management Figure 50: Session Management 82 F5 Signaling Delivery Controller Product Description Figure 51: Routing Management Figure 52: Logging control 83 F5 Signaling Delivery Controller Product Description Figure 53: Statistics and Performance reporting Figure 54: Signaling KPI Report 84 F5 Signaling Delivery Controller Product Description Figure 55: Dashboard Figure 56: Topology Monitoring Figure 57: Configured Tracing Rules 85 F5 Signaling Delivery Controller Product Description Figure 58: System and Site Monitoring 86 F5 Signaling Delivery Controller Product Description 14 Appendix B – Access Level Security System management is done using secure protocols. The access security supported in the system is summarized in the table below. Solution Element Access Control Model Access SDC Management Permissionbased model Web Management Console, Method Role/Permission Permission Description Read-Only User Read-Only Access Operator Manage Diameter Peers and Pools, Enable/Disable links to Peers, Backup and Restore Configuration, etc. Super-User (Administrator) Full Access Read-Only User Read-only access to logs, system files and information Web Services Operating System Permission and Groupbased model SSH, SFTP Operator Chassis Hardware Management Role and Permissionbased model Web Management Console, SNMP, SSH Networking Hardware Management Permissionbased model SSH (Configurable) In addition to User permissions, may be enabled to perform selected administration tasks (e.g.: capture network traffic samples). Super-User (Administrator) Full access Read-Only User Read-only access Super-User (Administrator) Full access Custom Role set (Configurable) Custom set, selected from a wide list of roles, with option to restrict access to specific subelements Read-Only User Read-only access Operator Read-Only access and permission to make temporary operational configuration changes to selected options, and reset ports. 87 F5 Signaling Delivery Controller Product Description Super-User Administrator) SNMP Monitoring and Management USM (Userbased security model) SNMP USM user ( Full access Per-user configured Read/Write/Notify permissions to specified SNMP objects(OIDs) In addition to that, SDC records of all user interactions in its auditing logs and all idle OAM sessions are terminated. 88 F5 Signaling Delivery Controller Product Description 15 Appendix C – Low Level SDC Pipeline The detailed message flow through the SDC pipeline is shown in Figure 59 2. 1F Routing + LB Session External Storage + Shared Memory Add Pending Session Remove Pending Decision Table In Transformation Out Transformation Peer Profile Peer FSM Peer FSM Decoder Protocol Dictionary Prioritization Thread Pool In Flow Control Resources Pool (Buffers/Queues) Encoder Out Flow Control Segmentation Decryption Encryption ACL Groovy Scripting Decision Flow Licensing Message Flow Idle Detector P2P Network Message Figure 59: Detailed System Flow 2 More details are available in Pipeline.xlsx and PeerFSM.xlsx 89 F5 Signaling Delivery Controller Product Description About F5 Networks F5 Networks (NASDAQ: FFIV) makes the connected world run better. F5 helps organizations meet the demands and embrace the opportunities that come with the relentless growth of voice, data, and video traffic, mobile workers, and applications—in the data center, the network, and the cloud. The world’s largest businesses, service providers, government entities, and consumer brands rely on F5’s intelligent services framework to deliver and protect their applications and services while ensuring people stay connected. For more information, visit www.F5.com, or contact us at [email protected]. 90