What is IS

Transcription

What is IS

The IS-IS Protocol
BSCI Module 4
Introducing IS-IS and Integrated IS-IS Routing
BSCI Module 4
Lesson 3
© 2006 Cisco Systems, Inc. All rights reserved.
Cisco Public
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What is IS-IS ?
IS stands for Intermediate System
IS is “OSI speak” for router
IS-IS is the Intermediate System to Intermediate
System intra-domain routing protocol
IS-IS was defined in 1992 in the ISO/IEC
recommendation 10589
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© 2006, Cisco Systems, Inc. All rights reserved.
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OSI: Two Network Services,
Two Network Protocols
CMNS (Connection Mode Network Service) – Requires establishment of a
path between transport layer entites.
CONP (Connection-Oriented Network Protocol) – OSI network layer protocol
that carries upper layer data over connection-oriented links.
CLNS (Connectionless Network Service) – Performs datagram support,
does not require circuit to be established
CLNP (Connectionless Network Protocol) – OSI network layer protocol that
carries upper layer data over connectionless links. (Similar to IP)
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IS-IS Protocol Options
IS-IS (ISO 10589)
Dynamic link state routing protocol used in an ISO CLNS
environment.
ISO-IGRP
Cisco IOS offers proprietary routing protocol for CLNS.
Based on IGRP, distance vector technology.
Can be used for Level 3 Routing, between IS-IS domains (next)
Integrated IS-IS (RFC 1195)
IS-IS for mixed ISO CLNS and IP environments.
Either:
Purely ISO
Purely IP (CCNP 1)
Both
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IS-IS versus OSPF
“IS-IS is exactly the same as OSPF only completely different”
OSPF – discussed in CCNA and CCNP (Single Area
and Multi-Area)
The following slides show terminology differences
between IS-IS and OSPF.
Similar to the differences between Spanish and Italian.
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Similarities Between IS-IS and OSPF
Integrated IS-IS and OSPF are both open standard linkstate protocols with the following similar features:
Link-state representation, aging timers, and LSDB
synchronization
SPF algorithms
Update, decision, and flooding processes
VLSM support
Scalability of link-state protocols has been proven
(used in ISP backbones).
They both converge quickly after changes.
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Advantages of Integrated IS-IS
Supports CLNP and IP
More extensible through TLV design
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Advantages of OSPF
OSPF has more features, including:
Has three area types: normal, stub, and NSSA
Defaults to scaled metric (IS-IS always 10)
OSPF is supported by many vendors.
Information, examples, and experienced engineers are
easier to find.
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IS-IS versus OSPF - Terminology
IS-IS
ES (End System)
OSPF
Host
Comments
IS (Intermediate System)
Circuit
Router
Link
SNPA
Datalink Address
(Subnetwork Point of Attachment)
PDU
Packet
(Protocol Data Unit)
DIS
DR
(Designated Intermediate System) (Designated Router)
N/A
IIH (IS-to-IS Hello Packet)
BDR
Hello packet
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IS-IS versus OSPF - Terminology
IS-IS
OSPF
Comments
LSP (Link-State Packet)
LSA (Link -State
Advertisement)
LSAs are actually
comparable to TLVs used in
LSPs.
CNSP (Complete Sequence
Number PDU or Packet)
PSNP (Partial Sequence
Routing Domain
DBD (Data Base
Description Packet)
LSAck or LSR (Link
State Request)
AS
Level 1 Area
Area (nonbackbone)
Level 2 Area
Backbone area
(Area 0)
The term routing domain is
also used with OSPF.
IS-IS uses a backbone path
connected by contiguous L2
routers. There is no
backbone area in IS-IS
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IS-IS versus OSPF – ISs (Routers)
IS-IS
OSPF
Comments
Level 1 IS (router)
Internal Non-backbone
Router
Internal, non-backbone
router in a Totally Stubby
Area
Level 2 IS (router)
Internal Backbone
Router or ASBR
Any Level 2 router can
distribute externals into
the domain. No special
name. (Cisco IOS allows
Level 1 routers to
distribute externals.)
Level 1-2 IS (router)
ABR
System ID
Router ID
The System ID is the key
for SPF calculations.
Sometimes the NET
address is thought of as
the Router ID.
AFI = 49
RFC 1918 Addresses
AFI is part of the NSAP.
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Introduction to IS-IS
Protocol
Routers
Areas
Levels
BSCI Module 4
Lesson 3
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IS-IS Link-State Operation
Routers identified as Level 1, Level 2, or Level 1-2:
Level 1 routers use LSPs to build topology for local area.
Level 2 routers use LSPs to build topology between different areas.
Level 1-2 routers act as border routers between Level 1 and Level 2
routing domains.
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Integrated IS-IS Design Principles
IP and CLNP addresses
must be planned.
Use two-level hierarchy
for scalability:
Limits LSP flooding
Provides opportunity
for summarization
Summarization:
Limits update traffic
Minimizes router memory and
CPU usages
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Four OSI Routing Levels
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OSI Routing Protocols: ES-IS and IS-IS
ISH
ESH
ES-IS
Analogous to Address Resolution Protocol (ARP) in IP
Not technically a routing protocol
Sometimes referred to as Level 0 routing.
ESs (hosts) discover nearest IS (router) by listening to IS Hello (ISH) packets
ISs (routers) know which hosts are on their subnetwork by listening to ES Hello
(ESH) packets.
Not applicable for IP networks
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OSI Routing Protocols: ES-IS and IS-IS
Boundary areas in
IS-IS exists on a link
between routers and
not on a router itself
as in OSPF.
These routers should
be entirely in Area 1
and Area 2.
IS-IS
OSI distinguishes between Level 1, Level 2, and Level 3 routing.
Level 1 Routing
If DA (destination address) is an ES on another subnetwork in the same area, the IS
knows the correct route and forwards packet appropriately.
Level 2 Routing
If DA is an ES on another area, the Level 1 IS sends the packet to the nearest Level 2
IS.
Level 3 Routing is between separate domains.
Pure CLNS environment IDRP or ISO-IGRP can be used, in IP, BGP is used.
(Not applicable to CCNP)
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IS-IS Areas
IS-IS Routers:
Level 1 IS (L1 IS, router)
Analogous to OSPF Internal non-backbone router (Totally Stubby)
Responsible for routing to ESs inside an area.
Analogous to OSPF Internal Backbone router
Responsible for routing between areas
Level 1 and Level 2 IS (L1-L2 IS, router)
Analogous to OSPF ABR router
Participate in both L1 intra-area routing and L2 inter-area routing.
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Level 1 Router
Analogous to OSPF Internal non-backbone router (Totally Stubby)
Responsible for routing to ESs inside an area.
A contiguous group of Level 1 routers define an area.
Level 1 routers maintain the Level 1 database for the area and exit
points to neighboring areas.
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Level 2 Router
Analogous to OSPF Internal Backbone router
Responsible for routing between areas
Also referred to as area routers.
Interconnect the Level 1 areas
Store separate database of only inter-area topology
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Level 1 – Level 2
Router
Level 1 and Level 2 IS (L1-L2 IS, router)
Analogous to OSPF ABR router
Participate in both L1 intra-area routing and L2 inter-area routing.
Maintain both Level 1 and Level 2 LSDB
Support Level 1 function communicating with other Level 1 routers
in their area
Inform other Level 1 routers that they are the exit point (default route)
from the area.
Support Level 2 function communicating with the rest of the
backbone path.
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IS-IS Backbone
IS-IS does not share the concept of a backbone area 0 with
OSPF.
An IS-IS backbone can appear as a set of distinct areas
interconnected by a chain of Level 2 routers, weaving their way
through and between the Level 1 Areas.
The IS-IS backbone (path) consists of a contiguous set of Level 12 and Level 2 routers.
Where is the backbone (path)?
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Hierarchy
IS-IS has 2 layers of hierarchy
The backbone is called level-2
Areas are called level-1
Same algorithms apply for L1 and L2
A router can take part in L1 and L2
Inter-area routing (or inter-level routing)
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Adjacency levels (later)
L1-Adjacency
L2-Adjacency
Router with adjacencies within
the same area.
However, needs to have a L2
database as well since it is a transit
node
Therefore L1L2 adjacency is required
L2-Adjacency
L2-Adjacency
L1L2
Adjacency
L1L2
Adjacency
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Level-1, Level-2 & Level-1-2 Routers
•Backbone MUST BE L2 contiguous
L1-only
L2-only
L1-L2
L1-only
L1-only
L1-L2
L1-L2
L1-only
This router has to behave as level-2
as well in order to guarantee backbone
continuity
L1-L2
L1-only
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Level-1, Level-2 & Level-1-2 Routers
•Backbone MUST BE L2 contiguous
L1-only
L2-only
L1-L2
L1-only
L1-L2
L1-L2
L1-L2
L1-L2
This router has to behave as level-2
as well in order to guarantee backbone
continuity
L1-only
L1-only
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Can an IS determine its level ?
Area 1
“I’m in area 2 and ALL
my neighbors are in the
same area. I must be a
L1-only router ?”
Area 3
Area 2
Area 4
!! NO !!
Rtr C must have a full L2 LSDB
to route between areas 1, 3 and
4. Remember, the backbone
must be contiguous.
ISIS router cannot determine if they need to be L1 or L1L2
Therefore By default all cisco routers will behave as L1L2
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OSI Addressing
NSAP (Area, System ID, NSEL)
LSPids
SNAP
BSCI Module 4
Lesson 3
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OSI terminology
SNPA = @MAC
NSAP = @IP
NET = @IP que identifica el node (router)
ES-IS = ARP
ES = Host
IS = Router
Domain = AS
Area = Area (OSPF)
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NSAPs and Addressing
NSAP=Network Service Access Point
The NSAP is the network layer address for CLNS
packets
One NSAP per box, not per interface (similar to
DECnet)
SNPA means SubNetwork Point of Attachment, which
is the layer2 or MAC address
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How do I read an NSAP ?
An NSAP consists of 3 parts
Area-address, systemID and n-selector
Total length between 8 and 20 bytes
Example: 49.0001.0000.0000.0007.00
Authority and Format ID+InterDomain ID = InterDomain Part
High-Order Domain Specific Part == Subnets
System ID == Station
NSEL == Application
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NSAPs
Format of the Cisco NSAP address consists of three parts.
Area address
System ID
NSAP selector byte
Area address is a variable length field
The system ID is the ES or IS identifier in an area, similar to the OSPF
router ID.
The system ID has a fixed length of six bytes as engineered in the Cisco IOS.
The NSAP selector byte is a service identifier.
Analogous to that of a port or socket in TCP/IP.
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How do I read an NSAP ?
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Do I need an NSAP if I want to
use IS-IS for IP routing ?
Yes, still needed for IP routing only
Area address is like OSPF area
SystemID is like an OSPF routerID
LSP identifier is derived from systemID
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Creating unique systemIDs
SystemID is 6 bytes
Start numbering 1, 2, 3, 4 …. etc
Convert your loopback IP address
192.31.231.16 -> 192.031.231.016 ->
systemID 1920.3123.1016
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Creating area addresses
If you do CLNS routing, request an official NSAP prefix
If you do just IP routing, use AFI 49
AFI 49 denotes private address space
like network 10.0.0.0 in IP
Just number your areas 49.0001… 49.0002…., 49.0003,… etc
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NSAPs – Cisco Format
Area – System ID – NSEL
49.0001.2222.2222.2222.00
NSEL (NSAP Selector)
NSEL is a service identifier.
Loosely equivalent to that of a port or socket in TCP/IP.
Must be specified by a single byte preceded by a period (.)
Not used in routing decisions.
NET
When NSEL = 00, it identifies the device itself, the network level address.
The NSAP with a NSEL = 00 is known as a Network Entity Title (NET)
A NET is an NSAP with the NSEL set to (00)
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NSAP (NETs)
Other Examples
Area – System ID – NSEL
49.0001.2222.2222.2222.00
Example 1: NSAP 47.0001.aaaa.bbbb.cccc.00
Area ID is 47.0001
System ID is aaaa.bbbb.cccc
NSAP selector byte is 00
Example 2: NSAP 39.0f01.0002.0000.0c00.1111.00
Area ID is 39.0f01.0002
System ID is 0000.0c00.1111
NSAP selector byte is 00
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Configuring IS-IS
(so far)
SanJose1
interface FastEthernet0/0
ip address 172.16.0.1 255.255.255.0
ip router isis
router isis
net 49.0001.1111.1111.1111.00
SanJose2
ip address 172.16.0.2 255.255.255.0
ip router isis
router isis
net 49.0001.2222.2222.2222.00
Area . System ID . NSEL
Area
49.0001
SanJose3
ip address 172.16.0.3 255.255.255.0
ip router isis
router isis
net 49.0001.3333.3333.3333.00
ip router isis: IS-IS must be enabled on the interface
Note: IS-IS routing cannot be enabled on an interface until an IP address
has been configured on the interface.
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Configuring IS-IS
(so far)
Area
49.0001
To display both ES and IS neighbors.
SNPA is the MAC address of the remote router.
If serial, would show encapsulation, I.e. HDLC
Cisco routers default to L1-L2 type routers.
We will see how to change this in a moment.
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Level-1 routing
L1-only routers know only topology of their own area (including all
ISs and ESs in the area)
L1L2 ISs set the “attached-bit” in their L1-LSP header
L1-only routers look at the attach-bit (ATT) in L1 LSPs to find the
closest L1L2 router
L1-only routers install a default route to the closest L1L2 router in
the area
Traffic to other areas is sent via the closest L2 IS
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The Attached bit
L1-LSDB
rtrA.00-00 ATT-bit
rtrB.00-00
rtrC.00-00
rtr A
L2-LSDB
rtrA.00-00
rtrD.00-00
L1-LSDB
rtrD.00-00 ATT-bit
rtrE.00-00
rtrF.00-00
rtr D
Area 1
Area 2
L1L2 routers set the ATT bit in their L1 LSP
L1 routers use ATT bit found in L1-LSDB as possible area exit point
ISIS for IP: level-1 router will install a 0.0.0.0/0 route towards the L1L2
with ATT-bit set
Shortest metric to the L1L2 who sets the ATT bit wins
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Suboptimal Routing
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IS-IS Adjacencies
Are we half way yet?
BSCI Module 4
Lesson 3
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Hello Messages
IS-IS uses Hello PDUs to establish adjacencies with other routers
(ISs) and ESs.
IS-IS has three types of Hello PDUs:
ESH, sent by ES to an IS
ISH, sent by IS to an ES
IIH, used between two ISs (CCNP 1)
Hello Level 1 LAN
Hello Level 2 LAN
Hello Point-to-Point
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Neighbors and
Adjacencies
IS-IS discover neighbors and forms adjacencies using IS-IS Hello
PDUs.
Transmitted every 10 seconds
Can be changed using the interface command, is hellointerval
Hold time defaults to 3 times the Hello time (30 seconds), before
declaring a neighbor dead.
Changed using the interface command is hello-multiplier
Default is 3
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LAN Representation and Adjacencies
DIS
Similar to the DR in OSPF…
DIS (Designated IS) is elected to generate the LSP (Link State
Packet, ie. LSA) representing the virtual router connecting all
attached routers to a star-shaped topology.
For SPF, the whole network must look like a collection of nodes
and point-to-point links.
LAN uses a virtual node called pseudonode.
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LAN Representation and Adjacencies
DIS
Election of DIS:
Router with highest priority (Cisco default is 64)
Router with highest MAC address
No “BDR”
No way to make a router ineligible from being DIS (no OSPF
priority 0)
New router (IS) can cause a new election, unlike OSPF
Used as circuit ID for all routers on LAN.
Periodically broadcasts CSNPs (OSPF DBD) every 10 seconds
Each router on the LAN simulates an interface on the pseudonode.
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Identifying nodes in a LSP
In IS-IS Nodes are identified by 7 bytes. SystemIDs are
6 bytes and NSEL is 1 byte.
A normal node (non-pseudonode) is identified by 6 bytes
systemID plus a zero.
00c0.0040.1234.00-00
A pseudonode is identified by the systemID of the DIS, plus 1
byte from the circuitID of the interface of the DIS.
00c0.0040.1234.01-00
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A pseudonode on a LAN
For SPF, the whole network must look like a collection of nodes
and point-to-point links.
Assume a virtual node for the LAN
This virtual node is called pseudonode. It is not a real router, but just
an extra LSP in the LSPDB
Physical view
Logical view
DIS
DIS
LAN
Pseudonode
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Who creates the pseudonode?
Created by Designated Router (DIS)
No Backup Designated Router in IS-IS
The DIS reports all LAN neighbours in the pseudonode LSP; with
metric 0
All LAN routers report connectivity to the pseudonode in their LSPs
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Adjacencies
LAN
Adjacencies
L1 routers form L1 adjacencies with L1 and L1-L2 routers in their
area.
L2 routers form L2 adjacencies with L2 and L1-L2 routers in their
area or another area.
L1L2 routers form L1 and L2 adjacencies with each other in their
area or another area.
L1 router does not form an adjacency with an L2 router
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WAN
Adjacencies
On point-to-point links the IIH PDUs are common to both Level 1
and Level 2.
Announce both their Level type and Area ID in the Hellos.
Remember, separate LSDBs for different Levels.
What are the adjacencies? L1? L2? L1L2? None?
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WAN
Adjacencies
What are the adjacencies? L1? L2? L1L2? None?
The adjacencies also determine what type of routes the IS
(router) will have in its routing table.
L1 – Intra-area routes (routes only within that area)
L2 – Inter-area routes (routes from other areas)
Or both
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Configuring IS-IS
(so far)
DIS
SanJose1
ip address 172.16.0.1 255.255.255.0
ip router isis
isis priority 100
router isis
net 49.0001.1111.1111.1111.00
SanJose2
ip address 172.16.0.2 255.255.255.0
ip router isis
router isis
net 49.0001.2222.2222.2222.00
Area . System ID . NSEL
Area
49.0001
SanJose3
ip address 172.16.0.3 255.255.255.0
ip router isis
router isis
net 49.0001.3333.3333.3333.00
isis priority: Sets DIS priority on a LAN interface, default 64
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LSP flooding
BSCI Module 4
Lesson 3
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Only 4 types of IS-IS packets
IS-IS Hello packet (IIH)
Link State Packet (LSP)
Partial Sequence Number Packet (PSNP)
Complete Sequence Number Packet (CSNP)
Packets are sometimes called Protocol Data Units
(PDU in OSI)
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IS-IS Hello PDUs
Also called IIHs
Used for maintaining adjacencies
Different on p2p links and LANs
Different from ISHs and ESHs (ES-IS)
IIHs are padded to full MTU size
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Link State PDUs
Called LSPs
Contains all info about one router
Adjacencies, connected IP prefixes, OSI endsystems, area
addresses, etc.
One LSP per router (plus fragments)
One LSP per LAN network
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Sequence Number PDUs
Partial (PSNP) and Complete (CSNP)
Used when flooding the LSPDB
PSNPs are like ACKs on p2p links
CSNPs are used for LSPDB synchronization over LANs
CSNP are also used to sync LSPDB over new p2p
adjacencies
IS-IS
OSPF
LSP (Link-State Packet)
LSA (Link -State Advertisement)
CNSP (Complete Sequence
DBD (Data Base Description
Packet)
PSNP (Partial Sequence
LSAck or LSR (Link State
Request)
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Why do we need flooding?
All routers generate an LSP
All LSPs need to be flooded to all routers in the
network
If LSPDB is not synchronised, routing loops or blackholes
might occur
IS-IS’ two components are the SPF computation and
reliable flooding
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What triggers a new LSP ?
When something changes …
Adjacency came up or went down
Interface up/down (connected IP prefix !)
Redistributed IP routes change
Inter-area IP routes change
An interface is assigned a new metric
Most other configuration changes
Periodic refresh
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Basic flooding rules
When receiving an LSP, compare with old version of
LSP in LSPDB
If newer:
Install it in the LSPDB
Acknowledge the LSP with a PSNP
Flood to all other neighbours
Check if need to run SPF
If same age:
If older:
Send our version of the same LSP
Wait for PSNP
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Sequence number
Each LSP (and LSP fragment) has its own sequence
number
When router boots, sets seqnr to one
When there is a change, the seqnr is incremented, a
new version of the LSP is generated with the new
seqnr
Higher seqnr means newer LSP
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Flooding on a P2P Link
LSP
id=x seqnr=22
RouterA
Receives LSP
id=x seqNr=22
It’s new. Put it in
the LSPDB
RouterB
LSP
id=x seqnr=22
Now flood it:
Set SRM bit.
Send over p2p.
Received ack
Clear SRMbit
(Send Routing
Message)
PSNP
id=x seqnr=22
Received it. Local
copy has seqNr = 21.
So the received one is
newer. Install it in LSDB.
Acknowledge it. Maybe
flood further.
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The Designated IS
DIS is like the DR in OSPF
DIS is only on LANs, not on p2p
DIS has two tasks
Create/update pseudonode LSP
Conduct flooding over the LAN
DIS sends periodic CSNPs
LSPid, SeqNr, Checksum, Lifetime of all LSPs present in the
LSPDB
No Backup DIS in ISIS
DIS is elected by priority and MAC
Actually is “self-elected”
LAN circuitID shows who is DIS
Use show clns interface
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Flooding on a LAN
DIS
Rtr-A
LAN
!!! Problem !!!
Dropped LSP
LSP
LSP
Received new LSP
id=x seqNr=22
Install in LSPDB.
Flood the LSP.
id=x seqNr=22
Local copies of LSP-y and
LSP-z are up-to-date but
local copy of LSP-x is older.
Request latest LSP-x via
PSNP
PSNP
CSNP
id=y seqnr=...
id=x seqNr=22
id=z ...
id=x seqNr=21
LSP
Got it. Install and
run SPF
Periodic CSNP
every 10 secs
Neighbor has an
old LSP, better
resend him latest
id=x seqNr=22
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IP routing specifics
BSCI Module 4
Lesson 3
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ISIS routing Levels
L1
2. Level-1 LSP with
IP prefix: 10.1.0.0/16
L1L2
3. Level-2 LSP with
IP prefix: 10.1.0.0/16
IP prefix: 10.10.0.0/16
L1
2. Level-1 LSP with
IP prefix: 10.10.0.0/16
1. Level-1 LSP with
Attached-bit (used
L1L2 as a default route by
all level-1routers
L1
Routers within an area do not
have any routing information
about prefixes originated outside
the area. Default routing (ATT-bit
or explicit 0.0.0.0/0) is used to reach
destinations outside the area.
L1
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ISIS routing Levels
3. Level-2 LSP with
IP prefix: 10.1.0.0/16
L2
0. Level-1 LSP with
ATT bit set
L2
3. Level-2 LSP with
IP prefix: 10.1.0.0/16
L1
L1L2
2. Level-2 LSP with
IP prefix: 10.1.0.0/16
L1L2
0. Level-1 LSP with
ATT bit set
L1
1. Level-1 LSP with
IP prefix: 10.1.0.0/16
2. Level-2 LSP with
IP prefix: 10.1.0.0/16
0. Level-1 LSP with L1L2
ATT bit set
L1
4. At this point the prefix
10.1.0.0/16 will NOT be inserted
in the L1 LSP (no route leaking
by default)
2. At this point prefix
10.1.0.0/16 will
is be
inserted in L2 LSP
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Configuration, Show,
& Debug Commands
BSCI Module 4
Lesson 3
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Cisco Public
Basic Configuration
L1router
Router-A
--------------
Router-B
--------------
interface Loopback0
interface Loopback0
ip address 192.168.1.5 255.255.255.255
ip address 192.168.1.1 255.255.255.255
!
!
interface Serial0
Interface Serial0
ip address 192.168.120.5 255.255.255.0
ip address 192.168.120.10 255.255.255.0
ip router isis
ip router isis
Rtr-A
S0
Area 49.0001
S1
Rtr-B
S0
L1L2 routers
!
!
router isis
interface Serial1
is-type level-1
ip address 192.168.222.1 255.255.255.0
passive-interface Loopback0
ip router isis
net 49.0001.1921.6800.1005.00
!
S1
S0
router isis
Rtr-C
Area 49.0002
S1
net 49.0001.1921.6800.1001.00
Rtr-D
L1router
72
Presentation_ID.scr
36
Basic Configuration
L1router
Router-C
--------------
Router-D
--------------
interface Loopback0
interface Loopback0
ip address 192.168.2.2 255.255.255.255
ip address 192.168.2.4 255.255.255.255
!
!
interface Serial0
interface Serial1
ip address 192.168.111.2 255.255.255.0
ip address 192.168.111.4 255.255.255.0
ip router isis
ip router isis
isis circuit-type level-1
!
!
router isis
interface Serial1
is-type level-1
ip address 192.168.222.2 255.255.255.0
ip router isis
net 49.0002.1921.6800.2004.00
Rtr-A
S0
Area 49.0001
S1
Rtr-B
S0
L1L2 routers
S1
S0
isis circuit-type level-2
Rtr-C
Area 49.0002
!
S1
router isis
Rtr-D
net 49.0002.1921.6800.2002.00
L1router
73
Troubleshooting Commands: CLNS
Router#
show clns
Displays information about the CLNS network
Router#
show clns [area-tag] protocol
Lists the protocol-specific information
Router#
show clns interface [type number]
Lists the CLNS-specific information about each interface
Router#
show clns [area-tag] neighbors [type number] [detail]
Displays both ES and IS neighbors
74
Presentation_ID.scr
37
Troubleshooting Commands:
CLNS and IS-IS
Router#
show isis [area-tag] route
Displays IS-IS Level 1 routing table (system IDs)
Router#
show clns route [nsap]
Displays IS-IS routing table (areas)
Router#
show isis [area-tag] database
Displays the IS-IS LSDB
Router#
show isis [area-tag] topology
Displays IS-IS least-cost paths to destinations
75
Show clns
L1L2 routers
S0
S1 Rtr-B
Area 49.0001
S1
Rtr-C
S0
Area 49.0002
S0
S1
Rtr-A
Rtr-D
L1routers
Rtr-B# show clns
Global CLNS Information:
2 Interfaces Enabled for CLNS
NET: 49.0001.1921.6800.1001.00
Configuration Timer: 60, Default Holding Timer: 300, Packet Lifetime 64
ERPDU's requested on locally generated packets
Running IS-IS in IP-only mode
76
Presentation_ID.scr
38
Show clns protocol
L1router
Rtr-A
S0
Rtr-B# show clns protocol
IS-IS Router: <Null Tag>
System Id: 1921.6800.1001.00 IS-Type: level-1-2
Manual area address(es):
49.0001
Routing for area address(es):
49.0001
Interfaces supported by IS-IS:
Serial1 - IP
Serial0 - IP
Redistribute:
static (on by default)
Distance for L2 CLNS routes: 110
Area 49.0001
S1
Rtr-B
S0
L1L2 routers
S1
Rtr-C
S0
Area 49.0002
S1
Rtr-D
L1router
77
Show clns neighbors
L1L2 routers
S0
S1 Rtr-B
S1
Rtr-C
S0
Area 49.0002
Area 49.0001
S0
S1
Rtr-A
Rtr-D
L1routers
Rtr-B# show clns neighbors
System Id
Interface SNPA
Rtr-C
Se0
*HDLC*
1921.6800.1005 Se1
*HDLC*
State Holdtime Type Protocol
Up 23
L2
IS-IS
Up 21
L1
IS-IS
78
Presentation_ID.scr
39
Show clns interface
L1router
Rtr-B# show clns int serial1
Serial1 is up, line protocol is up
Checksums enabled, MTU 1500, Encapsulation HDLC
ERPDUs enabled, min. interval 10 msec.
CLNS fast switching enabled
CLNS SSE switching disabled
DEC compatibility mode OFF for this interface
Next ESH/ISH in 47 seconds
Routing Protocol: IS-IS
Circuit Type: level-1-2
Interface number 0x2, local circuit ID 0x101
Level-1 Metric: 10, Priority: 64, Circuit ID: 1921.6800.1005.00
Number of active level-1 adjacencies: 1
Level-2 Metric: 10, Priority: 64, Circuit ID: Rtr-B.01
Next IS-IS Hello in 6 seconds
Rtr-A
S0
Area 49.0001
S1
Rtr-B
S0
L1L2 routers
S1
Rtr-C
S0
Area 49.0002
S1
Rtr-D
L1router
79
Show clns interface
Rtr-B# show clns int serial0
Serial0 is up, line protocol is up
Checksums enabled, MTU 1500, Encapsulation HDLC
ERPDUs enabled, min. interval 10 msec.
CLNS fast switching enabled
CLNS SSE switching disabled
DEC compatibility mode OFF for this interface
Next ESH/ISH in 30 seconds
Routing Protocol: IS-IS
Circuit Type: level-1-2
Interface number 0x1, local circuit ID 0x100
Level-1 Metric: 10, Priority: 64, Circuit ID: Rtr-C.01
Level-2 Metric: 10, Priority: 64, Circuit ID: Rtr-B.00
Next IS-IS Hello in 6 seconds
L1router
Rtr-A
S0
Area 49.0001
S1
Rtr-B
S0
L1L2 routers
S1
S0
Rtr-C
Area 49.0002
S1
Rtr-D
L1router
80
Presentation_ID.scr
40
Show clns traffic
L1router
IS-IS: Level-2 Hellos (sent/rcvd): 285/0
IS-IS: PTP Hellos (sent/rcvd): 420/415
IS-IS: Level-1 LSPs sourced (new/refresh): 8/2
IS-IS: Level-2 LSPs sourced (new/refresh): 9/1
IS-IS: Level-1 LSPs flooded (sent/rcvd): 5/8
IS-IS: Level-2 LSPs flooded (sent/rcvd): 7/8
IS-IS: LSP Retransmissions: 0
IS-IS: Level-1 CSNPs (sent/rcvd): 1/1
IS-IS: Level-2 CSNPs (sent/rcvd): 2/2
IS-IS: Level-1 PSNPs (sent/rcvd): 7/4
IS-IS: Level-2 PSNPs (sent/rcvd): 7/5
IS-IS: Level-1 DR Elections: 1
IS-IS: Level-2 DR Elections: 1
IS-IS: Level-1 SPF Calculations: 7
IS-IS: Level-2 SPF Calculations: 9
IS-IS: Level-1 Partial Route Calculations: 1
IS-IS: Level-2 Partial Route Calculations: 5
IS-IS: LSP checksum errors received: 0
IS-IS: Update process queue depth: 0/200
IS-IS: Update process packets dropped: 0
Rtr-A
S0
Area 49.0001
S1
Rtr-B
S0
L1L2 routers
S1
S0
Rtr-C
Area 49.0002
S1
Rtr-D
L1router
81
Example: Is Integrated IS-IS Running?
R2#show ip protocols
Routing Protocol is "isis"
Invalid after 0 seconds, hold down 0, flushed after 0
Outgoing update filter list for all interfaces is not set
Incoming update filter list for all interfaces is not set
Redistributing: isis
Address Summarization:
None
Maximum path: 4
Routing for Networks:
FastEthernet0/0
Loopback0
Serial0/0/1
Routing Information Sources:
Gateway
Distance
Last Update
10.10.10.10
115
00:00:02
10.30.30.30
115
00:00:03
Distance: (default is 115)
Displays the parameters and current state of the active
routing protocol processes
82
Presentation_ID.scr
41
Example: Are There Any IP Routes?
router#
show ip route [address [mask]] | [protocol [process-id]]
R2#show ip route isis
10.0.0.0/24 is subnetted, 5 subnets
i L2
10.30.30.0 [115/45] via 10.2.2.3, Serial0/0/1
i L1
10.10.10.0 [115/20] via 10.1.1.1, FastEthernet0/0
R2#
Displays the current state of the routing table
83
Q and A
84
Presentation_ID.scr
42
85
Presentation_ID.scr
43

What is IS

Transcription

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