Learn ISIS for IPv4 and IPv6
4.3 (310 ratings)
Course Ratings are calculated from individual students’ ratings and a variety of other signals, like age of rating and reliability, to ensure that they reflect course quality fairly and accurately.
17,386 students enrolled

Learn ISIS for IPv4 and IPv6

from Basic to Advance level.
4.3 (310 ratings)
Course Ratings are calculated from individual students’ ratings and a variety of other signals, like age of rating and reliability, to ensure that they reflect course quality fairly and accurately.
17,386 students enrolled
Created by sikandar Shaik
Last updated 12/2013
English
English [Auto]
Price: $19.99
30-Day Money-Back Guarantee
This course includes
  • 3 hours on-demand video
  • Full lifetime access
  • Access on mobile and TV
  • Certificate of Completion
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What you'll learn
  • Master ISIS from Basics
Requirements
  • Basic CCNA, CCNP Routing & switching Knowledge
  • using Gns3 Software for simulating Labs
Description

In recent years, the IS-IS routing protocol has become increasingly popular, with widespread usage among Service Providers a part from OSPF.

Many Cisco Engineers are good with routing protocols ( like OSPF, EIGRP, RIPv2)

ISIS is the protocol majorly used inside Service providers Networks apart from OSPF.

This course will be very handy for anyone who want to master ISIS from basics.

ISIS for IPV4/IPV6 already part of Cisco ( CCNA,CCNP,CCIE ) service Provider Track and even added to new CCIE RS version 5 .

Who this course is for:
  • candidate preparing for Cisco Service Provider Track ( CCNA to CCIE) any
  • Candidates preparing for new CCIE RS version 5
Course content
Expand all 11 lectures 02:51:21
+ ISIS
3 lectures 37:34

ISIS features

·Open standard (OSI)

oFirst developed by DEC and It was standardized by theISOin 1992 communication between network devices which are termed Intermediate Systems by the ISO.

·Link-state routing protocol

·Classless

oFLSM, VLSM and Manual summary

·Work on SPF or Dijkstra algorithm

·Incremental / trigger updates

·Updates are send as unicast /multicast (Layer 2)

·Metric= default (Cisco)

·Administrative distance = 115

·It is used by large ISP

·Protocol independent i.e. Support IP, IPX, Apple Talk

Preview 06:25

IS-IS Levels

·ISIS has a 2 layer hierarchy

oLevel-2 (the backbone)

oLevel-1 (the areas)

·IS-IS support three type of router levels

1.Level-1 (L1) router (intra-area routing)

2.Level-2 (L2) router (inter-area routing)

3.Level-1-2 (L1L2) router (intra and inter-area routing)

·Manually Need to define IS-type

·Default is level 1/Level 2

Preview 16:45

NSAP Address (Network Service Access Point)

·The simplest NSAP format used by most companies running IS-IS as their IGP is as follows:

·AFI set to 49

oReserved for private use.

·Area ID

oMust be at least one byte.

·SystemID: Defines an ES or IS in an area; Cisco implements

§a fixed length of 6 octets for the SystemID

·NSEL ( NSAP selector)

oAlways set to 00 for a ISIS in router.

·NSAP with NSEL 00 is also called as NET

oNET: Network Entity Title.

o Is the address of the network entity itself

o A NET is an NSAP where n-selector is 0 (common practice)

oA NET implies the routing layer of the IS itself (no transport layer)

o ISs (routers) do not have any transport layer (selector=0)

·Examples:

oExample : 49.0001.0000.0000.0007.00

understanding NSAP address in ISIS
14:24
+ ISIS lab Verfication
4 lectures 01:15:18

LAB: ISIS:

Configure ISIS routing for IPV4 and IPV6 as per the diagram

·Routers R1-R3–R4 should be in the same area 49.0134

·Use NET addresses in the format 49.0134.0000.0000.000X.00, where X is the router Numbers for routers R1-R3–R4

·Advertise the connected and Loopback interfaces of all the routers

·Enable Ipv6 unicast routing on all routers

LAB : Basic ISIS lab
22:52

·Unlike ospf, The ISIS DIS allows preemption,

· The default interface priority is 64 and the device with the highest SNPA (Layer2 identifier) becomes the DIS.

· If the SNPA addresses are the same then the system-id is the tie breaker.

·The DIS can be identified with either the show clns is-neighboror show isis neighbor. The device listed under the Circuit-Id field is the DIS.

ISIS DIS (Designated Intermediate System)
12:55

IS-IS Levels

·ISIS has a 2 layer hierarchy

oLevel-2 (the backbone)

oLevel-1 (the areas)

·IS-IS support three type of router levels

1.Level-1 (L1) router (intra-area routing)

2.Level-2 (L2) router (inter-area routing)

3.Level-1-2 (L1L2) router (intra and inter-area routing)

·Manually Need to define IS-type

·Default is level 1/Level 2

LAB : Changing ISIS Levels
30:58

·To change metric (default is 10)

oRouter(config-if)# isis metric



ISIS Metrics
08:33
+ Advance ISIS
4 lectures 58:29

TASK

·Configure authentication between the link R3 – R4 using clear text password cisco123

·Configure authentication between thelink R5– R6 using MD5 password ccie123

ISIS Authentication
08:17

IS-IS Route Leaking for IPV4

·Configure IS-IS Route Leaking from Level 2 to Level 1 on the L1/L2 routers as follows:

oR1 should advertise the L2 prefix 6.6.6.6/32 to its L1 routers (R3, R4)

oR2 should advertise the L2 prefix 4.4.4.4/32 to its L1 routers (R5, R6)

By default R4/R3 will receive a default route for all the routes coming from different area ( AREA 49.0256) from the nearest L1/L2 router (R1)

in order to allow some of the specific routes to get from nearest L1/L2 router ( R1) to all the inside L1 routers (R3/R4) generally called as route leaking feature.


ISIS Route leaking
17:59

Here I said Spanning-tree for SPF ( but it is shortest path first for ISIS ) ..

ISIS SINGLE AND MULTITOPOLOGY

ISIS supports routing for both IPv6 and IPv4. There are new TLVs which are encoded inside the ISIS to support IPv6 addressing. IPv6 routing can be configured as either Multi-topology or Single-topology

Single Topology IS-IS

·Single Topology IS-IS is used when multiple protocol stacks, such as IPv4 and IPv6, are configured in an identical 1:1 basis on all interfaces in the topology.

·Single topology has the following characteristics –

  • Shares path calculation with IPv4 routing Table. Only one SPF calculation.
  • It requires 1:1 correlation of IPv4 and IPv6 interfaces i.e Ipv4 and IPv6 interfaces should be same.

·Simplifying database single calculation and protocol overhead as multiple protocol stacks (IPv4 and IPv6) configured in an identical 1:1 basis.

·In other words, for single topology IS-IS to work, each interface that runs IPv4 must also run IPv6, and each interface that runs IPv6 must also run IPv4.

·This is one of the design advantages of IS-IS over OSPF, as OSPFv2 and OSPFv3 are unrelated protocols used to route IPv4 and IPv6 respectively, while IS-IS can route both with a single calculation, arguably resulting in a more efficient design.

·By default :Regular IOS --> IS-IS instances run in Single Topology modeIOS XR --> ISIS instances run in Multiple Topology mode

Multi Topology IS-IS

In Multi Topology IS-IS, separate protocol stacks maintain separate database structures and use separate SPF runs, which means that one topology is independent of another.

However enabling multi-topology mode will have following effect

·Independent path calculation from IPv4 routing table. Separate SPF calculation.

·IPv4 and IPv6 configuration are completely different i.e IPv4 & IPv6 interfaces can be asymmetric.

Multi -Topology IS-IS is most useful in practical IPv4 to IPv6 migration scenarios, where IPv6 is slowly introduced to the already existing IPv4 core. During migration the IPv4 and IPv6 topologies are kept separate from a database calculation point of view inside of IS-IS. Once the migration is complete and IPv4 and IPv6 run on a 1:1 basis with each other, Single Topology IS-IS can be enabled, which means that both IPv4 and IPv6 topology share the same database and SPF run.

Note that this design is only possible if IPv4 runs on all interfaces that IPv6 runs on and vice-versa, otherwise database inconsistencies can occur which can result in loss of reachability in the network

ISIS single Multi topology
23:43

ISIS troubleshooting

    ·Sh isis neighbor

    ·sh run part router isis

    ·sh run int ---

=====================

    ·sh ip route isis

    ·sh ipv6 route isis

=======================ISIS issues

    ·net id is correct according to quetion

    ·ip router isis /ipv6 router isis missing under interface

    ·isis protocol shutdown under interface

int g0/0.10

isis protocol shutdown

end

    ·level mismatch ( router mode/interface mode)

    ·network type under interface

    ·In case of the below, routes will not be exchanged but still forms neighbors

    ·metric-style mismatch

    ·topology mismatch

ISIS Trouble shooting ISIS
08:30