IGP ISIS Not that different from OSPF Engineering

IGP: IS-IS Not that different from OSPF Engineering Workshops

IGP – IS/IS • Distance Vector IGP’s – – RIP 2 IGRP EIGRP • Link State IGP’s – OSPF – IS/IS Engineering Workshops

IGP – IS/IS • OSI Developed • In the magic OSI fantasy world everything is either an End System (ES) or an Intermediate System (IS. ) • ES=Hosts • IS=Routers • IS/IS: A protocol to let Intermediate Systems talk to other Intermediate Systems. IE: Router to Router. IE: Routing Engineering Workshops

IGP – IS/IS • IS/IS carries routing information for the OSI protocols. • It is also VERY easy to modify to carry other protocols, like IPv 4 and IPv 6. • The language is different, but the concepts are the same as in OSPF (Well, not really, but close enough. ) • OSPF Areas=IS/IS Levels • OSPF Neighbors=IS/IS Adjacencies Engineering Workshops

IGP - IS/IS • Only two levels allowed: Levels Two (backbone) and Level One (stub. ) Level 1 Level 2 Level 1 Engineering Workshops

IGP – IS/IS • • • Always use Wide Metrics. Always set your metrics. Always disable Level 1 and force Level 2. OSI MTU must be <= 1500. You need one Unique OSI address per router. An ES-IS state means something is wrong. • Don’t forget: It needs OSI/CLNS to work. Engineering Workshops

IGP – IS/IS – Cisco Interface Config • interface POS 0/0 • description BACKBONE: OC 48 to IPLSng • mtu 9180 • ip router isis • ipv 6 router isis • clns mtu 1497 Engineering Workshops

IGP – IS/IS Cisco Routing • • • router isis redistribute connected metric-type external redistribute static ip ! address-family ipv 6 redistribute connected exit-address-family net 49. 0000. 0006. 00 is-type level-2 -only metric-style wide Engineering Workshops

IGP – IS/IS Cisco Commands • ipls-gsr#sh clns neigh • System Id Interface SNPA • clev-gsr PO 2/0 *HDLC* • IPLSng PO 0/0 *HDLC* State Holdtime Type Protocol Up 21 L 2 IS-IS Up 26 L 2 IS-IS Engineering Workshops

IGP – IS/IS – Cisco Commands • ipls-gsr#sh isis top • • • IS-IS paths to level-2 routers System Id Metric Next-Hop atla-gsr 588 IPLSng-re 0 chin-gsr 262 IPLSng-re 0 clev-gsr 324 clev-gsr dnvr-gsr 1194 IPLSng-re 0 hstn-gsr 1457 IPLSng-re 0 ipls-gsr -kscy-gsr 550 IPLSng-re 0 losa-gsr 2850 IPLSng-re 0 Interface SNPA PO 0/0 *HDLC* PO 2/0 *HDLC* PO 0/0 *HDLC* Engineering Workshops

IGP – IS/IS Juniper Interface Config • Interface – so-0/0/0 • unit 0 – Family iso » Mtu 1497 – Lo 0 • Unit 0 – Family iso » Address 49. 0000. 0018. 00 Engineering Workshops

IGP – IS/IS – Juniper Routing • Protocols – Isis • level 2 wide-metrics-only • interface so-0/0/0. 0 { level 1 disable; level 2 metric 548; } • interface so-0/1/0. 0 { level 2 metric 260; level 1 disable; } Engineering Workshops

IGP – IS/IS Juniper Commands • gcbrowni@IPLSng-re 0> show isis adjacency • Interface so-0/0/0. 0 • so-0/1/0. 0 • so-1/2/1. 0 • so-1/3/0. 0 System L State KSCYng-re 0 2 Up CHINng-re 0 2 Up atla-gsr 2 Up ipls-7200 -6 2 Up ipls-gsr 2 Up Hold (secs) 24 25 23 Engineering Workshops

IGP – IS/IS Juniper Commands • • • gcbrowni@IPLSng-re 0> show isis database IS-IS level 1 link-state database: LSP ID Sequence Checksum Lifetime Attributes IPLSng-re 0. 00 -00 0 xf 65 0 xa 1 fc 400 L 1 L 2 1 LSPs • • IS-IS level 2 link-state database: LSP ID Sequence Checksum Lifetime Attributes atla-gsr. 00 -00 0 x 60 a 2 0 x 7 cae 1068 L 1 L 2 chin-gsr. 00 -00 0 x 5 eac 0 xc 1 d 9 1110 L 1 L 2 chin-gsr. 01 -00 0 x 1 a 15 0 x 99 ed 525 L 1 L 2 clev-gsr. 00 -00 0 x 62 a 2 0 xcf 0 e 584 L 1 L 2 dnvr-gsr. 00 -00 0 x 5 ca 7 0 x 332 e 1019 L 1 L 2 Engineering Workshops

IGP – IS/IS Lab • Bring up IS/IS on your EXTERNAL links. • Your external interfaces will be advertised by IS/IS while your internal interface will be advertised by your BGP aggregate. • Longest Match and Distance/Preference will keep things working correctly. Engineering Workshops