Topology Analysis of the junos isis Region

Topology Analysis of the junos isis Region
Typical ISIS topology types:
Refer to AREA 49.0001 R1 (L1 only) and R2 (L1/L2). R3 (L2 only) needs to configure the same region address, while R3 and R4 (L2) configure IP addresses in different regions for the adjacent vro.
There are three types of vrol1 roles: L1: similar to the full-ended area L1/L2 in OSPF: similar to the ABR vrol2 L2 In OSPF: for details about the core region 0 Attached bit in the ISIS network, refer to R1.R2. topology of R3: If the ISO address is 49.0001, R2 will not release attached bit "1" to the LSA of R1 ", that is to say, R1 will not have a "0.0.0.0" default route. When R1 needs an external route, it can be completed by "route leak" on R2. Note: when the L2 router connected to L1/L2 is configured with the same ISO address, then L1/L2 (not considered to have learned the external route) does not consider it necessary to publish attached bit to L1; www.2cto.com
Test@RTE-10.0.3.4 # run show isis database logical-system r3 IS-IS level 1 link-state database: lsp id Sequence Checksum Lifetime Attributes RTE-10.0.3.4-r1.00-00 0x7f5 0x7f28 1192 L1 RTE-10.0.3.4-r2.00-00 0x84d 0xd74e 1174 L1 RTE-10.0.3.4-r2.02-00 0x14 0x9f0c 579 L1 RTE-10.0.3.4-r2.03-00 0x15 0xc946 794 L1 RTE-10.0.3.4-r2.04-00 0x14 0xf7d3 579 L1 RTE-10.0.3.4-r3.00-00 0x15 0x7707 643 L1 L2 RTE-10.0.3.4-r3.02-00 0x15 0x1214 946 L1 L2 RTE-10.0.3.4-r4.00-00 0x15 0x388d 790 L1 L2
Refer to the topology of R6.R5. R4:
R5 and R4 are configured with a different ISO address test@RTE-10.0.3.4 # run show isis database logical-system r3 IS-IS level 1 link-state database: lsp id Sequence Checksum Lifetime Attributes RTE-10.0.3.4-r1.00-00 0x80a 0xccc5 1187 L1 RTE-10.0.3.4-r2.00-00 0x85c 0x6aac 1195 L1 RTE-10.0.3.4-r2.02-00 0x15 0x9d0d 1162 L1 RTE-10.0.3.4-r2.03-00 0x16 0xc747 1162 L1 RTE-10.0.3.4-r2.04-00 0x15 0xf5d4 1162 L1 RTE-10.0.3.4-r3.00-00 0x17 0x7bf8 1165 L1 L2 Attached RTE-10.0.3.4-r3.02-00 0x16 0x1015 1164 L1 L2 RTE-10.0.3.4-r4.00-00 0x17 0x3c7f 1159 L1 L2 Attached 8 LSPs also has a point when the L1/L2 router is lost with other L2 Routers connection (ISIS ), then L1/L2 routes will no longer generate the "attached bit" JNCIP Learning Guide Topology

R3----R5 R3----R4 For L2 Neighbor Relationship, R3 other interfaces for L1 neighbor relationship, when the interface between R3 and R5 closed, then R3 no L2 neighbor relationship, r3 learned a 0/0 default route from R4, because R4 IS equivalent to R3 L2 router www.2cto.com test @ RTE # run show isis database logical-system r3 IS-IS level 1 link-state database: lsp id Sequence Checksum Lifetime Attributes RTE-r3.00-00 0x8 0x291d 3578 L1 L2 Attached before shutting down the interface for the R3------R5, RTE-r3.03-00 0x5 0x7ccc 3577 L1 L2 RTE-r3.04-00 0x5 0x356f 3577 L1 L2 RTE-r4.00-00 0x5 0xe290 3576 L1 L2 Attached RTE-r4.03-00 0x5 0xa4a1 3576 L1 L2 RTE-r1.00-00 0x5 0x9a5 3576 L1 l2 RTE-r1.02-00 0x5 0x4f52 3576 L1 L2 RTE-r1.03-00 0x5 0xc807 3576 L1 L2 RTE-r2.00-00 0x5 0xf663 3576 L1 L2 9 LSPsIS-IS level 2 link-state database: lsp id Sequence Checksum Lifetime Attributes RTE-r3.00-00 0xa 0x3a24 3578 L1 L2 RTE-r3.02-00 0x5 0x891b 3578 L1 L2 RTE-r4.00-00 0x5 0xd689 3574 L1 L2 RTE-r4.02-00 0x5 0xb1ef 3574 L1 L2 RTE-r5.00-00 0x8 0xd003 3576 L1 L2 5 LSPstest @ RTE # run show isis database logical-system r3 IS-IS level 1 link-state database: lsp id Sequence Checksum Lifetime Attributes RTE-r3.00-00 0x6 0x252b 3590 L1 L2 after shutting down the interface for the R3------R5, no longer notice to R1 Attached bit RTE-r3.03-00 0x4 0x7ecb 3590 L1 L2 RTE-r3.04-00 0x4 0x376e 3590 L1 L2 RTE-r4.00-00 0x4 0xe48f 3588 L1 L2 Attached RTE-r4.03-00 0x4 0xa6a0 3588 L1 L2 RTE-r1.00-00 0x4 0xba4 3588 L1 L2 RTE-r1.02-00 0x4 0x5151 L1 L2 RTE-r1.03-00 0x4 0xca06 3588 L1 L2 RTE-r2.00-00 0x4 0xd981 3588 L1 L2 9 LSPs www.2cto.com IS-IS level 2 link-state database: lsp id Sequence Checksum Lifetime Attributes RTE-r3.00-00 0x7 0xa771 3590 L1 L2 RTE-r3.02-00 0x4 0 L1 L2 RTE-r4.00-00 0x3 0xda87 3066 L1 L2 RTE-r4.02-00 0x3 0xb5ed 3066 L1 L2 RTE-r5.00-00 0x4 0xec9 3068 L1 L2 5 LSPs author junos_tech