Hello, Do a "show isis database" and you will see who is setting the ATT bit. R2 and R3 are setting the ATT bits and these get flooded to R1 and then across to each other in L1. Probably looks like this:
R1#sho isis database IS-IS Level-1 Link State Database: LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL R1.00-00 * 0x00000003 0x5524 1173 0/0/0 R2.00-00 0x00000003 0x7E42 1161 1/0/0 R3.00-00 0x00000003 0xC8F2 1179 1/0/0 -Bryan -----Original Message----- From: cisco-nsp-boun...@puck.nether.net [mailto:cisco-nsp-boun...@puck.nether.net] On Behalf Of Ibrahim Abo Zaid Sent: Monday, August 17, 2009 2:47 PM To: cisco_nsp; ci...@groupstudy.com Subject: [c-nsp] ISIS Problem Hi All I have a problem with the below ISIS toplogy , All ADJ of R1 are L1 and interface between R2 is in A2 from R2 side and in A3 side from R3 side so R2 and R3 have L2-ADJ betwene them , as expected both R2 and R3 send LSP with ATT bit set so R1 has 2 L1 default routes point to both R2 and R3 , the wired result there is L1 on both R2 and R3 points to R1 !! but R1 don't set ATT bit in its LSP do you explainsation why R1 sends this default route ? and how we can stop it Topology R2--------L-1------------ | | | | L2 A-1 R1 | | | | R3---------L-1----------- Configuration R1 ! interface Serial1/0 description to R2 ip address 10.10.12.1 255.255.255.0 ip router isis encapsulation ppp ! interface Serial1/1 description to R3 ip address 10.10.13.1 255.255.255.0 ip router isis encapsulation ppp ! router isis net 49.0001.0000.0000.0001.00 is-type level-1 R2 interface Serial1/0 description to R1 ip address 10.10.12.2 255.255.255.0 ip router isis encapsulation ppp ! interface Serial1/1 description to R3 ip address 10.10.23.2 255.255.255.0 ip router isis 2 encapsulation ppp ! router isis 2 net 49.0002.0000.0000.0002.00 is-type level-2-only ! router isis net 49.0001.0000.0000.0002.00 is-type level-1 R3 interface Serial 1/0 description to R1 ip address 10.10.13.3 255.255.255.0 ip router isis encapsulation ppp ! interface Serial 1/1 description to R2 ip address 10.10.23.3 255.255.255.0 ip router isis 3 encapsulation ppp ! router isis 3 net 49.0003.0000.0000.0003.00 is-type level-2-only ! router isis net 49.0001.0000.0000.0003.00 is-type level-1 Logs ------- R1#sh clns neighbors System Id Interface SNPA State Holdtime Type Protocol R2 Se1/0 *PPP* Up 22 L1 IS-IS R3 Se1/1 *PPP* Up 23 L1 IS-IS R2#sh clns neighbors Area 2: System Id Interface SNPA State Holdtime Type Protocol R3 Se1/1 *PPP* Up 28 L2 IS-IS Area null: System Id Interface SNPA State Holdtime Type Protocol R1 Se1/0 *PPP* Up 26 L1 IS-IS R3#sh clns neighbors Area 3: System Id Interface SNPA State Holdtime Type Protocol R2 Se1/1 *PPP* Up 22 L2 IS-IS Area null: System Id Interface SNPA State Holdtime Type Protocol R1 Se1/0 *PPP* Up 28 L1 IS-IS routing tables ----------------- R1#sh ip route isis i*L1 0.0.0.0/0 [115/10] via 10.10.13.3, Serial1/1 [115/10] via 10.10.12.2, Serial1/0 R2#sh ip route isis i L2 10.10.13.1/32 [115/20] via 10.10.23.3, Serial1/0 i L1 10.10.13.0/24 [115/20] via 10.10.12.1, Serial1/0 i*L1 0.0.0.0/0 [115/20] via 10.10.12.1, Serial1/0 R3#sh ip route isis i L1 10.10.12.0/24 [115/20] via 10.10.13.1, Serial1/0 i L2 10.10.12.1/32 [115/20] via 10.10.23.2, Serial1/1 i*L1 0.0.0.0/0 [115/20] via 10.10.13.1, Serial1/0 _______________________________________________ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/ _______________________________________________ cisco-nsp mailing list cisco-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/