From: Michael Snyder (msnyder@revolutioncomputer.com)
Date: Sun Nov 30 2003 - 21:28:42 GMT-3
-----Original Message-----
From: R&S Groupstudy [mailto:rsg@synergy-networking.co.uk]
Sent: Sunday, November 30, 2003 4:04 PM
To: Michael Snyder; ccielab@groupstudy.com
Subject: RE: Silly ISIS Question.
the L1 router installs a default route pointing towards the nearest
router
with it's attached bit set.
do a "show isis database" on your L1 routers and see the entry for a L2
router: notice the attached bit set to 1
the L2 router will only set it's attached bit if it has a L2 database -
i.e.
some L2 routing information
Adam
------------------------------------------------------------------------
---Ok, I've broke something then.
R6 is a L1L2 router connected to L2 routers R2,R4,R5 by full mesh which seems to be working.
R7 shares a Ethernet connection to R6 & R5 and is only L1. R8 connecects to R7 as a L1 link. I don't see anything with the attached bit set. Configs Below.
R6#sr Building configuration...
Current configuration : 2354 bytes ! version 12.2 no service single-slot-reload-enable no service timestamps debug uptime no service timestamps log uptime no service password-encryption service linenumber ! hostname R6 ! logging rate-limit console 10 except errors ! clock timezone CST -6 clock summer-time CDT recurring ip subnet-zero no ip finger ip tcp synwait-time 5 no ip domain-lookup ! no ip dhcp-client network-discovery ! ! ! ! interface Loopback0 ip address 192.168.6.6 255.255.255.255 ! interface Ethernet0 ip address 172.16.136.6 255.255.255.128 ip router isis isis circuit-type level-1 ! interface Serial0 ip address 172.16.100.6 255.255.255.0 ip router isis encapsulation frame-relay frame-relay map clns 605 broadcast frame-relay map clns 604 broadcast frame-relay map clns 601 broadcast frame-relay map ip 172.16.100.2 601 broadcast frame-relay map ip 172.16.100.4 604 broadcast frame-relay map ip 172.16.100.5 605 broadcast frame-relay map ip 172.16.100.6 601 broadcast no frame-relay inverse-arp frame-relay lmi-type cisco isis circuit-type level-2-only ! interface Serial1 ip address 172.16.56.6 255.255.255.252 ! interface TokenRing0 no ip address no ip route-cache no ip mroute-cache shutdown ring-speed 16 ! router isis passive-interface Loopback0 default-information originate net 49.0001.0000.0000.0006.00 area-password michael ! ip kerberos source-interface any ip classless no ip http server ! ! banner motd ^C
Router R6 - Cisco 2513 Interfaces S0 S1 E0 To0
S0 - Frame Relay S1 - Connects to G-S0 E0 - connects to 3550 F0/9
^C ! line con 0 exec-timeout 1440 0 privilege level 15 logging synchronous length 21 history size 30 transport input none line aux 0 line vty 0 4 exec-timeout 1440 0 privilege level 15 logging synchronous no login length 21 history size 30 transport input telnet ! end
R6#show isis da
IS-IS Level-1 Link State Database: LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL R5.00-00 0x0000002A 0x55C0 779 0/0/0 R6.00-00 * 0x00000029 0x15FB 719 0/0/0 R6.01-00 * 0x00000023 0x7C9E 635 0/0/0 R7.00-00 0x0000001C 0xA0FF 876 0/0/0 R7.01-00 0x00000014 0xC3F2 588 0/0/0 R8.00-00 0x0000001A 0xBFD9 588 0/0/0 IS-IS Level-2 Link State Database: LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL R2.00-00 0x0000002A 0x983B 825 0/0/0 R4.00-00 0x00000029 0xA801 509 0/0/0 R5.00-00 0x0000002D 0x4BBD 522 0/0/0 R6.00-00 * 0x0000002D 0x2C4A 514 0/0/0 R6.01-00 * 0x00000021 0x6E20 1071 0/0/0 R6#show clns nei
System Id Interface SNPA State Holdtime Type Protocol R7 Et0 00e0.1e5d.95b7 Up 9 L1 IS-IS R5 Et0 0000.0c3e.ab27 Up 26 L1 IS-IS R4 Se0 DLCI 604 Up 23 L1L2 IS-IS R5 Se0 DLCI 605 Up 23 L1L2 IS-IS R2 Se0 DLCI 601 Up 25 L1L2 IS-IS R6#show ip route Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area * - candidate default, U - per-user static route, o - ODR P - periodic downloaded static route
Gateway of last resort is not set
192.168.8.0/32 is subnetted, 1 subnets i L1 192.168.8.8 [115/20] via 172.16.136.7, Ethernet0 i L2 192.168.40.0/24 [115/10] via 172.16.100.4, Serial0 172.16.0.0/16 is variably subnetted, 4 subnets, 3 masks C 172.16.136.0/25 is directly connected, Ethernet0 C 172.16.56.4/30 is directly connected, Serial1 i L1 172.16.35.4/30 [115/20] via 172.16.136.7, Ethernet0 C 172.16.100.0/24 is directly connected, Serial0 192.168.4.0/32 is subnetted, 1 subnets i L2 192.168.4.4 [115/10] via 172.16.100.4, Serial0 192.168.5.0/32 is subnetted, 1 subnets i L1 192.168.5.5 [115/10] via 172.16.136.5, Ethernet0 192.168.6.0/32 is subnetted, 1 subnets C 192.168.6.6 is directly connected, Loopback0 192.168.7.0/32 is subnetted, 1 subnets i L1 192.168.7.7 [115/10] via 172.16.136.7, Ethernet0 192.168.2.0/32 is subnetted, 1 subnets i L2 192.168.2.2 [115/10] via 172.16.100.2, Serial0 R6#
R7# R7#sr Building configuration...
Current configuration : 2217 bytes ! version 12.2 no service single-slot-reload-enable no service timestamps debug uptime no service timestamps log uptime no service password-encryption service linenumber ! hostname R7 ! logging rate-limit console 10 except errors ! username user1 password 0 pass1 username user2 password 0 pass2 clock timezone CST -6 clock summer-time CDT recurring ip subnet-zero no ip finger ip tcp synwait-time 5 no ip domain-lookup ! no ip dhcp-client network-discovery ! ! ! ! interface Loopback0 ip address 192.168.7.7 255.255.255.255 ! interface Ethernet0 ip address 172.16.136.7 255.255.255.128 ip router isis isis circuit-type level-1 ! interface Serial0 ip address 172.16.35.5 255.255.255.252 ip router isis encapsulation ppp no peer neighbor-route no fair-queue service-module 56k clock source internal ppp quality 80 ppp authentication pap ppp pap sent-username user2 password 7 140713181F56 isis circuit-type level-1 ! interface Serial1 no ip address shutdown ! router isis passive-interface Loopback0 net 49.0001.0000.0000.0007.00 is-type level-1 area-password michael ! ip kerberos source-interface any ip classless no ip http server ! ! banner motd ^C
Router R7 - Cisco 2524 Interfaces S0 S1 E0
E0 connects to 3550 port F0/11 S0 connects to R8-S0
Use ubr924 voice router V2 on 3550 port F0/20
^C ! line con 0 exec-timeout 1440 0 privilege level 15 logging synchronous length 21 history size 30 transport input none line aux 0 exec-timeout 1440 0 privilege level 15 logging synchronous length 21 history size 30 line vty 0 4 exec-timeout 1440 0 privilege level 15 logging synchronous no login length 21 history size 30 transport input telnet ! end
R7#show isis dat
IS-IS Level-1 Link State Database: LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL R5.00-00 0x0000002A 0x55C0 492 0/0/0 R6.00-00 0x00000029 0x15FB 431 0/0/0 R6.01-00 0x00000024 0x7A9F 1145 0/0/0 R7.00-00 * 0x0000001C 0xA0FF 592 0/0/0 R7.01-00 * 0x00000015 0xC1F3 1067 0/0/0 R8.00-00 0x0000001B 0xBDDA 1125 0/0/0 R7#show clns nei
System Id Interface SNPA State Holdtime Type Protocol R8 Se0 *PPP* Up 24 L1 IS-IS R6 Et0 0000.0c4e.30ab Up 23 L1 IS-IS R5 Et0 0000.0c3e.ab27 Up 22 L1 IS-IS R7#show ip route Codes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGP i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area * - candidate default, U - per-user static route, o - ODR P - periodic downloaded static route
Gateway of last resort is not set
192.168.8.0/32 is subnetted, 1 subnets i L1 192.168.8.8 [115/10] via 172.16.35.6, Serial0 172.16.0.0/16 is variably subnetted, 2 subnets, 2 masks C 172.16.136.0/25 is directly connected, Ethernet0 C 172.16.35.4/30 is directly connected, Serial0 192.168.5.0/32 is subnetted, 1 subnets i L1 192.168.5.5 [115/10] via 172.16.136.5, Ethernet0 192.168.6.0/32 is subnetted, 1 subnets i L1 192.168.6.6 [115/10] via 172.16.136.6, Ethernet0 192.168.7.0/32 is subnetted, 1 subnets C 192.168.7.7 is directly connected, Loopback0 R7#
R8#si
Gateway of last resort is not set
C 192.168.8.8 is directly connected, Loopback0 i L1 172.16.136.0/25 [115/20] via 172.16.35.5, Serial0 C 172.16.35.4/30 is directly connected, Serial0 i L1 192.168.5.5 [115/20] via 172.16.35.5, Serial0 i L1 192.168.6.6 [115/20] via 172.16.35.5, Serial0 i L1 192.168.7.7 [115/10] via 172.16.35.5, Serial0 C 150.50.4.0 is directly connected, Ethernet0 R8#show isis mu R8#show isis da
IS-IS Level-1 Link State Database: LSPID LSP Seq Num LSP Checksum LSP Holdtime ATT/P/OL R5.00-00 0x0000002B 0x53C1 848 0/0/0 R6.00-00 0x0000002A 0x13FC 903 0/0/0 R6.01-00 0x00000024 0x7A9F 740 0/0/0 R7.00-00 0x0000001D 0x9E01 878 0/0/0 R7.01-00 0x00000015 0xC1F3 662 0/0/0 R8.00-00 * 0x0000001B 0xBDDA 723 0/0/0 R8#
-----Original Message----- From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of Michael Snyder Sent: 30 November 2003 20:58 To: ccielab@groupstudy.com Subject: Silly ISIS Question.
I have a bunch of Level 2 routers connected to some Level 1 routers, all in the same area. I assumed that the level one routers would get passed or figure it out for themselves that the level-1-2 neighbor should be their default route.
Guess I was thinking it would work like a ospf stub no summary or nssa area, with the abr passing the route.
How do does the level 1 routers decide to use their level 1-2 neighbor as a default route?
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