From: Frank Liang (liangfrank@xxxxxxxxxxx)
Date: Sun Feb 04 2001 - 12:26:05 GMT-3
Hi Jay,
be aware that 192.168.10.8/29 is not in part of the same major net as your
IGRP interface (which is 192.168.1.0/24) at R1. So IGRP will advertise it as
192.168.10.0/24, using the same mask as its IGRP interface.
Frank
>From: Jay Chandradas <jachandr@cisco.com>
>Reply-To: Jay Chandradas <jachandr@cisco.com>
>To: <ccielab@groupstudy.com>
>Subject: VLSM question
>Date: Sun, 04 Feb 2001 02:22:33 -0800
>
>Hi all,
>
>I am trying a VLSM and classful routing prot. issue. I am little confused
>when I tried in my set up. Can u help me?
>
>set up :
>
>
>
>R2 -------------------------------------------------------------
>R1------------------------------------------------------R3 networks
>included : 192.168.10.0/20
> ( IGRP 192.168.1.0/24 IGRP ) (
>ospf 192.168.5.0/24 ospf)
>192.168.2.0/27
>
>
>my aim is to ping the vlsm networks from R2, which is running only IGRP. I
>thought R2 will not be able to ping 192.168.10.9 ( with a mask /29) . I was
>trying to put a defalut network statement in R1 , thinking it will
>propagate the default route to the down stream router R2. and it did. Then
>I removed the default network statement from R1. But still I am able to
>ping the vlsm networks from R2. Am I missing something here?.. I will show
>the routing table for all the three routers for clarity.
>
>i know that for IGRP, if the route is a part of same major net as the
>interface but has a different mask , IGRP does not advertise the route out
>the interface- why is R1 advertizing the vlsm routes to R2?
>
>
>router2#sh 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, * - candidate
>default
> U - per-user static route, o - ODR
>
>Gateway of last resort is not set
>
>I 192.168.10.0/24 [100/8576] via 192.168.1.1, 00:00:33, Serial0
>I 192.168.5.0/24 [100/10476] via 192.168.1.1, 00:00:33, Serial0
>I 10.0.0.0/8 [100/8576] via 192.168.1.1, 00:00:33, Serial0
>C 193.168.1.0/24 is directly connected, Ethernet0
>C 192.168.1.0/24 is directly connected, Serial0
>I 192.168.2.0/24 [100/8576] via 192.168.1.1, 00:00:33, Serial0
>router2#ping 192.168.10.9
>
>Type escape sequence to abort.
>Sending 5, 100-byte ICMP Echos to 192.168.10.9, timeout is 2
>seconds: <------------------------------------ PINGS !!! I thought
>wthout a default route it will not ping.
>!!!!!
>Success rate is 100 percent (5/5), round-trip min/avg/max = 68/68/68 ms
>router2#
>
>router1#sh ip r
>09:50:52: %SYS-5-CONFIG_I: Configured from console by consoleoute
>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, * - candidate
>default
> U - per-user static route, o - ODR
>
>Gateway of last resort is not set
>
> 192.168.10.0/29 is subnetted, 1 subnets
>O 192.168.10.8 [110/65] via 192.168.5.3, 00:14:04,
>Serial0 <-----------------------------192.168.10.0 is
>having 1 /29 bit mask.
>C 192.168.5.0/24 is directly connected, Serial0
>O E2 10.0.0.0/8 [110/100] via 192.168.5.3, 00:14:04, Serial0
>I 193.168.1.0/24 [100/8576] via 192.168.1.2, 00:00:20, Serial1
>C 192.168.1.0/24 is directly connected, Serial1
> 192.168.2.0/27 is subnetted, 1 subnets
>O 192.168.2.32 [110/74] via 192.168.5.3, 00:14:04, Serial0
>router1#
>router3#
>09:51:19: %SYS-5-CONFIG_I: Configured from console by consolesh 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, * - candidate
>default
> U - per-user static route, o - ODR
>
>Gateway of last resort is not set
>
> 192.168.10.0/29 is subnetted, 1 subnets
>C 192.168.10.8 is directly connected, Loopback10
>C 192.168.5.0/24 is directly connected, Serial1
>C 10.0.0.0/8 is directly connected, Loopback1
>O E2 193.168.1.0/24 [110/100] via 192.168.5.1, 00:14:38, Serial1
>O E2 192.168.1.0/24 [110/100] via 192.168.5.1, 00:14:38, Serial1
> 192.168.2.0/27 is subnetted, 1 subnets
>C 192.168.2.32 is directly connected, Ethernet0
>router3#
>
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