From: Paul Cocker (paul.cocker@inbox.com)
Date: Fri Nov 30 2007 - 23:07:08 ART
Hi all.
I've been looking at the next-hop feature in RIP, and am a little confused.
Using 3 routers in a hub and spoke fashion. Router 1 the hub, 2 & 3 as the
spokes.
At the hub, a multipoint subinterface, I've disabled split horizon.
Now, on one spoke I'm receiving routes from the other spoke, but with the
next hop set to an IP that I don't have layer 3 reachablity. (10.0.0.1 is
the hub, 10.0.0.3 the other spoke).
#sh ip route rip
R 1.0.0.0/8 [120/1] via 10.0.0.1, 00:00:10, Serial1/0
R 3.0.0.0/8 [120/2] via 10.0.0.3, 00:00:10, Serial1/0 < - - - this
one
Fair enough, I should have a mapping as follows,
frame-relay map ip 10.0.0.3 201
however, for fun(!), I thought that it would be possible to put a static
route to the hub as follows
ip route 10.0.0.3 255.255.255.255 10.0.0.1
I can now ping 10.0.0.3, however the recursive lookup doesn't appear to
happen for the 3.0.0.0 network, as per below.
ping 3.0.0.3 repeat 1
Type escape sequence to abort.
Sending 1, 100-byte ICMP Echos to 3.0.0.3, timeout is 2 seconds:
*Mar 1 00:57:19.491: IP: tableid=0, s=10.0.0.2 (local), d=3.0.0.3
(Serial1/0), routed via RIB
*Mar 1 00:57:19.491: IP: s=10.0.0.2 (local), d=3.0.0.3 (Serial1/0), len
100, sending
*Mar 1 00:57:19.495: IP: s=10.0.0.2 (local), d=3.0.0.3 (Serial1/0), len
100, encapsulation failed.
I would expect a recursive lookup to happen as per below..
#sh ip route 3.0.0.3
Routing entry for 3.0.0.0/8
Known via "rip", distance 120, metric 2
Redistributing via rip
Last update from 10.0.0.3 on Serial1/0, 00:00:23 ago
Routing Descriptor Blocks:
* 10.0.0.3, from 10.0.0.1, 00:00:23 ago, via Serial1/0
Route metric is 2, traffic share count is 1
#sh ip route 10.0.0.3
Routing entry for 10.0.0.3/32
Known via "static", distance 1, metric 0
Routing Descriptor Blocks:
* 10.0.0.1
Route metric is 0, traffic share count is 1
sh ip route 10.0.0.1
Routing entry for 10.0.0.0/8
Known via "connected", distance 0, metric 0 (connected, via interface)
Redistributing via rip
Advertised by rip
Routing Descriptor Blocks:
* directly connected, via Serial1/0
Route metric is 0, traffic share count is 1
sh frame-relay map | inc 10.0.0.1
Serial1/0 (up): ip 10.0.0.1 dlci 201(0xC9,0x3090), static,
But I guess I'm missing a concept here. Hope that the above is clear? Any
ideas?
Thanks,
Paul
This archive was generated by hypermail 2.1.4 : Sat Dec 01 2007 - 06:37:32 ART