From: Brian Dennis (bdennis@internetworkexpert.com)
Date: Thu Jul 06 2006 - 14:48:15 ART
You seem to not fully understand my reply so let me try to clarify it for you.
<quote>
RIP does not care if the other end point is down or not, if RIP does not receive the updates from a router on a point-to-point or multipoint interface, it has two timers that it will use to handle that situation, invalidation timer and Flush timer.
</quote>
Read what I said about the interface state. I'm not referring to any RIP timers. If you are receiving RIP updates on an interface and that interface goes down, the RIP timers you specified above do not actually come into play. The routes are immediately removed from the routing table not matter what value those timers are set to. See below:
Rack1R1#sho clock
*00:07:32.147 UTC Mon Mar 1 1993
Rack1R1#sho ip rout rip
150.1.0.0/24 is subnetted, 2 subnets
R 150.1.3.0 [120/1] via 10.1.1.3, 00:00:00, Serial0/1
Rack1R1#
*Mar 1 00:07:39.391: %LINK-3-UPDOWN: Interface Serial0/1, changed state to down
*Mar 1 00:07:39.391: is_up: 0 state: 0 sub state: 1 line: 0 has_route: True
*Mar 1 00:07:39.391: RT: del 150.1.3.0/24 via 10.1.1.3, rip metric [120/1]
*Mar 1 00:07:39.391: RT: delete subnet route to 150.1.3.0/24
*Mar 1 00:07:39.395: RT: NET-RED 150.1.3.0/24
*Mar 1 00:07:39.395: RT: NET-RED queued, Queue size 1
*Mar 1 00:07:39.395: RT: interface Serial0/1 removed from routing table
*Mar 1 00:07:39.395: RT: del 10.1.1.0/24 via 0.0.0.0, connected metric [0/0]
*Mar 1 00:07:39.395: RT: delete subnet route to 10.1.1.0/24
*Mar 1 00:07:39.395: RT: NET-RED 10.1.1.0/24
*Mar 1 00:07:39.395: RT: NET-RED queued, Queue size 2
*Mar 1 00:07:40.391: %LINEPROTO-5-UPDOWN: Line protocol on Interface Serial0/1, changed state to down
*Mar 1 00:07:40.391: is_up: 0 state: 0 sub state: 1 line: 0 has_route: False
Rack1R1#sho ip rout rip
Rack1R1#sho clock
*00:07:48.511 UTC Mon Mar 1 1993
Rack1R1#
As you can clearly see the RIP route (150.1.3.0/24) was removed from the routing table without involving the timers you mentioned above.
<quote>
There are two reasons that Cisco came up with this extension:
The periodic updates (every 30 seconds be default) can keep the circuit up, and the second reason is to cut down on the number of periodic updates even on a Point-to-point connections.
</quote>
Cisco did not come up with IP RIP triggered as it is defined in an RFC. What I did with my reply was add understanding as to why the restrictions are in place and not just saying because "Cisco said so" ;-)
HTH,
Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
bdennis@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987
Direct: 775-745-6404 (Outside the US and Canada)
From: Narbik Kocharians [mailto:narbikk@gmail.com]
Sent: Thursday, July 06, 2006 9:47 AM
To: Brian Dennis
Cc: Sami; ccielab@groupstudy.com
Subject: Re: RIP triggered
RIP does not care if the other end point is down or not, if RIP does not receive the updates from a router on a point-to-point or multipoint interface, it has two timers that it will use to handle that situation, invalidation timer and Flush timer.
There are two reasons that Cisco came up with this extension:
The periodic updates (every 30 seconds be default) can keep the circuit up, and the second reason is to cut down on the number of periodic updates even on a Point-to-point connections.
Its because of these two points that the command "ip rip triggered" is only available on the wan interfaces and it has nothing to do with neighbor down detection, it has provisions for that already. I am sorry but I have to disagree.
Narbik Kocharians
CCIE# 12410 (R&S, SP, Security)
CCSI# 30832
Network Learning, Inc. (CCIE class Instructor)
www.ccbootcamp.com (CCIE Training)
On 7/6/06, Brian Dennis <bdennis@internetworkexpert.com> wrote:
Think about it like this. If you run RIP triggered across a P2P serial
link and the remote end goes down, your local interface should also go
down. This will allow your local router to detect that the remote
router's routes should be removed from the routing table. Now if it's a
multipoint interface like Ethernet (more than one endpoint possible)
then if the remote router goes down, the Ethernet interface will not
normally go down assuming a hub or switch is being used. This means
that even though the remote router is down, its routes will not be
removed from your local router's routing table since you are not
expecting periodic updates and you can not determine based on the
interface state if the remote router is down.
HTH,
Brian Dennis, CCIE #2210 (R&S/ISP-Dial/Security)
bdennis@internetworkexpert.com
Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987
Direct: 775-745-6404 (Outside the US and Canada)
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Sami
Sent: Thursday, July 06, 2006 4:56 AM
To: ccielab@groupstudy.com
Subject: RIP triggered
Group,
ip rip triggered command is not under ethernet interface ? is there any
speific reason for not having it ?
R4(config)#int fastEthernet 0/0
R4(config-if)#ip rip ?
advertise Specify update interval
authentication Authentication control
receive advertisement reception
send advertisement transmission
v2-broadcast send ip broadcast v2 update
R4(config)#int s0/0/0
R4(config-if)#ip rip ?
advertise Specify update interval
authentication Authentication control
receive advertisement reception
send advertisement transmission
triggered enable rfc2091 triggered rip
v2-broadcast send ip broadcast v2 update
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