I wanted to test whether the holddown timers of RIP work. The all in one
CCIE guide say that hold-down timers in RIP are not used by default.
EXPERIMENT :
I setup p1-r1, and p1-r3 with RIP using the Default timers:
Configuration on p1-r1 was: (router rip, network 10.0.0.0)
Configuration on p1-r3 was (router rip, network 10.0.0.0)
diagram:
(s1)
.
.
(s3)...p1-r1..(s2).......(s0)..p1-r3..(s1).........
.
.(s0)
OBSERVATIONS:
Part I: At 8:46 p1-r1 knows about network 10.1.100.0/24
Part II: At 8:47 serial 1 is shut on router p1-r3. p1-r3
sends a poisoned route to p1-r1 via s0
Part III: 10 seconds later I check the routing table and the route to
10.1.100 was already GONE!
CONCLUSION: It looks like the holddown timers did not kick in!
I am puzzled. When doing a show ip protocols, I do have holddown timers set
to 180 seconds!
Can someone explain?
DATA:
------------------------Part I-------------------------------------------
Jan 28 08:46:59: subnet 10.1.100.0 metric 2
p1-r1#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, 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
10.0.0.0/8 is variably subnetted, 6 subnets, 2 masks
S 10.0.0.2/32 is directly connected, Serial3
C 10.1.3.0/24 is directly connected, Serial2
C 10.1.2.0/24 is directly connected, Serial1
C 10.1.1.0/24 is directly connected, Serial0
C 10.1.0.0/24 is directly connected, Serial3
R 10.1.100.0/24 [120/1] via 10.1.3.2, 00:00:09, Serial2
p1-r1#
R0>3
------------------------Part II--------------------------------------------
p1-r3(config-if)#shut
p1-r3(config-if)#
R0>1
[Resuming connection 1 to p1-r1 ... ]
Jan
Jan 28 08:47:17: RIP: received v1 update from 10.1.3.2 on Serial2
Jan 28 08:47:17: 10.1.100.0 in 16 hops (inaccessible)
p1-r1#
Jan 28 08:47:19: RIP: sending v1 flash update to 255.255.255.255 via Serial0
(10.1.1.1)
Jan 28 08:47:19: RIP: build flash update entries
Jan 28 08:47:19: subnet 10.1.100.0 metric 16
Jan 28 08:47:19: RIP: sending v1 flash update to 255.255.255.255 via Serial1
(10.1.2.1)
Jan 28 08:47:19: RIP: build flash update entries
Jan 28 08:47:19: subnet 10.1.100.0 metric 16
Jan 28 08:47:19: RIP: sending v1 flash update to 255.255.255.255 via Serial2
(10.1.3.1)
Jan 28 08:47:19: RIP: build flash update entries
Jan 28 08:47:19: subnet 10.1.100.0 metric 16
Jan 28 08:47:19: RIP: sending v1 flash update to 255.255.255.255 via Serial3
(10.1.0.2)
p1-r1#
Jan 28 08:47:19: RIP: build flash update entries
Jan 28 08:47:19: subnet 10.1.100.0 metric 16
------------------------ Part III ----------------------------------
Jan 28 08:47:28:
p1-r1#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, 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
10.0.0.0/8 is variably subnetted, 5 subnets, 2 masks
S 10.0.0.2/32 is directly connected, Serial3
C 10.1.3.0/24 is directly connected, Serial2
C 10.1.2.0/24 is directly connected, Serial1
C 10.1.1.0/24 is directly connected, Serial0
C 10.1.0.0/24 is directly connected, Serial3
p1-r1#
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=33426&t=33426
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