From: Prasad Shemrudkar (pshemrud) (pshemrud@cisco.com)
Date: Sat Aug 04 2007 - 13:44:21 ART
Hi Donghai,
I too think this will work, but from exam point of view, not sure how
good it is to use a dynamic routing protocol when not asked to!!
Just wanted to check if my logic was right and everyone was with me on
this one.
Prasad
________________________________
From: Donghai Zhang [mailto:zdh1207@gmail.com]
Sent: Saturday, August 04, 2007 7:12 PM
To: Prasad Shemrudkar (pshemrud)
Cc: Cisco certification
Subject: Re: OSPF default route
Dear Prasad,
I think you're right. the C route is indeed there even when BB1 is
disconncted.I think you could try another way. Since you need to make
sure BB1 is ACTIVE otherwise you would not advertise the default route.
So you have to let R1 know if BB1 is alive. There is a way to solve
this. Make a Rip between R1 and BB1, from which R1 should learn a
route(say,a Loopback address)from BB1.If the learned route
disappear,then R1 knows it lose the connection to BB1.Here is the
configuration:
R1
router rip
version 2
no auto
network 204.12.0.0
route-map RIP
match ip address 1
access-list 1 permit 3.0.0.0
router os 1
default-information originate route-map RIP
BB1
int loopback 1
ip add 3.3.3.3 255.255.255.0
router rip
version 2
no auto
network 3.0.0.0
network 204.12.0.0
------------------------------------------------------
Now you got what you want.
2007/8/4, Prasad Shemrudkar (pshemrud) <pshemrud@cisco.com>:
Hi,
I have a situation wherein there are 2 routers say R1 and BB1 connected
to a switch. The subnet is 204.12.1.0/24. R1 needs to conditionally
advertise a default route in ospf domain if it is CONNECTED to BB1. Now
I have used the following configuration on R1 but do not think its
correct (for the reason explained below the configuration).
router ospf 1
router-id 150.1.3.3
log-adjacency-changes
area 0 authentication message-digest
area 23 virtual-link 150.1.2.2
area 34 authentication
area 34 virtual-link 150.1.4.4
redistribute connected subnets route-map CONNECTED
redistribute rip subnets route-map RIP-->OSPF
network 191.1.13.3 0.0.0.0 area 13
network 191.1.23.3 0.0.0.0 area 23
network 191.1.34.3 0.0.0.0 area 34
default-information originate route-map DEFAULT
!
route-map DEFAULT permit 10
match ip address prefix-list BB1
!
ip prefix-list BB1 seq 10 permit 204.12.1.0/24
My point is, that since both router connect on Ethernet (via switch),
even if BB1 looses connectivity to the switch, the directly connected
route "C 204.12.1.0/24 <http://204.12.1.0/24> is directly
connected, Ethernet1/0" will still
be shown in R1's routing table (as that one is still connected) and
hence R1 will continue advertising the default route in OSPF even though
there is no connectivity between R1 and BB1.
I dunno but got a feeling, have a wrong logic as the solution has
configured it the same way too!!
Thanks in Advance,
Prasad
This archive was generated by hypermail 2.1.4 : Sat Sep 01 2007 - 11:32:09 ART