02-20-2009 01:09 PM - edited 03-04-2019 03:40 AM
I am working in Netsim, and have 4 routers. I am trying to get RIP working.
Router 1= corp router = s0/0 10.1.1.1, s0/1 10.1.2.1, s0/2 10.1.3.1
Router 2= branch router s0/0 10.1.1.2, e1/0 10.1.5.1, e1/1 10.1.6.1
Router 3= branch router s0/0 10.1.2.2, e1/0 10.1.7.1, e1/1 10.1.8.1
Router 4= branch router s0/0 10.1.3.2
I used the following commands on all routers:
rip router
network 10.0.0.0
When I do a sh ip route...no rip routes.
Below are two excerpts:
Corp router:
interface Serial0/0
ip address 10.1.1.1 255.255.255.0
no ip directed-broadcast
clock rate 64000
!
interface Serial0/1
ip address 10.1.2.1 255.255.255.0
no ip directed-broadcast
clock rate 64000
!
router rip
network 10.0.0.0
Gateway of last resort is not set
10.0.0.0/24 is subnetted, 4 subnets
C 10.1.1.0 is directly connected, Serial0/0
C 10.1.4.0 is directly connected, Serial0/3
C 10.1.2.0 is directly connected, Serial0/1
C 10.1.3.0 is directly connected, Serial0/2
Branch router1:
interface Serial0/0
ip address 10.1.1.2 255.255.255.0
no ip directed-broadcast
!
!
interface Ethernet1/0
ip address 10.1.5.1 255.255.255.0
no ip directed-broadcast
!
interface Ethernet1/1
ip address 10.1.6.1 255.255.255.0
no ip directed-broadcast
router rip
network 10.0.0.0
10.0.0.0/24 is subnetted, 4 subnets
C 10.1.5.0 is directly connected, Ethernet1/0
C 10.1.6.0 is directly connected, Ethernet1/1
C 10.1.1.0 is directly connected, Serial0/0
C 10.1.4.0 is directly connected, Serial0/1
02-20-2009 01:26 PM
You are experiencing the split-horizon rule.
All the subnets you mentioned are the same in their classful nature so the router won't accept advertisement it already knows about.
If you can fix this problem by going with version 2 under RIP and enable no auto-summary
__
Edison.
02-20-2009 01:26 PM
You need to configure "version 2" in router configuration mode.
RIP version 1 doesn't support variable-length subnet masking. The RIP process on each of your routers is therefore only reporting network 10.0.0.0. Since each router already has this network, with a)longer masks/prefixes and b)lower administrative distance (directly connected vs RIP); they won't place any of RIP's info into their routing tables.
Set each one up for RIPv2 and you should be in better shape.
(please remember to rate helpful posts)
02-20-2009 01:57 PM
Edison
I do not see how you analyze this as a split horizon issue. In the original post it is pretty clear that the Branch router is connected via its serial to the Corp router. And the Branch router has 2 subnets on its Ethernet interfaces that match the RIP network statement. So how does split horizon prevent the Branch from advertising its Ethernet subnets over the serial interface?
Seth
How do you analyze this as a variable length subnet issue. In the original post it is pretty clear that all subnets are 255.255.255.0. All are the same length and not variable.
I am not clear what the problem is, but I do not believe that it is either split horizon or VLSM.
I would like to see a more complete configuration of these router to try to identify what the issue is. I would also like to see the output of show cdp neighbor detail to verify that the routers are connected as the original post suggests that they are. And the output of show ip protocol would also be helpful.
HTH
Rick
02-20-2009 02:07 PM
Hmmm, yes I suppose they are all 24-bit masks. I shoulda looked more closely at the configs.
But you are right, we need more info on the configs as well as on the layer 2 state of things.
02-20-2009 02:42 PM
Ok guys, here is the config from the Corp router and one of the branch routers. You are correct there is two subnets off the branch router (10.1.5.0/24, 10.1.6.0/24).
Please note this is in Netsim.
************************
Corp router
**********************
corprouter#sh run
Building configuration...
!
Version 12.1
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname corprouter
!
!
!
!
ip subnet-zero
!
!
!
!
!
!
!
!
!
interface Serial0/0
ip address 10.1.1.1 255.255.255.0
no ip directed-broadcast
clock rate 64000
!
interface Serial0/1
ip address 10.1.2.1 255.255.255.0
no ip directed-broadcast
clock rate 64000
!
interface Serial0/2
ip address 10.1.3.1 255.255.255.0
no ip directed-broadcast
clock rate 64000
!
interface Serial0/3
ip address 10.1.4.1 255.255.255.0
no ip directed-broadcast
clock rate 64000
!
interface Ethernet1/0
no ip address
no ip directed-broadcast
shutdown
!
interface Ethernet1/1
no ip address
no ip directed-broadcast
shutdown
!
interface Ethernet1/2
no ip address
no ip directed-broadcast
shutdown
!
interface Ethernet1/3
no ip address
no ip directed-broadcast
shutdown
!
!
router rip
network 10.0.0.0
!
!
!
ip classless
no ip http server
!
!
!
!
!
line con 0
transport input none
line aux 0
line vty 0 4
!
no scheduler allocate
end
*********************
BRANCH ROUTER
*********************
Router#SH RUN
Building configuration...
!
Version 12.1
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname Router
!
!
!
!
ip subnet-zero
!
!
!
!
!
!
!
!
!
interface Serial0/0
ip address 10.1.1.2 255.255.255.0
no ip directed-broadcast
!
interface Serial0/1
ip address 10.1.4.2 255.255.255.0
no ip directed-broadcast
!
interface Serial0/2
no ip address
no ip directed-broadcast
shutdown
!
interface Serial0/3
no ip address
no ip directed-broadcast
shutdown
!
interface Ethernet1/0
ip address 10.1.5.1 255.255.255.0
no ip directed-broadcast
!
interface Ethernet1/1
ip address 10.1.6.1 255.255.255.0
no ip directed-broadcast
!
interface Ethernet1/2
no ip address
no ip directed-broadcast
shutdown
!
interface Ethernet1/3
no ip address
no ip directed-broadcast
shutdown
!
!
router rip
network 10.0.0.0
!
!
!
ip classless
no ip http server
!
!
!
!
!
line con 0
transport input none
line aux 0
line vty 0 4
!
no scheduler allocate
end
________________________________
From the Corp router I can ping:
10.1.1.2
From the branch router I can ping:
10.1.1.1
10.1.5.1
10.1.6.1
10.1.5.11 (one of the PC's)
________________________
******************
CORP ROUTER
******************
corprouter#SH IP ROUTE
Gateway of last resort is not set
10.0.0.0/24 is subnetted, 4 subnets
C 10.1.1.0 is directly connected, Serial0/0
C 10.1.4.0 is directly connected, Serial0/3
C 10.1.2.0 is directly connected, Serial0/1
C 10.1.3.0 is directly connected, Serial0/2
**********************
BRANCH ROUTER
**********************
Router#sh ip route
Gateway of last resort is not set
10.0.0.0/24 is subnetted, 4 subnets
C 10.1.5.0 is directly connected, Ethernet1/0
C 10.1.6.0 is directly connected, Ethernet1/1
C 10.1.1.0 is directly connected, Serial0/0
C 10.1.4.0 is directly connected, Serial0/1
02-20-2009 05:56 PM
But from the corp router you can't ping 10.1.2.1 or 10.1.3.1?
So far you've only verified layer 2 connectivity to Router 2. What about the other branch routers?
Can you give us the output of "show ip rip database" on the corp router?
02-20-2009 06:29 PM
Yes. I can ping all the branch routers from the corp router.
I cannot however ping any networks connected via the branch routers.
"sh ip rip database" is not available in netsim.
If I add a static route to 10.1.5.1 on the corp router. They are able to ping each other.
02-20-2009 06:34 PM
The configs as posted look ok and I would expect RIP to be advertising the subnets. If the route tables are not showing that I wonder if there is some aspect of netsim that we are encountering. Perhaps the output of show ip interface brief and the output of show ip protocol might shed some light on this.
HTH
Rick
02-20-2009 08:57 PM
Here is the output. - Thanks for your help.
**************
Corp Router
**************
Interface IP-Address OK? Method Status Protocol
Serial0/0 10.1.1.1 YES unset up up
Serial0/1 10.1.2.1 YES unset up up
Serial0/2 10.1.3.1 YES unset up up
Serial0/3 10.1.4.1 YES unset up up
Ethernet1/0 unassigned YES unset administratively down down
Ethernet1/1 unassigned YES unset administratively down down
Ethernet1/2 unassigned YES unset administratively down down
Ethernet1/3 unassigned YES unset administratively down down
Routing Protocol is "rip"
Sending updates every 30 seconds, next due in 28 seconds
Invalid after 180 seconds, hold down 180, flushed after 240
Outgoing update filter list for all interfaces is
Incoming update filter list for all interfaces is
Redistributing: rip
Default version control: send version 1, receive any version
Interface Send Recv Key-chain
Serial0/0 1 1 2
Serial0/1 1 1 2
Serial0/2 1 1 2
Serial0/3 1 1 2
Routing for Networks:
10.0.0.0
Routing Information Sources:
10.1.2.2 120 00:00:03
10.1.1.2 120 00:00:015
Distance: (default is 120)
***************
Branch Router
***************
Router#sh ip int brief
Interface IP-Address OK? Method Status Protocol
Serial0/0 10.1.2.2 YES unset up up
Serial0/1 unassigned YES unset administratively down down
Serial0/2 unassigned YES unset administratively down down
Serial0/3 unassigned YES unset administratively down down
Ethernet1/0 10.1.7.1 YES unset up up
Ethernet1/1 10.1.8.1 YES unset up up
Ethernet1/2 unassigned YES unset administratively down down
Ethernet1/3 unassigned YES unset administratively down down
Router#sh ip protocol
Routing Protocol is "rip"
Sending updates every 30 seconds, next due in 29 seconds
Invalid after 180 seconds, hold down 180, flushed after 240
Outgoing update filter list for all interfaces is
Incoming update filter list for all interfaces is
Redistributing: rip
Default version control: send version 1, receive any version
Interface Send Recv Key-chain
Serial0/0 1 1 2
Ethernet1/0 1 1 2
Ethernet1/1 1 1 2
Routing for Networks:
10.0.0.0
Routing Information Sources:
10.1.2.1 120 00:00:06
Distance: (default is 120)
02-20-2009 09:46 PM
could you try to issue the no auto-summary command under the rip process on each router?
router(config)#router rip
router(config-router)#no auto-summary
by default, rip will summarize networks to its classful boundary. in your config, the 10.0.0.0 network would be advertised using a subnet mask of 255.0.0.0. this goes against your config on each router interface which has a subnet mask of 255.255.255.0. give it a try.
02-21-2009 10:52 AM
John, I also thought that was the problem, till rburts pointed out that all routers have the same subnet mask. RIPv1 effectively supports a non-classful mask as long as the mask is the same length on all interfaces.
I recreated the op's issue in my lab, with actual 2500 routers, and the 24-bit Ethernet subnets (loopbacks in my lab) were reported to a RIP neighbor, over a separate point-to-point link, just fine. I confirmed both routers were running RIP verion 1.
So it really does look more like a netsim issue than a configuration one.
02-21-2009 08:21 AM
Thanks for the additional information. I do not see anything in it that really points to what the problem is. I do see something that I believe is significant. From the output of show ip protocol from the Corp router:
Routing Information Sources:
10.1.2.2 120 00:00:03
10.1.1.2 120 00:00:015
This indicates that it has received a RIP update from the branch router at 10.1.1.2. If it has received a RIP update then why are there no RIP routes in its routing table?
I do note that the branch router does not report receiving a RIP update from the Corp router.
I am not familiar with netsim and how it deals with certain aspects of routing but I am coming to feel that we are dealing with some problem in netsim rather than a problem with the config.
HTH
Rick
02-21-2009 01:35 PM
Thanks for verifying that. I didn't see anything wrong based on my limited knowledge, but wanted to double-check with some of you pros.
This site is just incredible.
Thanks again for all of your time and effort.
K
Find answers to your questions by entering keywords or phrases in the Search bar above. New here? Use these resources to familiarize yourself with the community: