09-15-2008 06:43 AM - edited 03-03-2019 11:33 PM
Hello All,
In my experiment with EIGRP on a hub and spokes topology with three routers, i realized that once i configured one of the spokes to have neighbor (nei X.X.X.X int- name) relation with the hub, the second spoke is totally cut off from reaching even the hub's loopback address.
In order to ascertain what went wrong i went further to experiment the same on an Ethernet network, unfortunately i got the same result....have i done anything wrong or this is the normal behaviour of EIGRP?.
Unlike RIP where i was able to determined the types of updates on an interface by interface basis.
Your help to clarify my concerns shall be greatly appreciated.
Regards
09-15-2008 07:18 AM
No !!! this is not normal behaviour of EIGRP.
Definitely something is wrong with the configuration or interfaces.
Can you attach the config of all 3 routers. ??
09-15-2008 09:29 AM
Hello,
Thanks for the great response.
Here is the outputs as demanded. I hope it can help you to help me further?.
THE HUB ROUTER (R1)
interface Loopback0
ip address 1.0.0.1 255.0.0.0
interface Ethernet0/0
ip address 10.0.0.1 255.0.0.0
router eigrp 1
network 0.0.0.0
no auto-summary
neighbor 10.0.0.2 Ethernet0/0
THE SPOKE WITH NEIGHBORSHIP (R2)
interface Loopback0
ip address 2.0.0.2 255.0.0.0
interface Ethernet0/0
ip address 10.0.0.2 255.0.0.0
router eigrp 1
network 0.0.0.0
no auto-summary
neighbor 10.0.0.1 Ethernet0/0
THE SECOND SPOKE (R3)
interface Loopback0
ip address 3.0.0.3 255.0.0.0
!
interface FastEthernet0/0
ip address 10.0.0.3 255.0.0.0
router eigrp 1
network 0.0.0.0
no auto-summary
09-15-2008 09:57 AM
Hi newnetman,
Have you already tried adding this on the HUB router:
neighbor 10.0.0.3 Ethernet 0/0
Cheers:
Istvan
09-15-2008 11:21 AM
Hello Istan,
I did not add the neighbor statement on the hub for (R3) because that was exactly what i wanted to see the outcome of.
My aim was to see (R1)the hub send unicast update to (R2) while it send multicast update to (R3), as this was possible with RIP, isn't it possible with EIGRP?.
Thank you once again,
09-15-2008 01:01 PM
So what do we conclude here - when you configure a specific EIGRP neighbor and you include an interface name in the command, EIGRP then prevents that interface from forming dynamic neighborships? All other neighbors with Layer 2 connections through that same interface must be statically configured?
09-15-2008 01:16 PM
hello Sir,
Many thanks for clarifying my. I wonder then why the experimental question asked me to crate a neighborship with one of the spokes with the hub. Could that be to prevent the second spoke from the network, except for it directly connected interface to the hub?.
Thanks a million once again for the help
10-27-2008 11:41 AM
http://www.cisco.com/en/US/tech/tk365/technologies_q_and_a_item09186a008012dac4.shtml#ten
Note this part...
"The ideal behavior of this command is for EIGRP to start sending EIGRP packets as unicast packets to the specified neighbor, but not stop sending and receiving multicast packets on that interface. Since the command does not behave as intended, the neighbor command should be used carefully, understanding the impact of the command on the network."
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