05-05-2003 01:17 AM - edited 03-02-2019 07:06 AM
Hi,
We have a two catalyst 4000 IOS ver 12.1(8a) connected to two 7204 router. The two routers and switches are connected in a full mesh configuration. To reach a destination x.x.x.x I can see four equal cost paths in the switch routing table. Now how can I do a load sharing/balacing among these four paths so that all the four paths are utilised efficiently. I am running OSPF in my catalyst switch. The two routers are running EIGRP.
Does it help if I configure CEF?
Thanks and Best Regards,
Raj.
05-05-2003 01:57 PM
if you see 4 routes for each destination it means the router is already loadbalancing the traffic.
Enabling CEF will just help you select what type of loadbalancing you want.
We have per-packet or per-destination.
The command is 'ip load [per-packet|per-destination]'
Gilles.
05-05-2003 05:55 PM
Hi Giles,
Thanks for the info. Just to clarify some points.
I had that in my mind what you said "ip load [per-packet|per-destination]". I read a cisco doc which says perpacket load balancing is not possible in L3 switching. So does catalyst 4000 support per packet load balancing.
The reason I ask this because we have two links connected to two routers for destination X. I find all the traffic is passing via link-1. But link-2 is under utilized, I want to share the load across the two links.
I have captured the route for one particular subnet from both the switches.
Switch-1>sh ip rou 10.192.0.0 255.255.0.0
Routing entry for 10.192.0.0/16
Known via "ospf 123", distance 110, metric 20
Tag 888, type extern 2, forward metric 1
Last update from 10.197.1.18 on Vlan6, 4d08h ago
Routing Descriptor Blocks:
10.197.1.10, from 192.168.197.18, 4d08h ago, via Vlan5
Route metric is 20, traffic share count is 1
* 10.197.1.18, from 192.168.197.18, 4d08h ago, via Vlan6
Route metric is 20, traffic share count is 1
10.197.1.9, from 192.168.201.13, 4d08h ago, via Vlan5
Route metric is 20, traffic share count is 1
10.197.1.17, from 192.168.201.13, 4d08h ago, via Vlan6
Route metric is 20, traffic share count is 1
switch-2>sh ip rou 10.192.0.0 255.255.0.0
Routing entry for 10.192.0.0/16
Known via "ospf 123", distance 110, metric 20
Tag 888, type extern 2, forward metric 1
Last update from 10.197.1.18 on Vlan6, 4d08h ago
Routing Descriptor Blocks:
10.197.1.10, from 192.168.197.18, 4d08h ago, via Vlan5
Route metric is 20, traffic share count is 1
* 10.197.1.18, from 192.168.197.18, 4d08h ago, via Vlan6
Route metric is 20, traffic share count is 1
10.197.1.9, from 192.168.201.13, 4d08h ago, via Vlan5
Route metric is 20, traffic share count is 1
10.197.1.17, from 192.168.201.13, 4d08h ago, via Vlan6
Route metric is 20, traffic share count is 1
From the route statements we see both the active routes point to the Vlan6. Is it possible to have each switches goes to different vlans (5 &6).
If I configure Ip load per packet does it help? I guess I can configure this only on Vlan interface level. So do I have to configure for all Vlan's.
Thanks for your comments.
Best Regards,
Raj.
07-21-2003 12:47 PM
We are having the same problem with our 4006 switches w/ the layer 3 card. We see 4 equal cost routes(2 ethernets per router), however one router gets considerably more traffic than the other. We are currently doing process switching with the no ip route-cache.
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide