Load Balancing 2 T1s with 2 routers

I have two 3845 routers with IOS version 12.4(2)T1. The T1s are connected to a private MPLS cloud used by my company for remote sites. On the LAN side of the routers, HSRP is employed with one of the routers, called RTR01 used as primary, with the other, RTR02 as secondary for failover. On the WAN side, the routers broadcast EIGRP for LAN-connected subnets. Originally, all traffic flowed in and out of RTR01's T1 and RTR02 had no load. EIGRP was setup so that RTR01 had a better metric for Static (we use heavy weighted static routes to our dialup router when the MPLS connection goes down at a remote site) as follows: On RTR01 router eigrp 100 redistribute static 1500 10 255 1 1500 On RTR02 router eigrp 100 redistribute static 1000 10 255 1 1500 In an attempt to balance traffic across the two T1s and the two routers, I set the metric to "1500 10 255 1 1500". Now after the change, all incoming traffic flows through the T1 on RTR01 and all outbound traffic flows on the T1 out RTR02. Unfortunately, I am losing bandwidth by not having both incoming and outgoing traffic across the two T1s and routers. What is the next step? I am a little lost as to why the network would work this way when two routes are being given. Should I try it without any metrics and hope that it balances properly? Thanks.

Reply to
russianj
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For outbound, take a look at GLBP - Gateway Load Balancing Protocol

For inbound, ask You provider if they can support EIBGP load balancing (note the EIBGP part - it is important)

Reply to
Merv

The scenario that you are talking about, I believe, is to attempt to load balance the individual packets. That is not necessarily what I am going for. Currently, if I fill up either of the two T1s, the additional traffic that attempts to go across does not get balanced to the additional T1s. That is more specifically the problem. If I understand EIGRP correctly, then if metrics are not specified, then as connections use up bandwidth on one of the T1s, then the metric for the other T1 will be more favorable, and traffic will go through the second T1 accordingly. That is how EIGRP is designed to work, correct?

Reply to
russianj

nope

the default value for the "k" variables are K1=1, K2 =0, K3=1,K4=0, K5=0

so link load does not come into play

the bandwidth referred to in metric calcluation is a fix value of the interface bandwidth - it is not dynamic link utilization

Reply to
Merv

Forgot to mention that K2, K4 and K5 were meaning for IGRP which used periodic updates

They are not useful for EIGRP for which updates are event driven

Reply to
Merv

I would rather not change to BGP if at all possible. I will speak with our provider, but a change in routing protocol would necessitate changing every router in remote locations as well to speak BGP. CEF does load balancing across interfaces, so maybe that is more the scenario that I am thinking of in this case. Can CEF work across more than one router? Thanks for clearing this up.

Reply to
russianj

I just thought that CEF comment through. Please ignore that comment. Thanks.

Reply to
russianj

Suggest starting with GLBP for outbound traffic and go from there

Reply to
Merv

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