Load balance 2 Cisco 2600

[dphantom]

Got a situation I've been thrown into. I am not a Cisco guy, but can move around the CLI ok adn do basic admin type stuff.

Have a company with 2 26xx routers each with a T-1 to the Internet. Company wants to load balance the routers so load is distributed evenly across both T-1s.

Not sure yet what IOS they have but believe it is 12.2 or 12.3. Can anyone point me in the right direction to get started. Did do some searching and found GLBP. Having never done this, I certainly want to tread carefully.

Any help much appreciated.

 

[spidey07]

Just use BGP. *snicker*

Otherwise you could put a two static routes on the one used as the default gateway for hosts - one to the Internet and the other to the other router. This is cludgy though and you'll need to turn of ICMP redirects.

Use GLBP but it's not going to "really distribute the load" because if one host sends a ton of data it's always going to a single router.

Or if you have a firewall behind your border routers, put two default routes on that and you'll achieve some amount of load balancing.

hope this helps

-edit-
And you need to explain to them that they'll never see the load evenly distributed unless they do per-packet routing which is generally a bad idea because it leads to assymetrc routing. I've seen this all the time, people want to see the load perfectly shared without understanding that it's not really possible unless you use multilink PPP or IMA - each of which will have will have to be supported by the provider and the router on your end.

 

[dphantom]

Thanks, Spidey. I thought I was on the right track. I do understand GLBP isn't true load balancing, but in most cases is probably close enough.

The config I would use should look like this??

interface fastethernet 0/0
ip address 10.10.8.30 255.255.255.0
glbp 10 ip 10.10.8.10

The virtual gateway being .10.

edit:
Another question. As this is now the virtual gateway, does that mean I need to change the gateway configuration on my Windows 2000/XP clients as well? Or does the existing gateway stay and the virtual gateway just internal to the routers to handle GLBP?

 

[randal]

If they are going to the same ISP, stick an additional wic in one of the routers and run 1) MLPPP or 2) CEF + multiple default routes. Very easy to do either.

 

[dphantom]

Originally posted by: randal
If they are going to the same ISP, stick an additional wic in one of the routers and run 1) MLPPP or 2) CEF + multiple default routes. Very easy to do either.

And that I have done (MLPPP) before but is not an option in this case. Not my decision, but they want some measure of redundancy besides the load balance part with the second router.

 

[Cooky]

Another approach I've seen is use HSRP on the two routers, one being the active, which does policy routing.
You'd split the Internet into half (excuse my language, I know some of you get irritated when people use the word Internet inappropriately), each router handles each half.
#1 0.0.0.0 - 127.255.255.255
#2 128.0.0.0 - 255.255.255.255

This is kinda stupid, and doesn't really achieve real load balancing, but once again w/o BGP, your options are very limited.

 

[dphantom]

Thanks everyone for the input.

One last question and that concerns the virtual gateway for GLBP. Since the 2 routers will have a virtual gateway on the ethernet port now, does that entail a change on the client devices to use the new virtual gateway?

 

[spidey07]

just make the virtual IP the address the clients are using now.

 

[dphantom]

I understand. Thanks again for your help Spidey.

 

[Goosemaster]

ripv2