Have two data T's, want to load balance with a Cisco 1720

[johnnyice]

Have two full data T's. I want load balance the circuits to yield 3meg for our internet connection. I have a cisco 1720 with two Wics. Serial0 is current active with the first T. I read some info on Multilink but can't find a sample config to use with the valid commands to implement this feature.

If there is a better way or someone has a working config that I can use, please send it my way.

Thanks,

John Nikirk
All Network Systems
jnikirk@allnetsys.com

 

[fmonteiro]

Suppose you have the currently active T with the address, let's say, 172.16.1.1/30 and that you have a default route pointing to the other end of the link:
ip route 0.0.0.0 0.0.0.0 172.16.1.2

Just add the second link, let's say, with the address 172.16.2.1/30. Add a second default ip route:
ip route 0.0.0.0 0.0.0.0 172.16.2.2

That's all! Traffic to the default gateway will be load-balanced between the two circuits.

 

[routerman]

The way I've done on HDLC links is to use unnumbered WAN linksm tying both to the same loopback locally.

Then apply 2 equal cost routes, one point down each serial interface.

int lo0
ip addr 1.2.3.4 255.255.255.255

int s0/0
ip unnumberd lo0

int s0/1
ip unnumbered lo0

ip route 0.0.0.0 0.0.0.0 s0/0
ip route 0.0.0.0 0.0.0.0 s0/1

Dont expect identical traffic counters, depending on the switching mechanism running in the router (fast switch, CEF etc) you will get either per packet or per session load sharing.

 

[dx1]

For MLPPP, you will need to check with your ISP to see if they support it. See sample config below:

interface multilink 1
ip address xxx.xxx.xxx.xxx
ppp multilink
multilink group 1

Do this for both serial int:
int s0
no ip address
encaps ppp
ppp multilink
multilink group 1

Here's a link to Cisco's site that explains other alternatives:

http://www.cisco.com/en/US/products/hw/modules/ps2033/products_white_paper09186a0080091d4b.shtml