Load Sharing / Balancing on multiple routes 1

[Guest_imported]

I have a Serial interface and a Bri interface on a 2610 router at my remote sites. I use the Bri as a backup for the Serial link.

I also want to use the Bri for 'top-up' to provide additional bandwidth to my connection to my central site when the serial link gets congested. I configured the backup load command for this. "backup load 80 50" . This works but I have problem balancing the traffic over the two active links.

I am running RIP and tried this with EIGRP as well. What happens is that the transmit traffic goes over one link(SERIAL) and receive over the other link (BRI). I suppose this is a form of load sharing/ balancing but this actually is not very effective if for instance there is a bigger load of transmit traffic (e.g FTP from remote to central site) than a receive load. The result is the transmit traffic is still quite slow despite the route on the BRI also being up, which is also an unnecessary cost for the company.

Is there a way to truly load balance the traffic on these two active links (half tx and rx on Serial(64K), and half rx and tx on BRI(64K))

 

[jeter]

ppp multilink may be your answer . you will have to set up multilink groups and a ppp mutlilink interface , however this should work . Go to Cisco.com and search on ppp multilink, Good Luck !!!

 

[AllenTech]

I forgot to mention that we use frame-relay encapsulation on our serial links and ppp on our bri so unfortunately we cannot use ppp multilink as this works with ppp encapsulation only.

 

[jeter]

ok then, I wonder if you can get away with equal cost load balancing using static
routes ? The routers assume that all routes have the same bandwidth regardless
of what the actual bandwidth . Therefore, the router distributes the outgoing traffic
among multiple routes equally. You will have to set up 2 ip routes on both routers .
If you can go this route make sure that ip route-cache is active for per destination ,
with this active is does not perform a routing table lookup each time . I hope this helps Good Luck !!! #-)

 

[AllenTech]

Thanks Jeter

I moved my config to a 1600.
I disabled ip route-cache on each interface with the
'no ip route-cache' on my
serial 0
bri0
I also specified bandwidth of 64 on both:
serial 0 - this is important to monitor the load
bri0 (this is not affect any functionality and does not need to be specified as the 2 data channels have 64k each with isdn basic-net 3)
I also used static routes to sort out the routing table so that there are equal cost routes via the serial and bri.
Static routes configured:
ip route 0.0.0.0 0.0.0.0 s0.1
ip route 0.0.0.0 0.0.0.0 bri0

Although this is not quite what u recommended, u set me on the right track.

I now however need to work with activating the 2nd bri channel to provide a 128k path on bri for a 128k serial link. I experimented with ppp multink but cannot seem to activate the 2nd channel. Without ppp multilink it activates
but does not load balance on the two channels. I got the dialer load-threshold command configured to activate the 2nd channel. I also tried specifiying 128k bandwidth on the bri interface.

Can you shed light on this? Is it perhaps the router (1600)
or IOS [IOS (tm) 1600 Software (C1600-Y-L), Version 11.2(4)XA]

 

[jeter]

We have these working on a few 1720, however it should work on your equipment .
One thought comes to mind, have you tried setting up 2ea dialer strings to your other end? Leave your bandwidth at 128. Oh , another thing you can possibly try is to
set your ( dialer load-threshold 1 either). #-) Good Luck !!!