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New Member

Possible Load Balancing on a 2821?

I have a 2821 Router, with a VWIC2-2MFT card in it, with two T1s going into that card.  The two T1s are a bundled MPLS line.

I then have a cable modem connection going into the gigabit Ethernet GE 0/1 port on the router.

Right now, the cable modem provides a backup connection in case the T1s go down.

What I was wondering is if there was a way to 'combine' the bandwidth from the two T1s with the cable modem?


Hall of Fame Super Gold

Possible Load Balancing on a 2821?


If you are looking for something that would combine the T1s and the cable modem into one virtual link (similar to what it sounds like has been done for the T1s) I do not think that you will find it. But it is possible to use both interfaces and to do some load sharing with them. I had a similar situation at a customer site and what we did was to configure normal routing to use the T1s multilink and to use the cable modem as a backup. (which I think you say you have already done) And then I configured Policy Based Routing to take some traffic (in our case it was web surfing originating from the user subnet) and to send it over the cable modem. This worked fairly well and resulted in some use of the cable modem (and reduction in use of the multilink T1s) and still preserved the failover capability. I think something like that might work for you.



New Member

Possible Load Balancing on a 2821?


Thank you so much for your help.

Do you have any links that specify in more detail the process of implementing what you recommend?  I'm still fairly green when it comes to these systems.

Thanks again!

Hall of Fame Super Gold

Possible Load Balancing on a 2821?


Configuring PBR has some options that can make it complex, but the basics are fairly simple. I would suggest that you approach it like this:

- configure an access list that will identify the traffic that you want to send out the cable modem.

- configure a route map  which has a match statement using that access list and a set statement that sets the next hop ip address to use the cable modem.

- assign the route map to the inbound interface where the traffic is received by the router using the ip policy route-map command.

The config might look something like this

access-list 151 permit tcp any eq http

route-map use_cable permit 10

match ip address 151

set ip next-hop

interface fastethernet0/1

ip policy route-map use_cable

I hope that this link has some details that may be helpful for you



New Member

Possible Load Balancing on a 2821?

If you are using routing protocols such as EIGRP or BGP you can use load balancing  for outgoing packets but if you are using static route you have 2 solution:

1- load balancing based on destination address:

you can use staic route with same metric for both interfaces but you should set load balancing to "per packet" or "per destination" in CEF route mode or use per packet in route caching

2- Load balancing based on source address:

if you want to use load balancing based on source address this is not equal and you should use PBR (policy base routing" that richard explained it

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