load balancing your EIGRP in a VOIP environment

[NAVIN PARWAL]

Folks,

I have a remote site connected via 2 T1's. I would like to do load balancing. What would be recommended if it is a voip environment? per packet or per destination?

Thanks

[thisisshanky]

Never use per packet LB in a voip world! This can cause voip packets to come out of order. Use CEF, MLPPP to bundle the link and use LLQ and LFI (Link fragmentation and Interleaving) for QOS. HEre is a link to it.

http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a0080094660.shtml

[NAVIN PARWAL]

i have 2 T1's, would you still recommend LFI?? I thought LFI was for links less that 768K.

Thanks

[thisisshanky]

You dont need it if you have plenty of bandwidth. LFI is not strictly required in your case as it is typically used in low bandwidth links. But make sure you have LLQ configured.

[roluce]

I before E, except....

We use per-packet load balancing over dual T1's with VoIP. Oh, the heresy! :-)

But, it's not something you should do if you don't have a complete understanding of what you are getting yourself into. There are very good reasons to use other solutions if they are available. They simply weren't available in our case, and I can honestly say it works very well when you've covered all the bases.

The main issue, as it was pointed out, is out of order packet receipt. Solve this issue, and VoIP works exceptionally well.

I would -not- use per-destination, you lose all forms of bandwidth predictability in a per-destination scenario.

[dlkoch]

Set your LFI to 1600 which kick in the dual buffers