rate-limit and burst size for home lab?

fonestar1978

Hi there,

I have about 17.5 Mb down on my cable modem feeding into my 2611XM/2950/7940G. I'm just wondering how I should configure my rate-limit and burst size so my connection will function comfortably along with my phone?

I imagine Cisco has a rule of thumb for this but I haven't found it and haven't really gotten too far deep into the voice side of things yet.

Thanks!

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Comments

Daniel333

Sorry, I am on day 3 here. But why would you want to limit anything? Isn't your call going to be a tiny 80k no matter what. I can understand policing if you had too much data out going. But you really just need that 80k for your phone on the download.

fonestar1978

Daniel333 wrote: »

Sorry, I am on day 3 here. But why would you want to limit anything? Isn't your call going to be a tiny 80k no matter what. I can understand policing if you had too much data out going. But you really just need that 80k for your phone on the download.

Thanks for the reply Daniel,

I was wondering about that, I didn't think the voice would take much but wasn't sure how burst and fair-que would effect SIP traffic. Anyways, I've removed all limit settings from my 2611XM as both the VoIP and data-download quality seemed to suffer.

peanutnoggin

Daniel333 wrote: »

Sorry, I am on day 3 here. But why would you want to limit anything? Isn't your call going to be a tiny 80k no matter what. I can understand policing if you had too much data out going. But you really just need that 80k for your phone on the download.

Just curious... are voice packets 80k or 64k per packet? Thanks.

pitviper

peanutnoggin wrote: »

Just curious... are voice packets 80k or 64k per packet? Thanks.

hehehe, not exactly a cut and dry answer:

Voice Over IP - Per Call Bandwidth Consumption - Cisco Systems

You need to factor in codec/bitrate, voice payload, L2 header info, compression, and so on. Chances are, you probably aren’t going to use G.711 over the WAN, so the actual bandwidth of a G.729 call is about 25k-ish.

Daniel333

peanutnoggin wrote: »

Just curious... are voice packets 80k or 64k per packet? Thanks.

Actually that is an entire section on the CCNA:Voice exam. You gota factor in all the overhead and what compression you want to use. The CBTNuggets say assume 80k normally.