Calculating Bandwidth for SIP Trunks Made Easy

May 23, 2016 · by Andrew Prokop · in SIP · 3 Comments

I’ve previously addressed bandwidth calculation here on SIP Adventures, but I thought it was time to update the material and share it with my No Jitter audience. So, even if you’ve already read through my previous explanations, you might enjoy this refresher.

Tags: SIP, Unified Communications, VoIP

3 comments

jonathan · May 23, 2016 - 6:21 am · Reply→

Hi Andrew

Great post!

I actually did a very similar post recently as well:

https://afterthenumber.com/2016/05/15/voip-bandwidth-calculations/

Just for your reference (and just a word of warning!), interestingly at 90kbps you’re going to see packet loss on your QoS policy on a Cisco switch. I would suggest a 5% overhead, taking the 87.2kbps (G711, ethernet) to 91.5kbps. This is described pretty well here:

https://www.collabcert.com/blog/qos/how-much-bandwidth-does-1-call-consume/

I’ve made a few Cisco-centric references that can be ignored to keep this all agnostic, but the basics remain the same.

Hope this helps some folks as well!

– Jonathan
1. Andrew Prokop · May 23, 2016 - 8:53 am · Reply→
  
  Thanks! Good to know.
jonathan · May 23, 2016 - 6:36 am · Reply→

Oh, and just for clarity, that figure is obviously including Layer 2 overheads…