No Jitter: IPv6 Impact on VoIP

No Jitter logoHow well do voice-over-IP (VoIP) and unified communications (UC) systems work with IPv6?  That’s a topic that has long been a personal passion of mine – and we maintain a page here on Deploy360 specifically about IPv6 and VoIP/UC systems. So naturally I was very pleased when right before the holidays on December 20, 2013, Gary Audin wrote a piece on the No Jitter site about IPv6 and VoIP.

Gary identifies several issues that enterprises need to think about with regard to migrating their VoIP systems to IPv6, including:

  • Increased bandwidth needs due to expanded IPv6 headers
  • Upgrading IP PBXs, IP phones, softphones and gateways to IPv6
  • Running dual stack operations with both IPv4 and IPv6
  • Network Address Translation modifications
  • Port sharing for signaling protocols

From my own perspective of having worked in the VoIP field  I think his second bullet is probably going to be the most problematic, particularly the IP phones.  Many of the older IP desk phones used by enterprises are severely resource constrained and may not be able to support dual-stack operations and may not be upgraded to IPv6.  In many cases it may be the newer IP phones and the softphones that will lead the way to IPv6.

But interestingly in this article Gary is more focused on the potential bandwidth increases.  He’s right that one of the differences in VoIP traffic from, say, web or file traffic is that VoIP is composed of a zillion tiny packets. This has to do with how most VoIP systems use a very small sampling size – they slice the voice stream into very tiny pieces, typically around 20 milliseconds, and then send those pieces in individual packets.

So, given all the tiny little packets, any increase in the overall size of the VoIP packets results in an increase in bandwidth.  Gary’s argument is that the increased size of IPv6 headers will have an impact on bandwidth.  Not necessarily a huge impact, perhaps only a 10% increase in needed bandwidth, but still, there will be an impact. Though I have not done the math as Gary has to make his table, I can see his argument.

His main point, really, is that as enterprises plan their moves to IPv6 they need to think not only about potential software and hardware upgrades, but also about additional bandwidth requirements.  It’s good advice to think about.

Are you ready to migrate your VoIP or UC system to IPv6?  Or have you already done so?  If you haven’t, check out our page on VoIP and UC resources for IPv6 – and if you have already done so, we’d love to talk to you about writing up a case study! 🙂

3 replies on “No Jitter: IPv6 Impact on VoIP”

You wrote, “Not necessarily a huge impact, perhaps only a 10% increase in needed bandwidth, but still, there will be an impact.”

There’s a question hiding in that statement – how many enterprise networks (or individual sites/links within the enterprise) are currently running at 90% of capacity BEFORE implementing IPv6?

Of the dozens of enterprise networks with which I’ve worked over the last 2-3 years, I would estimate that more than 70% of them experience peak utilization above 90% on a near-daily basis. In fact, most of the network designers and engineers with whom I’ve worked tell me that, due to business/financial restraints, they can’t even start a discussion of “increasing bandwidth” for their affected site(s) until they can show routine usage above 90% AND demonstrate that such congestion is detrimental to “core business operations.”

The impact of that “perhaps only a 10% increase” may be far more significant than you might think. Bandwidth planning is DEFINITELY necessary.

Wes, Thanks for the note. I haven’t worked with enterprise networks to the degree that you have and so I do appreciate the insight. I was not aware that enterprise networks were as highly-utilized, although it makes sense given the amount of applications and services now running over those networks.


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