IAX2 or SIP vote

Which is Better IAX2 or SIP

  • SIP
  • IAX2
  • Neither (Explain what you use then)

0 voters

Hi * Users :smiley:

I would like to poll on what peoples thoughts are on using IAX2 or SIP and which one you deem to be more stable and provides better connectivity and why?

Depends what you will be doing and what features you want to use.

This is a difficult comparison. It’s like asking “What’s better, a car or a pickup truck”. You cannot answer this question as one is not unquestionably better than the other, they both have their uses. If you haul heavy piles of dirt and stuff then you will really really not want a car, but if you are just driving to the office and parking in a low garage you would prefer the car over the truck and it burns less gas too.

SIP is more finicky than IAX esp. when it comes to NAT. However it also supports things like BLF and SLA that I don’t think IAX does.

IAX handles NAT much better than SIP, and in trunking mode can be a big bandwidth saver in reducing overhead. However not many phones support IAX and Asterisk is pretty much the only soft-switch that does.

agree, it depends on the situation. but at least IAX just works when it comes to NAT, which is a huge relief. so I cast my vote for IAX.

BTW, who else is just underwhelmed by 1.4…?

underwhelmed by what, specifically? i have to confess i haven’t “upgraded” yet, but mainly because i’m using freepbx and haven’t heard it supports 1.4 at this time.

I am leaning toward IAX2 because of how well it deals with NAT and firewalls. Am anxiously awaiting formal approval of IAX2 as an Internet standard. I believe once that happens, there should be a flood of hard and softphones that support IAX2. Right now, Counterpath has no plans to support IAX2 in their Eyebeam softphone. See below links:

support.counterpath.com/viewtopi … 0ed8f3aa73
support.counterpath.com/viewtopi … 0ed8f3aa73


I understand that different situations call for Different protocols to be used, i guess i was mainly getting at what would you always lean to although you know one might be better for that particular situation.

For me i have Multiple Asterisk boxes deployed, we use SIP to Interconnect them have them talk to each other, however i am strongly considering moving them to IAX interconnect even though NAT is not an issue.

Why, Well from what i have read on here, people generally find IAX to be more stable then SIP, and considering that IAX was developed for Asterisk it only makes sense to me to use it when speaking from one Asterisk box to another.

But hey i may have been mis reading people, hence my reason for a poll.



ah that’s a much better question.

You are asking: I have many Asterisk boxes, and what should I use to link them together?

The answer is generally IAX. If you have more than 4 concurrant calls on any of the links use IAX in trunking mode (requires a non-broken timing source on both sides), this will save a fair bit of overhead.
However if SIP is working fine for you, there’s no compelling reason to change it…

[quote=“IronHelix”]ah that’s a much better question.

You are asking: [/quote]

Well kind of in a way i guess, but what i was mainly after as well is too see what people are using, and also to help with any decisions i make it wanted to gauge of peoples opinions of the two protocols.

For me it ain’t a problem configuring the systems to use IAX or SIP is not an issue, if wont don’t work then use another :wink:, I wanted to see from a persons perspective what they perceive to be the subtle differences, sometimes these little things can make all the difference.

However thank you for you your advice, you learn something new everyday i guess.



by the fact that there’s no real good reason to upgrade. from what i understand, the sip stack is still weak, the dns issues haven’t been resolved and SLA isn’t implemented.

in a distributed network - like the internet at large - SIP is definitely better, since only call setup data go to the server while actual calls go shortest route.
Now, most of us deal with phone systems for offices and the like - the scenario where SIP shines would be a company with multiple offices but just one central server.
I guess most systems are not really like that … at least mine is not.
And once you are no longer dependent on that specific advantage, you can benefit from what IAX gives you.
btw: although a minority, there are even some IAX phones on the market