[asterisk-users] Some IAX calls do not disconnect.

[Tim Panton]

On 7 Jul 2009, at 05:05, Steve Totaro wrote:

> On Mon, Jul 6, 2009 at 9:41 PM, Tim Nelson<tnelson at rockbochs.com>  
> wrote:
>> ----- "Steve Totaro" <stotaro at asteriskhelpdesk.com> wrote:
>>> Just use SIP and solve all your problems.
>>
>> I seem to be noticing a common element to your posts about IAX. :-)
>>
>> I've been successfully using IAX in a large scale environment with  
>> no problems... yet. Can you shed some light on the reasoning behind  
>> your obvious dislike of IAX2? It is supposed to be the 'killer' of  
>> SIP from a usability standpoint (NAT traversal is quick to my  
>> mind...). BUT, is it just not robust enough in your experience? Are  
>> there inherent problems with the protocol itself? Is this changing  
>> now that IAX2 has it's own RFC? Is it the implementation within  
>> Asterisk that is the problem? I'm very interested to to know where  
>> your disdain comes from. :-)
>>
>> Thanks Steve!
>>
>> --Tim
>>
>
> First define large scale.  It certainly means different things to
> different people.
>
> Second, It comes from huge amounts of audio problems over many, many
> years, and many, many implementations.
>
> I actually don't have a disdain for it, it has made me a good deal of
> money by fixing ITSPs/carrier's audio issues by switching them to SIP
> and still does so I have a fondness for it.  Keep up the sub par
> protocol, it helps with the balance sheet!
>
> Third, it will never kill SIP.
>
> First of all, Digium owns the name and we have seen what they are
> willing to do to attack people for trademark or copyright infringement
> (think about the Google Adwords debacle and the the Open letter to
> Digium drafted by Trixter that I am not sure was ever fully addressed
> by Digium.)
>
> It would have to be renamed or something.  I think the same thing of
> DAHDI.  They want control over the the names Inter Asterisk Exchange
> and Digium (whatever the heck the rest of it means.)
>
> Second, SIP is the industry standard.  Only a couple of goofy phones
> do IAX2 as far as I know, some crappy handsets I wouldn't even bother
> testing if offered as a free demo unit.  SNOM might now, I am not sure
> but I think I read interest in it or it was actually accomplished.
> SNOM is OK but I was never a big fan.
>
> When I see it on a Polycom, Cisco, NEC, 3Com, or any other major
> vendor's phones or platforms, then I may rethink my ideas.
>
> If 3Com and Digium are partnered up now, how come the NBX for V3000
> doesn't support IAX2?  They do have SIP.
>
> Second, there are work arounds for just about every downfall of SIP,
> like NAT traversal and the like.
>
> Third, ALL REAL TIME VOICE traffic is on a single port.  There is a
> big issue there, I won't elaborate, but just think about it.
>
> SIP is here to stay until some other protocol comes about, but
> certainly not IAX2.  It will be along the evolution of H323 to SIP to
> X., but not IAX,lol.
>
> Do you realize that most providers are dropping IAX2 support, even
> IAX.cc recommends SIP, gotta wonder why?
>
> Maybe it is all good now, but I won't bank my reputation on it.  I use
> what I know works well, period.
>
> Even unnamed Digium Employees have poo pooed IAX2, albeit a year or  
> two ago.
>
> It looks good on paper, didn't perform well historically, and now just
> like anything that I have lost trust in, it has to earn my trust back
> and that is not easy.
>
> -- 

Obviously Steve and I don't agree about this.

There are places where IAX can go that SIP just can't.

When Steve says just use SIP, what he is actually recommending is
to use SIP/STUN/SDP/RTP/IPSEC to get the same result.
(at a 50% bandwidth overhead)

i.e. replace a single 100 page RFC with something like 100 RFCs :-)

In a big organization where you control the network infrastructure,  
that is
an entirely viable solution, but when you want to get calls through a  
messy
network without having to fill out an infinite number of change  
requests to
the firewall team you should consider IAX.

The mess that SIP makes is reflected in the number of bugs and the  
code size.
I'm currently working with a SIP stack that is about 10x the size of  
the comparable IAX
codebase, which matters in some environments.

As to the 'everything over a single port' issue, this is no longer  
such a big deal.
(And it is exactly this feature which provides IAX's firewall  
penetration)

Most modern Linuxes support multiple threads reading datagrams from a  
single
datagram socket. The current IAX implementation in Asterisk doesn't  
support it,
but that's an implementation issue, not the protocol itself.

Also IAX now supports redirecting the media - which could be used to  
send
it to a separate port on the same box.


Various Digium employees have also badmouthed SIP (I think we all have
after a bad day at the SDP coalface), so you can't take such remarks  
too seriously.

I overheard a senior Cisco employee saying "So you were right all  
along about IAX "
to a very senior Digium employee, which also proves nothing much :-)

Competition is a good thing - even amongst protocols.

T.

Tim Panton - Web/VoIP consultant and implementor
www.westhawk.co.uk



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