[Asterisk-Users] iax or sip

[Brian Capouch]

Randy Bush wrote:

> 
> iax uses udp and traverses nats.  neither of these seems useful to
> me.  i loathe nats, and udp is not well-behaved in the sense of
> congestion avoidance.
> 

You may indeed loathe NATted networks, but in general they're very hard 
to avoid.  Why would you criticize a protocol for dealing with such a 
thing efficiently--which, quite famously, SIP does not?

Also I suspect if you spent about 2.5453 nanoseconds on a call done 
using *only* TCP, you would quickly have your answer wrt the use of UDP 
for VoIP.

Do you know of a successful VoIP protocol that is entirely TCP-based?

> trunking will save some bytes in flight iff one has four or more
> streams moving between two pbxes.  but who would want to have the
> pbxes in the data stream anyway?  reinvite rules, especially in a
> geographically distributed use scenario.
>

I would want the PBX in the datastream in cases where multiple endpoint 
connections would pass through multiple IAX boxen, and in that case the 
trunking would save the decidedly-costly IP overhead that would be 
required if the endpoints were simply communicating directly--if 
bandwidth efficiency is a desideratum.

Perhaps in your case your networks are all public-IP, running on DS3s or 
OC48s.  In that case I don't reckon efficiency would matter much. . . .

> 
> what am i missing here?
> 

?? My guess would be experience, but that might be presumptous of me. 
I'll let others weigh in.  Maybe I'm completely misreading this.

B.