[asterisk-users] IAX vs SIP

[Edgar Guadamuz]

Hi,

Just to review the test I did:

-----------    SIP extension    ------------------     Trunk
-----------------
| SIPp  |<----------------------->| Asterisk 1  |<---------------->|
Asterisk 2 |
-----------                            -------------------
       ------------------

Both Asterisk boxes are virtual machines in VirtualBox and version
1.4.21.2. I generated calls using SIPp, and I monitored the cpu
utilization in the Asterisk 1 with top. I compare the cpu utilization
when I used IAX and when I used SIP as Trunk protocol. The following
are the results (averages) I got with ulaw codecs in both sides:

Calls	IAX 	SIP
4	6,0	1,8
10	9,2	4,6
20	19,5	8,6
30	28,2	13,5
34	36,9	16,2
40	38,2	19,5
50	36,9	24,3

As you can see, IAX almost doubles the cpu cycles. I repeated the test
using gsm as the trunk codec, and in this scenario IAX shows a better
performance (Sip extension continues with ulaw):

IAX 	SIP
1,8	25,7
12,8	41,5
29,2	47,0
45,7	69,4
54,2	78,5
53,3	83,3
65,7	87,1

And finally I repeated with iLBC in the trunk, and SIP won again:

IAX 	SIP
8,5	9,4
29,3	14,5
57,6	23,6
74,4	37,3
84,3	41,5
--	51,2
--	67,0


Does this makes sense? Any feedback? Has anybody done similar test for
comparison?