I was playing around with voice configuration lately and I started wondering... Am I interpreting the output of this show command correctly?
The setup is pretty straight forward. I have one voice gateway (2811) and a bunch of phones registered to it. The gateway is connected to another 2811 router over an E1 line and the call is terminated to a Cisco IP phone registerd to it.
On the the voice gateway where the call is originated from I've got:
HQ-2#show voice dsp active
DSP DSP DSPWARE CURR BOOT PAK TX/RX
TYPE NUM CH CODEC VERSION STATE STATE RST AI VOICEPORT TS ABORT PACK COUNT
==== === == ======== ========== ===== ======= === == ========= == ===== ============
edsp 0001 01 ilbc 0.1 busy 50/0/1.1
edsp 0002 02 g729r8 p 0.1 IDLE 50/0/1.2
edsp 0003 01 g711ulaw 0.1 busy 50/0/2.1
edsp 0004 02 g729r8 p 0.1 IDLE 50/0/2.2
edsp 0005 01 g711ulaw 0.1 IDLE 50/0/3.1
edsp 0006 02 g729r8 p 0.1 IDLE 50/0/3.2
----------------------------FLEX VOICE CARD 0 -----------------------
-------
*DSP ACTIVE VOICE CHANNELS*
DSP DSPWARE VOX DSP SIG DSP PAK TX/RX
TYPE VERSION CODEC NUM CH TS VOICEPORT SLT NUM CH TS RST AI ABRT PACK COUNT
====== ========== ======== === == == ========= === === == == === == ==== ============
C5510 27.3.3 ilbc 001 01 08 0/2/0:15 000 001 08 08 0 0 0 20122/20135
C5510 27.3.3 g711ulaw 001 02 07 0/2/0:15 000 001 07 07 0 0 0 7351/7360
------------------------END OF FLEX VOICE CARD 0 --------------------
On the terminating gateway, I've got:
PSTN#show voice dsp active
DSP DSP DSPWARE CURR BOOT PAK TX/RX
TYPE NUM CH CODEC VERSION STATE STATE RST AI VOICEPORT TS ABORT PACK COUNT
==== === == ======== ========== ===== ======= === == ========= == ===== ============
edsp 0001 01 g711ulaw 0.1 IDLE 50/0/1.1
edsp 0002 02 g711ulaw 0.1 IDLE 50/0/1.2
edsp 0003 01 g711ulaw 0.1 IDLE 50/0/2.1
edsp 0004 02 g729r8 p 0.1 IDLE 50/0/2.2
edsp 0005 01 g711ulaw 0.1 IDLE 50/0/3.1
edsp 0006 02 g729r8 p 0.1 IDLE 50/0/3.2
edsp 0007 01 g729r8 p 0.1 IDLE 50/0/4.1
edsp 0008 02 g729r8 p 0.1 IDLE 50/0/4.2
edsp 0009 01 g711ulaw 0.1 IDLE 50/0/5.1
edsp 0010 02 g729r8 p 0.1 IDLE 50/0/5.2
edsp 0011 01 g711ulaw 0.1 IDLE 50/0/6.1
edsp 0012 02 g711ulaw 0.1 IDLE 50/0/6.2
edsp 0013 01 g711ulaw 0.1 busy 50/0/7.1
edsp 0014 02 g711ulaw 0.1 IDLE 50/0/7.2
edsp 0015 01 g711ulaw 0.1 busy 50/0/8.1
edsp 0016 02 g729r8 p 0.1 IDLE 50/0/8.2
edsp 0017 01 g711ulaw 0.1 IDLE 50/0/9.1
edsp 0018 02 g729r8 p 0.1 IDLE 50/0/9.2
edsp 0019 01 g729r8 p 0.1 IDLE 50/0/10.1
edsp 0020 02 g729r8 p 0.1 IDLE 50/0/10.2
edsp 0021 01 g729r8 p 0.1 IDLE 50/0/11.1
edsp 0022 02 g729r8 p 0.1 IDLE 50/0/11.2
edsp 0023 01 g711ulaw 0.1 IDLE 50/0/12.1
edsp 0024 02 g729r8 p 0.1 IDLE 50/0/12.2
----------------------------FLEX VOICE CARD 0 -----------------------
-------
*DSP ACTIVE VOICE CHANNELS*
DSP DSPWARE VOX DSP SIG DSP PAK TX/RX
TYPE VERSION CODEC NUM CH TS VOICEPORT SLT NUM CH TS RST AI ABRT PACK COUNT
====== ========== ======== === == == ========= === === == == === == ==== ============
C5510 27.3.3 g711ulaw 001 01 08 0/1/0:15 000 002 08 08 0 0 0 38971/13399
C5510 27.3.3 g711ulaw 001 02 07 0/1/0:15 000 002 07 07 0 0 0 26179/26196
------------------------END OF FLEX VOICE CARD 0 --------------------
So, the first section is pretty clear. For every extension I have two voice channels associated with it, because I'm using "dual=line" configuration.
The second part of the output, where the the active voice channels are listed is where I'm wondering. To me it looks like this:
1. The originating gateway HQ-2 is doing codec transcoding, That is why the media stream between it and the local phone is iLBC.
2. The codec over the E1 line is g711Alaw.
3. The terminating gateway implements standart voice termination function on the E1 line and does not perform any transcoding.
Are my assumptions correct? The thing that is bugging me is... The first output shows that the the codec over the E1 line is iLBC, and then on the terminating gateway the codecs listed in the active voice channels are only g711Alaw. So that's why I'm assuming that the originating gateway does not only standard voice termination but also transcoding and only g711Alaw is used over the E1 line...
