Hi all,
I have a couple of IAD 243x (specifically IAD2431 and IAD2432) running IOS 15.1(4)M5 that I'm using as SIP to E1 PRI ISDN gateways. They're configured with one POTS dial-peer for the ISDN and a couple of VoIP dial-peers depending on the incoming called number from the ISDN. This has been working fine with G.711 A-law end-to-end, but now I'm trying to get it to work with iLBC and having problems.
My dial-peer configuration looks like this:
dial-peer voice 1 pots
description Peer for ISDN30
translation-profile incoming inbound-from-bt
service session
destination-pattern .T
progress_ind alert strip 8
no digit-strip
direct-inward-dial
port 1/0:15
forward-digits all
!
dial-peer voice 3 voip
tone ringback alert-no-PI
description Peer for bearer number
huntstop
service session
destination-pattern 01234567890
rtp payload-type nte-tone 102
rtp payload-type comfort-noise 13
session protocol sipv2
session target ipv4:1.2.3.4:5060
voice-class codec 1
dtmf-relay rtp-nte digit-drop
ip qos dscp cs3 signaling
clid network-provided
clid substitute name
!
dial-peer voice 65008 voip
tone ringback alert-no-PI
description Peer for main range
huntstop
service session
destination-pattern 01234567[1-8].
rtp payload-type nte-tone 102
rtp payload-type comfort-noise 13
session protocol sipv2
session target ipv4:1.2.3.4:5060
voice-class codec 1
dtmf-relay rtp-nte digit-drop
ip qos dscp cs3 signaling
clid network-provided
clid substitute name
Other relevant config:
voice rtp send-recv
!
voice service pots
rtcp keepalive
!
voice service voip
ip address trusted list
ipv4 1.2.3.4
rtcp keepalive
dtmf-interworking standard
fax protocol t38 version 0 ls-redundancy 0 hs-redundancy 0 fallback pass-through g711alaw
sip
transport switch udp tcp
no anat
block 183 sdp present
!
voice class codec 1
codec preference 1 ilbc mode 30
codec preference 2 g729r8
codec preference 3 g711alaw
!
Now, when I place a call from ISDN through the gateway, the SDP it offers to my SBC is:
v=0
o=CiscoSystemsSIP-GW-UserAgent 7963 1810 IN IP4 6.7.8.9
s=SIP Call
c=IN IP4 6.7.8.9
t=0 0
m=audio 18710 RTP/AVP 116 18 8 101 13
c=IN IP4 6.7.8.9
a=rtpmap:116 iLBC/8000
a=fmtp:116 mode=30
a=rtpmap:18 G729/8000
a=fmtp:18 annexb=no
a=rtpmap:8 PCMA/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
a=rtpmap:13 CN/8000
This is great - both ends agree iLBC and the call comes up. However, if I make a call from the SIP side through to the ISDN, I offer this:
v=0
o=- 78207127932020 78207127932020 IN IP4 1.2.3.4
s=-
c=IN IP4 1.2.3.4
t=0 0
m=audio 24132 RTP/AVP 110 8 127
a=rtpmap:110 iLBC/8000
a=rtpmap:127 telephone-event/8000
a=fmtp:110 mode=30
a=silenceSupp:on - - - -
a=ptime:20
It then gives me a 200 OK with this:
v=0
o=CiscoSystemsSIP-GW-UserAgent 9977 8349 IN IP4 6.7.8.9
s=SIP Call
c=IN IP4 6.7.8.9
t=0 0
m=audio 17650 RTP/AVP 8 127
c=IN IP4 6.7.8.9
a=rtpmap:8 PCMA/8000
a=rtpmap:127 telephone-event/8000
a=fmtp:127 0-16
a=ptime:20
This means we use G.711 A-Law. If I remove this from the offer and just propose iLBC, the IAD rejects the call request.
Clearly it supports calls using G.711 over the ISDN and iLBC on the SIP side - how do I persuade it to allow calls initiated from the SIP side to work as well as calls initiated from the ISDN side?
Many thanks in advance for any suggestions!
Sean
