Basic Scenarios

Examples provided in this section are supported by the following codec policy and media profiles.

codec-policy
        name	net192
        allow-codecs	*
        add-codecs-on-egress	AMR::PT96 AMR-WB::PT97 AMR::PT98 
	AMR-WB::PT99
        order-codecs
        force-ptime	disabled
        packetization-time	30
        dtmf-in-audio	disabled


media-profile
        name                      AMR
        subname                   PT96
        media-type                audio
        payload-type              96
        transport                 RTP/AVP
        req-bandwidth             0
        frames-per-packet         0
        parameters
        average-rate-limit        0
        peak-rate-limit           0
        max-burst-size            0
        sdp-rate-limit-headroom   0
        sdp-bandwidth             disabled
        police-rate               0
        standard-pkt-rate         0


media-profile
        name                      AMR-WB
        subname                   PT97
        media-type                audio
        payload-type              97
        transport                 RTP/AVP
        req-bandwidth             0
        frames-per-packet         0
        parameters
        average-rate-limit        0
        peak-rate-limit           0
        max-burst-size            0
        sdp-rate-limit-headroom   0
        sdp-bandwidth             disabled
        police-rate               0
        standard-pkt-rate         0


media-profile
        name                      AMR
        subname                   PT98
        media-type                audio
        payload-type              98
        transport                 RTP/AVP
        req-bandwidth             0
        frames-per-packet         0
        parameters                mode-set="0,1,2,3"
        average-rate-limit        0
        peak-rate-limit           0
        max-burst-size            0
        sdp-rate-limit-headroom   0
        sdp-bandwidth             disabled
        police-rate               0
        standard-pkt-rate         0


media-profile
        name                      AMR-WB
        subname                   PT99
        media-type                audio
        payload-type              99
        transport                 RTP/AVP
        req-bandwidth             0
        frames-per-packet         0
        parameters                mode-set="0,1,2,3"
        average-rate-limit        0
        peak-rate-limit           0
        max-burst-size            0
        sdp-rate-limit-headroom   0
        sdp-bandwidth             disabled
        police-rate               0
        standard-pkt-rate         0

The following SDP reflects the case where the session responder answers with the same codec and payload type as presented by the session initiator.

SDP	Contents
Offer received from session initiator	m=audio xx RTP/AVP 96 a=rtpmap:96 AMR/8000 INVITE SDP (partial, codec information only)
Offer sent to responder (per the net192 codec policy)	m=audio xx RTP/AVP 97 98 99 96
from AMR-WB/PT97 media profile	a=rtpmap:97 AMR-WB/16000/1
from AMR-WB/PT98 media profile	a=rtpmap:98 AMR/8000 a=fmtp:98 mode-set=0,1,2,3
from AMR-WB/PT99 media profile	a=rtpmap:99 AMR-WB/16000/1 a=fmtp:99 mode-set=0,1,2,3
initiator offer	a=rtpmap:96 AMR/8000
Answer received from responder	m=audio xx RTP/AVP 96 a=rtpmap:96 AMR/8000
Answer sent to initiator	m=audio xx RTP/AVP 96 a=rtpmap:96 AMR/8000

Codecs	Match	Values
codec	match	AMR/AMR
payload formats	match	bandwidth-efficient (default value)
mode-sets	match	inclusive mode-set (0,1,2,3,4,5,6,7)
payload mapping	match	96/96

Here, given the identical offer and answer, neither transcoding nor payload type mapping is required.

The following SDP reflects the case where the session responder answers with the codec offered by the session initiator, but with a different payload type.

SDP	Contents
Offer received from session initiator	m=audio xx RTP/AVP 96 a=rtpmap:96 AMR/8000 INVITE SDP (partial, codec information only)
Offer sent to responder (per the net192 codec policy)	m=audio xx RTP/AVP 97 98 99 96
from AMR-WB/PT97 media profile	a=rtpmap:97 AMR-WB/16000/1
from AMR-WB/PT98 media profile	a=rtpmap:98 AMR/8000 a=fmtp:98 mode-set=0,1,2,3
from AMR-WB/PT99 media profile	a=rtpmap:99 AMR-WB/16000/1 a=fmtp:99 mode-set=0,1,2,3
initiator offer	a=rtpmap:96 AMR/8000
Answer received from responder	m=audio xx RTP/AVP 97 a=rtpmap:97 AMR/8000
Answer sent to initiator	m=audio xx RTP/AVP 96 a=rtpmap:96 AMR/8000

Codecs	Match	Values
codecs	match	AMR/AMR
payload formats	match	bandwidth-efficient (default value)
mode-sets	match	inclusive mode-set (0,1,2,3,4,5,6,7)
payload mapping	no match	96/97

Here, given the identical offer/answer except for the payload type, transcoding is not required; payload type mapping is used.

The following SDP reflects the case where the session responder answers with a codec not offered by the session initiator.

SDP	Contents
Offer received from session initiator	m=audio xx RTP/AVP 96 a=rtpmap:96 AMR/8000 INVITE SDP (partial, codec information only)
Offer sent to responder (per the net192 codec policy)	m=audio xx RTP/AVP 97 98 99 96
from AMR-WB/PT97 media profile	a=rtpmap:97 AMR-WB/16000/1
from AMR-WB/PT98 media profile	a=rtpmap:98 AMR/8000 a=fmtp:98 mode-set=0,1,2,3
from AMR-WB/PT99 media profile	a=rtpmap:99 AMR-WB/16000/1 a=fmtp:99 mode-set=0,1,2,3
initiator offer	a=rtpmap:96 AMR/8000
Answer received from responder	m=audio xx RTP/AVP 97 a=rtpmap:97 AMR/16000
Answer sent to initiator	m=audio xx RTP/AVP 96 a=rtpmap:96 AMR/8000

Codecs	Match	Values
codecs	no match	AMR/AMR-WB
payload formats	match	bandwidth-efficient (default value)
mode-sets	match	inclusive mode-set (0,1,2,3,4,5,6,7)
payload mapping	no match	96/97

Here, given that the offer and answer codecs (AMR and AMR-WB) are not identical, transcoding is required.

The following SDP reflects the case where the offer specifies the inclusive mode-set, and the answer specifies a non-inclusive mode-set.

SDP	Contents
Offer received from session initiator	m=audio xx RTP/AVP 96 a=rtpmap:96 AMR/8000 INVITE SDP (partial, codec information only)
Offer sent to responder (per the net192 codec policy)	m=audio xx RTP/AVP 97 98 99 96
from AMR-WB/PT97 media profile	a=rtpmap:97 AMR-WB/16000/1
from AMR-WB/PT98 media profile	a=rtpmap:98 AMR/8000 a=fmtp:98 mode-set=0,1,2,3
from AMR-WB/PT99 media profile	a=rtpmap:99 AMR-WB/16000/1 a=fmtp:98 mode-set=0,1,2,3
initiator offer	a=rtpmap:96 AMR/8000
Answer received from responder	m=audio xx RTP/AVP 98 a=rtpmap:96 AMR/8000 a=fmtp: 98 mode-set=0,1,2,3
Answer sent to initiator	m=audio xx RTP/AVP 96 a=rtpmap:96 AMR/8000

Codecs	Match	Values
codecs	match	AMR/AMR-WB
payload formats	match	bandwidth-efficient (default value)
mode-sets	intersect	(0,1,2,3,4,5,6,7) / (0,1,2,3)
payload mapping	no match	96/98

Here, given that the answer mode-set (0,1,2,3) intersects with the offered mode-set (0,1,2,3,4,5,6,7), transcoding is not required; payload type mapping is used.

The following SDP reflects the case where the offer specifies a non-inclusive mode-set, and the answer specifies the inclusive mode-set.

SDO	Contents
Offer received from session initiator	m=audio xx RTP/AVP 98 a=rtpmap:98 AMR/8000 a=fmtp:98 mode-set=0,1,2,3 INVITE SDP (partial, codec information only)
Offer sent to responder (per the net192 codec policy)	m=audio xx RTP/AVP 96 97 99 98
from AMR/PT96 media profile	a=rtpmap:96 AMR/8000
from AMR-WB/PT97 media profile	a=rtpmap:97 AMR-WB/16000/1
from AMR-WB/PT99 media profile	a=rtpmap:99 AMR-WB/16000/1 a=fmtp:99 mode-set=0,1,2,3
initiator offer	a=rtpmap:98 AMR/8000 a=fmtp:98 mode-set=0,1,2,3
Answer received from responder	m=audio xx RTP/AVP 96 a=rtpmap:96 AMR/8000
Answer sent to initiator	m=audio xx RTP/AVP 98 a=rtpmap:98 AMR/8000 a=fmtp:98 mode-set=0,1,2,3

Codecs	Match	Values
codecs	match	AMR/AMR
payload formats	match	bandwidth-efficient (default value)
mode-sets	intersect	(0,1,2,3) / (0,1,2,3,4,5,6,7)
payload mapping	no match	98/96

Here, given that the offer mode-set (0,1,2,3) intersects with the answer mode-set (0,1,2,3,4,5,6,7), transcoding is not required; payload type mapping is used.