draft-ietf-mmusic-media-loopback-11.txt   draft-ietf-mmusic-media-loopback-12.txt 
Internet Draft K. Hedayat Internet Draft K. Hedayat
Expires: March 7, 2010 EXFO Expires: June 30, 2010 EXFO
N. Venna N. Venna
EXFO EXFO
P. Jones P. Jones
Cisco Systems, Inc. Cisco Systems, Inc.
A. Roychowdhury A. Roychowdhury
Hughes Systique Corp. Hughes Systique Corp.
C. SivaChelvan C. SivaChelvan
Cisco Systems, Inc. Cisco Systems, Inc.
N. Stratton N. Stratton
BlinkMind, Inc. BlinkMind, Inc.
October 7, 2009 January 30, 2010
An Extension to the Session Description Protocol (SDP) for Media An Extension to the Session Description Protocol (SDP) for Media
Loopback Loopback
draft-ietf-mmusic-media-loopback-11 draft-ietf-mmusic-media-loopback-12
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with This Internet-Draft is submitted to IETF in full conformance with
the provisions of BCP 78 and BCP 79. the provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
skipping to change at page 1, line 43 skipping to change at page 1, line 43
documents at any time. It is inappropriate to use Internet-Drafts documents at any time. It is inappropriate to use Internet-Drafts
as reference material or to cite them other than as "work in as reference material or to cite them other than as "work in
progress." progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on August 18, 2009. This Internet-Draft will expire on June 30, 2010.
Copyright Notice Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the Copyright (c) 2009 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
skipping to change at page 3, line 4 skipping to change at page 3, line 4
Table of Contents Table of Contents
1. Introduction .................................................. 3 1. Introduction .................................................. 3
2. Terminology ................................................... 4 2. Terminology ................................................... 4
3. Offering Entity Behavior ...................................... 4 3. Offering Entity Behavior ...................................... 4
4. Answering Entity Behavior ..................................... 4 4. Answering Entity Behavior ..................................... 4
5. SDP Constructs Syntax ......................................... 5 5. SDP Constructs Syntax ......................................... 5
5.1 Loopback Type Attribute ................................... 5 5.1 Loopback Type Attribute ................................... 5
5.2 Loopback Mode Attribute ................................... 6 5.2 Loopback Mode Attribute ................................... 6
5.3 Generating the Offer for Loopback Session ................. 7 5.3 Generating the Offer for Loopback Session ................. 6
5.4 Generating the Answer for Loopback Session ................ 8 5.4 Generating the Answer for Loopback Session ................ 7
5.5 Offerer Processing of the Answer ......................... 10 5.5 Offerer Processing of the Answer .......................... 9
5.6 Modifying the Session .................................... 10 5.6 Modifying the Session ..................................... 9
5.7 Priming the loopback pump ................................. 9
6. RTP Requirements ............................................. 10 6. RTP Requirements ............................................. 10
7. Payload formats for Packet loopback .......................... 11 7. Payload formats for Packet loopback .......................... 11
7.1 Encapsulated Payload format .............................. 11 7.1 Encapsulated Payload format .............................. 11
7.2 Direct loopback RTP payload format ....................... 13 7.2 Direct loopback RTP payload format ....................... 13
8. RTCP Requirements ............................................ 15 8. Payload formats for Priming the Loopback Pump ................ 15
9. Congestion Control ........................................... 15 8.1 Usage of RTP Header fields ............................... 15
10. Examples .................................................... 15 8.2 Usage of SDP ............................................. 15
10.1 Offer for specific media loopback type .................. 15 9. RTCP Requirements ............................................ 15
10.2 Offer for choice of media loopback type ................. 16 10. Congestion Control .......................................... 16
10.3 Offer for choice of media loopback type with 11. Examples .................................................... 16
rtp-start-loopback ........................................... 17 11.1 Offer for specific media loopback type .................. 16
10.4 Response to INVITE request rejecting loopback media ..... 18 11.2 Offer for choice of media loopback type ................. 17
10.5 Response to INVITE request rejecting loopback media with 11.3 Offer for choice of media loopback type with loopback
rtp-start-loopback ........................................... 19 primer ....................................................... 18
11. Security Considerations ..................................... 20 11.4 Response to INVITE request rejecting loopback media ..... 19
12. Implementation Considerations ............................... 20 11.5 Response to INVITE request rejecting loopback media with
13. IANA Considerations ......................................... 20 loopback primer payload type ................................. 20
13.1 SDP Attributes .......................................... 20 12. Security Considerations ..................................... 20
13.2 MIME Types .............................................. 21 13. Implementation Considerations ............................... 21
14. Acknowledgements ............................................ 30 14. IANA Considerations ......................................... 21
15. Normative References ........................................ 30 14.1 SDP Attributes .......................................... 21
14.2 MIME Types .............................................. 22
15. Acknowledgements ............................................ 35
16. Normative References ........................................ 36
1. Introduction 1. Introduction
The overall quality, reliability, and performance of VoIP, The overall quality, reliability, and performance of VoIP,
Real-time Text and Video over IP services rely on the performance Real-time Text and Video over IP services rely on the performance
and quality of the media path. In order to assure the quality of
the delivered media there is a need to monitor the performance of the delivered media there is a need to monitor the performance of
the media transport. One method of monitoring and managing the the media transport. One method of monitoring and managing the
overall quality of VoIP, Real-time Text and Video over IP Services overall quality of VoIP, Real-time Text and Video over IP Services
is through monitoring the quality of the media in an active is through monitoring the quality of the media in an active
session. This type of "active monitoring" of services is a method session. This type of "active monitoring" of services is a method
of pro-actively managing the performance and quality of VoIP based of pro-actively managing the performance and quality of VoIP based
services. services.
The goal of active monitoring is to measure the media quality of a The goal of active monitoring is to measure the media quality of a
VoIP, Real-time Text or Video over IP session. A way to achieve VoIP, Real-time Text or Video over IP session. A way to achieve
skipping to change at page 5, line 19 skipping to change at page 5, line 24
5.1 Loopback Type Attribute 5.1 Loopback Type Attribute
The loopback type is a property media attribute with the following The loopback type is a property media attribute with the following
syntax: syntax:
a=loopback:<loopback-type> a=loopback:<loopback-type>
Following is the Augmented BNF [RFC5234] for loopback-type: Following is the Augmented BNF [RFC5234] for loopback-type:
loopback-type = loopback-type-choices | loopback-type-choice-3 loopback-type = loopback-choice [1*SP loopback-choice]
loopback-choices = loopback-type-choice-1 | loopback-type-choice-2 loopback-choice = loopback-type-pkt / loopback-type-media
| loopback-type-choice-1 1*space loopback-type-choice-2 | loopback-type-pkt = "rtp-pkt-loopback"
loopback-type-choice-2 1*space loopback-type-choice-1 loopback-type-media = "rtp-media-loopback"
loopback-type-choice-1 = "rtp-pkt-loopback"
loopback-type-choice-2 = "rtp-media-loopback"
loopback-type-choice-3 = "rtp-start-loopback"
The loopback type is used to indicate the type of loopback. The The loopback type is used to indicate the type of loopback. The
loopback-type values are rtp-pkt-loopback, rtp-media-loopback, and loopback-type values are rtp-pkt-loopback, and rtp-media-loopback.
rtp-start-loopback.
rtp-pkt-loopback: In this mode, the RTP packets are looped back to rtp-pkt-loopback: In this mode, the RTP packets are looped back to
the sender at a point before the encoder/decoder function in the the sender at a point before the encoder/decoder function in the
receive direction to a point after the encoder/decoder function in receive direction to a point after the encoder/decoder function in
the send direction. This effectively re-encapsulates the RTP the send direction. This effectively re-encapsulates the RTP
payload with the RTP/UDP/IP overheads appropriate for sending it in payload with the RTP/UDP/IP overheads appropriate for sending it in
the reverse direction. Any type of encoding related functions, the reverse direction. Any type of encoding related functions,
such as packet loss concealment, MUST NOT be part of this type of such as packet loss concealment, MUST NOT be part of this type of
loopback path. In this mode the RTP packets are looped back with a loopback path. In this mode the RTP packets are looped back with a
new payload type and format. Section 7 describes the payload new payload type and format. Section 7 describes the payload
formats that MUST be used for this type of loopback. formats that MUST be used for this type of loopback.
rtp-media-loopback: This loopback is activated as close as possible rtp-media-loopback: This loopback is activated as close as possible
to the analog interface and after the decoder so that the RTP to the analog interface and after the decoder so that the RTP
packets are subsequently re-encoded prior to transmission back to packets are subsequently re-encoded prior to transmission back to
the sender. the sender.
rtp-start-loopback: In certain scenarios it is possible that the
media transmitted by the loopback-source is blocked by a network
element until the loopback-mirror starts transmitting packets.
Loopback-source and loopback-mirror are loopback modes defined in
section 5.2. One example of this scenario is the presence of an
RTP relay in the path of the media. RTP relays exist in VoIP
networks for purpose of NAT and Firewall traversal. If an RTP
relay is present, the loopback-source's packets are dropped by the
RTP relay until the loopback-mirror has started transmitting media
and the media state within the RTP relay is established. This
loopback attribute is used to specify the media type for
transmitting media packets by the loopback-mirror prior to the
loopback process for the purpose of setting media state within the
network. In the presence of this loopback attribute the
loopback-mirror will transmit media, according to the description
that contains this attribute, until it receives media from the
loopback-source. The loopback-mirror MAY include this attribute in
the answer if it is not present in the offer. This may be
necessary if the loopback-mirror is aware of NAT's, firewalls, or
RTP relays on the path of the call. In this case the loopback-
source MUST accept media according to rtp-start-loopback attribute.
After the first media packet is received from the loopback-source,
the loopback-mirror MUST terminate the transmission of
rtp-start-loopback media and MUST start looping back media as
defined by the other loopback attributes present in the offer. If
an offer includes the rtp-start-loopback attribute it MUST also
include at least one other attribute as defined in this section.
The loopback-source is able to filter rtp-start-loopback packets
from other types of loopback with the payload type of the packet.
The media port number for rtp-start-loopback MUST be the same as
the corresponding loopback attribute that will take over after the
reception of first media packet from the offering entity.
It is recommended that an offering entity specifying media with
either rtp-pkt-loopback or rtp-media-loopback attribute also
specify the rtp-start-loopback attribute unless the offering entity
is certain that its media will not be blocked by a network entity
as explained above.
5.2 Loopback Mode Attribute 5.2 Loopback Mode Attribute
The loopback mode is a value media attribute that is used to The loopback mode is a value media attribute that is used to
indicate the mode of the loopback. These attributes are additional indicate the mode of the loopback. These attributes are additional
mode attributes like sendonly, recvonly, etc. The syntax of the mode attributes like sendonly, recvonly, etc. The syntax of the
loopback mode media attribute is: loopback mode media attribute is:
a=<loopback-mode>:<fmt>... a=<loopback-mode>:<fmt>...
The loopback-mode values are loopback-source and loopback-mirror. The loopback-mode values are loopback-source and loopback-mirror.
loopback-source: This attribute specifies that the sender is the loopback-source: This attribute specifies that the sender is the
media source and expects the receiver to act as a loopback-mirror. media source and expects the receiver to act as a loopback-mirror.
loopback-mirror: This attribute specifies that the receiver will loopback-mirror: This attribute specifies that the receiver will
mirror (echo) all received media back to the sender of the RTP mirror (echo) all received media back to the sender of the RTP
stream. No media is generated locally by the receiver for stream. No media is generated locally by the receiver for
transmission in the mirrored stream unless rtp-start-loopback is transmission in the mirrored stream unless the loopback primer
requested by the loopback-source or included in the response by payload type (described in Section 8 of this document) is requested
by the loopback-source or included in the response by
loopback-mirror. loopback-mirror.
<fmt> is a media format description. The format descrption has the <fmt> is a media format description. The format description has the
semantics as defined in section 5.14 of RFC 4566[RFC4566]. When semantics as defined in section 5.14 of RFC 4566[RFC4566]. When
loopback-mode is specified as loopback-source, the media format loopback-mode is specified as loopback-source, the media format
corresponds to the RTP payload types the source is willing to send. corresponds to the RTP payload types the source is willing to send.
When loopback-mode is specified as loopback-mirror, the media When loopback-mode is specified as loopback-mirror, the media
format corresponds to the RTP payload types the mirror is willing format corresponds to the RTP payload types the mirror is willing
to receive. The payload types specified in m= line for a to receive. The payload types specified in m= line for a
loopback-source specify the payloads the source is willing to loopback-source specify the payloads the source is willing to
receive. Similarly, for the loopback-mirror these payload types receive. Similarly, for the loopback-mirror these payload types
specify the payloads it is willing to send. specify the payloads it is willing to send.
The loopback mode attribute does not apply to rtp-start-loopback
attribute and MUST be ignored if received by the answering entity.
5.3 Generating the Offer for Loopback Session 5.3 Generating the Offer for Loopback Session
If an offerer wishes to make a loopback request, it MUST include If an offerer wishes to make a loopback request, it MUST include
both the loopback-type and loopback-mode attribute in a valid SDP both the loopback-type and loopback-mode attribute in a valid SDP
offer: offer:
Example: m=audio 41352 RTP/AVP 0 8 Example: m=audio 41352 RTP/AVP 0 8 100
a=loopback:rtp-media-loopback a=loopback:rtp-media-loopback
a=loopback-source:0 8 a=loopback-source:0 8 100
a=rtpmap:0 pcmu/8000
a=rtpmap:8 pcma/8000
a=rtpmap:100 G7221/16000/1
Note: A loopback offer in a given media description MUST NOT Note: A loopback offer in a given media description MUST NOT
contain the standard mode attributes sendonly, recvonly, sendrecv contain the standard mode attributes sendonly, recvonly, sendrecv
or inactive. The loopback-mode attributes (loopback-source and or inactive. The loopback-mode attributes (loopback-source and
loopback-mirror) replace the standard attributes. loopback-mirror) replace the standard attributes.
The offerer may offer more than one loopback-type in the SDP offer. The offerer may offer more than one loopback-type in the SDP offer.
In this case the answer MUST include only one of the loopback types In this case the answer MUST include only one of the loopback types
that are accepted by the answerer. The answerer SHOULD give that are accepted by the answerer. The answerer SHOULD give
preference to the first loopback-type in the SDP offer. preference to the first loopback-type in the SDP offer.
skipping to change at page 10, line 31 skipping to change at page 9, line 42
target UA. target UA.
5.6 Modifying the Session 5.6 Modifying the Session
At any point during the loopback session, either participant may At any point during the loopback session, either participant may
issue a new offer to modify the characteristics of the previous issue a new offer to modify the characteristics of the previous
session. In case of SIP this is defined in section 8 of RFC 3264 session. In case of SIP this is defined in section 8 of RFC 3264
[RFC3264]. This also includes transitioning from a normal media [RFC3264]. This also includes transitioning from a normal media
processing mode to loopback mode, and vice a versa. processing mode to loopback mode, and vice a versa.
5.7 Priming the loopback pump
In certain scenarios it is possible that the media transmitted by
the loopback-source is blocked by a network element until the
loopback-mirror starts transmitting packets. One example of this
scenario is the presence of an RTP relay in the path of the media.
RTP relays exist in VoIP networks for purpose of NAT and Firewall
traversal. If an RTP relay is present, the loopback-source's
packets are dropped by the RTP relay until the loopback-mirror has
started transmitting media and the media state within the RTP relay
is established. This results in a chicken and egg scenario as the
looback-mirror cannot transmit any media until it receives the
media packets from the loopback-source but for the loopback-mirror
to receive any packets it needs to send one first. In order to
resolve this dilemma, Section 8 introduces a new payload type whose
sole purpose is to establish the media state in the intermediate
devices. In the presence of this payload type, the loopback-mirror
will transmit media according to the payload description until it
receives media from the loopback-source. The loopback-mirror MAY
include this payload type in the answer if it is not present in the
offer. This may be necessary if the loopback-mirror is aware of
NAT's, firewalls, or RTP relays on the path of the call. In this
case the loopback-source MUST accept media corresponding to this
payload type. After the first media packet is received from the
loopback-source, the loopback-mirror MUST terminate the
transmission of media for this payload type and MUST start looping
back media as defined by the other loopback attributes present in
the offer.
6. RTP Requirements 6. RTP Requirements
An answering entity that is compliant to this specification and An answering entity that is compliant to this specification and
accepting a media with rtp-pkt-loopback loopback-type MUST loopback accepting a media with rtp-pkt-loopback loopback-type MUST loopback
the incoming RTP packets using either the encapsulated RTP payload the incoming RTP packets using either the encapsulated RTP payload
format or the direct loopback RTP payload format as defined in format or the direct loopback RTP payload format as defined in
section 7 of this specification. section 7 of this specification.
An answering entity that is compliant to this specification and An answering entity that is compliant to this specification and
accepting a media with rtp-media-loopback loopback-type MUST accepting a media with rtp-media-loopback loopback-type MUST
skipping to change at page 12, line 6 skipping to change at page 11, line 45
used or more likely signaled dynamically out-of-band (e.g., using used or more likely signaled dynamically out-of-band (e.g., using
SDP; section 7.1.3 defines the name binding). SDP; section 7.1.3 defines the name binding).
Marker (M) bit: If the received RTP packet is looped back in Marker (M) bit: If the received RTP packet is looped back in
multiple RTP packets, the M bit is set to 1 in the last packet, multiple RTP packets, the M bit is set to 1 in the last packet,
otherwise it is set to 0. otherwise it is set to 0.
Extension (X) bit: Defined by the RTP Profile used. Extension (X) bit: Defined by the RTP Profile used.
Sequence Number: The RTP sequence number SHOULD be generated by the Sequence Number: The RTP sequence number SHOULD be generated by the
loopback-mirror in the usual manner with a constant random offset. loopback-mirror in the usual manner with a constant random offset
as described in RFC 3550 [RFC3550].
Timestamp: The RTP timestamp denotes the sampling instant for when Timestamp: The RTP timestamp denotes the sampling instant for when
the loopback-mirror is transmitting this packet to the loopback- the loopback-mirror is transmitting this packet to the loopback-
source. The RTP timestamp MUST be based on the same clock used by source. The RTP timestamp MUST use the same clock rate used by the
the loopback-source. The initial value of the timestamp SHOULD be loopback-source. The initial value of the timestamp SHOULD be
random for security reasons (see Section 5.1 of RFC 3550 random for security reasons (see Section 5.1 of RFC 3550
[RFC3550]). [RFC3550]).
SSRC: set as described in RFC 3550 [RFC3550]. SSRC: set as described in RFC 3550 [RFC3550].
CC and CSRC fields are used as described in RFC 3550 [RFC3550]. CC and CSRC fields are used as described in RFC 3550 [RFC3550].
7.1.2 RTP Payload Structure 7.1.2 RTP Payload Structure
The RTP header in the encapsulated packet MUST be followed by the The RTP header in the encapsulated packet MUST be followed by the
skipping to change at page 12, line 50 skipping to change at page 12, line 47
| contributing source (CSRC) identifiers | | contributing source (CSRC) identifiers |
| .... | | .... |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
The 12 octets after the receive timestamp are identical to the RTP The 12 octets after the receive timestamp are identical to the RTP
header in the received packet except for the first 4 bits of the header in the received packet except for the first 4 bits of the
first octet. first octet.
Receive Timestamp: 32 bits Receive Timestamp: 32 bits
The Receieve timestamp denotes the sampling instant for when the The Receive timestamp denotes the sampling instant for when the
last octet of the media packet that is being encapsulated by the last octet of the received media packet that is being encapsulated
loopback-mirror is received from the loopback-source. The Receive by the loopback-mirror is received from the loopback-source. The
timestamp MUST be based on the same clock used by the loopback- Receive timestamp MUST be based on the same clock used by the
source. The initial value of the timestamp SHOULD be random for loopback-source. The initial value of the timestamp SHOULD be
security reasons (see Section 5.1 of RFC 3550 [RFC3550]). random for security reasons (see Section 5.1 of RFC 3550
[RFC3550]).
Fragmentation (F): 2 bits Fragmentation (F): 2 bits
First Fragment (00) /Last Fragment (01) /No Fragmentation(10)/ First Fragment (00) /Last Fragment (01) /No Fragmentation(10)/
Intermediate Fragment (11). This field identifies how much of the Intermediate Fragment (11). This field identifies how much of the
received packet is encapsulated in this packet by the loopback- received packet is encapsulated in this packet by the loopback-
mirror. If the received packet is not fragmented, this field is mirror. If the received packet is not fragmented, this field is
set to 10; otherwise the packet that contains the first fragments set to 10; otherwise the packet that contains the first fragments
sets this field to 00, the packet that contains the last fragment sets this field to 00, the packet that contains the last fragment
sets this field to 01, all other packets set this field to 11. sets this field to 01, all other packets set this field to 11.
skipping to change at page 15, line 10 skipping to change at page 15, line 8
negotiated using a mechanism like SDP. There is no static payload negotiated using a mechanism like SDP. There is no static payload
type assignment for the stream, so dynamic payload type numbers type assignment for the stream, so dynamic payload type numbers
MUST be used. The binding to the name is indicated by an rtpmap MUST be used. The binding to the name is indicated by an rtpmap
attribute. The name used in this binding is "rtploopback". attribute. The name used in this binding is "rtploopback".
The following is an example SDP fragment for encapsulated RTP. The following is an example SDP fragment for encapsulated RTP.
m=audio 41352 RTP/AVP 112 m=audio 41352 RTP/AVP 112
a=rtpmap:112 rtploopback/8000 a=rtpmap:112 rtploopback/8000
8. RTCP Requirements 8. Payload format for Priming the Loopback Pump
The sole purpose of the payload format described in this section is
to prime the loopback pump in cases where the loopback process
cannot start because of intermediate devices in the network as
described in Section 5.7.
8.1 Usage of RTP Header fields
Payload Type (PT): The assignment of an RTP payload type for this
packet format is outside the scope of this document; it is either
specified by the RTP profile under which this payload format is
used or more likely signaled dynamically out-of-band (e.g., using
SDP; section 8.2 defines the name binding).
All other fields are set as described in RFC 3550 [RFC3550].
8.2 Usage of SDP
The payload type number for the loopback primer stream can be
negotiated using a mechanism like SDP. There is no static payload
type assignment for the loopback primer stream, so dynamic payload
type numbers MUST be used. The binding to the name is indicated by
an rtpmap attribute. The name used in this binding is
"loopbkprimer".
The following is an example SDP fragment for loopback primer RTP
stream.
m=audio 41352 RTP/AVP 112
a=rtpmap:112 loopbkprimer/8000
9. RTCP Requirements
The use of the loopback attribute is intended for monitoring of The use of the loopback attribute is intended for monitoring of
media quality of the session. Consequently the media performance media quality of the session. Consequently the media performance
information should be exchanged between the offering and the information should be exchanged between the offering and the
answering entities. An offering or answering entity that is answering entities. An offering or answering entity that is
compliant to this specification SHOULD support RTCP per [RFC3550] compliant to this specification SHOULD support RTCP per [RFC3550]
and RTCP-XR per RFC 3611 [RFC3611]. Furthermore, if the client or and RTCP-XR per RFC 3611 [RFC3611]. Furthermore, if the client or
the server choose to support RTCP-XR, they SHOULD support RTCP-XR the server choose to support RTCP-XR, they SHOULD support RTCP-XR
Loss RLE report block, Duplicate RLE report block, Statistics Loss RLE report block, Duplicate RLE report block, Statistics
Summary report block, and VoIP Metric Reports Block per sections Summary report block, and VoIP Metric Reports Block per sections
4.1, 4.2, 4.6, and 4.7 of RFC 3611 [RFC3611]. The client and the 4.1, 4.2, 4.6, and 4.7 of RFC 3611 [RFC3611]. The client and the
server MAY support other RTCP-XR reporting blocks as defined by RFC server MAY support other RTCP-XR reporting blocks as defined by RFC
3611 [RFC3611]. 3611 [RFC3611].
9. Congestion Control 10. Congestion Control
All the participants in a loopback session SHOULD implement All the participants in a loopback session SHOULD implement
congestion control mechanisms as defined by the RTP profile under congestion control mechanisms as defined by the RTP profile under
which the loopback mechanism is implemented. For audio video which the loopback mechanism is implemented. For audio video
profiles, implementations SHOULD conform to the mechanism defined profiles, implementations SHOULD conform to the mechanism defined
in Section 2 of RFC 3551. in Section 2 of RFC 3551.
10. Examples 11. Examples
This section provides examples for media descriptions using SDP for This section provides examples for media descriptions using SDP for
different scenarios. The examples are given for SIP-based different scenarios. The examples are given for SIP-based
transactions and are abbreviated and do not show the complete transactions and are abbreviated and do not show the complete
signaling for convenience. signaling for convenience.
10.1 Offer for specific media loopback type 11.1 Offer for specific media loopback type
A client sends an INVITE request with SDP which looks like: A client sends an INVITE request with SDP which looks like:
v=0 v=0
o=user1 2890844526 2890842807 IN IP4 192.0.2.11 o=user1 2890844526 2890842807 IN IP4 192.0.2.11
s=Example s=Example
i=An example session i=An example session
e=user@example.com e=user@example.com
c=IN IP4 192.0.2.12/127 c=IN IP4 192.0.2.12/127
t=0 0 t=0 0
m=audio 49170 RTP/AVP 0 m=audio 49170 RTP/AVP 0
a=loopback:rtp-media-loopback a=loopback:rtp-media-loopback
a=loopback-source:0 a=loopback-source:0
a=rtpmap:0 pcmu/8000
The client is offering to source the media and expects the server The client is offering to source the media and expects the server
to mirror the RTP stream per rtp-media-loopback loopback type. to mirror the RTP stream per rtp-media-loopback loopback type.
A server sends a response with SDP which looks like: A server sends a response with SDP which looks like:
v=0 v=0
o=user1 2890844526 2890842807 IN IP4 192.0.2.11 o=user1 2890844526 2890842807 IN IP4 192.0.2.11
s=Example s=Example
i=An example session i=An example session
e=user@example.com e=user@example.com
c=IN IP4 192.0.2.12/127 c=IN IP4 192.0.2.12/127
t=0 0 t=0 0
m=audio 49270 RTP/AVP 0 m=audio 49270 RTP/AVP 0
a=loopback:rtp-media-loopback a=loopback:rtp-media-loopback
a=loopback-mirror:0 a=loopback-mirror:0
a=rtpmap:0 pcmu/8000
The server is accepting to mirror the media from the client at the The server is accepting to mirror the media from the client at the
media level. media level.
10.2 Offer for choice of media loopback type 11.2 Offer for choice of media loopback type
A client sends an INVITE request with SDP which looks like: A client sends an INVITE request with SDP which looks like:
v=0 v=0
o=user1 2890844526 2890842807 IN IP4 192.0.2.11 o=user1 2890844526 2890842807 IN IP4 192.0.2.11
s=Example s=Example
i=An example session i=An example session
e=user@example.com e=user@example.com
c=IN IP4 192.0.2.12/127 c=IN IP4 192.0.2.12/127
t=0 0 t=0 0
m=audio 49170 RTP/AVP 0 112 113 m=audio 49170 RTP/AVP 0 112 113
a=loopback:rtp-media-loopback rtp-pkt-loopback a=loopback:rtp-media-loopback rtp-pkt-loopback
a=loopback-source:0 a=loopback-source:0
a=rtpmap:0 pcum/8000
a=rtpmap:112 encaprtp/8000 a=rtpmap:112 encaprtp/8000
a=rtpmap:113 rtploopback/8000 a=rtpmap:113 rtploopback/8000
The client is offering to source the media and expects the server The client is offering to source the media and expects the server
to mirror the RTP stream at either the media or rtp level. to mirror the RTP stream at either the media or rtp level.
A server sends a response with SDP which looks like: A server sends a response with SDP which looks like:
v=0 v=0
o=user1 2890844526 2890842807 IN IP4 192.0.2.11 o=user1 2890844526 2890842807 IN IP4 192.0.2.11
s=Example s=Example
i=An example session i=An example session
e=user@example.com e=user@example.com
c=IN IP4 192.0.2.12/127 c=IN IP4 192.0.2.12/127
t=0 0 t=0 0
m=audio 49270 RTP/AVP 112 m=audio 49270 RTP/AVP 112
a=loopback:rtp-pkt-loopback a=loopback:rtp-pkt-loopback
a=loopback-mirror:0 a=loopback-mirror:0
a=rtpmap:0 pcmu/8000
a=rtpmap:112 encaprtp/8000 a=rtpmap:112 encaprtp/8000
The server is accepting to mirror the media from the client at the The server is accepting to mirror the media from the client at the
packet level using the encapsulated RTP payload format. packet level using the encapsulated RTP payload format.
10.3 Offer for choice of media loopback type with rtp-start-loopback 11.3 Offer for choice of media loopback type with loopback primer
A client sends an INVITE request with SDP which looks like: A client sends an INVITE request with SDP which looks like:
v=0 v=0
o=user1 2890844526 2890842807 IN IP4 192.0.2.11 o=user1 2890844526 2890842807 IN IP4 192.0.2.11
s=Example s=Example
i=An example session i=An example session
e=user@example.com e=user@example.com
c=IN IP4 192.0.2.12/127 c=IN IP4 192.0.2.12/127
t=0 0 t=0 0
m=audio 49170 RTP/AVP 0 112 113 m=audio 49170 RTP/AVP 0 112 113 114
a=loopback:rtp-media-loopback rtp-pkt-loopback a=loopback:rtp-media-loopback rtp-pkt-loopback
a=loopback-source:0 a=loopback-source:0
a=rtpmap:0 pcmu/8000
a=rtpmap:112 encaprtp/8000 a=rtpmap:112 encaprtp/8000
a=rtpmap:113 rtploopback/8000 a=rtpmap:113 rtploopback/8000
m=audio 49170 RTP/AVP 100 a=rtpmap:114 loopbkprimer/8000
a=loopback:rtp-start-loopback
The client is offering to source the media and expects the server The client is offering to source the media and expects the server
to mirror the RTP stream at either the media or rtp level. The to mirror the RTP stream at either the media or rtp level. The
client also expects the server to source media until it receives client also expects the server to source media until it receives
packets from the server per media described with the packets from the server per media described with the loopbkprimer
rtp-start-loopback attribute. payload type.
A server sends a response with SDP which looks like: A server sends a response with SDP which looks like:
v=0 v=0
o=user1 2890844526 2890842807 IN IP4 192.0.2.11 o=user1 2890844526 2890842807 IN IP4 192.0.2.11
s=Example s=Example
i=An example session i=An example session
e=user@example.com e=user@example.com
c=IN IP4 192.0.2.12/127 c=IN IP4 192.0.2.12/127
t=0 0 t=0 0
m=audio 49270 RTP/AVP 113 m=audio 49270 RTP/AVP 113
a=loopback:rtp-pkt-loopback a=loopback:rtp-pkt-loopback
a=loopback-mirror:0 a=loopback-mirror:0 114
a=rtpmap:0 pcmu/8000
a=rtpmap:113 rtploopback/8000 a=rtpmap:113 rtploopback/8000
m=audio 49270 RTP/AVP 100 a=rtmpa:114 loopbkprimer/8000
a=rtpmap:100 pcmu/8000
a=loopback:rtp-start-loopback
The server is accepting to mirror the media from the client at the The server is accepting to mirror the media from the client at the
packet level using the direct loopback RTP payload format. The packet level using the direct loopback RTP payload format. The
server is also accepting to source media until it receives media server is also accepting to source media until it receives media
packets from the client. packets from the client.
10.4 Response to INVITE request rejecting loopback media 11.4 Response to INVITE request rejecting loopback media
A client sends an INVITE request with SDP which looks like: A client sends an INVITE request with SDP which looks like:
v=0 v=0
o=user1 2890844526 2890842807 IN IP4 192.0.2.11 o=user1 2890844526 2890842807 IN IP4 192.0.2.11
s=Example s=Example
i=An example session i=An example session
e=user@example.com e=user@example.com
c=IN IP4 192.0.2.12/127 c=IN IP4 192.0.2.12/127
t=0 0 t=0 0
m=audio 49170 RTP/AVP 0 m=audio 49170 RTP/AVP 0
a=loopback:rtp-media-loopback a=loopback:rtp-media-loopback
a=loopback-source:0 a=loopback-source:0
a=rtpmap:0 pcmu/8000
The client is offering to source the media and expects the server The client is offering to source the media and expects the server
to mirror the RTP stream at the media level. to mirror the RTP stream at the media level.
A server sends a response with SDP which looks like: A server sends a response with SDP which looks like:
v=0 v=0
o=user1 2890844526 2890842807 IN IP4 192.0.2.11 o=user1 2890844526 2890842807 IN IP4 192.0.2.11
s=Example s=Example
i=An example session i=An example session
e=user@example.com e=user@example.com
c=IN IP4 192.0.2.12/127 c=IN IP4 192.0.2.12/127
t=0 0 t=0 0
m=audio 0 RTP/AVP 0 m=audio 0 RTP/AVP 0
a=loopback:rtp-media-loopback a=loopback:rtp-media-loopback
a=loopback-mirror:0 a=loopback-mirror:0
a=rtpmap:0 pcmu/8000
NOTE: Loopback request may be rejected by either not including the NOTE: Loopback request may be rejected by either not including the
loopback mode attribute (for backward compatibility) or setting the loopback mode attribute (for backward compatibility) or setting the
media port number to zero, or both, in the response. media port number to zero, or both, in the response.
10.5 Response to INVITE request rejecting loopback media with 11.5 Response to INVITE request rejecting loopback media with loopback
rtp-start-loopback primer payload type
A client sends an INVITE request with SDP which looks like: A client sends an INVITE request with SDP which looks like:
v=0 v=0
o=user1 2890844526 2890842807 IN IP4 192.0.2.11 o=user1 2890844526 2890842807 IN IP4 192.0.2.11
s=Example s=Example
i=An example session i=An example session
e=user@example.com e=user@example.com
c=IN IP4 192.0.2.12/127 c=IN IP4 192.0.2.12/127
t=0 0 t=0 0
m=audio 49170 RTP/AVP 0 m=audio 49170 RTP/AVP 0 100
a=loopback:rtp-media-loopback a=loopback:rtp-media-loopback
a=loopback-source:0 a=loopback-source:0
m=audio 49170 RTP/AVP 100 a=rtpmap:0 pcum/8000
a=loopback:rtp-start-loopback a=rtpmap:100 loopbkprimer/8000
The client is offering to source the media and expects the server The client is offering to source the media and expects the server
to mirror the RTP stream at the media level. The client also to mirror the RTP stream at the media level. The client also
expects the server to source media until it receives packets from expects the server to source media until it receives packets from
the server per media described with the rtp-start-loopback the server using the loopbkprimer payload type.
attribute.
A server sends a response with SDP which looks like: A server sends a response with SDP which looks like:
v=0 v=0
o=user1 2890844526 2890842807 IN IP4 192.0.2.11 o=user1 2890844526 2890842807 IN IP4 192.0.2.11
s=Example s=Example
i=An example session i=An example session
e=user@example.com e=user@example.com
c=IN IP4 192.0.2.12/127 c=IN IP4 192.0.2.12/127
t=0 0 t=0 0
m=audio 0 RTP/AVP 0 m=audio 0 RTP/AVP 0
a=loopback:rtp-media-loopback a=loopback:rtp-media-loopback
a=loopback-mirror:0 a=loopback-mirror:0
m=audio 0 RTP/AVP 0
a=loopback:rtp-start-loopback
NOTE: Loopback request may be rejected by either not including the NOTE: Loopback request may be rejected by either not including the
loopback mode attribute (for backward compatibility) or setting the loopback mode attribute (for backward compatibility) or setting the
media port number to zero, or both, in the response. media port number to zero, or both, in the response.
11. Security Considerations 12. Security Considerations
The security considerations of [RFC3261] apply. Furthermore, given The security considerations of [RFC3261] apply. Furthermore, given
that media loopback may be automated without the end user's that media loopback may be automated without the end user's
knowledge, the server of the media loopback should be aware of knowledge, the server of the media loopback should be aware of
denial of service attacks. It is recommended that sessions with denial of service attacks. It is recommended that sessions with
media loopback are authenticated and the frequency of such sessions media loopback are authenticated and the frequency of such sessions
is limited by the server. is limited by the server.
12. Implementation Considerations 13. Implementation Considerations
The media loopback approach described in this document is a The media loopback approach described in this document is a
complete solution that would work under all scenarios. However, it complete solution that would work under all scenarios. However, it
is believed that the solution may not be light-weight enough for is believed that the solution may not be light-weight enough for
the common case. In light of this concern, this section clarifies the common case. In light of this concern, this section clarifies
which features of the loopback proposal MUST be implemented for all which features of the loopback proposal MUST be implemented for all
implementations and which features MAY be deferred if the complete implementations and which features MAY be deferred if the complete
solution is not desired. solution is not desired.
All implementations MUST support the rtp-pkt-loopback option for All implementations MUST support the rtp-pkt-loopback option for
loopback-type attribute. In addition, for the loopback-mode loopback-type attribute. In addition, for the loopback-mode
attribute, all implementations of an offerer MUST at a minimum be attribute, all implementations of an offerer MUST at a minimum be
able to act as a loopback-source. All implementation MUST also at a able to act as a loopback-source. All implementation MUST also at a
minimum support the direct media loopback payload type. Remaining minimum support the direct media loopback payload type. The rtp-
attribute values including rtp-media-loopback and media-loopback attribute MAY be implemented in complete
rtp-start-loopback MAY be implemented in complete implementations implementations of this draft.
of this draft.
13. IANA Considerations 14. IANA Considerations
13.1 SDP Attributes 14.1 SDP Attributes
This document defines three new media-level SDP attributes. IANA This document defines three new media-level SDP attributes. IANA
has registered the following attributes: has registered the following attributes:
Contact name: Kaynam Hedayat Contact name: Kaynam Hedayat
<kaynam.hedayat@exfo.com>. <kaynam.hedayat@exfo.com>.
Attribute name: "loopback". Attribute name: "loopback".
Type of attribute: Media level. Type of attribute: Media level.
Subject to charset: No. Subject to charset: No.
Purpose of attribute: The 'loopback' attribute is used to Purpose of attribute: The 'loopback' attribute is used to
indicate the type of media loopback. indicate the type of media loopback.
Allowed attribute values: The parameters to 'loopback' may be Allowed attribute values: The parameters to 'loopback' may be
one or more of "rtp-pkt-loopback," one or more of "rtp-pkt-loopback" and
"rtp-media-loopback," and "rtp-media-loopback". See section 5
"rtp-start-loopback". See section 5
of this document for syntax. of this document for syntax.
Contact name: Kaynam Hedayat Contact name: Kaynam Hedayat
<kaynam.hedayat@exfo.com>. <kaynam.hedayat@exfo.com>.
Attribute name: "loopback-source". Attribute name: "loopback-source".
Type of attribute: Media level. Type of attribute: Media level.
Subject to charset: No. Subject to charset: No.
Purpose of attribute: The 'loopback-source' attribute Purpose of attribute: The 'loopback-source' attribute
specifies that the sender is the media specifies that the sender is the media
source and expects the receiver to act source and expects the receiver to act
as a loopback-mirror. as a loopback-mirror.
Allowed attribute values: The parameter to 'loopback-source' is Allowed attribute values: The parameter to 'loopback-source' is
a media format ("<fmt>") description a media format ("<fmt>") description
as defined in RFC 4566 Section 5.14. as defined in RFC 4566 Section 5.14.
Contact name: Kaynam Hedayat Contact name: Kaynam Hedayat
skipping to change at page 21, line 41 skipping to change at page 22, line 27
Type of attribute: Media level. Type of attribute: Media level.
Subject to charset: No. Subject to charset: No.
Purpose of attribute: The 'loopback-mirror' attribute Purpose of attribute: The 'loopback-mirror' attribute
specifies that the receiver will specifies that the receiver will
mirror (echo) all received media back mirror (echo) all received media back
to the sender of the RTP stream. to the sender of the RTP stream.
Allowed attribute values: The parameter to 'loopback-mirror' is Allowed attribute values: The parameter to 'loopback-mirror' is
a media format ("<fmt>") description a media format ("<fmt>") description
as defined in RFC 4566 Section 5.14. as defined in RFC 4566 Section 5.14.
13.2 MIME Types 14.2 MIME Types
The IANA has registered the following MIME types: The IANA has registered the following MIME types:
13.2.1 audio/encaprtp 14.2.1 audio/encaprtp
To: ietf-types@iana.org To: ietf-types@iana.org
Subject: Registration of media type audio/encaprtp Subject: Registration of media type audio/encaprtp
Type name: audio Type name: audio
Subtype name: encaprtp Subtype name: encaprtp
Required parameters: Required parameters:
rate:RTP timestamp clock rate, which is equal to the rate:RTP timestamp clock rate, which is equal to the
sampling rate. The typical rate is 8000; other rates sampling rate. The typical rate is 8000; other rates
may be specified. may be specified.
Optional parameters: none Optional parameters: none
skipping to change at page 22, line 17 skipping to change at page 23, line 5
rate:RTP timestamp clock rate, which is equal to the rate:RTP timestamp clock rate, which is equal to the
sampling rate. The typical rate is 8000; other rates sampling rate. The typical rate is 8000; other rates
may be specified. may be specified.
Optional parameters: none Optional parameters: none
Encoding considerations: This media type is framed Encoding considerations: This media type is framed
binary data. binary data.
Security considerations: See Section 11 of this document. Security considerations: See Section 12 of this document.
Interoperability considerations: none Interoperability considerations: none
Published specification: This MIME type is described fully Published specification: This MIME type is described fully
within this document. within this document.
Applications which use this media type: Applications wishing Applications which use this media type: Applications wishing
to monitor and ensure the quality of transport to the to monitor and ensure the quality of transport to the
edge of a given VoIP, Real-Time Text or Video Over IP edge of a given VoIP, Real-Time Text or Video Over IP
Service. Service.
skipping to change at page 23, line 5 skipping to change at page 23, line 37
framing, and hence is only defined for transfer via framing, and hence is only defined for transfer via
RTP. Transfer within other framing protocols is not RTP. Transfer within other framing protocols is not
defined at this time. defined at this time.
Author: Author:
Kaynam Hedayat. Kaynam Hedayat.
Change controller: IETF Audio/Video Transport working Change controller: IETF Audio/Video Transport working
group delegated from the IESG. group delegated from the IESG.
13.2.2 video/encaprtp 14.2.2 video/encaprtp
To: ietf-types@iana.org To: ietf-types@iana.org
Subject: Registration of media type video/encaprtp Subject: Registration of media type video/encaprtp
Type name: video Type name: video
Subtype name: encaprtp Subtype name: encaprtp
Required parameters: Required parameters:
rate:RTP timestamp clock rate, which is equal to the rate:RTP timestamp clock rate, which is equal to the
sampling rate. The typical rate is 8000; other rates sampling rate. The typical rate is 8000; other rates
may be specified. may be specified.
Optional parameters: none Optional parameters: none
Encoding considerations: This media type is framed Encoding considerations: This media type is framed
binary data. binary data.
Security considerations: See Section 11 of this document. Security considerations: See Section 12 of this document.
Interoperability considerations: none Interoperability considerations: none
Published specification: This MIME type is described fully Published specification: This MIME type is described fully
within this document. within this document.
Applications which use this media type: Applications wishing Applications which use this media type: Applications wishing
to monitor and ensure the quality of transport to the to monitor and ensure the quality of transport to the
edge of a given VoIP, Real-Time Text or Video Over IP edge of a given VoIP, Real-Time Text or Video Over IP
Service. Service.
skipping to change at page 24, line 8 skipping to change at page 24, line 42
framing, and hence is only defined for transfer via framing, and hence is only defined for transfer via
RTP. Transfer within other framing protocols is not RTP. Transfer within other framing protocols is not
defined at this time. defined at this time.
Author: Author:
Kaynam Hedayat. Kaynam Hedayat.
Change controller: IETF Audio/Video Transport working Change controller: IETF Audio/Video Transport working
group delegated from the IESG. group delegated from the IESG.
13.2.3 text/encaprtp 14.2.3 text/encaprtp
To: ietf-types@iana.org To: ietf-types@iana.org
Subject: Registration of media type text/encaprtp Subject: Registration of media type text/encaprtp
Type name: text Type name: text
Subtype name: encaprtp Subtype name: encaprtp
Required parameters: Required parameters:
rate:RTP timestamp clock rate, which is equal to the rate:RTP timestamp clock rate, which is equal to the
sampling rate. The typical rate is 8000; other rates sampling rate. The typical rate is 8000; other rates
may be specified. may be specified.
Optional parameters: none Optional parameters: none
Encoding considerations: This media type is framed Encoding considerations: This media type is framed
binary data. binary data.
skipping to change at page 24, line 29 skipping to change at page 25, line 15
rate:RTP timestamp clock rate, which is equal to the rate:RTP timestamp clock rate, which is equal to the
sampling rate. The typical rate is 8000; other rates sampling rate. The typical rate is 8000; other rates
may be specified. may be specified.
Optional parameters: none Optional parameters: none
Encoding considerations: This media type is framed Encoding considerations: This media type is framed
binary data. binary data.
Security considerations: See Section 11 of this document. Security considerations: See Section 12 of this document.
Interoperability considerations: none Interoperability considerations: none
Published specification: This MIME type is described fully Published specification: This MIME type is described fully
within this document. within this document.
Applications which use this media type: Applications wishing Applications which use this media type: Applications wishing
to monitor and ensure the quality of transport to the to monitor and ensure the quality of transport to the
edge of a given VoIP, Real-Time Text or Video Over IP edge of a given VoIP, Real-Time Text or Video Over IP
Service. Service.
skipping to change at page 25, line 13 skipping to change at page 25, line 47
framing, and hence is only defined for transfer via framing, and hence is only defined for transfer via
RTP. Transfer within other framing protocols is not RTP. Transfer within other framing protocols is not
defined at this time. defined at this time.
Author: Author:
Kaynam Hedayat. Kaynam Hedayat.
Change controller: IETF Audio/Video Transport working Change controller: IETF Audio/Video Transport working
group delegated from the IESG. group delegated from the IESG.
13.2.4 application/encaprtp 14.2.4 application/encaprtp
To: ietf-types@iana.org To: ietf-types@iana.org
Subject: Registration of media type Subject: Registration of media type
application/encaprtp application/encaprtp
Type name: application Type name: application
Subtype name: encaprtp Subtype name: encaprtp
Required parameters: Required parameters:
rate:RTP timestamp clock rate, which is equal to the rate:RTP timestamp clock rate, which is equal to the
skipping to change at page 25, line 35 skipping to change at page 26, line 22
rate:RTP timestamp clock rate, which is equal to the rate:RTP timestamp clock rate, which is equal to the
sampling rate. The typical rate is 8000; other rates sampling rate. The typical rate is 8000; other rates
may be specified. may be specified.
Optional parameters: none Optional parameters: none
Encoding considerations: This media type is framed Encoding considerations: This media type is framed
binary data. binary data.
Security considerations: See Section 11 of this document. Security considerations: See Section 12 of this document.
Interoperability considerations: none Interoperability considerations: none
Published specification: This MIME type is described fully Published specification: This MIME type is described fully
within this document. within this document.
Applications which use this media type: Applications wishing Applications which use this media type: Applications wishing
to monitor and ensure the quality of transport to the to monitor and ensure the quality of transport to the
edge of a given VoIP, Real-Time Text or Video Over IP edge of a given VoIP, Real-Time Text or Video Over IP
Service. Service.
skipping to change at page 26, line 19 skipping to change at page 27, line 5
framing, and hence is only defined for transfer via framing, and hence is only defined for transfer via
RTP. Transfer within other framing protocols is not RTP. Transfer within other framing protocols is not
defined at this time. defined at this time.
Author: Author:
Kaynam Hedayat. Kaynam Hedayat.
Change controller: IETF Audio/Video Transport working Change controller: IETF Audio/Video Transport working
group delegated from the IESG. group delegated from the IESG.
13.2.5 audio/rtploopback 14.2.5 audio/rtploopback
To: ietf-types@iana.org To: ietf-types@iana.org
Subject: Registration of media type audio/rtploopback Subject: Registration of media type audio/rtploopback
Type name: audio Type name: audio
Subtype name: rtploopback Subtype name: rtploopback
Required parameters: Required parameters:
rate:RTP timestamp clock rate, which is equal to the rate:RTP timestamp clock rate, which is equal to the
sampling rate. The typical rate is 8000; other rates sampling rate. The typical rate is 8000; other rates
may be specified. may be specified.
Optional parameters: none Optional parameters: none
Encoding considerations: This media type is framed Encoding considerations: This media type is framed
binary data. binary data.
Security considerations: See Section 11 of this document. Security considerations: See Section 12 of this document.
Interoperability considerations: none Interoperability considerations: none
Published specification: This MIME type is described fully Published specification: This MIME type is described fully
within this document. within this document.
Applications which use this media type: Applications wishing Applications which use this media type: Applications wishing
to monitor and ensure the quality of transport to the to monitor and ensure the quality of transport to the
edge of a given VoIP, Real-Time Text or Video Over IP edge of a given VoIP, Real-Time Text or Video Over IP
Service. Service.
skipping to change at page 27, line 17 skipping to change at page 28, line 4
EMail: kaynam.hedayat@exfo.com EMail: kaynam.hedayat@exfo.com
Intended usage: COMMON Intended usage: COMMON
Restrictions on usage: This media type depends on RTP Restrictions on usage: This media type depends on RTP
framing, and hence is only defined for transfer via framing, and hence is only defined for transfer via
RTP. Transfer within other framing protocols is not RTP. Transfer within other framing protocols is not
defined at this time. defined at this time.
Author: Author:
Kaynam Hedayat. Kaynam Hedayat.
Change controller: IETF Audio/Video Transport working Change controller: IETF Audio/Video Transport working
group delegated from the IESG. group delegated from the IESG.
13.2.6 video/rtploopback 14.2.6 video/rtploopback
To: ietf-types@iana.org To: ietf-types@iana.org
Subject: Registration of media type video/rtploopback Subject: Registration of media type video/rtploopback
Type name: video Type name: video
Subtype name: rtploopback Subtype name: rtploopback
Required parameters: Required parameters:
rate:RTP timestamp clock rate, which is equal to the rate:RTP timestamp clock rate, which is equal to the
sampling rate. The typical rate is 8000; other rates sampling rate. The typical rate is 8000; other rates
may be specified. may be specified.
Optional parameters: none Optional parameters: none
Encoding considerations: This media type is framed Encoding considerations: This media type is framed
binary data. binary data.
Security considerations: See Section 11 of this document. Security considerations: See Section 12 of this document.
Interoperability considerations: none Interoperability considerations: none
Published specification: This MIME type is described fully Published specification: This MIME type is described fully
within this document. within this document.
Applications which use this media type: Applications wishing Applications which use this media type: Applications wishing
to monitor and ensure the quality of transport to the to monitor and ensure the quality of transport to the
edge of a given VoIP, Real-Time Text or Video Over IP edge of a given VoIP, Real-Time Text or Video Over IP
Service. Service.
skipping to change at page 28, line 27 skipping to change at page 29, line 13
framing, and hence is only defined for transfer via framing, and hence is only defined for transfer via
RTP. Transfer within other framing protocols is not RTP. Transfer within other framing protocols is not
defined at this time. defined at this time.
Author: Author:
Kaynam Hedayat. Kaynam Hedayat.
Change controller: IETF Audio/Video Transport working Change controller: IETF Audio/Video Transport working
group delegated from the IESG. group delegated from the IESG.
13.2.7 text/rtploopback 14.2.7 text/rtploopback
To: ietf-types@iana.org To: ietf-types@iana.org
Subject: Registration of media type text/rtploopback Subject: Registration of media type text/rtploopback
Type name: text Type name: text
Subtype name: rtploopback Subtype name: rtploopback
Required parameters: Required parameters:
rate:RTP timestamp clock rate, which is equal to the rate:RTP timestamp clock rate, which is equal to the
sampling rate. The typical rate is 8000; other rates sampling rate. The typical rate is 8000; other rates
may be specified. may be specified.
Optional parameters: none Optional parameters: none
Encoding considerations: This media type is framed Encoding considerations: This media type is framed
binary data. binary data.
Security considerations: See Section 11 of this document. Security considerations: See Section 12 of this document.
Interoperability considerations: none Interoperability considerations: none
Published specification: This MIME type is described fully Published specification: This MIME type is described fully
within this document. within this document.
Applications which use this media type: Applications wishing Applications which use this media type: Applications wishing
to monitor and ensure the quality of transport to the to monitor and ensure the quality of transport to the
edge of a given VoIP, Real-Time Text or Video Over IP edge of a given VoIP, Real-Time Text or Video Over IP
Service. Service.
Additional information: none Additional information: none
skipping to change at page 29, line 32 skipping to change at page 30, line 18
framing, and hence is only defined for transfer via framing, and hence is only defined for transfer via
RTP. Transfer within other framing protocols is not RTP. Transfer within other framing protocols is not
defined at this time. defined at this time.
Author: Author:
Kaynam Hedayat. Kaynam Hedayat.
Change controller: IETF Audio/Video Transport working Change controller: IETF Audio/Video Transport working
group delegated from the IESG. group delegated from the IESG.
13.2.8 application/rtploopback 14.2.8 application/rtploopback
To: ietf-types@iana.org To: ietf-types@iana.org
Subject: Registration of media type Subject: Registration of media type
application/rtploopback application/rtploopback
Type name: application Type name: application
Subtype name: rtploopback Subtype name: rtploopback
skipping to change at page 30, line 6 skipping to change at page 30, line 40
rate:RTP timestamp clock rate, which is equal to the rate:RTP timestamp clock rate, which is equal to the
sampling rate. The typical rate is 8000; other rates sampling rate. The typical rate is 8000; other rates
may be specified. may be specified.
Optional parameters: none Optional parameters: none
Encoding considerations: This media type is framed Encoding considerations: This media type is framed
binary data. binary data.
Security considerations: See Section 11 of this document. Security considerations: See Section 12 of this document.
Interoperability considerations: none Interoperability considerations: none
Published specification: This MIME type is described fully Published specification: This MIME type is described fully
within this document. within this document.
Applications which use this media type: Applications wishing Applications which use this media type: Applications wishing
to monitor and ensure the quality of transport to the to monitor and ensure the quality of transport to the
edge of a given VoIP, Real-Time Text or Video Over IP edge of a given VoIP, Real-Time Text or Video Over IP
Service. Service.
skipping to change at page 30, line 38 skipping to change at page 31, line 25
framing, and hence is only defined for transfer via framing, and hence is only defined for transfer via
RTP. Transfer within other framing protocols is not RTP. Transfer within other framing protocols is not
defined at this time. defined at this time.
Author: Author:
Kaynam Hedayat. Kaynam Hedayat.
Change controller: IETF Audio/Video Transport working Change controller: IETF Audio/Video Transport working
group delegated from the IESG. group delegated from the IESG.
14. Acknowledgements 14.2.9 audio/loopbkprimer
To: ietf-types@iana.org
Subject: Registration of media type audio/loopbkprimer
Type name: audio
Subtype name: loopbkprimer
Required parameters:
rate:RTP timestamp clock rate, which is equal to the
sampling rate. The typical rate is 8000; other rates
may be specified.
Optional parameters: none
Encoding considerations: This media type is framed
binary data.
Security considerations: See Section 12 of this document.
Interoperability considerations: none
Published specification: This MIME type is described fully
within this document.
Applications which use this media type: Applications wishing
to monitor and ensure the quality of transport to the
edge of a given VoIP, Real-Time Text or Video Over IP
Service.
Additional information: none
Person & email address to contact for further information:
Kaynam Hedayat
EMail: kaynam.hedayat@exfo.com
Intended usage: COMMON
Restrictions on usage: This media type depends on RTP
framing, and hence is only defined for transfer via
RTP. Transfer within other framing protocols is not
defined at this time.
Author:
Kaynam Hedayat.
Change controller: IETF Audio/Video Transport working
group delegated from the IESG.
14.2.10 video/loopbkprimer
To: ietf-types@iana.org
Subject: Registration of media type video/loopbkprimer
Type name: video
Subtype name: loopbkprimer
Required parameters:
rate:RTP timestamp clock rate, which is equal to the
sampling rate. The typical rate is 8000; other rates
may be specified.
Optional parameters: none
Encoding considerations: This media type is framed
binary data.
Security considerations: See Section 12 of this document.
Interoperability considerations: none
Published specification: This MIME type is described fully
within this document.
Applications which use this media type: Applications wishing
to monitor and ensure the quality of transport to the
edge of a given VoIP, Real-Time Text or Video Over IP
Service.
Additional information: none
Person & email address to contact for further information:
Kaynam Hedayat
EMail: kaynam.hedayat@exfo.com
Intended usage: COMMON
Restrictions on usage: This media type depends on RTP
framing, and hence is only defined for transfer via
RTP. Transfer within other framing protocols is not
defined at this time.
Author:
Kaynam Hedayat.
Change controller: IETF Audio/Video Transport working
group delegated from the IESG.
14.2.11 text/loopbkprimer
To: ietf-types@iana.org
Subject: Registration of media type text/loopbkprimer
Type name: text
Subtype name: encaprtp
Required parameters:
rate:RTP timestamp clock rate, which is equal to the
sampling rate. The typical rate is 8000; other rates
may be specified.
Optional parameters: none
Encoding considerations: This media type is framed
binary data.
Security considerations: See Section 12 of this document.
Interoperability considerations: none
Published specification: This MIME type is described fully
within this document.
Applications which use this media type: Applications wishing
to monitor and ensure the quality of transport to the
edge of a given VoIP, Real-Time Text or Video Over IP
Service.
Additional information: none
Person & email address to contact for further information:
Kaynam Hedayat
EMail: kaynam.hedayat@exfo.com
Intended usage: COMMON
Restrictions on usage: This media type depends on RTP
framing, and hence is only defined for transfer via
RTP. Transfer within other framing protocols is not
defined at this time.
Author:
Kaynam Hedayat.
Change controller: IETF Audio/Video Transport working
group delegated from the IESG.
14.2.12 application/loopbkprimer
To: ietf-types@iana.org
Subject: Registration of media type
application/loopbkprimer
Type name: application
Subtype name: loopbkprimer
Required parameters:
rate:RTP timestamp clock rate, which is equal to the
sampling rate. The typical rate is 8000; other rates
may be specified.
Optional parameters: none
Encoding considerations: This media type is framed
binary data.
Security considerations: See Section 12 of this document.
Interoperability considerations: none
Published specification: This MIME type is described fully
within this document.
Applications which use this media type: Applications wishing
to monitor and ensure the quality of transport to the
edge of a given VoIP, Real-Time Text or Video Over IP
Service.
Additional information: none
Person & email address to contact for further information:
Kaynam Hedayat
EMail: kaynam.hedayat@exfo.com
Intended usage: COMMON
Restrictions on usage: This media type depends on RTP
framing, and hence is only defined for transfer via
RTP. Transfer within other framing protocols is not
defined at this time.
Author:
Kaynam Hedayat.
Change controller: IETF Audio/Video Transport working
group delegated from the IESG.
15. Acknowledgements
The authors wish to thank Nagarjuna Venna, Flemming Andreasen, Jeff The authors wish to thank Nagarjuna Venna, Flemming Andreasen, Jeff
Bernstein, Paul Kyzivat, and Dave Oran for their comments and Bernstein, Paul Kyzivat, and Dave Oran for their comments and
suggestions. suggestions.
15. Normative References 16. Normative References
[RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G.,
Johnston, A., Peterson, J., Sparks, R., Handley, M. Johnston, A., Peterson, J., Sparks, R., Handley, M.
and E. Schooler, "SIP: Session Initiation Protocol", and E. Schooler, "SIP: Session Initiation Protocol",
RFC 3261, June 2002. RFC 3261, June 2002.
[RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer [RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer
Model with the Session Description Protocol (SDP)", Model with the Session Description Protocol (SDP)",
RFC 3264, June 2002. RFC 3264, June 2002.
[RFC3550] Schulzrinne, H., Casner, S., Frederick, R. and V. [RFC3550] Schulzrinne, H., Casner, S., Frederick, R. and V.
Jacobson, "RTP: A Transport Protocol for Real-Time Jacobson, "RTP: A Transport Protocol for Real-Time
Applications", STD 64, RFC 3550, July 2003. Applications", STD 64, RFC 3550, July 2003.
 End of changes. 76 change blocks. 
151 lines changed or deleted 387 lines changed or added

This html diff was produced by rfcdiff 1.38. The latest version is available from http://tools.ietf.org/tools/rfcdiff/