draft-ietf-mmusic-reservation-flows-00.txt   draft-ietf-mmusic-reservation-flows-01.txt 
Internet Engineering Task Force SIP WG Internet Engineering Task Force SIP WG
Internet Draft G. Camarillo Internet Draft G. Camarillo
Ericsson Ericsson
A. Monrad A. Monrad
Ericsson Ericsson
draft-ietf-mmusic-reservation-flows-00.txt draft-ietf-mmusic-reservation-flows-01.txt
October 14, 2002 October 29, 2002
Expires: April 2003 Expires: April 2003
Mapping of Media Streams to Resource Reservation Flows Mapping of Media Streams to Resource Reservation Flows
STATUS OF THIS MEMO STATUS OF THIS MEMO
This document is an Internet-Draft and is in full conformance with This document is an Internet-Draft and is in full conformance with
all provisions of Section 10 of RFC2026. all provisions of Section 10 of RFC2026.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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This document defines an extension to the SDP grouping framework. It This document defines an extension to the SDP grouping framework. It
allows requesting that a group of media streams is mapped into a allows requesting that a group of media streams is mapped into a
single resource reservation flow. single resource reservation flow.
Table of Contents Table of Contents
1 Introduction ........................................ 3 1 Introduction ........................................ 3
1.1 Terminology ......................................... 3 1.1 Terminology ......................................... 3
2 SRF Semantics ....................................... 3 2 SRF Semantics ....................................... 3
3 Examples ............................................ 4 3 Applicability Statement ............................. 4
4 IANA Considerations ................................. 4 4 Examples ............................................ 4
5 Security Considerations ............................. 5 5 IANA Considerations ................................. 5
6 Authors' Addresses .................................. 5 6 Security Considerations ............................. 5
7 Normative References ................................ 5 7 Acknowledgements .................................... 5
8 Informative References .............................. 5 8 Authors' Addresses .................................. 5
9 Normative References ................................ 6
10 Informative References .............................. 6
1 Introduction 1 Introduction
Resource reservation protocols assign network resources to particular Resource reservation protocols assign network resources to particular
flows of IP packets. When a router receives an IP packet, it applies flows of IP packets. When a router receives an IP packet, it applies
a filter in order to map the packet to the flow it belongs. The a filter in order to map the packet to the flow it belongs. The
router provides the IP packet with the Quality of Service (QoS) router provides the IP packet with the Quality of Service (QoS)
corresponding to its flow. Routers typically use the source and the corresponding to its flow. Routers typically use the source and the
destination IP addresses and port numbers to filter packets. destination IP addresses and port numbers to filter packets.
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Media lines grouped using SRF semantics SHOULD be mapped into the Media lines grouped using SRF semantics SHOULD be mapped into the
same resource reservation flow. Media lines that do not belong to a same resource reservation flow. Media lines that do not belong to a
particular SRF group SHOULD NOT be mapped into the reservation flow particular SRF group SHOULD NOT be mapped into the reservation flow
used for that SRF group. used for that SRF group.
Note that an SRF group MAY consist of a single media line. In that Note that an SRF group MAY consist of a single media line. In that
case, following the definition above, that media line will be mapped case, following the definition above, that media line will be mapped
into one reservation flow. That reservation flow will carry traffic into one reservation flow. That reservation flow will carry traffic
from that media line, and from no other media lines. from that media line, and from no other media lines.
3 Examples 3 Applicability Statement
The way resource reservation works in some scenarios makes it
unnecessary the use of the mechanism described in this document. Some
resource reservation protocols allow the entity generating the SDP
session description to allocate resources in both directions (i.e.,
sendrecv) for the session. In this case, the generator of the session
description can chose any particular mapping of media flows and
reservation flows.
The mechanism described in this document is useful when the remote
party needs to be involved in the resource reservation.
4 Examples
For this example, we have chosen to use SIP [4] to transport SDP For this example, we have chosen to use SIP [4] to transport SDP
sessions and RSVP [5] to establish reservation flows. However, other sessions and RSVP [5] to establish reservation flows. However, other
protocols or mechanisms could be used instead without affecting the protocols or mechanisms could be used instead without affecting the
SDP syntax. SDP syntax.
A user agent receives a SIP INVITE with the SDP below: A user agent receives a SIP INVITE with the SDP below:
v=0 v=0
o=Laura 289083124 289083124 IN IP4 one.example.com o=Laura 289083124 289083124 IN IP4 one.example.com
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a=mid:1 a=mid:1
m=video 30002 RTP/AVP 31 m=video 30002 RTP/AVP 31
a=mid:2 a=mid:2
This user agent uses RSVP to perform resource reservation. Since both This user agent uses RSVP to perform resource reservation. Since both
media streams are part of a SRF group, the user agent will establish media streams are part of a SRF group, the user agent will establish
a single RSVP session. An RSVP session is defined by the triple: a single RSVP session. An RSVP session is defined by the triple:
(DestAddress, ProtocolId[, DstPort]). Table 1 shows the parameters (DestAddress, ProtocolId[, DstPort]). Table 1 shows the parameters
used to establish the RSVP session. used to establish the RSVP session.
If the same user agent received an SDP session description with the
same media streams but without the group line, it would be free to
map the two media streams into two different RSVP sessions.
Session Number DestAddress ProtocolId DstPort Session Number DestAddress ProtocolId DstPort
________________________________________________ ________________________________________________
1 192.0.0.1 UDP any 1 192.0.0.1 UDP any
Table 1: Parameters needed to establish the RSVP session Table 1: Parameters needed to establish the RSVP session
If the same user agent received an SDP session description with the 5 IANA Considerations
same media streams but without the group line, it would be free to
map the two media streams into two different RSVP sessions.
4 IANA Considerations
IANA needs to register the following new "semantics" attribute for IANA needs to register the following new "semantics" attribute for
the SDP grouping framework [2]: the SDP grouping framework [2]:
Semantics Token Reference Semantics Token Reference
------------------- ----- --------- ------------------- ----- ---------
Single Reservation flow SRF [RFCxxxx] Single Reservation flow SRF [RFCxxxx]
It should be registered in the SDP parameters registry It should be registered in the SDP parameters registry
(http://www.iana.org/assignments/sdp-parameters) under Semantics for (http://www.iana.org/assignments/sdp-parameters) under Semantics for
the "group" SDP Attribute. the "group" SDP Attribute.
5 Security Considerations 6 Security Considerations
An attacker adding group lines using the SRF semantics to an SDP An attacker adding group lines using the SRF semantics to an SDP
session description could force a user agent to establish a larger or session description could force a user agent to establish a larger or
a smaller number of resource reservation flows than needed. This a smaller number of resource reservation flows than needed. This
could consume extra resources in the end-point or degrade the quality could consume extra resources in the end-point or degrade the quality
of service for a particular session. It is thus RECOMMENDED that some of service for a particular session. It is thus RECOMMENDED that some
kind of integrity protection is applied to SDP session descriptions. kind of integrity protection is applied to SDP session descriptions.
6 Authors' Addresses 7 Acknowledgements
Jonathan Rosenberg provided useful comments about the applicability
of the mechanism described in this document.
8 Authors' Addresses
Gonzalo Camarillo Gonzalo Camarillo
Ericsson Ericsson
Advanced Signalling Research Lab. Advanced Signalling Research Lab.
FIN-02420 Jorvas FIN-02420 Jorvas
Finland Finland
electronic mail: Gonzalo.Camarillo@ericsson.com electronic mail: Gonzalo.Camarillo@ericsson.com
Atle Monrad Atle Monrad
Ericsson Ericsson
N-4898 Grimstad N-4898 Grimstad
Norway Norway
electronic mail: atle.monrad@ericsson.com electronic mail: atle.monrad@ericsson.com
7 Normative References 9 Normative References
[1] M. Handley and V. Jacobson, "SDP: session description protocol," [1] M. Handley and V. Jacobson, "SDP: session description protocol,"
RFC 2327, Internet Engineering Task Force, Apr. 1998. RFC 2327, Internet Engineering Task Force, Apr. 1998.
[2] G. Camarillo, J. Holler, G. Eriksson, and H. Schulzrinne, [2] G. Camarillo, J. Holler, G. Eriksson, and H. Schulzrinne,
"Grouping of m lines in SDP," Internet Draft, Internet Engineering "Grouping of m lines in SDP," Internet Draft, Internet Engineering
Task Force, Feb. 2002. Work in progress. Task Force, Feb. 2002. Work in progress.
[3] S. Bradner, "Key words for use in RFCs to indicate requirement [3] S. Bradner, "Key words for use in RFCs to indicate requirement
levels," RFC 2119, Internet Engineering Task Force, Mar. 1997. levels," RFC 2119, Internet Engineering Task Force, Mar. 1997.
8 Informative References 10 Informative References
[4] J. Rosenberg, H. Schulzrinne, et al. , "SIP: Session initiation
protocol," Internet Draft, Internet Engineering Task Force, Feb.
2002. Work in progress.
[5] R. Braden, L. Zhang, S. Berson, S. Herzog, and S. Jamin, [4] J. Rosenberg, H. Schulzrinne, G. Camarillo, A. Johnston, J.
"Resource ReSerVation protocol (RSVP) -- version 1 functional Peterson, R. Sparks, M. Handley, and E. Schooler, "SIP: session
initiation protocol," RFC 3261, Internet Engineering Task Force, June
2002.
[5] "Resource ReSerVation protocol (RSVP) -- version 1 functional
specification," RFC 2205, Internet Engineering Task Force, Sept. specification," RFC 2205, Internet Engineering Task Force, Sept.
1997. 1997.
Full Copyright Statement Full Copyright Statement
Copyright (c) The Internet Society (2002). All Rights Reserved. Copyright (c) The Internet Society (2002). All Rights Reserved.
This document and translations of it may be copied and furnished to This document and translations of it may be copied and furnished to
others, and derivative works that comment on or otherwise explain it others, and derivative works that comment on or otherwise explain it
or assist in its implementation may be prepared, copied, published or assist in its implementation may be prepared, copied, published
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