Telecommunications Industry Association
(TIA)
TR-30.1/10208093
August 6-9, 2002, Waltham, MA
COMMITTEE CONTRIBUTION
Technical Committee TR-30 Meetings
SOURCE:
The CommWorks Corp., a 3Com company
TITLE:
Comparison of proposals for MoIP SDP
DISTRIBUTION:
Members of TR-30.1
CONTACT:
Jim Renkel
Office: +1.847.262.2539
E-mail: james_renkel@commworks.com
____________________
ABSTRACT
This contribution compares the two proposals that have been made for SDP for MoIP.
The company represented by this individual may have patents or published pending patent applications, the use of
which may be essential to the practice of all or part of this contribution incorporated in a TIA Publication and the
company represented by this individual is willing to grant a license to applicants for such intellectual property
contained in this contribution in a manner consistent with 2a) or 2b) of Annex H of the TIA Engineering Manual.
COPYRIGHT STATEMENT:
The contributor grants a free, irrevocable license to the Telecommunications Industry Association (TIA) to
incorporate text or other copyrightable material contained in this contribution and any modifications thereof in the
creation of a TIA Publication; to copyright and sell in TIA's name any TIA Publication even though it may include all
or portions of this contribution; and at TIA's sole discretion to permit others to reproduce in whole or in part such
contributions or the resulting TIA Publication. This contributor will also be willing to grant licenses under such
copyrights to third parties on reasonable, non-discriminatory terms and conditions for purpose of practicing a TIA
Publication incorporates this contribution.
This document has been prepared by the Source Company(s) to assist the TIA Engineering Committee. It is
proposed to the Committee as a basis for discussion and is not to be construed as a binding proposal on the Source
Company(s). The Source Company(s) specifically reserves the right to amend or modify the material contained
herein and nothing herein shall be construed as conferring or offering licenses or rights with respect to any
intellectual property of the Source Company(s) other than provided in the copyright statement above.
Telecommunications Industry Association (TIA)
August 6-9, 2002, Waltham, MA
Page 2 of 6
Table of Contents
Introduction .......................................................................................................................................... 3
MoIP SDP examples .............................................................................................................................. 4
2.1
When a UDP port is shared by RTP and SPRT ............................................................................. 4
2.2
When separate UDP ports are used for RTP and SPRT ............................................................... 5
3 Differences between the two proposals ................................................................................................. 6
1
2
Table of Figures
Figure 1 - 10206061 proposed SDP for shared UDP port for RTP and SPRT ............................................. 4
Figure 2 - 10206063 proposed SDP for shared UDP port for RTP and SPRT ............................................. 4
Figure 3 - 10206061 proposed SDP for separate UDP ports for RTP and SPRT ........................................ 5
Figure 4 - 10206063 proposed SDP for separate UDP ports for RTP and SPRT ........................................ 5
Table of Tables
Table 1 - Differences between the 10206061 and 10206063 SDP proposals .............................................. 6
3Com / CommWorks
Comparison of proposals for MoIP SDP
TR-30.1/10208093
Telecommunications Industry Association (TIA)
August 6-9, 2002, Waltham, MA
1
Page 3 of 6
Introduction
At the Columbia, MD, meeting of TIA committee TR-30.1, June 12-14, 2002, two contributions
(10206061.doc and 10206063.doc) were made proposing the SDP to be used to describe a multi-media
session that included MoIP capabilities.
While contribution 10206061 gave examples of the complete SDP required to describe a session with
MoIP capabilities (Both with a shared UDP port for RTP and SPRT and with separate UDP ports for RTP
and SPRT), contribution 10206063 only gave the SDP that would be added to a session description to
add the MoIP capability (And only for the case where RTP and SPRT shared a UDP port; a technique
was described in the Columbia meeting for how to describe a session where RTP and SPRT had
separate UDP ports (with restrictions), but the technique was not included in the written contribution.).
Section 2 of this contribution gives the complete SDP for a session with MoIP capabilities using the
proposals of the two contributions, for both shared and separate UDP ports (Coincidentally, the example
presented in 10206061 for the case of separate UDP ports meets the restriction required for the use of
the 10206063 technique.): for the 10206061 proposal, the SDP is copied from that contribution; for the
10206063 proposal, the SDP in constructed to show the same examples given in 10206061.).
Section 3 of this contribution then itemizes the differences between the two SDP proposals. It attempts to
do this neutrally and objectively, without alluding in any way to the possible advantages or disadvantages
of either proposal.
3Com / CommWorks
Comparison of proposals for MoIP SDP
TR-30.1/10208093
Telecommunications Industry Association (TIA)
August 6-9, 2002, Waltham, MA
2
MoIP SDP examples
2.1
When a UDP port is shared by RTP and SPRT
Page 4 of 6
Contribution 10206061 proposes the following SDP for a session including MoIP capabilities when RTP
and SPRT share a single UDP port:
v=0
o=- 25678 753849 IN IP4 128.96.41.1
s=
c=IN IP4 128.96.41.1
t=0 0
m=audio 49230 RTP/AVP 0 2 8 97 98 99
a=rtpmap:97 telephone-event/8000
a=fmtp:97 0-15,32,33,34,35,66,70
a=rtpmap:98 PCMU/8000
a=gfmtp:98 vbd=yes
a=rtpmap:99 PCMA/8000
a=gfmtp:99 vbd=yes
a=sqn:0
a=cdsc:1 application udpsprt 100
a=cpar:a=sprtmap:100 vxxx/8000
a=cpar:a=modemRelayType:V8
a=cpar:a=mgType:STCX
Figure 1 - 10206061 proposed SDP for shared UDP port for RTP and SPRT
The SDP for this same session, using the proposal made in contribution 10206063, follows (Assuming the
ITU-T has assigned 707 as the recommendation number for V.moip.):
v=0
o=- 25678 753849 IN IP4 128.96.41.1
s=
c=IN IP4 128.96.41.1
t=0 0
m=audio 49230 RTP/AVP 0 2 8 97 101
a=rtpmap:97 telephone-event/8000
a=fmtp:97 0-15,32,33,34,35,66,70
a=rtpmap:101 v707/8000
a=v707parm: 1,v8
a=v707VBD: 0,8
a=v707SPRT: 100
a=v707TCX: 1
Figure 2 - 10206063 proposed SDP for shared UDP port for RTP and SPRT
3Com / CommWorks
Comparison of proposals for MoIP SDP
TR-30.1/10208093
Telecommunications Industry Association (TIA)
August 6-9, 2002, Waltham, MA
2.2
Page 5 of 6
When separate UDP ports are used for RTP and SPRT
Contribution 10206061 proposes the following SDP for a session including MoIP capabilities when RTP
and SPRT use separate UDP ports:
v=0
o=- 25678 753849 IN IP4 128.96.41.1
s=
c=IN IP4 128.96.41.1
t=0 0
m=audio 49230 RTP/AVP 0 2 8 97 98 99
a=rtpmap:97 telephone-event/8000
a=fmtp:97 0-15,32,33,34,35,66,70
a=rtpmap:98 PCMU/8000
a=gfmtp:98 vbd=yes
a=rtpmap:99 PCMA/8000
a=gfmtp:99 vbd=yes
m=application 49232 udpsprt 100
a=sprtmap:100 vxxx/8000
a=modemRelayType:V8
a=mgType:STCX
Figure 3 - 10206061 proposed SDP for separate UDP ports for RTP and SPRT
The SDP for this same session, using the proposal made in contribution 10206063, follows:
v=0
o=- 25678 753849 IN IP4 128.96.41.1
s=
c=IN IP4 128.96.41.1
t=0 0
m=audio 49230/2 RTP/AVP 0 2 8 97 101
a=rtpmap:97 telephone-event/8000
a=fmtp:97 0-15,32,33,34,35,66,70
a=rtpmap:101 v707/8000
a=v707parm: 1,v8
a=v707VBD: 0,8
a=v707SPRT: 100
a=v707TCX: 1
Figure 4 - 10206063 proposed SDP for separate UDP ports for RTP and SPRT
3Com / CommWorks
Comparison of proposals for MoIP SDP
TR-30.1/10208093
Telecommunications Industry Association (TIA)
August 6-9, 2002, Waltham, MA
3
Page 6 of 6
Differences between the two proposals
The following table summarizes the differences between the two proposals.
Table 1 - Differences between the 10206061 and 10206063 SDP proposals
Item
1. VBD CODEC declaration
2. VBD CODEC list
3. SSE / SPRT declaration
4. SSE / SPRT declaration
5. SSE / SPRT payload
numbers
6. MoIP parameters
7. Modem relay modulations
8. Transcompression protocols
9. Non-standard facilities /
vendor specific options
10206061 proposal
CODECs with static payload
numbers to be used in VBD
mode must be redeclared with
dynamic payload numbers
Each CODEC to be used in VBD
mode is identified with gfmtp
attribute
SPRT is explicitly declared, along
with payload number to
distinguish SPRT packets from
RTP packets; payload number
must be even
Capability sets are required to
declare SPRT when it shares a
UDP port with RTP
SSE is assumed to use payload
number n+1, where n is the
payload number used to
distinguish SPRT packets from
RTP packets
Each has separate a= line
Given as comma separated list of
integer values and integer ranges
Given as comma separated list of
protocols
Vendor identified by country and
vendor codes
3Com / CommWorks
Comparison of proposals for MoIP SDP
TR-30.1/10208093
10206063 proposal
CODECs with static payload
numbers to be used in VBD
mode need not be redeclared
with dynamic payload numbers
CODECs to be used in VBD
mode are listed as attribute of
v707 (SSE) "CODEC"
SSE is explicitly declared, along
with its payload number
Capability sets are not required
Payload number used to
distinguish SPRT packets from
RTP packets is explicitly
declared; payload number need
not be even
Related parameters are grouped
on one a= line
Given as one bit mapped integer
Given as one bit mapped integer
Vendor identified by IANA
registered private enterprise
number