SS7 Internet BOF
Monday, August 24, 1998
Chairs: Lyndon Ong - email@example.com
Nancy Greene - firstname.lastname@example.org
Reported by Matt Holdrege - email@example.com
The BOF agenda and goals were presented as follows:
1. Agenda & Goals - Lyndon Ong and Nancy Greene
2. Scott Bradner's AD guidance
3. SS7 & Dial-UP internet access - Matt Holdrege for Q.931+ and Nancy Greene
for Diameter Resource Control
4. SS7 & IP Telephony - Christian Huitema for SGCP and Ike Elliot for IPDC
5. ISUP/TCAP over IP - Esa Turtiainen and Ian Rytina for ISUP over IP
6. ITU SG11 and SG16 and ETSI TIPHON
There were no objections to the agenda.
The room was overflowing and it was noted that the topic is popular. The Area Director
encouraged the chairs to be aggressive to understand the problem space and whether the
IETF should be involved. There could be 0-n working groups to cover the problems. We
aren't trying to find solutions today.
Nancy Greene provided slides and a brief discussion on the reference architecture, which
Identifies Signaling Gateway (SG), Media Gateway Control (MC) and Media Gateway (MG)
Identification of requirements:
Each of the proposals coming into the meeting was briefly discussed to identify the
requirements that generated that proposal, and the relationship to the reference architecture.
RSGP requirements (Matt Holdrege): these were presented and a specific reference
architecture was identified. The problem space for RSGP is integrating dial-up Internet
access with SS7 in traditional carrier networks. It was noted that Q.931 is the same protocol
that is used on ISDN today. RSGP uses Q.931 over IP with a few extra messages to help
manage the NAS resources.
Diameter Resource Control requirements (Nancy Greene): These requirements were to
support standard interfaces, be a lightweight protocol, support both TCP and UDP and be
able to change resources in a session's lifetime.
SGCP requirements (Christian Huitema): SGCP was designed back in February 1998 to
solve a problem with new Telecommunications providers that use IP (or in some cases ATM) infrastructures. New providers like CLEC's typically want to provide both voice services
using VoIP and "network access services" on the behalf of ISPs. Christian proposed that
the WG should address a controller receiving and sending ISUP and TCAP messages from
an SG, and call control between the controller and the MG.
IPDC requirements (Ike Elliott): IPDC is a suite of protocols which Ike applied to Nancy's
slide. It is 4 protocols: Backhaul, connection control, media control, and device management.
Ike proposed two WG's. One for signaling transport and one for MG control.
Etheric requirements (Esa Turtiainen and Ian Rytina): Etheric is meant for an access server
integrated in a switch. The NAS is connected by a TDM bus for bearer channels and ISUP
over IP over Ethernet for signaling.
Related activities in other bodies include ITU-T and ETSI TIPHON.
ITU-T Activities (Selvam Rengasami, representing ITU-T SG11/Q.11): ITU-T is
investigating how they should be involved. Selvam is interested in what changes in Q.931
would be needed. Selvam noted that they had received a Q.931+ proposal at the last meeting,
but they would not discuss it at the upcoming interim meeting. Issued needed working on
is the layer 2 protocol and Q.921-like control, and what part is the IETF going to do and
what part is SG11 going to do. Selvam suggested a liaison. The next main SG11 meeting
is March, 1999 in Geneva.
ETSI TIPHON Activities (Gur Kimchi, representing TIPHON): Gur presented the TIPHON
reference configuration. TIPHON plans to standardize a protocol between the MG and a controller/gateway. It may adopt results from the IETF depending on their relevance.
Scott Bradner noted that the IETF wants to work with other groups such as the ITU and
ETSI. Scott noted that the IETF and ITU worked closely together on IP Fax and it was
successful. Scott noted that the IETF and ITU have very different operational issues that
he would like to resolve.
Nancy first presented a wrap-up, showing that each proposal fit into the architecture
framework. The group then discussed different ways to approach the issues.
Proposals from the floor included the following:
- It was suggested that IPDC's 4 different protocols should be separated into 4 different
WG's, and that VoIP is only one service and that we should try to include all services
in some of these protocols (Scott Petrack). It was noted that one IPDC draft on
requirements for IP Device Control was not included in the input to this BOF, and will
be forwarded later via the mailing list (Tom Taylor).
- It was suggested that we should try to solve all the problems in one all encompassing
work statement (Jim McEachern). The Area Director noted that the more a working
group takes on the less it gets done.
- It was proposed that device/resource control and call control should be combined
in the same protocol. This has been determined by implementation experience
- We may want to have a separate reference architecture for services such as TCAP.
Goutam Shaw suggested that there could be the equivalent of an "IP Service Control
Point" that centralizes policy and service control logic and information across multiple
MCs, and can download logic to an MC. This could be another interface, or a use for
- It was suggested that signaling backhaul is separate from gateway controllers and should
be worked separately (Bob Bell).
- It was proposed that performance requirements should be a consideration (Michael
Romalho). It was noted by the Area Director that IETF is working on a number of QoS
areas. The IETF will continue to try to understand the QoS requirements for this group
as well as a number of others. We should also understand the performance requirements
of the signaling systems.
- It was suggested that low level telemetry and inband signaling issues may also belong
in device control. Inband signaling such as R2 may need to be transported in some
fashion between the MG and MC due to the requirement for signaling backhaul (Ike
Elliott, Mauricio Arrango).
- It was proposed that SNMP v3 has many improvements which could be used in this
problem space (Jeff Case). Jeff volunteered to be a reference resource for folks who
don't want to wade through all the SNMPv3 drafts. It was noted that specific suggestions
like SNMP and others should be done in the form of Internet Drafts, where this can be
described in detail.
- It was suggested that we may wish to look at the G.960 series for device control for
similar types of control. ITU-T SG13 is where this is handled (Lawrence Conroy).
- We should look to what extent existing Internet protocols can solve the problems for
telephony signaling and gateway control. SIP with generic notification as proposed in
other WG's seems to meet the requirements and should be considered as a better
candidate (Henry Sinnreich).
The following rough consensus was reached (documented by Nancy Greene):
a) that we should have a signaling transport/backhaul signaling working group which would
cover transport of ISUP/IP, Q.931+, etc.
b) that we should have a second working group focusing on device control signaling (i.e.,
what IPDC, SGCP, Diameter resource control, etc. are addressing).
c) that the groups should work from a common document on architecture & requirements,
including performance requirements.
d) there was some sentiment that TCAP/IP will eventually need to be a separate WG, but
initially inputs will be covered under signaling transport.
SGCP and Internet Telephony/Network Access Servers
Work Group Requirements
Etheric, Simplified Call Control
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