draft-ietf-sipping-sbc-funcs-02.txt   draft-ietf-sipping-sbc-funcs-03.txt 
SIPPING Working Group J. Hautakorpi, Ed. SIPPING Working Group J. Hautakorpi, Ed.
Internet-Draft G. Camarillo Internet-Draft G. Camarillo
Expires: October 15, 2007 Ericsson Intended status: Informational Ericsson
R. Penfield Expires: October 19, 2007 R. Penfield
Acme Packet Acme Packet
A. Hawrylyshen A. Hawrylyshen
Ditech Networks Inc. Ditech Networks Inc.
M. Bhatia M. Bhatia
NexTone Communications 3CLogic
April 13, 2007 April 17, 2007
Requirements from SIP (Session Initiation Protocol) Session Border Requirements from SIP (Session Initiation Protocol) Session Border
Control Deployments Control Deployments
draft-ietf-sipping-sbc-funcs-02.txt draft-ietf-sipping-sbc-funcs-03.txt
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of 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
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in 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 October 15, 2007. This Internet-Draft will expire on October 19, 2007.
Copyright Notice Copyright Notice
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2007).
Abstract Abstract
This documents describes functions implemented in Session Initiation This document describes functions implemented in Session Initiation
Protocol (SIP) intermediaries known as Session Border Controllers Protocol (SIP) intermediaries known as Session Border Controllers
(SBCs). The goal of this document is to describe the commonly (SBCs). The goal of this document is to describe the commonly
provided functions of SBCs. A special focus is given to those provided functions of SBCs. A special focus is given to those
practices that are viewed to be in conflict with SIP architectural practices that are viewed to be in conflict with SIP architectural
principles. This document also explores the underlying requirements principles. This document also explores the underlying requirements
of network operators that have led to the use of these functions and of network operators that have led to the use of these functions and
practices in order to identify protocol requirements and determine practices in order to identify protocol requirements and determine
whether those requirements are satisfied by existing specifications whether those requirements are satisfied by existing specifications
or additional standards work is required. or additional standards work is required.
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3.4.2. Architectural Issues 3.4.2. Architectural Issues
This approach to NAT traversal does not work when end-to-end This approach to NAT traversal does not work when end-to-end
confidentiality or integrity-protection is used. The SBC would be confidentiality or integrity-protection is used. The SBC would be
seen as a MitM modifying the messages between the user-agent and the seen as a MitM modifying the messages between the user-agent and the
registrar. registrar.
There is also a problem related to the method how SBCs choose the There is also a problem related to the method how SBCs choose the
value for the validity of a registration period. This value should value for the validity of a registration period. This value should
be as high as possible, but it still needs to be low enough to be as high as possible, but it still needs to be low enough to
maintain the NAT bindind. Typically SBCs do not have any maintain the NAT binding. Typically SBCs do not have any
deterministic method for choosing a suitable value. deterministic method for choosing a suitable value.
3.4.3. Example 3.4.3. Example
Consider the following example scenario: The SBC resides between the Consider the following example scenario: The SBC resides between the
UA and Registrar. Previously the UA has sent a REGISTER request to UA and Registrar. Previously the UA has sent a REGISTER request to
Registrar, and the SBC receives the registration response shown in Registrar, and the SBC receives the registration response shown in
Figure 10. Figure 10.
SIP/2.0 200 OK SIP/2.0 200 OK
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Alan Hawrylyshen Alan Hawrylyshen
Ditech Networks Inc. Ditech Networks Inc.
Suite 200, 1167 Kensington Cres NW Suite 200, 1167 Kensington Cres NW
Calgary, Alberta T2N 1X7 Calgary, Alberta T2N 1X7
Canada Canada
Email: ahawrylyshen@ditechnetworks.com Email: ahawrylyshen@ditechnetworks.com
Medhavi Bhatia Medhavi Bhatia
NexTone Communications 3CLogic
101 Orchard Ridge Drive 9700 Great Seneca Hwy.
Gaithersburg, MD 20878 Rockville, MD 20850
US US
Email: mbhatia@nextone.com Email: mbhatia@3clogic.com
Full Copyright Statement Full Copyright Statement
Copyright (C) The IETF Trust (2007). Copyright (C) The IETF Trust (2007).
This document is subject to the rights, licenses and restrictions This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors contained in BCP 78, and except as set forth therein, the authors
retain all their rights. retain all their rights.
This document and the information contained herein are provided on an This document and the information contained herein are provided on an
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