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November 03, 2005

UBC Award

Outstanding Young Alumnus Award - UBC Alumni Association

October 30, 2005

Managing Client Initiated Connections in the Session Initiation Protocol (SIP)

"Managing Client Initiated Connections in the Session Initiation Protocol (SIP)", C. Jennings, R. Mahy, October 2005, draft-ietf-sip-outbound-01

  • Abstract: Session Initiation Protocol (SIP) allows proxy servers to initiate TCP connections and send asynchronous UDP datagrams to User Agents in order to deliver requests. However, many practical considerations, such as the existence of firewalls and NATs, prevent servers from connecting to User Agents in this way. Even when a proxy server can open a TCP connection to a User Agent, most User Agents lack a certificate suitable to act as a TLS server. This specification defines behaviors for User Agents, registrars and proxy servers that allow requests to be delivered on existing connections established by the User Agent. It also defines keep alive behaviors needed to keep NAT bindings open and specifies the usage of multiple connections for high availability systems.

Payment for Services in Session Initiation Protocol (SIP)

"Payment for Services in Session Initiation Protocol (SIP)", C. Jennings, G. Jun, J. Fischl, H. Tschofenig, October 2005, draft-jennings-sipping-pay-03.txt

  • Abstract: Service usage might require some form of compensation and this is also true for many communication systems where an entity receiving a call should be able to charge the caller. This is necessary for allowing fair communication between two communicating parties and is a major strategy for reducing the viability of SPAM. This draft proposes an approach for doing this in SIP using the Security Assertion Markup Language (SAML). It relies on a third party to act as a payment provider and is designed for low value transactions. It does not aim to provide the same capability as other authentication, authorization and accounting systems. This draft is in a fairly early state and has many details that are missing. Earlier versions of this document did not use SAML. This version offers a sketch of what the SAML based solution would look like but still lacks many details that would be needed for an actual implementation.

Remote Call Control in SIP using the REFER method and the session-oriented dialog package

"Remote Call Control in SIP using the REFER method and the session-oriented dialog package", R. Mahy, C. Jennings, Oct 2005, draft-mahy-sip-remote-cc-02

  • Abstract: This document describes how to use the SIP REFER method and the dialog package to manipulate conversations, dialogs, and sessions on remote User Agents. Specifically it extents the REFER mechinims to allow the specificate of a response that a UA should send in a dialog. This functionality is most useful for collections of loosely coupled User Agents that wish to present a coordinated user experience. It does not require a Third-Party Call Control controller to be involved in any of the manipulated dialogs.

Computational Puzzles for SPAM Reduction in SIP

"Computational Puzzles for SPAM Reduction in SIP", C. Jennings, October 2005, draft-jennings-sip-hashcash-03

Abstract: One of the techniques used in SPAM prevention and various solutions for denial of service attacks is to force the SIP client requesting a service to perform a calculation that limits the rate and increases the cost of the request. This draft defines a way to allow a UAS to ask the UAC to compute a computationally expensive hash based function and present the result to the UAS. Although the computation is expensive for the UAC to compute, it is cheap for the UAS to verify. The solution also allows for proxies to compute and check the puzzle on behalf of the UAC or UAS.

The Internet Assigned Number Authority (IANA) tel Uniform Resource Identifier (URI) Parameter Registry

"The Internet Assigned Number Authority (IANA) tel Uniform Resource Identifier (URI) Parameter Registry", C. Jennings, October 2005, draft-jennings-iptel-tel-reg-00

  • Abstract: This document creates an Internet Assigned Number Authority (IANA) registry for the tel Uniform Resource Identifier (URI) parameters, and their values. It also lists the already existing parameters to be used as initial values for that registry.

July 19, 2005

Drafts from this IETF

? "NAT Behavioral Requirements for Unicast UDP", F. Audet, C. Jennings, July 2005, draft-ietf-behave-nat-udp-03
? Abstract: This document defines basic terminology for describing different types of NAT behavior when handling Unicast UDP and also defines a set of requirements that would allow many applications, such as multimedia communications or on-line gaming, to work consistently. Developing NATs that meet this set of requirements will greatly increase the likelihood that these applications will function properly.
? "A P2P Approach to SIP Registration and Resource Location", D. A. Bryan, C. Jennings, July 2005, draft-bryan-sipping-p2p-01
? Abstract: This document outlines the motivation and requirements for a Peer-to-Peer (P2P) based approach for SIP registration and resource discovery using distributed hash tables, and presents the architectural design for such a system. This design removes the need for central servers from SIP, while offering full backward compatibility with SIP, allowing reuse of existing clients, and allowing P2P enabled nodes to communicate with conventional SIP entities. A basic introduction to the concepts of P2P is presented, backward compatibility issues addressed, and the security considerations are considered. This is very early work to explore the characteristics that a P2P system might have. It is less secure in many ways than the traditional approach to SIP but has certain other interesting characteristics that may make it desirable in some situations. This work is being discussed on the sipping@ietf.org mailing list.
? "The Message Session Relay Protocol", B. Campbell, R. Mahy, C. Jennings, July 2005, draft-ietf-simple-message-sessions-11.txt
? Abstract: This document describes the Message Session Relay Protocol, a protocol for transmitting a series of related instant messages in the context of a session. Message sessions are treated like any other media stream when setup via a rendezvous or session setup protocol such as the Session Initiation Protocol.
? "Relay Extensions for the Message Sessions Relay Protocol (MSRP)", C. Jennings, R. Mahy, A. B. Roach, July 2005, draft-ietf-simple-msrp-relays-05.txt
? Abstract: The SIMPLE Working Group uses two separate models for conveying instant messages. Pager-mode messages stand alone and are not part of a SIP (Session Initiation Protocol) session, whereas Session-mode messages are set up as part of a session using the SIP protocol. MSRP (Message Sessions Relay Protocol) is a protocol for near-real-time, peer-to-peer exchanges of binary content without intermediaries, which is designed to be signaled using a separate rendezvous protocol such as SIP. This document introduces the notion of message relay intermediaries to MSRP and describes the extensions necessary to use them.
? "Response Identity and Authentication in Session Initiation Protocol", F. Cao, C. Jennings, July 2005, draft-cao-sip-response-auth-00
? Abstract: This draft describes some extensions for verifying SIP response identity and enhancing SIP response authentication. Some mechanisms are demonstrated for providing and verifying the identity of SIP responses. In order to prevent several kinds of security attacks through SIP response, SIP response authentication should be provided through a chain of trust of the SIP responses. Some extensions are proposed to enhance the per-hop authentication for handling SIP response. This draft is an early work in progress and suggests some approaches but there is still significant discussion needed. Some of the attacks discussed in this draft can be mitigated by using the sips URL.
? "Managing Client Initiated Connections in the Session Initiation Protocol (SIP)", C. Jennings, R. Mahy, July 2005, draft-ietf-sip-outbound-00
? Abstract: Session Initiation Protocol (SIP) allows proxy servers to initiate TCP connections and send asynchronous UDP datagrams to User Agents in order to deliver requests. However, many practical considerations, such as the existence of firewalls and NATs, prevent servers from connecting to User Agents in this way. Even when a proxy server can open a TCP connection to a User Agent, most User Agents lack a certificate suitable to act as a TLS server. This specification defines behaviors for user agents, registrars and proxy servers that allow requests to be delivered on existing connections established by the User Agent. It also defines keep alive behaviors needed to keep NAT bindings open and specifies the usage of multiple connections for high availability systems.
? "Certificate Management Service for The Session Initiation Protocol (SIP)", C. Jennings, J. Peterson, July 2005, draft-ietf-sipping-certs-02
? Abstract: This draft defines a Credential Service that allows SIP User Agents to use a SIP package to discover the certificates of other users. This mechanism allows user agents that want to contact a given Address-of-Record (AOR) to retrieve that AOR's certificate by subscribing to the Credential Service. The Credential Service also allows users to store and retrieve their own certificates and private keys.
? "NAT Classification Test Results", C. Jennings, July 2005, draft-jennings-behave-test-results-01
? Abstract: IETF has several groups that are considering the impact of NATs on various protocols. Having a classification of the types of NATs that are being developed and deployed is useful in gauging the impact of various solutions. This draft records the results of classifying NATs. This draft is not complete and has only a few test results but it is worth discussing all the testing we wish to do before all the test results are collected. The test results here are very old and work is being done to update them with more current information. This work is being discussed on the ietf-behave@list.sipfoundry.org mailing list
? "vCard Extensions for Instant Messaging (IM)", C. Jennings, July 2005, draft-jennings-impp-vcard-05
? Abstract: This document describes an extension to vCard to support Instant Messaging (IM) and Presence Protocol (PP) applications. IM and PP are becoming increasingly common ways of communicating, and users want to save this contact information in their address books. This draft allows a URI that is associated with IM or PP to be specified inside of a vCard.
? "Using DTLS as a Transport for SIP", C. Jennings, N. Modadugu, July 2005, draft-jennings-sip-dtls-01
? Abstract: This draft specifies how to use Datagram Transport Layer Security (DTLS) as a transport for SIP. DTLS is a new protocol for providing TLS security over a datagram protocol. This draft is being discussed on the sip@ietf.org mailing list.
? "Computational Puzzles for SPAM Reduction in SIP", C. Jennings, July 2005, draft-jennings-sip-hashcash-02
? Abstract: One of the techniques used in SPAM prevention and various solutions for denial of service attacks is to force the SIP client requesting a service to perform a calculation that limits the rate and increases the cost of the request. This draft defines a way to allow a UAS to ask the UAC to compute a computationally expensive hash based function and present the result to the UAS. Although the computation is expensive for the UAC to compute, it is cheap for the UAS to verify. The solution also allows for proxies to compute and check the puzzle on behalf of the UAC or UAS.
? "Example call flows using SIP security mechanisms", C. Jennings, K. Ono, July 2005, draft-jennings-sip-sec-flows-03
? Abstract: This document shows call flows demonstrating the use of SIPS, TLS, and S/MIME in SIP. This draft provides information that helps implementers build interoperable SIP software. It is purely informational. To help facilitate interoperability testing, it includes certificates used in the example call flows and a CA certificate to create certificates for testing. This work is being discussed on the sip@ietf.org mailing list.
? "Conventions for Voicemail URIs in SIP", C. Jennings, July 2005, draft-jennings-sip-voicemail-uri-04
? Abstract: The SIP protocol is often used to initiate connections to voicemail or unified messaging systems. This specification describes a convention for forming SIP Service URIs that request particular services from unified messaging systems.
? "Instance Identifiers for SIP User Agents", C. Jennings, July 2005, draft-jennings-sipping-instance-id-01.txt
? Abstract: There are circumstances in SIP-based communications systems in which it is useful to have a long-term, stable identifier for a particular user agent. This specification outlines requirements and discusses existing standards that can be used to satisfy this need.
? "SIP Offer/Answer with Multipart Alternative", C. Jennings, D. Wing, July 2005, draft-jennings-sipping-multipart-01
? Abstract: SIP needs a mechanism for general backwards compatibility for moving from SDP to SDPng or moving from non end-to-end encrypted SDP to end-to-end encrypted SDP. This document specifies how a SIP offer uses multipart/alternative, and how an answer indicates which part was selected.
? "Payment for Services in Session Initiation Protocol (SIP)", C. Jennings, G. Jun, J. Fischl, July 2005, draft-jennings-sipping-pay-02
? Abstract: Communication systems require that a person receiving a call be able able to charge the caller when they are from different administrative domains. This is necessary for making fair exchanges of service between two different communicating parties and is a major strategy for reducing the viability of SPAM. This draft proposes an approach for doing this in SIP. The approach relies on a third party to act as a payment service provider and is optimized for very simple, low value transactions. It does not provide the full range of services that are desirable in typical online trading systems. This draft is being discussed on the sipping@ietf.org mailing list. There is currently work to substantially change this draft to use SAML.
? "Conference State Change Protocol (CSCP)", C. Jennings, A. B. Roach, July 2005, draft-jennings-xcon-cscp-01
? Abstract: Conference State Control Protocol (CSCP) is a means to modify the state in a conference service. It extends the Binary Floor Control Protocol and adds commands to get, set, add, and delete fields in the conference state.
? "Media Conference Server Control for XCON", C. Jennings, B. Rosen, July 2005, draft-jennings-xcon-media-control-03
? Abstract: Conference servers have many controls that change how the media is combined for the various conference participants. It is necessary to describe these controls to the clients connected to a centralized conference, so that the clients can render a user interface and allow the user to manipulate them. This work is being discussed on the xcon@ietf.org mailing list. This draft has not changed since the 02 version.

July 07, 2005

More fluff?

I think some of the open source code written with security in mind has some of the best security around anywhere.

http://searchenterprisevoice.techtarget.com/qna/0,289202,sid66_gci1103827,00.html

February 21, 2005

The Session Initiation Protocol (SIP) and Spam

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Certificate Management Service for The Session Initiation Protocol (SIP)

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February 20, 2005

Payment for Services in Session Initiation Protocol (SIP)

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Media Conference Server Control for XCON

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The Message Session Relay Protocol

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February 19, 2005

Example call flows using SIP security mechanisms

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Relay Extensions for the Message Sessions Relay Protocol (MSRP)

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SIP Conventions for UAs with Outbound Only Connections

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February 18, 2005

SIP Computational Puzzles

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February 14, 2005

Guidelines for implementors using connection-oriented transports in the Session Initiation Protocol (SIP)

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February 13, 2005

NAT Classification Test Results

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February 12, 2005

Conference State Change Protocol (CSCP)

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SIP Offer/Answer with Multipart MIME

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Using DTLS as a Transport for SIP

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January 03, 2005

NAT Behavioral Requirements for Unicast UDP

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November 12, 2004

Computer Vision for Line Drawings

May 1993 MSC Thesis at the University of Calgary by Cullen Jennings

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