| Network Working Group | C. Christou |
| Internet-Draft | M. Lundberg |
| Intended status: Informational | C. Ross |
| Expires: September 11, 2013 | Booz Allen Hamilton Inc. |
| P. Saint-Andre | |
| Cisco Systems, Inc. | |
| March 10, 2013 |
Interoperability between the Session Initiation Protocol (SIP) and the Extensible Messaging and Presence Protocol (XMPP)
draft-christou-sip-xmpp-interop-00
This document is intended to serve as a reference point for developers and operators implementing the Session Initiation Protocol (SIP) and the Extensible Messaging and Presence Protocol (XMPP) within their networks. This document does not define any new protocols but does define the different reference models for deployment of combined use of SIP and XMPP ("CUSAX") clients and SIP-XMPP interworking to ensure consistency across the community.
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Across the industry, both the Session Initiation Protocol (SIP) and the Extensible Messaging and Presence Protocol (XMPP) have been implemented extensively by the vendor and developer community to provide Internet users real-time communication services, including voice, video, and IM/Chat. Initially, SIP was developed to provide the signaling underpinnings for telephony-based communication services. Similarly, XMPP was initially optimized for Instant Messaging and Chat-based communications. Since then both protocols have been extended to enable a more full-suite of features. For example, the SIMPLE protocol was defined to allow SIP to be used for IM, Chat, presence and other "enhanced" features, such as multi-user chat, server-stored contacts, file transfer, etc. The XMPP community developed the Jingle protocol extensions to define how XMPP implementations can establish end-to-end voice and video sessions.
With both suites of protocols providing similar capabilities, the adopter community has implemented both SIP/SIMPLE and XMPP. In certain cases, vendors integrating voice, video, and IM/Chat into their products have implemented SIP for telephony and XMPP for IM/Chat, especially since SIP was initially and optimized for voice/video signaling and XMPP optimized for internet-based chat. However, in other instances, vendors have implemented all capabilities using SIP/SIMPLE or XMPP/Jingle. Unfortunately, interoperability and interworking between SIP/SIMPLE and XMPP-based implementations has been fairly limited thus far.
To help alleviate this lack of interworking, two primary collection of IETF documents have emerged describing how to interoperate between SIP/SIMPLE and XMPP:
While these documents are helpful, they might not cover all deployment use cases for real-time communication services using SIP and XMPP. As a result, the goal of this document is threefold:
Therefore, this document is intended to serve as a reference point for developers and operators implementing SIP and XMPP within their networks. This document will not define any new standards or protocols but will define the different reference models for deployment of CUSAX clients and SIP-XMPP interworking to ensure consistency across the community.
This section defines the different reference models for the deployment of SIP and XMPP. These reference models are categorized as either "CUSAX", where a given network uses SIP for telephony and XMPP for IM/Chat, or as "Inter-Domain SIP/SIMPLE-XMPP", where one IM/chat domain using SIP/SIMPLE needs to interoperate with another XMPP IM/Chat domain.
In this use case, adopters deploy a single client which uses SIP for voice/video telephony and XMPP for IM/Chat and Presence. To successfully implement CUSAX using a single client, adopters need guidance on how to provision their systems to ensure consistent account information is configured between the SIP and XMPP infrastructures for the same user. There are no other interoperability issues since presence mapping occurs within the client and the two protocols do not interact elsewhere.
The CUSAX internet-draft [I-D.ivov-xmpp-cusax] explains this use case and provides guidance for implementers when configuring clients and server-side software.
In certain cases, CUSAX adopters might not have the opportunity to deploy SIP and XMPP in the same client. For example, a given service provider might implement a separate client for SIP telephony from the XMPP IM/Chat client. Alternatively, a service provider can deploy dedicated IP telephony devices (i.e., a phone) and a XMPP IM/Chat client. As a result, similar to what is provided in the CUSAX draft for a single client, guidance needs to be defined to explain how user accounts ought be configured between the two systems. This guidance will also need to define how presence is exchanged either client or server side.
The third use case involves implementing SIP and XMPP on separate clients by separate service providers. For example, a user might obtain their SIP-based telephony services from a telecommunications provider and their XMPP IM/Chat service from an Internet provider. To provide appropriate guidance for those interested in this use case, a document is needed to describe how to align account information between the two service providers and how to exchange presence consistently between the two service providers for the same user/account.
The second set of use cases involves scenarios where one domain deploys SIP/SIMPLE as its IM/Chat protocol and another domain implements XMPP as its IM/Chat protocol.
In order to consistently and effectively interoperate, four key areas need to be defined:
See the security considerations described in the specifications referenced herein.
This document has no actions for the IANA.