SIP Event Package Interoperability

Service providers often deploy a Oracle® Enterprise Session Border Controller on the border of an access network, where it sits between the SIP endpoints (user agents) and the service provider’s application server. The application server and the user agents sometimes use various SIP event packages to exchange and maintain state information. The SUBSCRIBE and NOTIFY methods are used to establish subscriptions to the event packages and to report state changes to the subscribing entity.

The SIP global contact option addresses interoperability in the Dialog and Presence event packages that are used in hosted PBX and IP Centrex offerings. State information is passed in the message body of a NOTIFY request; this message body is encoded in an XML format described by the Content-Type header. The Oracle® Enterprise Session Border Controller needs to update certain fields in the body to account for dialog mapping and SIP NAT functionality between the access and service provider realms. Often the subscriptions are established using URIs learned from Contact headers in the user agent registrations or dialog establishment (INVITE/SUBSCRIBE). For this, a Oracle® Enterprise Session Border Controllerrequires a Contact URI that is usable and routable outside of an existing dialog.

The SIP global contact option enables persistent URIs in the Contact headers inserted into outgoing SIP messages. If this option is not used, URIs placed in the Contact header of outgoing messages are only valid within the context of the dialog to which the message is associated.

RFCs associated with this feature are:

  • A. B. Roach, Session Initiation Protocol (SIP)-Specific Event Notification, RFC 3265, June 2002
  • J. Rosenberg, A Presence Event Package for the Session Initiation Protocol (SIP), RFC 3856, August 2004
  • J. Rosenberg, et al. Data Format for Presence Using XML, http://www.iptel.org/info/players/ietf/presence/outdated/draft-rosenberg-impp-pidf-00.txt, Work In Progress (expired), June 2000
  • J.Rosenberg, H. Schulzrinne, R. Mahy, An INVITE Initiated Dialog Event Package for the Session Initiation Protocol (SIP), draft-ietf-sipping-dialog-package-06.txt, Work In Progress, April 2005
  • H. Sugano, et al., Presence Information Data Format (PIDF), RFC 3863, August 2004
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