p2psip Y. Gao Internet-Draft Y. Meng Intended status: Standards Track ZTE Expires: January 28, 2010 July 27, 2009 A New SIP Usage for RELOAD draft-gaoyang-p2psip-new-sip-usage-00.txt Status of this Memo This Internet-Draft is submitted to IETF in full conformance with the provisions of BCP 78 and BCP 79. This document may not be modified, and derivative works of it may not be created, and it may not be published except as an Internet-Draft. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt. The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. This Internet-Draft will expire on January 28, 2010. Copyright Notice Copyright (c) 2009 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents in effect on the date of publication of this document (http://trustee.ietf.org/license-info). Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Gao & Meng Expires January 28, 2010 [Page 1] Internet-Draft A New SIP Usage for RELOAD July 2009 Abstract This document points out the main drawbacks of the solution in "draft-ietf-p2psip-sip-01". And solve such problems by introducing a new way. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Main drawbacks of the current solution . . . . . . . . . . . . 4 2.1. Hidden trouble in inter-domain interworking . . . . . . . . 4 2.2. Hidden trouble in sip users' mobility . . . . . . . . . . . 4 2.2.1. Compelling support for peers' mobility . . . . . . . . 4 2.2.2. Churn of the overlay . . . . . . . . . . . . . . . . . 4 2.3. Exclusivity towards overlay clients in sip usage . . . . . 4 3. How about words modification from Peers to Nodes . . . . . . . 5 4. The new solution . . . . . . . . . . . . . . . . . . . . . . . 6 4.1. Solution introduction . . . . . . . . . . . . . . . . . . . 6 4.2. More merits . . . . . . . . . . . . . . . . . . . . . . . . 6 4.2.1. Half spending . . . . . . . . . . . . . . . . . . . . . 6 4.2.2. Supporting clients' mobility inherently . . . . . . . . 7 5. Normative references . . . . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 9 Gao & Meng Expires January 28, 2010 [Page 2] Internet-Draft A New SIP Usage for RELOAD July 2009 1. Introduction As described in "draft-ietf-p2psip-sip-01", RELOAD's only role in sip usage is to set up the direct SIP connection between caller and callee. So, the sip users are more like clients than peers here. But "draft-ietf-p2psip-sip-01" restricts that caller and callee are peers of the overlay. Making bad thing worse, callee MUST be peers of the overlay while using the solution in "draft-ietf-p2psip-sip-01". The reason is that only peers can be reachable by routing table of the overlay. Gao & Meng Expires January 28, 2010 [Page 3] Internet-Draft A New SIP Usage for RELOAD July 2009 2. Main drawbacks of the current solution 2.1. Hidden trouble in inter-domain interworking Considering inter-domain interworking, caller can be user of other domain. If we use the solution in "draft-ietf-p2psip-sip-01", there should be a node in the other domain as peer of callee's overlay. That is not acceptable for overlay networking operating, as storing data in other domain's node can be nightmare. If we make sip users outside of the overlay just clients, there would not be such problem. In fact, making caller just client of the overlay can get rid of this problem. So, "draft-ietf-p2psip-sip-01" can abolish the restriction of caller as peer. What need to be mentioned is that sip users inside the overlay can register itself from peers of the overlay or from clients. 2.2. Hidden trouble in sip users' mobility 2.2.1. Compelling support for peers' mobility As sip users are peers, so the overlay compells the support of peers' mobility. If we make sip user just client of the overlay, there would not be such problem. It means that we can construct an overlay supporting clients' mobility without needing peers' mobility. 2.2.2. Churn of the overlay Considering sip users' mobility in wireless access network environment, there would be more probability for peers' joining, leaving of the overlay which has impact on the churn of the overlay. Further, peers can be more easily to lose its connection before sending Leave message in such wireless environment. And this will make the data stored in the peers unreachable. If we make mobile sip user just client of the overlay, there would not be such problem. 2.3. Exclusivity towards overlay clients in sip usage Exclusivity towards overlay clients in sip usage would have restriction on operating way for overlay network operators. Gao & Meng Expires January 28, 2010 [Page 4] Internet-Draft A New SIP Usage for RELOAD July 2009 3. How about words modification from Peers to Nodes "draft-ietf-p2psip-sip-01" can modify the words from *peers* to *node*(including clients). But the problem behind it is the routing problem. If an overlay can route requests to the reponsible peer by the client's ID, sophisticated arranging of nodes's NodeID is needed here. So, it is not feasible to demand clien routing by NodeID in any overlay. Further, AppAttach requested can not be routed to clients by NodeID using the way mentioned above. Then clients' reachability can not be guaranteed by any overlay when routing by NodeID for clients. So, it is not proper to define clients' reachability using NodeID for routing. And we should find a new way. Gao & Meng Expires January 28, 2010 [Page 5] Internet-Draft A New SIP Usage for RELOAD July 2009 4. The new solution The main difference is that sip user registers his address while not NodeID, under his AOR. 4.1. Solution introduction The process of a sip call: 1. Callee stores a mapping from his URI to his Node-ID in the overlay. And the NodeID of the peer choosed to store the mapping has hash relationship with callee's URI. 2. Caller looks up callee's URI in the overlay and retrieves callee's address. 3. Caller uses ICE's offer/answer to exchange caller's and callee's candidate addresses. The process of a sip call Caller Overlay Callee ------------------------------------------------- <------------------- Store Store -------------------> Fetch ----------------> <---------------- Fetch ICE Offer --------------------------------------> <------------------------------------- ICE Answer <------------------ ICE Checks -----------------> INVITE -----------------------------------------> <--------------------------------------------- OK ACK --------------------------------------------> <------------ ICE Checks for media -------------> <-------------------- RTP ----------------------> Figure 1 4.2. More merits 4.2.1. Half spending After fetching the callee's address, the caller can using ICE offer/ answer procedure directly, without AppAttach procedure in the overlay. Gao & Meng Expires January 28, 2010 [Page 6] Internet-Draft A New SIP Usage for RELOAD July 2009 4.2.2. Supporting clients' mobility inherently When callee changes its address, it can send a new registering message to overlay. Gao & Meng Expires January 28, 2010 [Page 7] Internet-Draft A New SIP Usage for RELOAD July 2009 5. Normative references [I-D.ietf-mmusic-ice] Rosenberg, J., "Interactive Connectivity Establishment (ICE): A Protocol for Network Address Translator (NAT) Traversal for Offer/Answer Protocols", draft-ietf-mmusic-ice-19 (work in progress), October 2007. [I-D.ietf-p2psip-base] Jennings, C., Lowekamp, B., Rescorla, E., Baset, S., and H. Schulzrinne, "REsource LOcation And Discovery (RELOAD) Base Protocol", draft-ietf-p2psip-base-03 (work in progress), July 2009. [I-D.ietf-p2psip-sip] Jennings, C., Lowekamp, B., Rescorla, E., Baset, S., and H. Schulzrinne, "A SIP Usage for RELOAD", draft-ietf-p2psip-sip-01 (work in progress), March 2009. Gao & Meng Expires January 28, 2010 [Page 8] Internet-Draft A New SIP Usage for RELOAD July 2009 Authors' Addresses Gao yang ZTE CHINA Email: gao.yang2@zte.com.cn Meng Yu ZTE CHINA Email: meng.yu@zte.com.cn Gao & Meng Expires January 28, 2010 [Page 9]