Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- WebSocket Transport for Session Initiation Protocol (SIP)
Iñaki Baz Castillo <ibc@aliax.net> Wed, 14 September 2011 08:41 UTC
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Date: Wed, 14 Sep 2011 10:43:30 +0200
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From: Iñaki Baz Castillo <ibc@aliax.net>
To: "Avasarala, Ranjit" <Ranjit.Avasarala@polycom.com>
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Cc: "rtcweb@ietf.org" <rtcweb@ietf.org>
Subject: Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- WebSocket Transport for Session Initiation Protocol (SIP)
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2011/9/14 Avasarala, Ranjit <Ranjit.Avasarala@polycom.com>: > I have few initial comments on your draft Hi Ranjit, replies inline: > 1) in Section 3, its mentioned that there is no real benefit of using SIP over Websockets. If this is the case, why are you proposing integrating SIP with Websockets? As Saul pointed out, the text says: There is no benefit on using SIP over WebSocket transport between two SIP nodes when none of them runs within a web browser. JavaScript can open a WebSocket connection from a web browser to a server, but not an arbitrary TCP or UDP connection. > 2) Also just integrating SIP for signaling case is really no use, as there are several other ways of achieving signaling in web - E.g. using libjingle of WebRTC, etc The fact that there are other alternatives for signaling in the web does not mean that using SIP is invalid. If I want to build a SIP phone in a web, why should I use libjingle rather than SIP protocol? Why should I code a complex server behaving as a gateway between Jingle and SIP protocols? Any protocol conversion (i.e. from Jingle to SIP) means loss of features. Our draft proposes the contrary: no protocol conversion (just SIP), and just transport protocol conversion (as already exists in SIP when bridging UDP/TCP/TLS-TCP/SCTP...). > 3) In Section 4, you mentioned that since Websocket is a reliable transport protocol, the websocket sub-protocol defined for SIP also becomes reliable. I don't agree with this - The websocket connection is actually initiated by the web browser client towards the web server and this connection needs to be kept alive through some keep alive mechanism. Otherwise the connection may close. I am not sure of reliability. "Reliability" does not mean that. "Reliability" means data delivery acknowledgment in the transport. This is true in TCP (so also in WebSocket which works on top of TCP) and false in UDP (which is not a reliable transport protocol). The keep-alive mechanism is needed for cases in which there is a NAT router in the path. Those routers usually close a TCP connection after some minutes of inactivity. This happens in any TCP connection from client to server through a NAT box. > 4) In Section 4.1,I am not clear of the Via transport parameter having the value of "WS". Why do you need this when the whole SIP message is going as part of WebSocket payload [Using websocket API]? This is how SIP protocol works and this is explained in RFC 3261. You can also check a similar example for SIP over SCTP transport at: http://tools.ietf.org/html/rfc4168#section-4 Best regards. -- Iñaki Baz Castillo <ibc@aliax.net>
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Markus.Isomaki
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Ravindran Parthasarathi
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Roman Shpount
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Iñaki Baz Castillo
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Igor Faynberg
- [rtcweb] draft-ibc-rtcweb-sip-websocket -- WebSoc… Iñaki Baz Castillo
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Markus.Isomaki
- [rtcweb] draft-ibc-rtcweb-sip-websocket -- WebSoc… José Luis Millán
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Markus.Isomaki
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Thomas
- Re: [rtcweb] draft-ibc-rtcweb-sip-vs-websocket Bernard Aboba
- Re: [rtcweb] draft-ibc-rtcweb-sip-vs-websocket Dzonatas Sol
- Re: [rtcweb] draft-ibc-rtcweb-sip-vs-websocket Ravindran Parthasarathi
- [rtcweb] draft-ibc-rtcweb-sip-websocket -- WebSoc… José Luis Millán
- Re: [rtcweb] draft-ibc-rtcweb-sip-vs-websocket Binod PG
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Patrick McManus
- Re: [rtcweb] draft-ibc-rtcweb-sip-vs-websocket Hadriel Kaplan
- Re: [rtcweb] draft-ibc-rtcweb-sip-vs-websocket Binod PG
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Avasarala, Ranjit
- Re: [rtcweb] draft-ibc-rtcweb-sip-vs-websocket Markus.Isomaki
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Saúl Ibarra Corretgé
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Iñaki Baz Castillo
- Re: [rtcweb] draft-ibc-rtcweb-sip-vs-websocket Iñaki Baz Castillo
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Christer Holmberg
- Re: [rtcweb] draft-ibc-rtcweb-sip-vs-websocket Ravindran Parthasarathi
- Re: [rtcweb] draft-ibc-rtcweb-sip-vs-websocket José Luis Millán
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Iñaki Baz Castillo
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Christer Holmberg
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Iñaki Baz Castillo
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Iñaki Baz Castillo
- Re: [rtcweb] draft-ibc-rtcweb-sip-vs-websocket Ravindran Parthasarathi
- Re: [rtcweb] draft-ibc-rtcweb-sip-vs-websocket Olle E. Johansson
- Re: [rtcweb] draft-ibc-rtcweb-sip-vs-websocket Tim Panton
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Tim Panton
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Roman Shpount
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Randell Jesup
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Roman Shpount
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Markus.Isomaki
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Roman Shpount
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Igor Faynberg
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Dzonatas Sol
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Randell Jesup
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Markus.Isomaki
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Dzonatas Sol
- [rtcweb] Need for Default signaling protocol for … Ravindran Parthasarathi
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Saúl Ibarra Corretgé
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Markus.Isomaki
- Re: [rtcweb] draft-ibc-rtcweb-sip-websocket -- We… Dan Wing