- From: Harald Alvestrand <harald@alvestrand.no>
- Date: Sun, 17 Jun 2012 15:47:21 +0200
- To: "Sunyang (Eric)" <eric.sun@huawei.com>
- CC: "public-webrtc@w3.org" <public-webrtc@w3.org>
- Message-ID: <4FDDDFE9.4030908@alvestrand.no>
On 06/17/2012 03:27 PM, Sunyang (Eric) wrote: > > Thanks. > > So components means pieces of media stream which request a single > address, it does not means the ICE candidates pair, > > But we need at least one candidates pair per component, right? > > So “connected” means all components have at least one pair per > component who have setup connections between A and B. > Yes, that fits my interpretation of the spec. > *发件人:*Harald Alvestrand [mailto:harald@alvestrand.no] > *发 送时间:*2012年6月17日19:30 > *收件人:*public-webrtc@w3.org > *主题:*Re: Spec question: precise meaning of PeerState and IceState > > On 06/17/2012 08:33 AM, Sunyang (Eric) wrote: > > Hi Uberti: > > Note: "new" has been removed, as such a state no longer exists; > "waiting"/"gathering" have been merged into "starting", as gathering > is not a well-defined state.Note: these represent more or less the > most pessimistic view across all the streams. *So “connected” means > all components are connected.** > > > * > > As I suppose, the components means all usable ICE candidates pairs > (local+remote), so I guess “connected” should not mean all components > are connected, because we have no reason that PeerConnection should > use all the ICE candidates pairs, we should use as few pairs as > possible to save the resources. So I think “connected” means > components needed by peerconnection are all connected. > > No, that's not what "component" means in this context. > > If we have a single RTP session, with RTP + RTCP multiplexed, we have > one component. > If we have a single RTP session, but RTP and RTCP use different ports, > we have two components. > If we have two RTP sessions (one for audio and one for video), and RTP > and RTCP use different ports, we have four components. > > We need to have at least one working pair connected for each component. > > The definition is in RFC 5245 (ICE) section 3: > > Component: A component is a piece of a media stream requiring a > single transport address; a media stream may require multiple > components, each of which has to work for the media stream as a > whole to work. For media streams based on RTP, there are two > components per media stream -- one for RTP, and one for RTCP. > > (this was written pre RTP/RTCP multiplexing, which is RFC 5761, and > pre BUNDLE) > > Harald >
Received on Sunday, 17 June 2012 13:47:52 UTC