Re: [hybi] Ping/Pong body (was Re: TSV-Directorate review of draft-ietf-hybi-thewebsocketprotocol-07)
Greg Wilkins <gregw@intalio.com> Wed, 25 May 2011 22:48 UTC
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Date: Thu, 26 May 2011 08:48:43 +1000
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From: Greg Wilkins <gregw@intalio.com>
To: Bruce Atherton <bruce@callenish.com>
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Subject: Re: [hybi] Ping/Pong body (was Re: TSV-Directorate review of draft-ietf-hybi-thewebsocketprotocol-07)
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+1 to all this. On 23 May 2011 05:47, Bruce Atherton <bruce@callenish.com> wrote: > It seems there are still a number of issues around Ping/Pong. Here are my > thoughts on them: > > 1) Should multiple Pings be allowed before a response Pong is received? > > Surely this is the business of the implementation/application and not the > specification. If someone has a use for such a thing, why not allow it? > > 2) Should Ping and Pong be allowed to have a body? > > I think it is a useful and desirable feature. It allows matching Pongs to > Pings, as well as being an area for experimenting with new ideas in how the > Ping and Pong are used. > > The argument has been brought up that the bodies are useless without a > standard way of interpreting them. This is absolutely true. Why not allow > experimentation so that people can come up with standards for them? > > What is the downside to allowing it? > > 3) Should there be an indicator for unsolicited Pongs and/or Pings that need > no response. > > I don't see why this is necessary or desirable so long as the body of the > Pong in some way indicates the Ping it is responding to. Allowing > unsolicited Pongs removes any usecase for Pings without responses as far as > I can see. As far as unsolicited Pongs go, if the Pong body does not match a > Ping that was sent out, then surely it can be assumed to be an unsolicited > Pong. > > What is the marker trying to indicate? That if we have a Pong that claims to > be solicited and does not match the Ping body that there is a bug in the > server implementation, or perhaps that the server is mistaken in the client > it thinks it is communicating with? Is this really necessary? > > 4) Should we allow the Pong body to contain extra data beyond just echoing > the Ping body? > > Again, I think this is a harmless way to allow experimentation on uses for > Ping and Pong. I don't see any reason for disallowing it. > > It has been claimed that there could not be any value in allowing additional > information because Ping/Pong frames run at a higher priority than other > Websocket traffic, and so any data they carry on network characteristics > would not reflect the behaviour of other data in the channel. This makes a > couple of assumptions that I think are questionable. First, are all possible > uses of Ping and Pong concerned with network characteristics? Even if so, > are all possible network characteristics rendered moot by higher priority > traffic? I don't see it necessarily follows that these two assumptions are > valid. > > So if it were up to me, I would just change the spec to indicate that the > Pong must respond with the Ping body, but is allowed to add any data it > wishes to afterward. In fact, you could even change it to respond with just > a hash of the Ping body followed by any other data it wanted to (SHA1 + > Base64 for consistency). > > I wouldn't add in a flag for unsolicited vs. solicited Pongs since the Pong > response does that for us by indicating the Ping it is responding to, but if > others wanted it then I wouldn't stand in their way. Although, if you are > going to specify a byte for a single flag then you may want to indicate the > other 7 bits are reserved for future use. > > _______________________________________________ > hybi mailing list > hybi@ietf.org > https://www.ietf.org/mailman/listinfo/hybi >
- [hybi] Ping/Pong body (was Re: TSV-Directorate re… Takeshi Yoshino
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Salvatore Loreto
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Bruce Atherton
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Takeshi Yoshino
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Gabriel Montenegro
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Piotr Kulaga
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Brian McKelvey
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Piotr Kulaga
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Greg Wilkins
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Brian McKelvey
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Patrick McManus
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Jamie Lokier
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Gabriel Montenegro
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Salvatore Loreto
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Bruce Atherton
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Pieter Hintjens
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Jamie Lokier
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Jamie Lokier
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Pieter Hintjens
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Bruce Atherton
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Takeshi Yoshino
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Patrick McManus
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Takeshi Yoshino
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Takeshi Yoshino
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Patrick McManus
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Willy Tarreau
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Takeshi Yoshino
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Patrick McManus
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Brian McKelvey
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Greg Wilkins
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Takeshi Yoshino
- Re: [hybi] Ping/Pong body (was Re: TSV-Directorat… Gabriel Montenegro