Subject: [BXXPwg] Maxium Size of the frame payload.

From: [email-masked]
Date: Tue, 10 Apr 2001 11:36:05 +0800

Hi all,

The mail list has been silent for a long time. Is there still anyone focusing on
this protocol?

These days I am devoting to write a BEEP library with C++. In my codes, I assume
that the size
of the frame payload is no bigger than 2K. Later I review the spec(RFC3080), it
hasn't any authorative
statement on the maxium frame payload size.I think this is important in
implementation. I can't accept
any size of a frame. There must be a upper limit. But what is it?

Thanks in advance.

Johnny Xia.

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From: "Huston" <[email-masked]>
Date: Mon, 9 Apr 2001 22:10:26 -0600

The upper limit is based on the transport mapping. For the TCP mapping
(RFC3081) the largest frame is the size of the advertised window for the
channel. By default this is 4k.

BTW, there is quite a bit of activity around the protocol. Check out the
beep related projects on sourceforge.net and www.beepcore.org.

--Huston

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From: Charles Graham <[email-masked]>
Date: Tue, 10 Apr 2001 00:14:37 -0400 (EDT)

I am a begginer, so please beer with me guys.

Maybe I am mistaken, but why is it that you asume that there has to be a
maximum size for a payload frame?  The transport service mapping makes
sure that all frames are dilivered to the respective BEEP peer as a whole.
Do we want to put restrictions on the users as to how much they can send
at a time? If so, why?

I thought that one of the good things about BEEP was that it provided an
abstraction so that we can send messages and frames of any size and be
sure that they would come out on the other end in tact without worrying
about how the underlying transport protocal does (or in the case of TCP,
does not do) the framing.

Respectfully,
	Charles Graham

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From: "Marshall T. Rose" <[email-masked]>
Date: Mon, 9 Apr 2001 21:24:11 -0700

> The mail list has been silent for a long time. Is there still anyone
focusing on

look at http://beepcore.org/

> any size of a frame. There must be a upper limit. But what is it?

i see several places that talk about a hard limit, viz.,

common     = channel SP msgno SP more SP seqno SP size
channel    = 0..2147483647
msgno      = 0..2147483647
more       = "." / "*"
seqno      = 0..4294967295
size       = 0..2147483647
ansno      = 0..2147483647

tells me that an individual frame has between 0 and ~2GB octets. of course,
flow control (c.f., RFC 3081) might impose limits as well...

/mtr

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From: "Huston" <[email-masked]>
Date: Mon, 9 Apr 2001 22:34:30 -0600

BEEP does allow for sending messages of any size. However, to allow multiple
channels to be multiplexed over a single connection with some level of
fairness the messages are divided into frames. Frames can not be any size
because one of the reasons for having frames is to prevent one channel from
monopolizing the connection. So frame size is determined by the transport
mapping based on what is best for the particular transport. In the TCP
mapping it states that a peer can only send a frame as large as the amount
of available channel window.

--Huston