Subject: Review: Section 2, TCP Port 179

From: "Michael C. Cambria" <[email-masked]>
Date: Sat, 07 Sep 2002 10:08:07 -0400

"BGP uses TCP port 179 for establishing its connections"

 From a first time reader point of view ....  does this mean both the 
source and destination use port 179?

Intuition (and a quick look at /etc/services) should make it clear that 
BGP listens on TCP port 179, but shouldn't the draft make clear what can 
and cannot be used for the source port?

MikeC

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From: [email-masked]
Date: Mon, 9 Sep 2002 11:29:15 -0700

It would be simple enough to change the text to "BGP listens on TCP
port 179, and transmits from an implementation-dependant port above
1024."

Do you think that would help clear things up?

Andrew

On Sat, Sep 07, 2002 at 10:08:07AM -0400, Michael C. Cambria wrote:
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From: Jeffrey Haas <[email-masked]>
Date: Mon, 9 Sep 2002 14:36:53 -0400

> Do you think that would help clear things up?

I would just document the listening port.  The convention of stuff > 1024
usually applies to end-hosts.

-- 
Jeff Haas 
NextHop Technologies

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From: [email-masked]
Date: Mon, 9 Sep 2002 11:41:09 -0700

Ok, so we have two options:

"BGP listens on TCP port 179."

Which leaves the transmit port undefined. Or:

"BGP listens on TCP port 179 and transmits from an implemetation-dependent
port."

Thinking of a new operational network engineer reading the spec, the latter
seems more clear.  What do you think as an implementor?

Andrew

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From: "Michael C. Cambria" <[email-masked]>
Date: Mon, 09 Sep 2002 14:39:16 -0400

> seems more clear.  What do you think as an implementor?

As an implementor, I'd just want to know what was legal.

Thus, with the suggested changes, if I picked 179 to transmit on, and 
the peer had a stack that didn't implement the TCP simultaneous open 
properly, it will be unambigous as to which was not complient.

MikeC

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From: "John G. Scudder" <[email-masked]>
Date: Mon, 9 Sep 2002 17:09:41 -0400

>seems more clear.  What do you think as an implementor?

Brevity is the soul of wit.  I prefer the former option.  Anyone who 
is a little bit familiar with TCP should understand that only the 
listen port needs to be 179.  As Yakov points out, it's a _BGP_ spec 
and IMO doesn't need to be a TCP tutorial.

(Furthermore, the second statement is technically incorrect because 
one of the two BGP speakers in any connection will be sourcing its 
traffic from port 179.)

Regards,

--John