[6102] in North American Network Operators' Group

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Re: Why doesn't BGP... -Reply

daemon@ATHENA.MIT.EDU (Alex.Bligh)
Tue Nov 12 12:58:38 1996

To: Avi Freedman <freedman@netaxs.com>
cc: Neal_Castagnoli@novell.com (Neal Castagnoli), edm@halcyon.com,
        deepak@jain.com, nanog@merit.edu
In-reply-to: Your message of "Tue, 12 Nov 1996 08:21:18 EST."
             <199611121321.IAA27938@access.netaxs.com> 
Date: Tue, 12 Nov 1996 17:34:16 +0000
From: "Alex.Bligh" <amb@xara.net>

 
> > What I don't know, is why is it that SS7, the telephone routing protocol,
> > can do some of the things that are required, like load sharing across
> > unequal paths, for example.  Does anyone have any insight into this?

I *believe* one main difference is that telco sig is connection oriented
whereas IP is pretty much collectionless (interesting comparison
to netflow switching though); hence telephony switching protocols
can afford to wait tenths of seconds finding a route whereas this
would not be an acceptable per packet switching overhead. Another
is that signalling between switches is carried out-of-band (i.e.
is not itself affected by line congestion) which is the bane of
many routing protocols. Also note that esp on intl circuits there
is still manual preening activity.

(prepares flame-suit for telco interconnect guru attack)

Alex Bligh
Xara Networks



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