At 11:59 PM 8/21/01, Tony Medeiros wrote:
>I always thought "split horizon" was a non intuitive term anyway. iBGP or
>whatever. Some engineers come up with the strangest names for things.
>
>Split horizon implys there is a big tree that is obstructing my view of the
>sunset. :>0
Is it a spanning tree? ;-)
I like the term split horizon and agree with the idea of using it
generically. I encourage the generic use of most terms so that people think
about what they really mean. See a discussion we had earlier about distance
vector, for example.
For spanning tree, I like the way Radia Perlman puts it:
"The purpose of the spanning tree algorithm is to have bridges dynamically
discover a subset of the topology that is loop-free (a tree) and yet has
enough connectivity so that where physically possible, there is a path
between every pair of LANs (the tree is spanning)."
I'm not sure I had ever thought about why the word "spanning" is in the
phrase. And I would add to her description:
A tree is a mathematical concept. A tree is a diagram or graph that
branches from a single stem without forming loops or polygons.
A lot of people learn these terms without understanding them.
And, back to the subject, I think split horizon can be used in this
situation, even though it's a bit different and the horizons aren't quite
the same.
Priscilla
(wishing she was looking over the Hawaiian horizon about now. ;-)
>Tony M.
>(Split personnality)
>
>----- Original Message -----
>From: "Chuck Larrieu"
>To:
>Sent: Tuesday, August 21, 2001 8:13 PM
>Subject: RE: A new networking term - thoughts? [7:16668]
>
>
> > I thought I was fairly careful in stating that with iBGP split-horizon,
an
> > iBGP router will not advertise a route to the same AS from which it
>receives
> > the route. This covers the interface issue.
> >
> > Chuck
> > whose mama didn't raise no fool, and whose lawyer wife has taught him the
> > hard way about wording things ;->
> >
> > -----Original Message-----
> > From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]On Behalf Of
> > Ole Drews Jensen
> > Sent: Tuesday, August 21, 2001 8:52 AM
> > To: [EMAIL PROTECTED]
> > Subject: RE: A new networking term - thoughts? [7:16668]
> >
> >
> > Chuck, I think there's a difference here. Split Horizon as you say, does
>not
> > advertise a route back out the interface that it received it on, but the
> > iBGP does not only not propagate a route learned from other iBGP out the
> > receiving interface, but it does not propagate it out any interfaces
>unless
> > it has been setup as a cluster server.
> >
> > If you would name this, it would probably be something like "iBGP
horizon"
> > :-)
> >
> > Just my 00000010 cents.
> >
> > Ole
> >
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > Ole Drews Jensen
> > Systems Network Manager
> > CCNA, MCSE, MCP+I
> > RWR Enterprises, Inc.
> > [EMAIL PROTECTED]
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > http://www.RouterChief.com
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> > NEED A JOB ???
> > http://www.oledrews.com/job
> > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> >
> >
> > -----Original Message-----
> > From: Chuck Larrieu [mailto:[EMAIL PROTECTED]]
> > Sent: Tuesday, August 21, 2001 10:29 AM
> > To: [EMAIL PROTECTED]
> > Subject: A new networking term - thoughts? [7:16668]
> >
> >
> > As a result of an off-list conversation, I came across the following
> > networking term:
> >
> > iBGP split horizon
> >
> > my first reaction was a sarcastic remark about never having come across
>the
> > term in the RFC's. but then I got to thinking about it, and I now see
this
> > as a descriptive and quite useful term.
> >
> > recall that distance vector protocols are subject to the rule of split
> > horizon. they do not advertise a route back out the interface that they
> > received that particular route.
> >
> > one of the gotchas of iBGP is the fact that iBGP routers do not propagate
> > routes learned from one iBGP neighbor to other iBGP neighbors. hence the
> > requirement for iBGP full mesh.
> >
> > so why not call this iBGP split horizon? and define it as follows: an
iBGP
> > router will not advertise a route back out the same AS from which it
>learned
> > the route?
> >
> > does this make sense? worth letting this one join the lexicon of
>networking
> > terminology?
> >
> > Chuck
________________________
Priscilla Oppenheimer
http://www.priscilla.com
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=16851&t=16668
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