nanog mailing list archives

Re: iBGP next hop and multi-access media


From: "Stephen J. Wilcox" <steve () telecomplete co uk>
Date: Mon, 7 Oct 2002 13:08:03 +0100 (BST)


Proxy arp will still send the data thro the other router tho, the only
difference is now router B believes router A to be the destination
station. Seems like your worse off than you were before. (Plus I hate proxy arp
in non-SOHO environments!)

Steve

-- 
Stephen J. Wilcox
BSc (Hons), CCNA, CCNP, CCIE wr.
Technical Director, Telecomplete
http://www.telecomplete.co.uk/

On Mon, 7 Oct 2002, Jared Mauch wrote:


On Mon, Oct 07, 2002 at 12:15:40AM -0400, Alex Rubenstein wrote:


OK, I'll bite.

I've been doing ip route statements going on 8 years now, and I can't
imagine why ever -- and how it would even work -- you'd want to ip route a
netblock with a next hop of a multi-access brandcast media. As in, the
next hop is still truly undetermined.

I guess I don't know this because I've never tried it. But, how does the
router determine where to send the packets for a route statement as
specified above (ip route a.b.c.d e.f.g.h f0/0) ?

      A cisco router with the default (ip proxy-arp) enabled on
the interface will spend all its time doing arp/proxy-arp for the hosts and
it will actually work believe it or not.

      You'll notice massive cpu utilization.

      People who do this tend to not have a lot of clue or notice
when their cpu is spending all its time doing this...  One should
always turn proxy-arp off on your interfaces both internal and customer
facing so they don't make your router bear the load because they can
not configure their devices logically.

      - Jared

So then what do you call a connected route (for an ethernet interface on a
router)?  If you use ethernet, at the edges of your network you HAVE to
route IP blocks to the ethernet.

-Ralph


-- Alex Rubenstein, AR97, K2AHR, alex () nac net, latency, Al Reuben --
--    Net Access Corporation, 800-NET-ME-36, http://www.nac.net   --





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