[4410] in North American Network Operators' Group

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Re: Top-50 Report

daemon@ATHENA.MIT.EDU (Mr. Jeremy Hall)
Mon Sep 16 09:58:45 1996

From: "Mr. Jeremy Hall" <jhall@rex.isdn.net>
To: vansax@atmnet.net (Jim Van Baalen)
Date: Mon, 16 Sep 1996 08:43:52 -0500 (CDT)
Cc: jon@branch.com, jfbb@atmnet.net, nanog@merit.edu
In-Reply-To: <199609161047.DAA20137@core.atmnet.net> from "Jim Van Baalen" at Sep 16, 96 03:47:28 am

-->
-->> 
-->> 
-->> There is no question that more people are needing more reliable 
-->> connections to the net.  With some education, tools, and the right 
-->> pricing models, people can be encouraged to get backup connectivity in 
-->> a manner that doesn't impact the size of the routing table.  
-->> Specifically, they should not announce any routes on their backup 
-->> connection unless their primary is down.  ISPs should provide
-->
-->Is there some trick here or are you saying that a duel homed ISP should
-->manually update their announcements when their primay pipe is down? I
-->think that, in theory, your statement makes sense, but I don't know how
-->one accomplishes it in practice. Outbound traffic is easy, but if one is
-->duel homed and wishes to have inbound traffic find their network "quickly"
-->and dynamically when their primary pipe is down, I believe it is necessary 
-->to advertise ones routes via ones backup at all times.
-->
-->Jim
-->

You might be able to set the backup interface in backup mode or standby 
mode or whatever cisco calls it, I don't remember. Anyway, if your 
primary line drops, the backup line would come up. Since the backup line 
would come up, you would begin peering with the backup peer. At this 
time, you would probably want to decide how much of a backup you want 
your backup to be. At what point do you declair an emergency and begin 
routing via your backup? I agree with the person who stated it earlier, 
the one saying that he'd rather use a backup all the time so he'd know 
whether a problem would come up when he needed his backup the most. Where 
this gets nasty is when your main ISP is having trouble peering at the 
peer points and so your connection is not down. At this time, I don't see 
how you could only announce to one peer at a time without a change in 
software.
-- 
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