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To: damian@cablenet.net (Damian Hamill)
cc: freebsd-isp@freebsd.org
Subject: Re: Router Cards?
References: <3.0.1.32.19971021182012.0098ad50@bailin.lan>
	<344F21C2.6EEA4806@cablenet.net>
From: Tony Li <tli@juniper.net>
Date: 23 Oct 1997 14:46:12 -0700
In-Reply-To: damian@cablenet.net's message of 23 Oct 97 10:06:59 GMT
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damian@cablenet.net (Damian Hamill) writes:

> There is another issue that as yet I haven't seen discussed regarding PC
> Unix routers versus dedicated routers.  Recently a large number of
> Internet routers went belly up as a major ISP loaded a large number of
> new routes into the routing tables.  This caused these dedicated routers
> to run out of memory and reboot, creating a lot of instability and route
> flapping.  Considering the (virtual) nature of PC Unix memory I do not
> know if any PC Unix routers suffered the same fate.

In fact, experience with VM routers in the Internet backbone shows that
they do not perform well when they begin to page.  Unlike normal program
execution, when real time systems start to page, it's really bad news.

> As I understand the main selling point of dedicated router products like
> cisco is reliability, in that their are no moving parts to wear out
> (other than the cooling fan).  However beyond a simple configuration and
> when lots of memory is needed they become VERY expensive.  If in fact
> they are not as reliable as PC Unix routers in the face of this kind of
> event then the whole point of buying them becomes redundant, given the
> fact that you can expect years of reliability out of PCs.

You perhaps shouldn't confuse hardware reliability with software
reliability.  The software failures that are seen are an orthogonal issue.

Tony