Enterprise Multihoming

Fri Mar 12 16:15:55 UTC 2004

>>> "Stephen J. Wilcox" <steve at telecomplete.co.uk> 3/12/04 9:06:38 AM
>>>
>I dont agree that connecting to two+ upstreams makes you better. In
my
>experience end networks have a couple of orders of magnitude more
downtime than
>a PoP in any reasonably large ISP. Ie the percentage theoretical
improvement is 
>small.
>
>In addition you seriously increase the complexity of your system,
chances are
>you're using the cheapest kit you could find (or at least cheaper and
smaller
>than what I would use).. its not great at BGP and may fall over when
you get a 
>minor DoS attack, you probably generate flaps quite a bit from adhoc
changes and 
>if you're announcing a /24 then thats going to get you dampened
quickly.. so you 
>actually create a new weakest link. Also most of the corporates I've
dealt with 
>take defaults rather than full tables.. so if the provider does have
an issue 
>you still forward the traffic, theres no failover of outbound
routing.
>
>Even if you spend (waste) the money on some decent gear, you're on
your own and 
>when a problem occurs the ISPs are going to be less helpful to you
(not by 
>choice, I mean they dont have control of your network any more.. there
knowledge 
>of whats causing problems is limited to the bit that they provide to
you), so 
>chances are your problems may be more serious and take longer to
diagnose and 
>fix.

The above arguments are rather similar to the ones I heard on the other
discussion list I mentioned, and they were somewhat compelling.

>
>IMHO avoid multihoming. You will know when you are big enough and you
*need* to 
>do it, if you're not sure or you only want to do it cause you heard
everyone 
>else is and its real cool then I suggest you dont.

In our case, we already are multihoming and I'm considering moving away
from that to a simpler solution. It's been my assertion that we didn't
need to multihome in the beginning. The decision was made at a level
higher than me. However, now that we have it I'm trying to determine the
pros and cons related to moving to a single provider.

Thanks,
John
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