"Stephen J. Wilcox" <steve@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 --