I can give you a quick review... Savvis is "better" than Cogent... here's generally speaking why:
1. Consistency of performance. Low cost networks have to save cash somethere. They do it by having less redudant routes in their network, among other things. So if an internal NY to Chicago route tanks, some traffic may take a detour to Texas for a while.
2. Peering relationships. No good network wants a peering partner that's dumping more traffic on them then they can counter sink. Cogent has a lot of traffic that they charge $15/Mb for, for someone like ATT... economics don't compel them to accept too much of it for "free". So if a NY cross connect gets saturated, some traffic will necessarily be routed to another peering point with ATT, perhaps in VA - possibly because ATT says "pay up, or a 1Gb cross connect is all you're gonna get in NY".
The top tier network generally peer in more locations with more networks and do it over faster interconnects. This is because the traffic exchange may be closer to parity, as is the network quality. Though I suspect this is less a factor with Cogent then it used to be, since they have a lot more eyeball networks on their net now then they used to.
3. Routing policy. A great way to save cash as a network operator is to include in your definition of "best route" low financial cost. While cost efficiency is a business reality, going too far can impact performance.
There is no reason to be anti-cogent as many seem to be... they maintain a price point that requires some compromises. You just have to be aware of what that means for your business.
Last edited by convergentns; 06-28-2005 at 12:27 AM.