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Brad Mitchell · 01-08-2008, 08:39 AM

Interestingly enough, however, we do have a better option on the table that we could (and would) automatically use if we started exchanging any significant traffic. In fact, we can almost cut that latency figure in half if we would have used (believe it or not) PCCW Global to send the traffic, which can reach that router in a mere 33ms. Our runner-up carrier would be another long-shot guess for most -- Cogent at 43ms. (See the graphic I'm pulling these stats from for yourself):

[URL="http://www.mojohost.com/gfy/LG-Output.JPG[/URL]

So, Thank you for your example traceroute -- I couldn't have scripted this scenario any better. This precisely illustrates the value of the FCP in our network. BTN just happened to have a direct peer in Dallas one hop away with Quest that seems to be a lot closer/faster to the source than WDC/L3 is. Would you have anticipated that would have been our best choice to reach that network? Not likely. Be honest -- it was even said in this thread that the general understanding that many have is that BTN has 'crappy coverage' of the East Coast. Is there any way your traffic engineer would have found that on his own and changed your policy to use that path without you or someone (or something) asking him to? Not likely at all.

Finally, you mentioned:

>> Quote:
>> Originally Posted by Maz
>> A host not using provider pricing as primary metric when making routing decisions, very hard to believe, but
>> maybe there are still good people left in this

>>> Interesting that you mention this - given that the one of the FCPs main selling points is the ability to make
>>> routing decisions based on cost (you enter cost per megabit per provider, and what you want your total cost to
>>> be) rather than the best route necessarily. E.g. it intentionally facilities not necessarily using the best
>>> route and utilize a cheaper "acceptable" route.

Of course the FCP is also taking link utilization and bandwidth cost into account. If it didn't, consider cost, it would be returned promptly to the cardboard box it came in. ;)

This response is already way too long, so I won't go into too much detail here other than to say that the FCP collects metrics on all probed paths and then performs multiple passes of logic to arrive at a list of optimizations (path changes) it wants to make. In our configuration, our box is in what is called "Performance Sensitive" mode -- meaning that the primary (first) pass looks strictly at performance data and does not consider

the cost of bandwidth. Once that list is generated, another pass determines what the cost implications of implementing that list of changes are, and if it would push an 'expensive' link over a desired threshold, it will see if there any traffic currently on that link that could go elsewhere without much performance penalty in a 'swap' if you will.

In some rare cases, is it possible that we would continue to use a link that gives us a 45ms RTT when we have a choice to drop to 40ms, but it would violate a 95th tier and increase a carrier bill by a few hundred bucks? Yes, it is possible. The farther apart those numbers get, however, the more insistent the FCP is about figuring out a way (a swap) to use the better link without violating the link's cost tier. The reverse is also true, sometimes we just have to live with a higher bill because of large scale problems with one of our carriers and the need to divert traffic en-masse off their link until its resolved.

Although quite valid, I think your question assumes a tighter relationship between provider cost and provider quality than often exists in reality. Most of the time the FCP has no problem finding both very good and very bad paths to networks over every provider we have. Look down on carrriers like Cogent or BTN all you want and praise ones like L3 and ATT and GBLX. If we were just single or dual-homed, I can promise you I'd be picking from the latter group muself. However I can tell you from experience that all carriers all have their good and bad points, and can back up my experience with some hard data if your're interested. Every carrier has value -- its just sometimes a lot of work to find out what it is. The FCP just makes that job much easier and more accurate. ;)

Sincerely,

Brad Mitchell

01-08-2008, 08:39 AM
Brad Mitchell Confirmed User Industry Role: Join Date: Nov 2001 Location: Southfield, MI Posts: 9,813	Interestingly enough, however, we do have a better option on the table that we could (and would) automatically use if we started exchanging any significant traffic. In fact, we can almost cut that latency figure in half if we would have used (believe it or not) PCCW Global to send the traffic, which can reach that router in a mere 33ms. Our runner-up carrier would be another long-shot guess for most -- Cogent at 43ms. (See the graphic I'm pulling these stats from for yourself): [URL="http://www.mojohost.com/gfy/LG-Output.JPG[/URL] So, Thank you for your example traceroute -- I couldn't have scripted this scenario any better. This precisely illustrates the value of the FCP in our network. BTN just happened to have a direct peer in Dallas one hop away with Quest that seems to be a lot closer/faster to the source than WDC/L3 is. Would you have anticipated that would have been our best choice to reach that network? Not likely. Be honest -- it was even said in this thread that the general understanding that many have is that BTN has 'crappy coverage' of the East Coast. Is there any way your traffic engineer would have found that on his own and changed your policy to use that path without you or someone (or something) asking him to? Not likely at all. Finally, you mentioned: >> Quote: >> Originally Posted by Maz >> A host not using provider pricing as primary metric when making routing decisions, very hard to believe, but >> maybe there are still good people left in this >>> Interesting that you mention this - given that the one of the FCPs main selling points is the ability to make >>> routing decisions based on cost (you enter cost per megabit per provider, and what you want your total cost to >>> be) rather than the best route necessarily. E.g. it intentionally facilities not necessarily using the best >>> route and utilize a cheaper "acceptable" route. Of course the FCP is also taking link utilization and bandwidth cost into account. If it didn't, consider cost, it would be returned promptly to the cardboard box it came in. ;) This response is already way too long, so I won't go into too much detail here other than to say that the FCP collects metrics on all probed paths and then performs multiple passes of logic to arrive at a list of optimizations (path changes) it wants to make. In our configuration, our box is in what is called "Performance Sensitive" mode -- meaning that the primary (first) pass looks strictly at performance data and does not consider the cost of bandwidth. Once that list is generated, another pass determines what the cost implications of implementing that list of changes are, and if it would push an 'expensive' link over a desired threshold, it will see if there any traffic currently on that link that could go elsewhere without much performance penalty in a 'swap' if you will. In some rare cases, is it possible that we would continue to use a link that gives us a 45ms RTT when we have a choice to drop to 40ms, but it would violate a 95th tier and increase a carrier bill by a few hundred bucks? Yes, it is possible. The farther apart those numbers get, however, the more insistent the FCP is about figuring out a way (a swap) to use the better link without violating the link's cost tier. The reverse is also true, sometimes we just have to live with a higher bill because of large scale problems with one of our carriers and the need to divert traffic en-masse off their link until its resolved. Although quite valid, I think your question assumes a tighter relationship between provider cost and provider quality than often exists in reality. Most of the time the FCP has no problem finding both very good and very bad paths to networks over every provider we have. Look down on carrriers like Cogent or BTN all you want and praise ones like L3 and ATT and GBLX. If we were just single or dual-homed, I can promise you I'd be picking from the latter group muself. However I can tell you from experience that all carriers all have their good and bad points, and can back up my experience with some hard data if your're interested. Every carrier has value -- its just sometimes a lot of work to find out what it is. The FCP just makes that job much easier and more accurate. ;) Sincerely, Brad Mitchell __________________ President at MojoHost \| brad at mojohost dot com \| Skype MojoHostBrad 71 industry awards for hosting and professional excellence since 1999 Last edited by Brad Mitchell; 01-08-2008 at 08:42 AM..