Outbound Route Optimization

Thu Jan 22 09:45:06 UTC 2004

On Jan 21, 2004, at 4:20 PM, vijay gill wrote:
>
> On Wed, Jan 21, 2004 at 09:05:46PM +0000, Paul Vixie wrote:
>>
>>>             My questions are these:
>>>
>>> "Is sub-optimal routing caused by BGP so pervasive it needs to be
>>> addressed?"
>>
>> that depends on your isp, and whether their routing policies (openness
>> or closedness of peering, shortest vs. longest exit, respect for MEDs)
>> are a good match for their technology/tools, skills/experience, and
>> resources/headroom.
>
> In practice, all of the above just turn out to be marketing sauce
> or in some cases, outright lies.
>
> There is no substitute for dollar spend (opex and capex) to make
> a network perform.  There is no magic sauce, there is no silver
> bullet. You have adequate resources, you will have adequate
> performance.

I dunno if the last sentence is a type-o or not, but it is definitely 
incorrect in at least some cases.  Having "adequate resources" in no 
way guarantees "adequate performance".  (Unless you define "resources" 
to include the political clout to override business decisions which 
help the bottom line but hurt performance - e.g. not peering with a 
network because they are too small.)

OTOH, having inadequate resources does give you a near perfect chance 
of having inadequate performance.

>> (experience says they're not going to trust your MEDs even if they're 
>> close
>> enough to hear them.)
>
> Most people don't trust MEDs for a reason paul, and it is not because
> they want to mess with your customers.

There are a variety of reasons for not listening to MEDs, including 
political reasons which may not be in the best interest of performance, 
or even may be detrimental to performance.

I've found most people willing to put in the time & effort to give you 
MEDs will give reasonably good MEDs.  It also seems the hight of hubris 
to assume you know what is happening inside someone else's network 
better than the people who run that network.  At least IMHO....

In any case, no matter how many resources or black boxes you have, you 
cannot guarantee good performance on the 'Net.  Too many people 
involved over which you have no control.  Even if you had control, BGP 
is not the right tool to exert such control in all cases.

-- 
TTFN,
patrick