You don't know how to do anything small, do you? :)))
Your pretty much "right on" across the board below. (Another person
realizes BGP is not manna from heaven nor ambrosia of the gods)
Here's some more to ponder.
What if your two ISP's only sent you only default routes to their AS's?
(instead of the full BGP tables) And, you have route caching turned on
(i.e. per-destination). Would this accomplish what the pointy-hair dude
wants?
What if you kept the above, but then had the ISP's send you full tables
also, but you filtered anything more than "N" AS's away (you limit the AS
path length you accept)? (Mr Pointy hair visits playboy.com frequently and
it's hosted off of ISP 1. ISP 1 and ISP 2 are twenty AS hops away from each
other. N is this case might be 10)
Rodgers Moore
""Chuck Larrieu"" <[EMAIL PROTECTED]> wrote in message
000b01c01629$f68bc840$[EMAIL PROTECTED]">news:000b01c01629$f68bc840$[EMAIL PROTECTED]...
> The question has been posted here once or twice. It goes something like
> this. "How do I use BGP to load balance between two ISP's?"
>
> I'm starting to get into BGP in earnest in preparation for the CCIE
written.
> And I have something of a fascination with design issues. Let me see if I
> can sort out my thoughts. Please comment where you can.
>
> 1) First of all, the load balancing issue. BGP itself has no mechanism
> within it for load balancing of any kind, whether that be per packet or
per
> destination.
>
> 2) If one could use BGP for per packet "load balancing" then one is in the
> position of doing suboptimal routing in many cases. For example, if I am
> connected to AS101 and AS202, and I want to go to a particular e-commerce
> site, and it is 5 hops via AS101 and 20 hops via AS202 then I have created
> problems for higher layers due to issues with packets arriving out of
> sequence. Potentially I have hurt my performance, maybe even killed it.
>
> 3) If one were to use BGP for per destination "load balancing" isn't is
> possible that the optimum path for all, or at least most, destinations
might
> still lie through one AS or the other? I mean, there is no way to predict
> this, is there?
>
> 4) So from a design perspective, assuming Mr. Pointy-Hair insists on "load
> balancing between two ISP's" the setup most likely would be something like
> this:
> Inside_router-----BGP_router_1--------ISP_1
> |------BGP_Router_2-------ISP_2
>
> and doing something like setting up two 0.0.0.0 routes, one to each BGP
> router, and letting the inside router to the "load balancing"
>
> 5) OR - taking in a full BGP route table, and letting the BGP router
> determine the best path to the destination, recognizing that "load
> balancing" may or may not occur.
>
> 6) Are there a different set of issues if "I" am the e-commerce site? I'm
> thinking yes, because then the issue is ability to reach me by the optimum
> path. This is not a matter of "load balancing" but of raw reachabilty from
> the outside.
>
> Comments welcome. Just trying to clear my thinking.
>
> Chuck
>
> Please check out my new footers for a new age
>
> 1) Altruism
> http://www.hungersite.com/
> Please help feed hungry people worldwide. A few seconds a day can make a
> difference to many people
>
> 2) Shameless Commerce
> http://www.certificationzone.com
> An excellent source for information, study materials, practice questions,
> practice exams, and practice labs. Applicable for all levels of
> certification, as well as the attainment of internetworking expertise.
Tell
> them Chuck Larrieu sent you. ( disclaimer - I will receive addition free
> months membership when enough people mention my name upon joining )
>
>
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