multi homing pressure

Wed Oct 19 17:35:29 UTC 2005

At 01:05 PM 10/19/2005, John Dupuy wrote:

>>For the customer with an Internet "mission critical app", being tied
>>to a Tier 2 has it's own set of problems, which might actually be
>>worse than being tied to a Tier 1.
>
>The key word is "might". In fact, I would posit that a Tier 2 with 
>multiply redundant transit to all of the Tier 1s could theoretically 
>have better connectivity than an actual Tier 1. The Tier 2 transit 
>provides flexibility that the transit-free Tier 1s do not have. Just 
>my opinion.
>
>Anyway, it has been my experience that most (but not all) of the 
>customers that want to "multihome" are _really_ wanting either: A. 
>geographic/router redundancy. or B. easy renumbering. Geographic 
>redundancy can be done within a single AS and IP block. They just 
>don't know to ask it that way. (And easy renumbering will eventually 
>be solved with v6. Eventually.)

It has been my experience that most needing to multihome wish to do 
so to avoid failures within an ISP, failures with a circuit to the 
ISP, and failures with routers.

I should think that with the recent L3/Cogent issue, it should be 
QUITE clear that multihoming requires linking to two separate 
backbones, or two separate regionals that buy transit from multiple 
backbones. Vagaries in backbone providers is high on the list, IMO, 
and rules out the "multihome to a single provider" approach.

>The demand for multi-homing might not be as great as suspected.
>
>John