North American Network Operators Group

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RE: genuity - any good?

  • From: Martin, Christian
  • Date: Fri Apr 12 14:35:30 2002

I think the argument is not about route filtering - it is the implementation
method.

Genuity uses ip extended access-lists.

Everyone else uses prefix-lists.

To a purist, the former is more granular, but performs poorly because it is
a linked list implementation.  The later, while less granular, performs
faster by using a trie.  It also allows insertion without list rebuilding.
Does this matter much?  I'm sure there are some that have tested convergence
between the two technologies, so I'd welcome comments out of curiosity.

They are somewhat anal with their lists as well.  If you have a /19, but you
want to deaggregate for inbound BGP TE, you will need to send them EVERY
route you will send.  That can be 64 subnets.  For a /16, it is waaayyy
worse.  Then again, it allows them to know exactly how many prefixes MAY be
announced from their customers, which I suppose has its merits.

chris

>-----Original Message-----
>From: [email protected] [mailto:[email protected]] 
>Sent: Friday, April 12, 2002 2:08 PM
>To: [email protected]
>Cc: [email protected]; [email protected]
>Subject: Re: genuity - any good?
>
>
>
>> 1) Their BGP polices are not as good as others.  They force you to 
>> register each route you want to advertise rather than 
>allowing you to 
>> advertise any reasonable route for your prefixes.  According 
>to one of 
>> their top people, prefix-lists were unreliable new technology.  We 
>> gave up and canceled the circuit.
>
>Man I don't know of a provider that doesn't do this - but the 
>fact is this is a good thing.
>