What frame relay switch is causing MCI/Worldcom such grief?

Alex Bligh amb at gxn.net
Mon Aug 9 22:09:31 UTC 1999

> Yes.

Not disagreeing with Sean, which whilst amusing is often unproductive:

One of the higher clue arguments in favour of maintaining an L2
mesh (and 'routing' protocol) is that it converges quicker than
than L3 as in theory it has less nodes. The normal counter arguments
1. that L1 (SONET/SDH) converges quicker still.
2. as MCI/Worldcom may well have aptly demonstrated, L2 routing
   protocols have their own problems.
3. L3 routing can be hierarchicalized (sp?) and tweaked to converge
   just as effectively - witness sending your loopback IP's round as
   next hops in BGP and running an underlying IGP such as OSPF/ISIS/EIGRP
   which cuts out many (though unfortunately not all) recomputations
   when the underlying fabric changes.
4. Implementation of L2 heavy protocols on routers is often poor. Witness
   how long it took Cisco to implement OAM management. So just how long
   does it take to notice a VC's gone down?

A more convincing argument for buying ATM circuits is that they
(are) / (used to be) dirt cheap. Recent experience suggests there may
be a reason for this.

Alex Bligh
GX Networks (formerly Xara Networks)

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