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Re: Where are ATM NAPs going?

  • From: Marshall Eubanks
  • Date: Mon Dec 18 14:09:18 2000 
Sean Donelan wrote:

> ATM is just a technology.  Over the last decade, depending on who had
> the faster chipset, folks have chosen an ATM chipset, an Ethernet or
> even a Frame-Relay chipset for their NAPs/Exchange Points.  At one point
> in time, the Gigaswitch was the fastest available.  Then ATM switches
> could do 155Mbps and OC12.  GigEthernet and 10 GigEthernet appeared,
> and folks went the other way.
>
> Both ATM and Ethernet exchange points have route-servers.  Equinix, PAIX,
> SBC, and Worldcom have route-servers at their exchange points in the USA.
> LINX and other have route-servers at exchange points outside the US.
> Fully filtering your peering sessions with route-servers is relatively
> simple.
>
> ATM has PVCs, Ethernet has VLANs.  Ethernet interface cards tend to be
> less inexpensive than ATM interface cards.  ATM is a natural wide-area
> technology, Ethernet is a natural local-area technology.  Frame-relay
> tends to be used for smaller exchange points, although it could also
> work in a mid-sized exchange points.
>
> The reliability between ATM and Ethernet isn't that different over the
> long term.  Most of the problems tend to be with the end-connections
> (congestion and broadcast loops), and not the fabric itself.  But there
> have been notable outages with atm switches and ethernet switches at
> exchange points.
>
> Multicast is an interesting problem in itself.  None of the ATM switches
> handle multicast very well, and even the ethernet switches have problems.

Generally, to date, multicasting has gone on a separate switched fabric when
the exchange allows it at all. Fixing this, or making it work better in general, will require
Layer 3 snooping. Anyone who is interested in this should contact me off-line.

                                 Regards
                                 Marshall Eubanks


T.M. Eubanks
Multicast Technologies, Inc
10301 Democracy Lane, Suite 410
Fairfax, Virginia 22030
Phone : 703-293-9624
Fax     : 703-293-9609
e-mail : [email protected]     [email protected]

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