[32917] in North American Network Operators' Group
Re: Where are ATM NAPs going?
daemon@ATHENA.MIT.EDU (Marshall Eubanks)
Mon Dec 18 14:06:45 2000
Message-ID: <3A3E5E9A.4972B0C8@21rst-century.com>
Date: Mon, 18 Dec 2000 13:59:38 -0500
From: Marshall Eubanks <tme@21rst-century.com>
Reply-To: tme@21rst-century.com
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To: Sean Donelan <sean@donelan.com>
Cc: nanog@merit.edu
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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 : tme@on-the-i.com tme@multicasttech.com
http://www.on-the-i.com http://www.buzzwaves.com
