From: William Herrin (no email)
Date: Fri Jan 18 2008 - 19:32:44 EST
On Jan 18, 2008 4:16 PM, <> wrote:
> Sooner or later, somebody is going to try to apply Google's
> approach to hardware in a network backbone. Imagine a network
> backbone with no Cisco or Juniper boxes in it, just lots of
> commodity boxes with triple-redundancy everywhere (quintuple
> in NFL cities).
Michael,
There's a missing piece here. You'd need a way to go from the 1-gige
interfaces that commodity hardware can keep up with to the 10gige-plus
interfaces that the backbone requires.
Suppose you build 10-gige mux/demuxes for $2000 each so that you can
break the backbone data rates down to 1gbps.
The mux/demux would have one 10-gige port and 12 1-gige ports. Packets
received on the 1-gige ports would be transmitted on the 10-gige port
in the order received. Packets received on the 10-gige port would be
transmitted on the 1-gige ports in a more or less round-robin fashion.
Two of the 1-gige ports would always be configured as backups with the
carrier held low until a piece of equipment attached to one of the
active ports failed.
You could then build a highly available 3 x 10gige port plus 22x1-gige
port "router" with the following components:
3 $2000 10gige mux/demuxes
10 $3000 1U servers (packet forwarders, 5 gig-e ports each)
1 $3000 1U server (BGP route manager, 2 gig-e ports)
2 $3000 1U servers (hot spares, 5 gig-e ports each)
2 $2000 24-port gig-e switch (interlink the 13 servers with redundancy)
62 gig-e cables
18 rack units
$50,000 total. But you can start to get Cisco and Juniper routers with
3 10-gige interfaces in the neighborhood of $50k and they neither take
up 18 rack units nor consume as much electricity as those 13 servers.
On the other hand, commodity memory is cheap. You could expand those
1-gige software-based forwarders to handle 100M routes in the FIB for
maybe another $10k. Since the theoretical limit for the count of
prefixes /24 and shorter is less than 34M, that could be handy. A
similar expansion in Cisco or Juniper big iron is not just expensive,
its hard.
And too, the notion of a Linux routing cluster is undeniably hot. :)
Regards,
Bill Herrin
-- William D. Herrin 3005 Crane Dr. Web: <http://bill.herrin.us/> Falls Church, VA 22042-3004
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