nanog mailing list archives

Re: The 100 Gbit/s problem in your network


From: Scott Helms <khelms () zcorum com>
Date: Tue, 12 Feb 2013 14:54:45 -0500

I really wish I could agree! It would have saved me some time dealing with
it.

There is the argument of alternative bit rates, compression, etc., but HD
streams are assumed[1] at 15 Mbps.

At 100Gbps, I can do max 6826 streams of HD streaming. Multicast
deployments laugh at this pathetically low number of viewers.

At an upstream aggregation point, I can easily serve ~128K subs (7 slots, 8
ports per slot, 3 ports per $ACCESS, 8K[3] users per $ACCESS, 1 slot for
upstream). I now assume 2.5 STBs per sub[2]. This results in, more or less,
320,000 STBs.


Multicast for inside of a given service provider is certainly not dead and
in fact its widely deployed for IPTV in DSL/FTTx networks.  FIOS doesn't
use it since they're not doing IPTV (traditional RFoG) but Uverse does as
do most telco TV providers I've spoken with.



To me, the math says its not dead and we'll need a couple of orders of
magnitude (to accommodate the core) in speed improvements to get the same
delivery unicast.

[1] http://www.cablelabs.com/specifications/OC-SP-CEP3.0-I04-121210.pdfLists
15Mbps as safe harbor value for HD
[2]
http://www.aceee.org/files/proceedings/2012/data/papers/0193-000294.pdfHas
some stat (good or bad) wrt STBs/household
[3] uBR10K (my $ACCESS comparison) specs out for max 64K CPE. One of my
guys indicates to me that the actual number might be closer to 15-25K CPE
on a given node. Please make adjustments as necessary.

(required note: employer is Cisco. Views are my own.)

--
William McCall




-- 
Scott Helms
Vice President of Technology
ZCorum
(678) 507-5000
--------------------------------
http://twitter.com/kscotthelms
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