What vexes VoIP users?

Frank Bulk frnkblk at iname.com
Wed Mar 2 10:47:04 CST 2011


Yes, that's how PacketCable works.

Here's some CLI output -- nothing like a quick example to make that clear.

Here's a customer with 8M/512K Internet service:

CMTS:7A#sh cable modem 0008.0ed2.0928 svc-flow-id
Service flow id  Interface   Flow Direction   Flow Max Rate
              1  cable  0/0  Upstream                 512000
              2  cable  0/0  Downstream              8000000
CMTS:7A#

Here's a customer with 128K/128K Internet service and two additional service
flows for voice signaling:

CMTS:7A#sh cable modem 0013.1192.f867 svc-flow-id
Service flow id  Interface   Flow Direction   Flow Max Rate
           3593  cable  0/1  Upstream                 128000
           3594  cable  0/1  Upstream                  12000
           3595  cable  0/1  Downstream               128000
           3596  cable  0/1  Downstream                30000
CMTS:7A#

And here's a customer with 2M/2M Internet service with a call in progress.
Note the additional service flows, with sufficient bandwidth and overhead
for a G.711 call.

CMTS:7A#show cable modem 0015.a275.efd3 svc-flow-id
Service flow id  Interface   Flow Direction   Flow Max Rate
           4425  cable  1/1  Upstream                2048000
           4426  cable  1/1  Upstream                  12000
           4427  cable  1/1  Downstream              2048000
           4428  cable  1/1  Downstream                30000
           8745  cable  1/1  Upstream                  92800
          29314  cable  1/1  Downstream                87200
CMTS:7A#

Remember, PacketCable is not Internet VoIP and I don't think any MSO has
claimed it is such.  It doesn't run over the Internet connection and is not
given priority within the Internet flow.  That's why there should be no net
neutrality concerns.

Frank

-----Original Message-----
From: Valdis.Kletnieks at vt.edu [mailto:Valdis.Kletnieks at vt.edu] 
Sent: Wednesday, March 02, 2011 9:40 AM
To: frnkblk at iname.com
Cc: 'Scott Helms'; nanog at nanog.org
Subject: Re: What vexes VoIP users?

On Tue, 01 Mar 2011 23:55:16 CST, Frank Bulk said:
> Are you saying that the large MSOs don't use CM configuration files that
> create separate downstream and upstream service flows for Internet,
> voice signaling, and voice bearer traffic?

So the cable company carves out a protected flow for its own triple-play
telephone, while third-party VoIP vendors have to contend on the Internet
flow?
 Why aren't the net-neutrality people busy having a cow over this?






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