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Re: [c-nsp] DOCSIS 3.0 & PPPoE/L2TP compatibility
From: Scott Helms <khelms () ispalliance net>
Date: Wed, 01 Aug 2012 11:23:29 -0400

I did PPPoE for open access on cable networks starting back in DOCSIS 1.0 and that (and PPTP for that matter) is a dead end IMO. Get to BSoD/TLS which is a CableLabs (the guys who write and test the DOCSIS spec) standard and will be supported on all of the D3 chassis no matter if its Arris, Cisco, Motorola, or Casa.

The guys at the cable company could have gone with a Cisco 10k or a 7225(smaller systems only) and I believe both of those still support being a LNS for PPPoE, but again Cisco is really the only one and good luck getting any help from their TAC on setting it up.

On 8/1/2012 10:57 AM, iptech wrote:

Yes PITA indeed.

Our 7200 are G2, but we were still planning on moving away from them.

I presume you guys are staying on the 7200s meantime, to accomodate the PPTP requirement?


On 7/31/2012 10:35 PM, Ray Burkholder wrote:
As far as I can tell, and from my conversations with the guys at Cablevision, there isn't anything underhanded. The ARRIS gear simply doesn't do PPPOE stuff. They've looked at various scenarios, and PPTP seems to be the winner.

Their Cisco CMTS gear was EOL'd a long time ago, and I don't think there is/was a migration path for handling recent DOCSIS and speeds. So they side stepped it. Their ARRIS box is a single chassis with a redundant cards in it. With DOCSIS 3, they get better speeds and stuff out of it.

I havn't seen the numbers, but I gather it will handily handle all the traffic for all the ISP's.

It does become a PITA for us as ISP's, as we have to convert all our subscribers over to PPTP.

What are you doing with your old 7200's?  Are they G2's?


-----Original Message-----
From: cisco-nsp-bounces () puck nether net [mailto:cisco-nsp-
bounces () puck nether net] On Behalf Of iptech
Sent: Tuesday, July 31, 2012 12:28
To: Brian Mengel
Cc: cisco-nsp () puck nether net
Subject: Re: [c-nsp] DOCSIS 3.0 & PPPoE/L2TP compatibility

Thanks Brian,

I am struggling with this one, as I suspect the cableco are skipping
round a problem with their in house setup, and trying to make me bend to
get it working, which I am reluctant to do, as its a big step backwards
for us.

They are moving from a Cisco CMTS to a Arris, therefore it is highly
possible this will be a new box. What they have told me is that their
CMTS setup will now be L3 as opposed to L2. The reasons behind this are
not clear.

Appreciate any pointers on this one.

Thanks v much.

On 7/31/2012 11:54 AM, Brian Mengel wrote:
We run a mix of Cisco and Arris CMTS in our network and have found
both to share the same feature set (at least for the features we
need).  If there is a problem with L2TP its not going to be the result
of the DOCSIS 3.0 upgrade but rather an issue with the Arris CMTS.  I
would recommend getting a technical contact at Arris from your partner
MSO and explaining your situation to them and seeing what they can
provide as a resolution.  Its possible that the Arris outright doesn't
support L2TP, but I suspect there may be other things going on.

On Sat, Jul 28, 2012 at 6:48 PM, iptech <iptech () northrock bm> wrote:

No takers?

Would really appreciate some feedback/pointers.

Thank you.

On 7/27/2012 2:57 PM, iptech wrote:

We are a small ISP and have a setup in place with the local cable
for terminating their users via L2TP for Internet access. However they
just announced to us that they are moving to a DOCSIS 3.0 compliant
and this standard no longer supports PPPoE via L2TP, and can now only
PPTP for terminating with us.

We have already begun replacing our Cisco 7206VXR LNS devices with
ASR 1Ks and as you will be aware the older 7206 can do both L2TP and
whereas the ASR1k can do only L2TP.

I do not have any experience in the cable arena, but from what I have
in the DOCSIS standards, each version has maintained backwards
compatibility, therefore I am very surprised our CableCo has claimed
cannot do PPPoE/L2TP anymore.

The CMTS they are currently using is a Cisco, and now they are moving to
new ARRIS CMTS. I have not been able to find any information on this
and what it can do or not.

With the ASR1K marked as the natural upgrade path for LNS functions,
therefore I cannot believe that it is not fully compatible with DOCSIS 3.0.

  From what I can tell the only way to accommodate the new CMTS PPTP
connections will be to terminate them on the legacy 7206VXR, which at
end of the day is a backwards step.

I would greatly appreciate if anyone can give me any pointers and/or
suggestions on this matter, so I can understand it and move it forward.

FYI: The driver for the CMTS upgrades is to offer higher bandwidth
speeds 15mb-20mb.

Thank you.

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Scott Helms
Vice President of Technology
(678) 507-5000

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