Re: IP Layer 2 Transport over L2TPv3

Hi Prasad,

Circa 9/23/2005 8:00 AM, Prasad Yadati said the following:
> Hi Carlos,
> 
> Please see in-line.
> 
> Carlos Pignataro wrote:
> 
>> Hi Prasad,
>>
>> Please see inline.
>>
>> Circa 9/20/2005 7:01 AM, Prasad Yadati said the following:
>>
>>> Carlos,
>>>
>>> Please see in-line.
>>>
>>> Carlos Pignataro wrote:
>>>
>>>
>>>> Prasad,
>>>>
>>>> Thanks. Please see a couple of comments inline.
>>>>
>>>> List,
>>>>
>>>> Any further comments on the request to accept this draft as a working
>>>> group document?
>>>>
>>>>
>>>> Circa 9/17/2005 5:50 AM, Prasad Yadati said the following:
>>>>
>>>>
>>>>> Good one Carlos.
>>>>> How about just specifying it as "IP transport over L2TPv3".
>>>>>
>>>>
>>>>
>>>> Thanks.
>>>>
>>>> The "IP Layer 2" was added there for 2 reasons:
>>>> 1. To somehow differentiate raw-IP from framed-IP being transported
>>>> over
>>>>   L2TPv3 while trying to reference the NSP function that interfaces the
>>>>   L2 AC with the IP PW Termination.
>>>> 2. Symmetry/parity name with the already defined PW Type for MPLS PWE3.
>>>>
>>>
>>> But as per this draft, no "IP layer 2" information is transported.
>>
>>
>>
>> Yes, only IP datagrams are transported, although there is a Layer 2
>> attachment circuit, and hence "IP Layer 2". The NSP function "extracts
> 
> 
> Attachment circuit layer 2 is already terminated. Isn't it ? L2TPv3 in
> this case does not aware of attachment circuit's layer 2. In fact it
> does not matter what kind of layer 2 IP was carried at the attachment
> circuit.
> I am sorry Corlos, I am still not clear.

Although the "IP Layer 2" was intended to make the NSP function
explicit, I understand (and agree on second thoughts) the argument that
can be confusing with what's actually being transported.

How about this to describe the main aspects of the draft:
"Signaling and Encapsulation for the Transport of IP over L2TPv3"

There are also two further items in the draft to possibly update:
1. "IP Layer 2 interface": I'd leave this one as is.
2. PW Type/PW name: If changing the title, I'd also update:
	IPL2PW IP Layer 2 Transport Pseudowires
	IP Layer 2 Transport Pseudowire Type.
   to:
	IPPW   IP Transport Pseudowires
	IP Transport Pseudowire Type.

Would this aid in clarity?

Thanks for your comments !

--Carlos.

> 
>> IP datagrams from the Layer 2 frames" and that's the motivation for the
>> name, make a distinction from framed-IP. See below as well.
>>
>>
>>> Rather we are trying to prevent the same. For me, "IP layer 2" seems to
>>> be mis-leading.
>>>
>>>
>>>
>>>> "IP transport" may possibly be too generic for the procedures defined.
>>>
>>>
>>>
>>> Corlos, for me, "IP transport" seems more appropriate than current. In
>>> this case as far as L2TPv3 is concerned, it is transporting IP rather
>>> than layer 2 frame.
>>
>>
>>
>> IMHO, "IP transport" is too generic, and does not fully convey what's
>> happening in the interface between the physical layer 2 interface and
>> the pseudowire termination. Other PW Types transport IP (framed-IP) as
>> well. I thought about "raw ip" and "native ip" but opted against them
>> for a similar reason. Any other suggestions?
> 
> 
> How about "Abstracted/Extracted IP over L2TPv3" ?
> If this draft can be, really generic, I mean if it  can be used even for
> non-pw cases where L2TPv3 carries generic IP datagrams, we may have "IP
> transport over L2TPv3" ?
> 
> Kind Regards
> Prasad
> 
> 
> 
>>
>>
>>>>
>>>>> Wondering whether we can have a generic "Layer 3 transport over
>>>>> L2TPv3"
>>>>> and specify transport of all layer 3 protocols (IP, IPX,....) in it
>>>>> including IP.
>>>>
>>>>
>>>>
>>>>
>>>> Do you mean multiple L3 protocols at the same time over the session?
>>>> I'd
>>>> think we can use existing L2 transports to accomplish that. OTOH, IP as
>>>> L3 stands out in the applications of an "IP L2" session.
>>>
>>>
>>> Sorry I was not clear. I meant to combine specification of other layer 3
>>> data packets over L2TPv3 in one draft. May be that is not needed. We may
>>> have separate similar such of these drafts for other layer 3 protocols.
>>> Please ignore this comment.
>>
>>
>>
>> OK. Thanks,
>>
>> --Carlos.
>>
>>
>>> Thanks
>>> Prasad
>>>
>>>
>>>> Thanks !
>>>>
>>>> --Carlos.
>>>>
>>>>
>>>>
>>>>> Regards
>>>>> Prasad
>>>>>
>>>>> Carlos Pignataro wrote:
>>>>>
>>>>>
>>>>>
>>>>>> Hi All,
>>>>>>
>>>>>> We submitted the following `IP Layer 2 Transport over L2TPv3' draft:
>>>>>> http://www1.ietf.org/mail-archive/web/i-d-announce/current/msg06623.html
>>>>>>
>>>>>>
>>>>>> that details the tunneling of IP datagrams directly over an L2TPv3
>>>>>> session, and defines the `CE IP Address AVP' as well.
>>>>>>
>>>>>> We would like it to become an l2tpext working group document, and
>>>>>> seek
>>>>>> review, feedback and comments from the WG.
>>>>>> So we ask here for the draft to be accepted as work item for the
>>>>>> group.
>>>>>> Your feedback will be most appreciated.
>>>>>>
>>>>>> Thanks,
>>>>>>
>>>>>
>>
> 

-- 
--Carlos.
Escalation RTP - cisco Systems