Re: [mpls] poll to see if we have support to make draft-xu-mpls-in-udp an mpls working group document

[Xuxiaohu <[e-mail]>]

Hi Pat,

This MPLS-in-UDP technology is intended to be used in the scenarios where existing MPLS over IP technologies (e.g., MPLS over GRE) have been used and are to be used. Data center is just one scenario but not the only one.

Xiaohu

发件人: Pat Thaler [mailto:[e-mail]]
发送时间: 2012年12月22日 4:49
收件人: Lucy yong; Andrew G. Malis; Shane Amante
抄送: [e-mail]; [e-mail]; [e-mail]
主题: RE: [mpls] poll to see if we have support to make draft-xu-mpls-in-udp an mpls working group document

Lucy,

If your draft is intended to address the NVO3 requirements, then it should be considered in NVO3 along with the other proposed solutions rather than bypassing that process by submitting it to MPLS.

The NVO charter requires that the preliminary analysis work be completed before completing solutions:
The NVO3 WG will write the following informational RFCs, which
must have completed Working Group Last Call before rechartering can be
considered:

Problem Statement
Framework document
Control plane requirements document
Data plane requirements document
Operational Requirements
Gap Analysis

Driven by the requirements and consistent with the gap analysis,
the NVO3 WG may request being rechartered to document solutions
consisting of one or more data plane encapsulations and
control plane protocols as applicable.

Based on the NVO3 charter, it is premature to consider solutions at this point and suggesting that something should go forward because it supports one item in a draft NVO3 requirements document is not justified.

Regards,
Pat

From: [e-mail] [mailto:[e-mail]] On Behalf Of Lucy yong
Sent: Friday, December 21, 2012 11:27 AM
To: Andrew G. Malis; Shane Amante
Cc: [e-mail]; [e-mail]; [e-mail]
Subject: Re: [mpls] poll to see if we have support to make draft-xu-mpls-in-udp an mpls working group document

Andy,

Here is the text from draft-ietf-nvo3-dataplane-requirements-00.txt

  3.3.2.1. LAG and ECMP

       For performance reasons, multipath over LAG and ECMP paths SHOULD be
       supported.

       LAG (Link Aggregation Group) [IEEE 802.1AX-2008] and ECMP (Equal
       Cost Multi Path) are commonly used techniques to perform load-
       balancing of microflows over a set of a parallel links either at
       Layer-2 (LAG) or Layer-3 (ECMP). Existing deployed hardware
       implementations of LAG and ECMP uses a hash of various fields in the
        encapsulation (outermost) header(s) (e.g. source and destination MAC
       addresses for non-IP traffic, source and destination IP addresses,
       L4 protocol, L4 source and destination port numbers, etc).
       Furthermore, hardware deployed for the underlay network(s) will be
       most often unaware of the carried, innermost L2 frames or L3 packets
       transmitted by the TS. Thus, in order to perform fine-grained load-
       balancing over LAG and ECMP paths in the underlying network, the
       encapsulation MUST result in sufficient entropy to exercise all
       paths through several LAG/ECMP hops. The entropy information MAY be
       inferred from the NVO3 overlay header or underlay header.

Our draft provides an advanced solution in this space.

Lucy

From: [e-mail]<mailto:[e-mail]> [mailto:[e-mail]]<mailto:[mailto:[e-mail]]> On Behalf Of Andrew G. Malis
Sent: Friday, December 21, 2012 12:32 PM
To: Shane Amante
Cc: [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>
Subject: Re: [mpls] poll to see if we have support to make draft-xu-mpls-in-udp an mpls working group document

I've commented earlier on this draft, and like Shane, I remain unconvinced of its utility. I still don't think it has any utility at all for core backbone networks - just use native MPLS, or if you must tunnel MPLS over IP, the GRE or L2TPv3 encapsulations. Regarding data center applications, I guess I could be convinced, but I would like to see a clear justification in the form of requirements from nvo3 that could only be met by this draft.

Thanks,
Andy

On Wed, Dec 19, 2012 at 9:38 AM, Shane Amante <[e-mail]<mailto:[e-mail]>> wrote:
Xiaohu,

On Dec 18, 2012, at 11:50 PM, Xuxiaohu <[e-mail]<mailto:[e-mail]>> wrote:
-----邮件原件-----
>> 发件人: Shane Amante [mailto:[e-mail]<mailto:[e-mail]>]
>> 发送时间: 2012年12月19日 11:58
>> 收件人: Rogers, Josh
>> 抄送: Shahram Davari; Xuxiaohu; [e-mail]<mailto:[e-mail]>;
>> [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>
>> 主题: Re: [mpls] poll to see if we have support to make draft-xu-mpls-in-udp an
>> mpls working group document
>>
>>
>> On Dec 18, 2012, at 8:50 AM, "Rogers, Josh" <[e-mail]<mailto:[e-mail]>>
>> wrote:
>>> I share your SP perspective, and do not see the problem this solution
>>> addresses in practice any longer.
>>
>> +1.  Please do not define yet another MPLS-over-IP encapsulation.  The IETF
>> already standardized MPLS over GRE.  The IETF has also standardized MPLS
>> over L2TPv3/UDP/IP, which had seen some deployment in at least one, very
>> large operator network that I'm aware of to support carriage of L3VPN over an
>> IP-only network.
>
> Hi Shane,
>
> Thank you for telling us there are actual deployments of MPLS over IP in at least one, very large operator network. This fact must be very valuable to those people who had believed there is no application of MPLS over IP in today's SP networks.
>
>> See: RFC's 4454, 4719, 4591, 4349 for PWE3 over L2TPv3
>> [NOTE: the dates the above were published was back in the 2006 timeframe!]
>>     RFC 4665 for requirements related to VPLS that say that VPLS may be
>> carried over L2TPv3
>>     And, here's evidence showing that at least one vendor has implemented
>> IPVPN's over L2TPv3:
>> http://www.cisco.com/en/US/docs/ios/12_0s/feature/guide/csgl3vpn.html
>
> Thanks again for sharing the above information. As mentioned in this draft AND other drafts, the mechanism of performing hash calculation on the Session ID field in the L2TPv3 header or the Key field in the GRE header as defined in [RFC 5640] is not widely supported by existing core routers so far.
FWIW, I have had success, in the relatively recent past, in requesting a core router vendor to support changes to the input-keys used in hash calculations in _existing_ hardware, already deployed (extensively) throughout my network.  Further, I suspect that most large network operators are savvy folks and understand the internal architecture of their HW fairly well.  As a result, those same operators know what is and is not technically possible in this regard.  Thus, it may be a question of "methods" necessary to convince their HW supplier(s) to make appropriate changes in their equipment to achieve their business goals.  :-)  However, this may not even be necessary ... see below.


> In contrast, most existing core routers are already capable of balancing IP traffic flows based on the hash of the five-tuple of UDP packets. By using the MPLS-in-UDP encapsulation, the already available load-balancing capability of most existing core routers can be leveraged without requiring any change to them. That is the major motivation of this draft.
If this is a concern, then why not encapsulate the traffic in MPLS/L2TPv3, which uses UDP/IP, in the first place?

IMHO, a better proposal may be to consider a [minor] (?) change to RFC 3931, which would allow the connection used for data packets (not control packets) to use a varying set of source ports (or, source IP addresses), based on a hash calculation, to achieve better load-balancing over existing equipment in an IP-only core.  L2TP end-system implementations would be better off just using the "Session ID" (and "Cookie") fields as the demultiplexor to associate incoming packets with the associated L2TP Control Channel.  In fact, it's not clear to me that existing implementations may /already/ do this, making any "check" on the incoming source port unnecessary for L2TP end-system implementations.

The beauty of the above approach is:
1) I would think that the above is most likely a change that is limited to the "control channel" (software) of existing L2TP end-system implementations.  Heck, it may even be backwards compatible with existing L2TPv3 implementations.  (L2TPv3 implementors would need to comment on that).
2) There is a substantial added security one gets by using "Session ID" and "Cookie" fields to ensure the received L2TPv3 packet is intended for the identified session.  Quoting from Section 8.2 of RFC 3931:
---snip---
   L2TPv3 provides traffic separation for its VPNs via a 32-bit Session
   ID in the L2TPv3 data header.  When present, the L2TPv3 Cookie
   (described in Section 4.1), provides an additional check to ensure
   that an arriving packet is intended for the identified session.
   Thus, use of a Cookie with the Session ID provides an extra guarantee
   that the Session ID lookup was performed properly and that the
   Session ID itself was not corrupted in transit.
---snip---
... in regard to this question alone, I know the Security Area folks have, in the past, had /substantial/ concerns about encapsulation of MPLS over IP transport.  In fact, this is why you see text in Section 7.6, "Security", of RFC 4665.  (There's likely similar language in other drafts that use MPLS for transport).  While I'm not sure that Security Area folks pay much attention to daily traffic on the MPLS WG mailing list, I'm fairly confident this concern will arise if/when this draft goes to the IESG ...
3) Finally, this approach only affects the end-systems that implement L2TP, for tunneling of MPLS/IP, and does not require an entire industry to support MPLS/UDP encapsulation in their product lines.

-shane


>
> Best regards,
> Xiaohu
>
>> If there was market demand for MPLS over IP, then clearly it would have been
>> more widely implemented by equipment vendors, with either MPLS over GRE or
>> MPLS over L2TPv3.  (Where there's a will, there's a way).  I would note that
>> the most likely reasons this did not pan out was there are several, practical
>> operational benefits one gets from going with native MPLS
>> encapsulation/switching within the data plane, namely:
>> - MPLS Fast Re-Route
>> - MPLS Traffic Engineering
>> ... to name, but a few.  Those have tended to be quite compelling arguments
>> to 'upgrade' network HW to support MPLS encapsulation/switching.
>>
>> -shane
>>
>>
>>> -Josh
>>>
>>>
>>> On 12/18/12 12:31 AM, "Shahram Davari" <[e-mail]<mailto:[e-mail]>> wrote:
>>>
>>>> For service provider domain, MPLS over IP is legacy and there is no need
>>>> to improve it.
>>>>
>>>> Regards,
>>>> Shahram
>>>>
>>>>
>>>> On Dec 17, 2012, at 8:02 PM, "Xuxiaohu" <[e-mail]<mailto:[e-mail]>> wrote:
>>>>
>>>>> Shahram,
>>>>>
>>>>> This draft is ONLY intended to provide a MPLS-over-IP encapsulation
>>>>> method with a better load-balancing applicability so far to those
>>>>> operators who happen to require transporting MPLS application traffic
>>>>> across IP networks. I believe MPLS-based VPN over IP, NVGRE and VXLAN
>>>>> each have their own advocators and use cases. If you absolutely believe
>>>>> it's meaningless of transporting MPLS application traffic across IP
>>>>> networks and therefore those existing RFCs related to MPLS over IP
>>>>> tunneling mechanisms should be moved to Historic status, please say so.
>>>>>
>>>>> By the way, it seems this
>>>>> (http://www.ietf.org/mail-archive/web/nvo3/current/msg01864.html) is
>>>>> just the right thread suitable for you to make the following argument
>>>>> (i.e., whether or not MPLS-based VPN is applicable to data centers). I
>>>>> had thought you would speak up at that time. Sadly, surprisingly silent
>>>>> till now.
>>>>>
>>>>> Sigh, I didn't intend to say the above otherwise.
>>>>>
>>>>> Xiaohu
>>>>>
>>>>>> -----邮件原件-----
>>>>>> 发件人: [e-mail]<mailto:[e-mail]> [mailto:[e-mail]<mailto:[e-mail]>] 代表
>> S.
>>>>>> Davari
>>>>>> 发送时间: 2012年12月15日 13:34
>>>>>> 收件人: Loa Andersson
>>>>>> 抄送: [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>;
>>>>>> [e-mail]<mailto:[e-mail]>
>>>>>> 主题: Re: [mpls] poll to see if we have support to make
>>>>>> draft-xu-mpls-in-udp an
>>>>>> mpls working group document
>>>>>>
>>>>>> I don't support this draft since it has no application in today's
>>>>>> modern metro
>>>>>> and core, where MPLS is dominant, and its only practical application
>>>>>> in in data
>>>>>> center, which already is crowded with other solutions such as NVGRE and
>>>>>> VXLAN.
>>>>>>
>>>>>> It seems the authors are trying to bypass the NVO3 solution selection
>>>>>> process
>>>>>> by advancing the draft in MPLS WG.
>>>>>>
>>>>>> Regards,
>>>>>> Shahram
>>>>>>
>>>>>>
>>>>>> On Dec 14, 2012, at 1:01 AM, Loa Andersson <[e-mail]<mailto:[e-mail]>> wrote:
>>>>>>
>>>>>>> Working group,
>>>>>>>
>>>>>>> This is to start a "two week" poll on adopting
>>>>>>> draft-xu-mpls-in-udp-06 as an MPLS working group document.
>>>>>>> Due to the holiday season this poll has been extended with one week.
>>>>>>>
>>>>>>> Please send your comments (support/not support) to the mpls working
>>>>>>> group mailing list (mpls at ietf.org<http://ietf.org>). Please give an technical
>>>>>>> motivation for your support/not support, especially if you think that
>>>>>>> the document should not be adopted as a working group document.
>>>>>>>
>>>>>>> This poll ends January 07, 2013.
>>>>>>>
>>>>>>> There is one IPR claim against this document -
>>>>>>> https://datatracker.ietf.org/ipr/1941/ .
>>>>>>>
>>>>>>> All the active co-authors has stated on the working group mailing list
>>>>>>> that they are not aware of any other IPR claims than those already
>>>>>>> disclosed.
>>>>>>>
>>>>>>> However, up to version -03 (the document that we used for the IPR
>>>>>>> poll)
>>>>>>> Marshall Eubanks was listed as one of the authors. Marshall has
>>>>>>> discontinued all interactions with the IETF, including the author team
>>>>>>> of draft-xu-mpls-in-udp-06. The working group chairs has tried to
>>>>>>> contact Marshall by other means, to try get a response on the IPR
>>>>>>> poll.
>>>>>>> We have had no success in this.
>>>>>>>
>>>>>>> From version -04 the authors decided to remove Marshall as a
>>>>>>> co-author.
>>>>>>>
>>>>>>> /Loa
>>>>>>> (mpls wg co-chair)
>>>>>>> --
>>>>>>>
>>>>>>>
>>>>>>> Loa Andersson                         email:
>>>>>> [e-mail]<mailto:[e-mail]>
>>>>>>> Sr Strategy and Standards Manager            [e-mail]<mailto:[e-mail]>
>>>>>>> Ericsson Inc                          phone: [phone]<tel:%2B46%2010%20717%2052%2013>
>>>>>>>                                          [phone]<tel:%2B46%20767%2072%2092%2013>
>>>>>>> _______________________________________________
>>>>>>> mpls mailing list
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