Re: [bess] draft-hao-bess-inter-nvo3-vpn-optionc

[<[e-mail]>]

2015-11-20, John E Drake:
> That presupposes that the group likes either of the two proposed solutions in your draft.

John, I think Lucy's "two solutions" was referring to 
draft-hao-bess-inter-nvo3-vpn-optionc solution and the 3-label Optionc 
MPLS/MPLS/UDP solution described by Wim.

-Thomas



>
>> -----Original Message-----
>> From: BESS [mailto:[e-mail]] On Behalf Of Lucy yong
>> Sent: Friday, November 20, 2015 11:49 AM
>> To: EXT - [e-mail]; Henderickx, Wim (Wim);
>> [e-mail]
>> Subject: Re: [bess] draft-hao-bess-inter-nvo3-vpn-optionc
>>
>> Share my 2 cent.
>>
>> Cloud providers want to tunnel its customer traffic through DC (AS)BR.
>> Option C is a way to realize it. Both solutions summarized by Thomas have no
>> change on WAN VPN side and seamlessly work with WAN VPN option C.
>> However, to support either solution, DC has to do some enhancement on DC
>> BR or ToR switch, etc, which dictates to different implementations within a
>> DC. Option C pro and con remains regardless what implementation is used in
>> a DC.
>>
>> Two solutions should not coexist in one DC (does not make a sense), but it
>> does not matter if one DC operator prefers to use one solution and another
>> DC prefers to use another solution. Since there are many cloud providers
>> today, it is worth for the WG to document both solutions and point out the
>> implementation requirements on impacted components. Then, up to
>> vendors and operators to select a solution for their DC.
>>
>> It does not make a sense for us to vote which solution is better here because
>> a better solution for a DC depends on many factors.
>>
>>
>> Lucy
>>
>>
>>
>>
>>
>> -----Original Message-----
>> From: BESS [mailto:[e-mail]] On Behalf Of
>> [e-mail]
>> Sent: Friday, November 20, 2015 3:02 AM
>> To: Henderickx, Wim (Wim); [e-mail]
>> Subject: Re: [bess] draft-hao-bess-inter-nvo3-vpn-optionc
>>
>> 2015-11-19, Henderickx, Wim (Wim):
>>> WH> I vote for a an evolution of switches/TORs that have proper
>>> support for this. I hope some HW vendors of TOR chips shime in, but I
>>> am told the MPLS solution is possible in the next generation chips
>>> they are working on.
>>
>> Well, it looks like the key questions are:
>> - when would ToR chips support MPLS/MPLS/UDP ?  (the generation that has
>> been released recently but not present in most shipping ToRs yet, the next
>> one ?)
>> - do we want an interim VXLAN-based solution ? (that will involve at best a
>> performance penalty with existing chips, and at worse impossible to
>> implement -- we haven't seen clear information in this thread)
>>
>> -Thomas
>>
>>
>>>> Zhuangshunwan  :
>>>>>
>>>>> Hi Diego,
>>>>>
>>>>> Thanks for your comments. Pls see inline with [Vincent].
>>>>>
>>>>> Vincent
>>>>>
>>>>> *发件人:*BESS [mailto:[e-mail]] *代表 *Diego Garcia
>> del Rio
>>>>> *发送时间:*2015年11月18日14:25 *收件人:*[e-mail] *主题
>> :*Re: [bess]
>>>>> draft-hao-bess-inter-nvo3-vpn-optionc
>>>>>
>>>>> Some comments from my side, I think the draft makes quite a few
>>>>> assumptions on specific implementation details that are way too
>>>>> general to be considered widely available. Most of the TOR devices
>>>>> today already pay a double-pass penalty when doing routing of
>>>>> traffic in/out of vxlan-type tunnels. Only the newest generation can
>>>>> route into tunnels without additional passes. And are definitively
>>>>> limited in being able to arbitrary select UDP ports on a per tunnel
>>>>> basis. In fact, most are even limited at using more than one VNID
>>>>> per "service" of sorts. [Vincent]: Yes, the new generation BCM
>>>>> chipset has already supported VXLAN routing without additional
>>>>> passes. For OVS/TOR, VXLAN encapsulation is more popular than
>>>>> MPLSoGRE/UDP, and has better performance. The IP-addressed based
>>>>> implementation which would, I assume, imply assigning one or more
>>>>> CIDRs to a loopback interface on the ASBR-d is also quite arbitrary
>>>>> and does not seem like a technically "clean" solution. (besides
>>>>> burning tons of IPs). As a side-note, most PE-grade routers i've
>>>>> worked with were quite limited in terms of IP addresses used for
>>>>> tunnel termination and it wasn't that just a simple pool can be
>>>>> used. [Vincent]: I think the larger VTEP IP address range on ASBR-d
>>>>> has no limitations.
>>>>> For the hardware on ASBR-d, it has capability to terminate multiple
>>>>> VXLAN tunnels with arbitrary destination VTEP IP addresses. Wim's
>>>>> mentions on cases where the Application itself, hosted in a
>>>>> datacenter, would be part of the option-C interconnect, was
>>>>> dismissed without much discussion so far, while, if we look in
>>>>> detail at the type of users which will even consider a complex
>>>>> topology like model-C its most likely users and operators very
>>>>> familiar with MPLS VPNs in the WAN. Those type of operators will
>>>>> most likely be very interested in deploying MPLS or WAN-grade
>>>>> applications (i.e., virtual-routers or other
>>>>> VNFs) in the DC and thus its highly likely that the interconnect
>>>>> would not terminate at the NVE itself but rather the TS (the virtual
>>>>> machine). Also, the use of UDP ports at random would imply quite
>>>>> complex logic on the ASBR-d IMHO. Im not saying its impossible, but
>>>>> since the received packet now not only has to be received on a
>>>>> random (though locally chosen) UDP port and this information
>>>>> preserved in the pipeline to be able to do the
>>>>> double-tunnel-stitching, it sounds quite complex. I am sure someone
>>>>> in the list will mention this has already been implemented
>>>>> somewhere, and I won't argue with that. And let's not even bring
>>>>> into account what this would do to any DC middlebox that now has to
>>>>> look at vxlan over almost any random port. We have to go back to the
>>>>> "is it a 4 or is it a 6 in byte x" heuristics to try to guess
>>>>> whether the packet is vxlan or just something entirely different
>>>>> running over IP. [Vincent]: Using NP or multi-core CPU hardware
>>>>> technology, it can be implemented although deeper packet inspection
>>>>> is needed to perform UDP port and MPLS stitching. In general I feel
>>>>> the proposed solution seems to be fitting of a specific use-case
>>>>> which is not really detailed
>>>>> in the draft and does not describe   a solution that would
>>>>> "elegantly" solve the issues at hand. It just feels like we're using
>>>>> any available bit-space to stuff data into places that do not
>>>>> necesarily belong. Yes, MPLS encapsulations on virtual switches are
>>>>> not yet fully available, and there can be some performance penalty
>>>>> on the TORs, but the solutions are much cleaner from a control and
>>>>> data plane point of view. Maybe I'm too utopic. [Vincent]: I think
>>>>> pure VXLAN solution has its scenario, it's general rather than
>>>>> specific. We can't require all OVS/NVEs support VXLAN + MPLSoGRE at
>>>>> the same time. Best regards, Diego
>>>>> --------------------------------------------------------------------
>>>>> -------------
>>>>>
>>>>>
>> Hi,
>>>>> The problem we are trying to solve is to reduce data center
>>>>> GW/ASBR-d's forwarding table size, the motivation is same as
>>>>> traditional MPLS VPN option-C. Currently, the most common practise
>>>>> on ASBR-d is to terminate VXLAN encapsulation, look up local routing
>>>>> table, and then perform MPLS encapsulation to the WAN network.
>>>>> ASBR-d needs to maintain all VM's MAC/IP. In Option-C method, only
>>>>> transport layer information needed to be maintained at GW/ASBR-d,
>>>>> the scalability will be greatly enhanced. Traditonal Option-C is
>>>>> only for MPLS VPN network interworking, because VXLAN is becoming
>>>>> pervasive in data center, the solution in this draft was proposed
>>>>> for the heterogeneous network interworking. The advantage of this
>>>>> solution is that only VXLAN encapsulation is required for OVS/TOR.
>>>>> Unlike Wim's solution, east-west bound traffic uses VXLAN encap,
>>>>> while north-south bound traffic uses MPLSoGRE/UDP encap. There are
>>>>> two solutions in this draft: 1. Using VXLAN tunnel destination IP
>>>>> for stitching at ASBR-d. No data plane modification requirements on
>>>>> OVS or TOR switches, only hardware changes on ASBR-d. ASBR-d
>>>>> normally is router, it has capability to realize the hardware
>>>>> changes. It will consume many IP addresses and the IP pool for
>>>>> allocation needs to be configured on ASBR-d beforehand. 2. Using
>>>>> VXLAN destination UDP port for stitching at ASBR-d. Compared with
>>>>> solution 1, less IP address will be consumed for allocation. If UDP
>>>>> port range is too large, we can combine with solution 1 and 2. In
>>>>> this solution, both data plane modification changes are needed at
>>>>> OVS/TOR and ASBR-d. ASBR-d also has capability to realize the
>>>>> hardware changes. For OVS, it also can realize the data plane
>>>>> changes. For TOR switch, it normally can't realize this function.
>>>>> This solution mainly focuses on pure software based overlay network,
>>>>> it has more scalability. In public cloud data center, software based
>>>>> overlay network is the majority case. Whether using solution 1 or 2
>>>>> depends on the operators real envionment. So I think our solution
>>>>> has no flaws, it works fine.
>>>>> Thanks, weiguo ________________________________ From: BESS
>>>>> [[e-mail] <mailto:[e-mail]>] on behalf of
>>>>> John E Drake [[e-mail] <mailto:[e-mail]>]
>>>>> Sent: Wednesday, November 18, 2015 2:49 To: Henderickx, Wim (Wim);
>>>>> EXT - [e-mail] <mailto:[e-mail]>;
>> BESS
>>>>> Subject: Re: [bess] draft-hao-bess-inter-nvo3-vpn-optionc Hi, I
>>>>> think Wim has conclusively demonstrated that this draft has fatal
>>>>> flaws and I don’t support it.  I also agree with his suggestion that
>>>>> we first figure out what problem we are trying to solve before
>>>>> solving it. Yours Irrespectively, John From: BESS
>>>>> [mailto:[e-mail] <mailto:[e-mail]>] On
>>>>> Behalf Of Henderickx, Wim (Wim) Sent: Tuesday, November 17, 2015
>>>>> 12:49 PM To: EXT - [e-mail]
>>>>> <mailto:[e-mail]>; BESS Subject: Re: [bess]
>>>>> draft-hao-bess-inter-nvo3-vpn-optionc — Snip — No, the spec as it is
>>>>> can be implemented in its VXLAN variant with existing vswitches
>>>>> (e.g. OVS allows to choose the VXLAN destination port, ditto for the
>>>>> linux kernel stack). (ToR is certainly another story, most of them
>>>>> not having a flexible enough VXLAN dataplane nor support for any
>>>>> MPLS-over-IP.) WH> and how many ports simultaneously would they
>>>>> support? For this to work every tenant needs a different VXLAN UDP
>>>>> destination port/receive port. There might be SW elements that could
>>>>> do some of this, but IETF defines solutions which should be
>>>>> implemented across the board HW/SW/etc.
>>>>> Even if some SW switches can do this, the proposal will impose so
>>>>> many issues in HW/data-plane engines that I cannot be behind this
>>>>> solution. To make this work generically we will have to make changes
>>>>> anyhow. Given this, we better do it in the right way and guide the
>>>>> industry to a solution which does not imply those complexities.
>>>>> Otherwise we will stick with these specials forever with all
>>>>> consequences (bugs, etc). - snip - From:
>>>>> "[e-mail]
>>>>>
>> <mailto:[e-mail]><mailto:[e-mail]
>>>>> <mailto:[e-mail]>>" <[e-mail]
>>>>>
>> <mailto:[e-mail]><mailto:[e-mail]
>>>>> <mailto:[e-mail]>>> Organization: Orange Date:
>>>>> Tuesday 17 November 2015 at 01:37 To: Wim Henderickx
>>>>> <[e-mail]
>>>>> <mailto:wim.henderickx@alcatel-
>> lucent.com><mailto:wim.henderickx@alc
>>>>> atel-lucent.com
>>>>>
>>>>>
>> <mailto:[e-mail]>>>, BESS <[e-mail]
>>>>> <mailto:[e-mail]><mailto:[e-mail]
>>>>> <mailto:[e-mail]>>> Subject: Re: [bess]
>>>>> draft-hao-bess-inter-nvo3-vpn-optionc Hi Wim, WG, 2015-11-16,
>>>>> Henderickx, Wim (Wim): 2015-11-13, Henderickx, Wim (Wim): Thomas,
>> we
>>>>> can discuss forever and someone need to describe requirements, but
>>>>> the current proposal I cannot agree to for the reasons explained.
>>>>> TM> Well, although discussing forever is certainly not the goal, the
>>>>> reasons for rejecting a proposal need to be thoroughly understood.
>>>>> WH> my point is what is the real driver for supporting a plain VXLAN
>>>>> data-plane here, the use cases I have seen in this txt is always
>>>>> where an application behind a NVE/TOR is demanding option c, but
>>>>> none of the NVE/TOR elements.
>>>>> My understanding is that the applications  are contexts where
>>>>> overlays are present is when workloads (VMs or baremetal) need to be
>>>>> interconnected with VPNs. In these contexts, there can be reasons to
>>>>> want Option C to reduce the state on ASBRs. In these context, its
>>>>> not the workload (VM or baremetal) that would typically handle VRFs,
>>>>> but really the vswitch or ToR. WH2> can it not be all cases:
>>>>> TOR/vswitch/Application. I would make the solution flexible to
>>>>> support all of these not? 2015-11-13, Henderickx, Wim (Wim): TM> The
>>>>> right trade-off to make may in fact depend on whether you prefer:
>>>>> (a) a new dataplane stitching behavior on DC ASBRs (the behavior
>>>>> specified in this draft) or
>>>>> (b) an evolution of the encaps on the vswitches and ToRs to support
>>>>> MPLS/MPLS/(UDP or GRE) WH> b depends on the use case I don't get
>>>>> what you mean by "b depends on the use case". WH> see my above
>>>>> comment. If the real use case is an application behind NVE/TOR
>>>>> requiring model C, than all the discussion on impact on NVE/TOR is
>>>>> void. As such I want to have a discussion on the real
>>>>> driver/requirement for option c interworking with an IP based
>>>>> Fabric. Although I can agree than detailing requirements can always
>>>>> help, I don't think one can assume a certain application to dismiss
>>>>> the proposal. WH> for me the proposal is not acceptable for the
>>>>> reasons explained: too much impact on the data-planes I wrote the
>>>>> above based on the idea that the encap used in MPLS/MPLS/(UDP or
>>>>> GRE), which hence has to be supported on the ToRs and vswitches.
>>>>> Another possibility would be service-label/middle-label/Ethernet
>>>>> assuming an L2 adjacency between vswitches/ToRs and ASBRs, but this
>>>>> certainly does not match your typical DC architecture. Or perhaps
>>>>> had you something else in mind ? WH> see above. The draft right now
>>>>> also requires changes in existing TOR/NVE so for me all this
>>>>> discussion/debate is void. No, the spec as it is can be implemented
>>>>> in its VXLAN variant with existing vswitches (e.g. OVS allows to
>>>>> choose the VXLAN destination port, ditto for the linux kernel
>>>>> stack). (ToR is certainly another story, most of them not having a
>>>>> flexible enough VXLAN dataplane nor support for any MPLS-over-IP.)
>>>>> WH> and how many ports simultaneously would they support? WH> and
>>>>> depending on implementation you don’t need to change any of the
>>>>> TOR/vswitches. Does this mean that for some implementations you may
>>>>> not need to change any of the TOR/vswitches, but that for some
>>>>> others you may ? WH> any proposal on the table requires changes, so
>>>>> for me this is not a valid discussion See above, the proposal in the
>>>>> draft does not necessarily need changes in vswitches. Let me take a
>>>>> practical example : while I can quite easily see how to implement
>>>>> the procedures in draft-hao-bess-inter-nvo3-vpn-optionc based on
>>>>> current vswitch implementations of VXLAN, the lack of
>>>>> MPLS/MPLS/(UDP, GRE) support in commonplace vswitches seems to
>> me as
>>>>> making that alternate solution you suggest harder to implement. WH>
>>>>> I would disagree to this. Tell me which switch/TOR handles multiple
>>>>> UDP ports for VXLAN ? I mentioned _v_switches, and many do support a
>>>>> variable destination port for VXLAN, which is sufficient to
>>>>> implement what the draft proposes. -Thomas From: Thomas Morin
>>>>> <[e-mail]
>>>>>
>> <mailto:[e-mail]><mailto:[e-mail]
>>>>> <mailto:[e-mail]>>> Organization: Orange Date:
>>>>> Friday 13 November 2015 at 09:57 To: Wim Henderickx
>>>>> <[e-mail]
>>>>> <mailto:wim.henderickx@alcatel-
>> lucent.com><mailto:wim.henderickx@alc
>>>>> atel-lucent.com
>>>>>
>>>>>
>> <mailto:[e-mail]>>>
>>>>> Cc: "[e-mail] <mailto:[e-mail]><mailto:[e-mail]
>>>>> <mailto:[e-mail]>>" <[e-mail]
>>>>> <mailto:[e-mail]><mailto:[e-mail]
>>>>> <mailto:[e-mail]>>> Subject: Re: [bess]
>>>>> draft-hao-bess-inter-nvo3-vpn-optionc Hi Wim, I agree on the
>>>>> analysis that this proposal is restricted to implementations that
>>>>> supports the chosen encap with non-IANA ports (which may be hard to
>>>>> achieve for instance on hardware implementations, as you suggest),
>>>>> or to context where managing multiple IPs would be operationally
>>>>> viable. However, it does not seem obvious to me how the alternative
>>>>> you propose [relying on 3-label option C with an
>>>>> MPLS/MPLS/(UDP|GRE) encap] addresses the issue of whether the
>> encap
>>>>> behavior is supported or not (e.g. your typical ToR chipset possibly
>>>>> may not support this kind of encap,  and even software-based
>>>>> switches may not be ready to support that today).
>>>>> My take is that having different options to adapt to various
>>>>> implementations constraints we may have would have value. (+ one
>>>>> question below on VXLAN...) -Thomas 2015-11-12, Henderickx, Wim
>>>>> (Wim): On VXLAN/NVGRE, do you challenge the fact that they would be
>>>>> used with a dummy MAC address that would be replaced by the right
>>>>> MAC by a sender based on an ARP request when needed ? Is the above
>>>>> the issue you had in mind about VXLAN and NVGRE ? WH> yes I you
>>>>> don't mind me asking : why do you challenge that ?
>>>>>
>>
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