Subject: [bess] Request for WG adoption of draft-mohanty-bess-evpn-df-election

From: "Satya Mohanty (satyamoh)" <[email-masked]>
Date: Tue, 31 Mar 2015 06:21:17 +0000

Hi,

Given the interest and technical discussions on the topic of the EVPN DF
Election, and the favorable response of the community to the benefits of
the HRW scheme, I would like to request the WG to adopt
draft-mohanty-bess-evpn-df-election.

Thanks to Jakob Heitz for presentation of slides at the IETF.

Best regards,
--Satya

On 3/27/15 8:52 PM, "Rabadan, Jorge (Jorge)"
<[email-masked]> wrote:

>Hi Thomas,
>
>You are right.
>
>Kishore, Weiguo and I were discussing face-to-face the scenario drawn by
>Weiguo below. And my conclusion is that there is no loop and there is
>nothing new that it was not discussed in this thread. EVPN single-active
>and split-horizon procedures take care of loops. If there are transient
>DF-DF periods, you can get some duplicate packets, but not infinite loops.
>And an implementation should allow a configurable timer that can be
>adjusted to the scale of the network so that the dual DF transient risk
>can be minimized or eliminated.
>
>About why all-active is not supported in the scenario below, I agree with
>your reasoning. RFC7432 only accepts LAG for all-active, since, otherwise,
>duplicate packets could be forwarded in normal state.
>draft-ietf-bess-dci-evpn-overlay-00 proposes an all-active MH network
>solution, but that is because EVPN runs in the access network too.
>
>Thanks.
>Jorge
>
>-----Original Message-----
>From: "[email-masked]" <[email-masked]>
>Organization: Orange
>Date: Friday, March 27, 2015 at 4:08 PM
>To: Jorge Rabadan <[email-masked]>, Haoweiguo
><[email-masked]>, "Satya Mohanty (satyamoh)" <[email-masked]>,
>"[email-masked]" <[email-masked]>
>Subject: Re: [bess] Handshaking among PEs in an EVPN ES based on Paxos
>algorithm
>
>>Hi Jorge,
>>
>>Jorge:
>>> If you have any other scenario, let’s talk offline. We are boring
>>>people
>>> ;-)
>>
>>I think its nice to keep the discussion on the list, which is here for a
>>reason (that is, not just for polls for adoption and WG last calls...).
>>
>>I'm sure these clarifications can be useful for some of the
>>participants, and the others can very much skip the thread.
>>
>>And there is, I think, perhaps one more thing worth spelling out.
>>
>>RFC7432 explains that for multi-homing in active-active mode, LAG is
>>required.
>>My understanding of the reason why, in this case, it is not supported to
>>connect the bridged
>>network via multiple CEs is that there is no technique to build a LAG
>>between two CEs and two PEs.
>>
>>Best,
>>
>>-Thomas
>>
>>
>>
>>Rabadan, Jorge :
>>> As I said:
>>> "Even if CE3 forwards to CE4->PE4, PE4 is NDF and will discard the
>>>frame.
>>> Remember MH network ES' as per your diagram below, only support
>>> single-active MH.”
>>>
>>> So there is NO LOOP.
>>>
>>>
>>>
>>>
>>> Thanks.
>>> Jorge
>>>
>>> -----Original Message-----
>>> From: Haoweiguo <[email-masked]>
>>> Date: Friday, March 27, 2015 at 9:00 AM
>>> To: Jorge Rabadan <[email-masked]>, "Satya Mohanty
>>> (satyamoh)" <[email-masked]>, "[email-masked]"
>>> <[email-masked]>, "[email-masked]" <[email-masked]>
>>> Subject: Re: [bess] Handshaking among PEs in an EVPN ES based on Paxos
>>> algorithm
>>>
>>>> Hi Jorge,
>>>> The picture in email is just for a simplified explanation. Source MAC
>>>>can
>>>> be the layer 3 device connecting to CE3, CE3 will not drop the frame
>>>>so
>>>> easily. This is an absolutely loop.
>>>>
>>>> Thanks,
>>>> weiguo
>>>>
>>>> ________________________________________
>>>> From: Rabadan, Jorge (Jorge) [[email-masked]]
>>>> Sent: Friday, March 27, 2015 23:39
>>>> To: Haoweiguo; Satya Mohanty (satyamoh); [email-masked];
>>>> [email-masked]
>>>> Subject: Re: [bess] Handshaking among PEs in an EVPN ES based on Paxos
>>>> algorithm
>>>>
>>>> Hi Weiguo,
>>>>
>>>> I disagree with your explanation below.
>>>>
>>>> This is the flow assuming PE1-PE2 *might* be both DF and PE3 is DF:
>>>>
>>>> CE3--->PE3------>PE2--->CE2---->CE1---->PE1---->PE3-->CE3――>DROP
>>>>
>>>> If the MAC SA of the frame is CE3’s MAC, CE3 will discard.
>>>> Even if CE3 forwards to CE4->PE4, PE4 is NDF and will discard the
>>>>frame.
>>>> Remember MH network ES' as per your diagram below, only support
>>>> single-active MH.
>>>>
>>>>
>>>> Thanks.
>>>> Jorge
>>>>
>>>> -----Original Message-----
>>>> From: Haoweiguo <[email-masked]>
>>>> Date: Friday, March 27, 2015 at 8:11 AM
>>>> To: Jorge Rabadan <[email-masked]>, "Satya Mohanty
>>>> (satyamoh)" <[email-masked]>, "[email-masked]"
>>>> <[email-masked]>, "[email-masked]" <[email-masked]>
>>>> Subject: RE: [bess] Handshaking among PEs in an EVPN ES based on Paxos
>>>> algorithm
>>>>
>>>>> Hi Jorge,
>>>>> Let give you another indefinitely forwarding loop case, the picture
>>>>>is as
>>>>> follows:
>>>>>
>>>>> CE3------------CE4
>>>>>   |                        |
>>>>> PE3                   PE4
>>>>>
>>>>>
>>>>>
>>>>> PE1                   PE2
>>>>> |                         |
>>>>> CE1------------CE2
>>>>>
>>>>> If PE1 and PE2 are dual DF PE in transiet time, assuing PE3 and PE4
>>>>>are
>>>>> in stable state ,PE3 is DF PE, PE4 is non-DF PE, the BUM traffic from
>>>>>CE3
>>>>> to CE1, the forwarding loop path is as follows;
>>>>> 
>>>>>CE3--->PE3------>PE2--->CE2---->CE1---->PE1---->PE3-->CE3-->CE4--->PE4
>>>>>-
>>>>>--
>>>>> -
>>>>>> forever......
>>>>> Do you think the harm is enough?
>>>>> Thanks,
>>>>> weiguo
>>>>> ________________________________________
>>>>> From: Rabadan, Jorge (Jorge) [[email-masked]]
>>>>> Sent: Friday, March 27, 2015 22:59
>>>>> To: Haoweiguo; Satya Mohanty (satyamoh); [email-masked];
>>>>> [email-masked]
>>>>> Subject: Re: [bess] Handshaking among PEs in an EVPN ES based on
>>>>>Paxos
>>>>> algorithm
>>>>>
>>>>> Hi Weiguo,
>>>>>
>>>>> OK, thanks for clarifying, that is the part I did not understand in
>>>>>your
>>>>> loop :-)
>>>>>
>>>>> To me a loop means you send a frame and that frame keeps being
>>>>>forwarded
>>>>> by the same nodes indefinitely till you take a corrective action.
>>>>> In this case, CE3 might get a few packets during the transient state,
>>>>>but
>>>>> those packets will have its own MAC SA so CE3 will discard them. I
>>>>>don’t
>>>>> think that is harmful for CE3 in most of the cases. And if it is, you
>>>>> just
>>>>> need to make sure the timers are long enough and the DF election
>>>>>properly
>>>>> implemented to avoid the transient DF-DF state.
>>>>>
>>>>> The handshaking is definitely overkilling IMHO.
>>>>>
>>>>> Thanks.
>>>>> Jorge
>>>>>
>>>>> -----Original Message-----
>>>>> From: Haoweiguo <[email-masked]>
>>>>> Date: Friday, March 27, 2015 at 7:29 AM
>>>>> To: Jorge Rabadan <[email-masked]>, "Satya Mohanty
>>>>> (satyamoh)" <[email-masked]>, "[email-masked]"
>>>>> <[email-masked]>, "[email-masked]" <[email-masked]>
>>>>> Subject: Re: [bess] Handshaking among PEs in an EVPN ES based on
>>>>>Paxos
>>>>> algorithm
>>>>>
>>>>>> Hi Jorge,
>>>>>> Sorry, maybe i have not explain clearly, pls allow me to clarify it
>>>>>>more
>>>>>> clearly.
>>>>>> In MHN case, assuming CE1 and CE2 are multti-homed to PE1 and PE2,
>>>>>>CE2
>>>>>> is
>>>>>> single homed to remote PE3. CE1 and CE2 forms one layer 2 network,
>>>>>>so it
>>>>>> multi-homed network scenario.
>>>>>>            CE3
>>>>>>              |
>>>>>>             PE3
>>>>>>
>>>>>>
>>>>>> PE1                  PE2
>>>>>>   |                       |
>>>>>> CE1-----------CE2
>>>>>>
>>>>>> In transiet period, PE1 and PE2 are both DF PE. At this time, CE3
>>>>>>sends
>>>>>> BUM traffic to CE1, the traffic will reach PE1 and PE2, CE1 will
>>>>>>receive
>>>>>> two copy of the traffic from CE3, also loop is formed, the form
>>>>>>path:
>>>>>>
>>>>>> CE3---->PE3---->PE2---->CE2---->CE1---->PE1--->PE3--->CE3
>>>>>>
>>>>>> I think the traffic loop is absolutely not allowed. In MHN case, the
>>>>>> loop
>>>>>> will formed due to dual-DF PE in transiet period.
>>>>>>
>>>>>> Thanks,
>>>>>> weiguo
>>>>>>
>>>>>>
>>>>>>
>>>>>> ________________________________________
>>>>>> From: Rabadan, Jorge (Jorge) [[email-masked]]
>>>>>> Sent: Friday, March 27, 2015 20:26
>>>>>> To: Haoweiguo; Satya Mohanty (satyamoh); [email-masked];
>>>>>> [email-masked]
>>>>>> Subject: Re: [bess] Handshaking among PEs in an EVPN ES based on
>>>>>>Paxos
>>>>>> algorithm
>>>>>>
>>>>>> Hi Weiguo,
>>>>>>
>>>>>> About this:
>>>>>>
>>>>>> [weiguo]: Traffic duplication and loop issue both exist in dual DF
>>>>>>PE
>>>>>> case. In multi-homed device case, say CE1 is multi-homed to PE1 and
>>>>>>PE2
>>>>>> and both PE are DF PE. When CE1 sends traffic to PE1, the traffic
>>>>>>will
>>>>>> loop back to CE1 through PE2. If CE1 can filter and drop the traffic
>>>>>>,
>>>>>> it
>>>>>> is fortunate, maybe no loop.
>>>>>> For multi-homed network scenario, say local network1(CE1 and CE2) is
>>>>>> multi-homed to PE1 and PE2. Similarly, the traffic from CE1 will
>>>>>>loop
>>>>>> back
>>>>>> through PE1-->PE2-->CE2, it is very serious. It is absolutely not
>>>>>> allowed.
>>>>>>
>>>>>>
>>>>>> [JORGE] In a MH device case: CE1->BUM->PE1->(ESI-label+BUM)->PE2.
>>>>>>PE2
>>>>>> will
>>>>>> not send the traffic back to CE1 due to the ESI-label and
>>>>>>split-horizon
>>>>>> procedures.
>>>>>> In MH network case PE2 will NOT send the traffic to CE2 for the same
>>>>>> reason.
>>>>>>
>>>>>> Let me know if you disagree please.
>>>>>>
>>>>>> Thanks.
>>>>>> Jorge
>>>>>>
>>>>>> -----Original Message-----
>>>>>> From: Haoweiguo <[email-masked]>
>>>>>> Date: Thursday, March 26, 2015 at 9:55 PM
>>>>>> To: "Satya Mohanty (satyamoh)" <[email-masked]>,
>>>>>> "[email-masked]" <[email-masked]>, "[email-masked]"
>>>>>> <[email-masked]>
>>>>>> Subject: Re: [bess] Handshaking among PEs in an EVPN ES based on
>>>>>>Paxos
>>>>>> algorithm
>>>>>>
>>>>>>> Hi Satya,
>>>>>>> Pls see inline.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> weiguo
>>>>>>>
>>>>>>> ________________________________________
>>>>>>> From: Satya Mohanty (satyamoh) [[email-masked]]
>>>>>>> Sent: Friday, March 27, 2015 12:11
>>>>>>> To: Haoweiguo; [email-masked]; [email-masked]
>>>>>>> Subject: Re: [bess] Handshaking among PEs in an EVPN ES based on
>>>>>>>Paxos
>>>>>>> algorithm
>>>>>>>
>>>>>>> Thomas,
>>>>>>>
>>>>>>> Thanks for your summary. It captures the essence of the discussion.
>>>>>>> [weiguo]: Yes, i agree.
>>>>>>>
>>>>>>> One feature of the HRW scheme is that it computes the Active and
>>>>>>>the
>>>>>>> Backup DF upfront.
>>>>>>> Whenever the Active PE, say PE1, dies;
>>>>>>> the Backup PE, PE2, can become the
>>>>>>> Active immediately upon receiving the withdraw of the ES route from
>>>>>>> PE1.
>>>>>>> It need not even have to wait for the 3 seconds time.
>>>>>>> [weiguo]: I think maybe your negligence, dies PE1 can't send
>>>>>>>withdraw
>>>>>>> message:) But when PE1 leaves ESI, it can withdraw the ES route
>>>>>>> immediately.
>>>>>>> When PE1 dies and recovers, assuming PE1 is DF PE, then PE1 and PE2
>>>>>>> will
>>>>>>> both act as PE for some transiet time.
>>>>>>>
>>>>>>> On the other hand, the 3 second timer will serve as a bulk and
>>>>>>>batch
>>>>>>> mechanism for the case when new PE(s) is(are) coming up, so we
>>>>>>>don¹t
>>>>>>> have
>>>>>>> to do a DF election ever so often.
>>>>>>>
>>>>>>> Haoweiguo,  I think the "loop" scenario is speculative.
>>>>>>> I think everybody understands that, yes, there may be some
>>>>>>>transient
>>>>>>> duplication of bum traffic; however, there is no "loop" problem to
>>>>>>>be
>>>>>>> solved.
>>>>>>> [weiguo]: Traffic duplication and loop issue both exist in dual DF
>>>>>>>PE
>>>>>>> case. In multi-homed device case, say CE1 is multi-homed to PE1 and
>>>>>>>PE2
>>>>>>> and both PE are DF PE. When CE1 sends traffic to PE1, the traffic
>>>>>>>will
>>>>>>> loop back to CE1 through PE2. If CE1 can filter and drop the
>>>>>>>traffic ,
>>>>>>> it
>>>>>>> is fortunate, maybe no loop.
>>>>>>> For multi-homed network scenario, say local network1(CE1 and CE2)
>>>>>>>is
>>>>>>> multi-homed to PE1 and PE2. Similarly, the traffic from CE1 will
>>>>>>>loop
>>>>>>> back through PE1-->PE2-->CE2, it is very serious. It is absolutely
>>>>>>>not
>>>>>>> allowed.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> --Satya
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On 3/26/15 9:08 PM, "Haoweiguo" <[email-masked]> wrote:
>>>>>>>
>>>>>>>> Hi Thomas,
>>>>>>>> I know you are neutral, sorry for my reply vulnerable to be
>>>>>>>> miunderstood.
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>> weiguo
>>>>>>>>
>>>>>>>> ________________________________________
>>>>>>>> From: [email-masked] [[email-masked]]
>>>>>>>> Sent: Friday, March 27, 2015 11:59
>>>>>>>> To: Haoweiguo; [email-masked]
>>>>>>>> Subject: Re: [bess] Handshaking among PEs in an EVPN ES based on
>>>>>>>>Paxos
>>>>>>>> algorithm
>>>>>>>>
>>>>>>>> Hi Weiguo,
>>>>>>>>
>>>>>>>> 2015-03-26, Haoweiguo:
>>>>>>>>> Thomas:
>>>>>>>>>> - RFC7432 may have transient periods where the DF election state
>>>>>>>>> is
>>>>>>>>>> not yet synchronized between the two peers:
>>>>>>>>> [weiguo]: Yes, i think RFC 7432 has transient periods of traffic
>>>>>>>>> loop
>>>>>>>> Note well that I didn't write that there can be transient _loops_
>>>>>>>>.
>>>>>>>> I tried to capture the exchange you had all, and what I gather is
>>>>>>>>that
>>>>>>>> the split-horizon procedure _prevents_loops_, independently of any
>>>>>>>> transient period where DF state is not synchronized and which may
>>>>>>>>lead
>>>>>>>> to transient _duplicates_.
>>>>>>>>
>>>>>>>> -Thomas
>>>>>>>>
>>>>>>>>> 26/03/2015 20:05, John E Drake :
>>>>>>>>>> Weiguo,
>>>>>>>>>>
>>>>>>>>>> I guess I wasn¹t clear.  I think you draft, for the reasons I
>>>>>>>>>>have
>>>>>>>>>> detailed, is a non-solution to a non-problem with tremendous
>>>>>>>>>> control
>>>>>>>>>> plane cost.
>>>>>>>>>>
>>>>>>>>>> Yours Irrespectively,
>>>>>>>>>>
>>>>>>>>>> John
>>>>>>>>>>
>>>>>>>>>> *From:*Haoweiguo [mailto:[email-masked]]
>>>>>>>>>> *Sent:* Thursday, March 26, 2015 6:17 PM
>>>>>>>>>> *To:* John E Drake; Patrice Brissette (pbrisset)
>>>>>>>>>> *Cc:* Ali Sajassi (sajassi); [email-masked]
>>>>>>>>>> *Subject:* RE: [bess] Handshaking among PEs in an EVPN ES based
>>>>>>>>>>on
>>>>>>>>>> Paxos algorithm
>>>>>>>>>>
>>>>>>>>>> Pls see below.
>>>>>>>>>>
>>>>>>>>>> Thanks,
>>>>>>>>>>
>>>>>>>>>> weiguo
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> 
>>>>>>>>>>-----------------------------------------------------------------
>>>>>>>>>>-
>>>>>>>>>>--
>>>>>>>>>> -
>>>>>>>>>> -
>>>>>>>>>> -
>>>>>>>>>> -
>>>>>>>>>>
>>>>>>>>>> *From:*John E Drake [[email-masked]]
>>>>>>>>>> *Sent:* Friday, March 27, 2015 6:00
>>>>>>>>>> *To:* Haoweiguo; Patrice Brissette (pbrisset)
>>>>>>>>>> *Cc:* Ali Sajassi (sajassi); [email-masked]
>>>>>>>>>><mailto:[email-masked]>
>>>>>>>>>> *Subject:* RE: [bess] Handshaking among PEs in an EVPN ES based
>>>>>>>>>>on
>>>>>>>>>> Paxos algorithm
>>>>>>>>>>
>>>>>>>>>> To recap,
>>>>>>>>>>
>>>>>>>>>> We have established that your proposal is untenable because of
>>>>>>>>>>its
>>>>>>>>>> control plane load.
>>>>>>>>>>
>>>>>>>>>> We have established that your proposal is based upon a flawed
>>>>>>>>>> understanding of the DF election in RFC 7432.
>>>>>>>>>>
>>>>>>>>>> [weiguo]: In ethernet world, traffic loop is serious than short
>>>>>>>>>> timer
>>>>>>>>>> traffic disruption. If you want to implement  transiet traffic
>>>>>>>>>>loop
>>>>>>>>>> process, i will modify my draft to solve your issue.
>>>>>>>>>>
>>>>>>>>>> If i am the developer, i will prefer short timer traffic
>>>>>>>>>>disruption
>>>>>>>>>> based on current EVPN protocol.
>>>>>>>>>>
>>>>>>>>>> What you are now arguing is that your draft prevents two or more
>>>>>>>>>> PEs
>>>>>>>>>> from being DF simultaneously. This is clearly nonsense.
>>>>>>>>>>
>>>>>>>>>> [weiguo]: I will modify the draft problem statements, and use
>>>>>>>>>>the
>>>>>>>>>> same
>>>>>>>>>> handshaking solution to solve it.
>>>>>>>>>>
>>>>>>>>>> Furthermore, we have established that having two or more DFs for
>>>>>>>>>> what
>>>>>>>>>> even you admit is a brief transient leads to duplicate traffic,
>>>>>>>>>> which
>>>>>>>>>> is acceptable, but not loops, your assertion to the contrary.
>>>>>>>>>>
>>>>>>>>>> [weiguo]: It is transient loop and traffic duplication issue.
>>>>>>>>>>
>>>>>>>>>> Yours Irrespectively,
>>>>>>>>>>
>>>>>>>>>> John
>>>>>>>>>>
>>>>>>>>>> *From:*Haoweiguo [mailto:[email-masked]]
>>>>>>>>>> *Sent:* Thursday, March 26, 2015 5:37 PM
>>>>>>>>>> *To:* John E Drake; Patrice Brissette (pbrisset)
>>>>>>>>>> *Cc:* Ali Sajassi (sajassi); [email-masked]
>>>>>>>>>><mailto:[email-masked]>
>>>>>>>>>> *Subject:* RE: [bess] Handshaking among PEs in an EVPN ES based
>>>>>>>>>>on
>>>>>>>>>> Paxos algorithm
>>>>>>>>>>
>>>>>>>>>> John,
>>>>>>>>>>
>>>>>>>>>> As your understanding of the EVPN draft, the DF election
>>>>>>>>>>mechanism
>>>>>>>>>> has
>>>>>>>>>> more serious side effect, it will have short time traffic
>>>>>>>>>> loop,i.e.,
>>>>>>>>>> dual DF PEs will exist for a short time. I think dual DF PEs is
>>>>>>>>>> absolutely not tolerated, because native ethernet header has no
>>>>>>>>>> TTL,
>>>>>>>>>> up to several hundred ms traffic loop normally not tolerated in
>>>>>>>>>> commertial networks.
>>>>>>>>>>
>>>>>>>>>> As your understanding, the PEs should do as following:
>>>>>>>>>>
>>>>>>>>>> 1. Accurate timer sync. NTP accuracy is bad, 1588v2 is good but
>>>>>>>>>> have
>>>>>>>>>> rarely deployment.
>>>>>>>>>>
>>>>>>>>>> Assuming PE1,PE2 and PE3 have consistent timer clock, when PE3
>>>>>>>>>> joins
>>>>>>>>>> ESI and trigger DF re-election. When reception timer expires:
>>>>>>>>>>
>>>>>>>>>> PE1 upgrades to DF PE.
>>>>>>>>>>
>>>>>>>>>> After reception timer+ ES route transmission timer:
>>>>>>>>>>
>>>>>>>>>> PE2 downloads to non-DF PE.
>>>>>>>>>>
>>>>>>>>>> So in timer clock sync case, dual DF PEs will exist at least
>>>>>>>>>> transmission timer.
>>>>>>>>>>
>>>>>>>>>> If NTP is used for timer sync, because it has bad accuracy, dual
>>>>>>>>>>DF
>>>>>>>>>> PEs will exist more longer timer.
>>>>>>>>>>
>>>>>>>>>> So as your understanding for DF election, the drawback is more
>>>>>>>>>> clear.
>>>>>>>>>>
>>>>>>>>>> Thanks,
>>>>>>>>>>
>>>>>>>>>> weiguo
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> 
>>>>>>>>>>-----------------------------------------------------------------
>>>>>>>>>>-
>>>>>>>>>>--
>>>>>>>>>> -
>>>>>>>>>> -
>>>>>>>>>> -
>>>>>>>>>> -
>>>>>>>>>>
>>>>>>>>>> *From:*John E Drake [[email-masked]]
>>>>>>>>>> *Sent:* Friday, March 27, 2015 4:41
>>>>>>>>>> *To:* Haoweiguo; Patrice Brissette (pbrisset)
>>>>>>>>>> *Cc:* Ali Sajassi (sajassi); [email-masked]
>>>>>>>>>><mailto:[email-masked]>
>>>>>>>>>> *Subject:* RE: [bess] Handshaking among PEs in an EVPN ES based
>>>>>>>>>>on
>>>>>>>>>> Paxos algorithm
>>>>>>>>>>
>>>>>>>>>> Weiguo,
>>>>>>>>>>
>>>>>>>>>> We have already established that your proposal is untenable
>>>>>>>>>>because
>>>>>>>>>> of
>>>>>>>>>> its control plane load.
>>>>>>>>>>
>>>>>>>>>> What we are now discussing is that your proposal is based upon a
>>>>>>>>>> misunderstanding of the algorithm in RFC 7432.  You are assuming
>>>>>>>>>> that
>>>>>>>>>> PE1 will advertise an ES route and then wait for the configured
>>>>>>>>>> interval before performing the DF election while PE2 and PE3
>>>>>>>>>>will
>>>>>>>>>> perform the DF election as soon as they receive the ES route
>>>>>>>>>>from
>>>>>>>>>> PE1.
>>>>>>>>>> This is not what RFC 7432 says.
>>>>>>>>>>
>>>>>>>>>> Rather, what is says is that the advertisement of the ES route
>>>>>>>>>>by
>>>>>>>>>> PE1
>>>>>>>>>> and its receipt by PE2 and PE3 causes all three PEs to start the
>>>>>>>>>> configured interval timer  - ³3. When the timer expires, each PE
>>>>>>>>>> builds an ordered list of the IP addresses of all the PE nodes
>>>>>>>>>> connected to the Ethernet segment (including itself), in
>>>>>>>>>>increasing
>>>>>>>>>> numeric value.²
>>>>>>>>>>
>>>>>>>>>> Yours Irrespectively,
>>>>>>>>>>
>>>>>>>>>> John
>>>>>>>>>>
>>>>>>>>>> *From:*Haoweiguo [mailto:[email-masked]]
>>>>>>>>>> *Sent:* Thursday, March 26, 2015 3:26 PM
>>>>>>>>>> *To:* John E Drake; Patrice Brissette (pbrisset)
>>>>>>>>>> *Cc:* Ali Sajassi (sajassi); [email-masked]
>>>>>>>>>><mailto:[email-masked]>
>>>>>>>>>> *Subject:* RE: [bess] Handshaking among PEs in an EVPN ES based
>>>>>>>>>>on
>>>>>>>>>> Paxos algorithm
>>>>>>>>>>
>>>>>>>>>> Pls read my detail replies to Satya. If you still can't catch
>>>>>>>>>>it,
>>>>>>>>>> pls
>>>>>>>>>> read my draft and EVPN base protocol,  thanks
>>>>>>>>>>
>>>>>>>>>> weiguo
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> 
>>>>>>>>>>-----------------------------------------------------------------
>>>>>>>>>>-
>>>>>>>>>>--
>>>>>>>>>> -
>>>>>>>>>> -
>>>>>>>>>> -
>>>>>>>>>> -
>>>>>>>>>>
>>>>>>>>>> *From:*John E Drake [[email-masked]]
>>>>>>>>>> *Sent:* Friday, March 27, 2015 1:28
>>>>>>>>>> *To:* Patrice Brissette (pbrisset)
>>>>>>>>>> *Cc:* Haoweiguo; Ali Sajassi (sajassi); [email-masked]
>>>>>>>>>> <mailto:[email-masked]>
>>>>>>>>>> *Subject:* Re: [bess] Handshaking among PEs in an EVPN ES based
>>>>>>>>>>on
>>>>>>>>>> Paxos algorithm
>>>>>>>>>>
>>>>>>>>>> I think Patrice is correct.  Your proposal doesn't solve the
>>>>>>>>>> problem
>>>>>>>>>> and it does so at huge cost.
>>>>>>>>>>
>>>>>>>>>> Sent from my iPhone
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> On Mar 26, 2015, at 10:34 AM, Patrice Brissette (pbrisset)
>>>>>>>>>> <[email-masked] <mailto:[email-masked]>> wrote:
>>>>>>>>>>
>>>>>>>>>>       Weiguo,
>>>>>>>>>>
>>>>>>>>>>       I¹m not sure I¹m following here.
>>>>>>>>>>
>>>>>>>>>>       Don¹t you have the same issue with your handshaking
>>>>>>>>>>mechanism?
>>>>>>>>>>
>>>>>>>>>>       If you don¹t know your peer, how can you handshake?
>>>>>>>>>>
>>>>>>>>>>       Regards,
>>>>>>>>>>
>>>>>>>>>>       Patrice
>>>>>>>>>>
>>>>>>>>>>       Image removed by sender.
>>>>>>>>>>
>>>>>>>>>>       *Patrice Brissette*
>>>>>>>>>>       TECHNICAL LEADER.ENGINEERING
>>>>>>>>>>
>>>>>>>>>>       [email-masked] <mailto:[email-masked]>
>>>>>>>>>>       Phone: *+1 613 254 3336*
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>       *Cisco Systems Canada Co. / Les Systemes Cisco Canada CIE*
>>>>>>>>>>       Canada
>>>>>>>>>>       Cisco.com <http://www.cisco.com/global/CA/>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>       Image removed by sender.Think before you print.
>>>>>>>>>>
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>>>>>>>>>>
>>>>>>>>>>       *From: *Haoweiguo <[email-masked]
>>>>>>>>>> <mailto:[email-masked]>>
>>>>>>>>>>       *Date: *Thursday, March 26, 2015 at 10:24 AM
>>>>>>>>>>       *To: *Patrice Brissette <[email-masked]
>>>>>>>>>>       <mailto:[email-masked]>>, John E Drake
>>>>>>>>>><[email-masked]
>>>>>>>>>>       <mailto:[email-masked]>>, Ali Sajassi
>>>>>>>>>><[email-masked]
>>>>>>>>>>       <mailto:[email-masked]>>, "[email-masked]
>>>>>>>>>>       <mailto:[email-masked]>" <[email-masked]
>>>>>>>>>><mailto:[email-masked]>>
>>>>>>>>>>       *Subject: *RE: [bess] Handshaking among PEs in an EVPN ES
>>>>>>>>>> based
>>>>>>>>>> on
>>>>>>>>>>       Paxos algorithm
>>>>>>>>>>
>>>>>>>>>>           Hi Patrice,
>>>>>>>>>>
>>>>>>>>>>           Up to reception timer traffic disruption in transient
>>>>>>>>>> phase
>>>>>>>>>> is
>>>>>>>>>>           one of the issues.
>>>>>>>>>>
>>>>>>>>>>           Thanks,
>>>>>>>>>>
>>>>>>>>>>           weiguo
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> 
>>>>>>>>>>-----------------------------------------------------------------
>>>>>>>>>>-
>>>>>>>>>>--
>>>>>>>>>> -
>>>>>>>>>> -
>>>>>>>>>> -
>>>>>>>>>> -
>>>>>>>>>>
>>>>>>>>>>           *From:*Patrice Brissette (pbrisset)
>>>>>>>>>>[[email-masked]
>>>>>>>>>>           <mailto:[email-masked]>]
>>>>>>>>>>           *Sent:* Thursday, March 26, 2015 20:54
>>>>>>>>>>           *To:* Haoweiguo; John E Drake; Ali Sajassi (sajassi);
>>>>>>>>>>           [email-masked] <mailto:[email-masked]>
>>>>>>>>>>           *Subject:* Re: [bess] Handshaking among PEs in an EVPN
>>>>>>>>>>ES
>>>>>>>>>>           based on Paxos algorithm
>>>>>>>>>>
>>>>>>>>>>           Weiguo,
>>>>>>>>>>
>>>>>>>>>>           You mention "But if your draft have not solved all
>>>>>>>>>> issues²,
>>>>>>>>>>
>>>>>>>>>>           Can you explain what Satya¹s draft is not solving?
>>>>>>>>>>
>>>>>>>>>>           Regards,
>>>>>>>>>>
>>>>>>>>>>           Patrice
>>>>>>>>>>
>>>>>>>>>>           Image removed by sender.
>>>>>>>>>>
>>>>>>>>>>           *Patrice Brissette*
>>>>>>>>>>           TECHNICAL LEADER.ENGINEERING
>>>>>>>>>>
>>>>>>>>>>           [email-masked] <mailto:[email-masked]>
>>>>>>>>>>           Phone: *+1 613 254 3336*
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>           *Cisco Systems Canada Co. / Les Systemes Cisco Canada
>>>>>>>>>>CIE*
>>>>>>>>>>           Canada
>>>>>>>>>>           Cisco.com <http://www.cisco.com/global/CA/>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>           Image removed by sender.Think before you print.
>>>>>>>>>>
>>>>>>>>>>           This email may contain confidential and privileged
>>>>>>>>>> material
>>>>>>>>>>           for the sole use of the intended recipient. Any
>>>>>>>>>>review,
>>>>>>>>>> use,
>>>>>>>>>>           distribution or disclosure by others is strictly
>>>>>>>>>> prohibited.
>>>>>>>>>>           If you are not the intended recipient (or authorized
>>>>>>>>>>to
>>>>>>>>>>           receive for the recipient), please contact the sender
>>>>>>>>>>by
>>>>>>>>>> reply
>>>>>>>>>>           email and delete all copies of this message.
>>>>>>>>>>
>>>>>>>>>>           Please click here
>>>>>>>>>>
>>>>>>>>>> 
>>>>>>>>>><http://www.cisco.com/web/about/doing_business/legal/cri/index.ht
>>>>>>>>>>m
>>>>>>>>>>l>
>>>>>>>>>>           for Company Registration Information.
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>           *From: *Haoweiguo <[email-masked]
>>>>>>>>>>           <mailto:[email-masked]>>
>>>>>>>>>>           *Date: *Wednesday, March 25, 2015 at 10:38 PM
>>>>>>>>>>           *To: *John E Drake <[email-masked]
>>>>>>>>>>           <mailto:[email-masked]>>, Ali Sajassi
>>>>>>>>>> <[email-masked]
>>>>>>>>>>           <mailto:[email-masked]>>, "[email-masked]
>>>>>>>>>>           <mailto:[email-masked]>" <[email-masked]
>>>>>>>>>> <mailto:[email-masked]>>
>>>>>>>>>>           *Subject: *Re: [bess] Handshaking among PEs in an EVPN
>>>>>>>>>>ES
>>>>>>>>>>           based on Paxos algorithm
>>>>>>>>>>
>>>>>>>>>>               Hi John,
>>>>>>>>>>
>>>>>>>>>>                Firstly i think EVPN community should reach
>>>>>>>>>>consensus
>>>>>>>>>> on
>>>>>>>>>>               the issues of current DF election mechanism. All
>>>>>>>>>>these
>>>>>>>>>>               issues should be resolved in a single new DF
>>>>>>>>>>election
>>>>>>>>>>               draft,rather than in multiple separate drafts. If
>>>>>>>>>>your
>>>>>>>>>>               draft can solve all these issues and stable, i
>>>>>>>>>>have no
>>>>>>>>>>               question for its progressing. But if your draft
>>>>>>>>>>have
>>>>>>>>>> not
>>>>>>>>>>               solved all issues, i think it had better combine
>>>>>>>>>>with
>>>>>>>>>>               other drafts to provide a comprehensive solution.
>>>>>>>>>>I
>>>>>>>>>> think
>>>>>>>>>>               the issues listed in
>>>>>>>>>>draft-rabadan-bess-evpn-ac-df-01
>>>>>>>>>> and
>>>>>>>>>>               draft-hao-bess-evpn-df-handshaking-00 is valid, it
>>>>>>>>>> should
>>>>>>>>>>               be resolved. So i think although your new Hash
>>>>>>>>>> algorithm
>>>>>>>>>>               for DF election is good, it only includes partial
>>>>>>>>>>               enhancements, maybe it still needs some time for
>>>>>>>>>> consensus.
>>>>>>>>>>
>>>>>>>>>>               Thanks,
>>>>>>>>>>
>>>>>>>>>>               weiguo
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> 
>>>>>>>>>>-----------------------------------------------------------------
>>>>>>>>>>-
>>>>>>>>>>--
>>>>>>>>>> -
>>>>>>>>>> -
>>>>>>>>>> -
>>>>>>>>>> -
>>>>>>>>>>
>>>>>>>>>>               *From:*John E Drake [[email-masked]
>>>>>>>>>>               <mailto:[email-masked]>]
>>>>>>>>>>               *Sent:* Thursday, March 26, 2015 7:16
>>>>>>>>>>               *To:* Haoweiguo; Ali Sajassi (sajassi);
>>>>>>>>>>[email-masked]
>>>>>>>>>>               <mailto:[email-masked]>
>>>>>>>>>>               *Subject:* RE: [bess] Handshaking among PEs in an
>>>>>>>>>>EVPN
>>>>>>>>>> ES
>>>>>>>>>>               based on Paxos algorithm
>>>>>>>>>>
>>>>>>>>>>               Weiguo,
>>>>>>>>>>
>>>>>>>>>>               Your proposal introduces a control plane
>>>>>>>>>>processing
>>>>>>>>>> load
>>>>>>>>>>               that is O(#EVIs * PEs) per DF election and given
>>>>>>>>>>that
>>>>>>>>>>               there can be 4K EVIs per ES, this looks like a
>>>>>>>>>>               **substantial** load. Furthermore,
>>>>>>>>>>
>>>>>>>>>>               you can¹t  use the ES route to co-ordinate DF
>>>>>>>>>>election
>>>>>>>>>>               because you would need to carry your new extended
>>>>>>>>>>               community for each EVI and they would not all fit.
>>>>>>>>>> You
>>>>>>>>>>               also can¹t use the Per EVI Ethernet AD route
>>>>>>>>>>because
>>>>>>>>>> that
>>>>>>>>>>               is processed by all PEs in the EVI.
>>>>>>>>>>
>>>>>>>>>>               I think that from a practical perspective the new
>>>>>>>>>>DF
>>>>>>>>>>               election proposed in Satya¹s draft is sufficiently
>>>>>>>>>> stable
>>>>>>>>>>               that it renders your draft moot, even if it could
>>>>>>>>>>be
>>>>>>>>>> made
>>>>>>>>>>               to work.
>>>>>>>>>>
>>>>>>>>>>               Yours Irrespectively,
>>>>>>>>>>
>>>>>>>>>>               John
>>>>>>>>>>
>>>>>>>>>>               *From:*BESS [mailto:[email-masked]] *On
>>>>>>>>>>Behalf
>>>>>>>>>> Of
>>>>>>>>>>               *Haoweiguo
>>>>>>>>>>               *Sent:* Wednesday, March 25, 2015 5:34 PM
>>>>>>>>>>               *To:* Ali Sajassi (sajassi); [email-masked]
>>>>>>>>>>               <mailto:[email-masked]>
>>>>>>>>>>               *Subject:* Re: [bess] Handshaking among PEs in an
>>>>>>>>>>EVPN
>>>>>>>>>> ES
>>>>>>>>>>               based on Paxos algorithm
>>>>>>>>>>
>>>>>>>>>>               Hi Ali,
>>>>>>>>>>
>>>>>>>>>>               Thanks for your information. I scanned through
>>>>>>>>>>this
>>>>>>>>>> draft,
>>>>>>>>>>               it really introduces inter-chassis message for DF
>>>>>>>>>> election
>>>>>>>>>>               handshaking, the requirements in this draft is to
>>>>>>>>>>               eliminate transiet Loop and traffic duplication.
>>>>>>>>>> Current
>>>>>>>>>>               EVPN DF election mechanism already eliminated loop
>>>>>>>>>>and
>>>>>>>>>>               traffic duplication by configuring long reception
>>>>>>>>>> timer
>>>>>>>>>> on
>>>>>>>>>>               each multi-homed PE, but up to reception timer
>>>>>>>>>>traffic
>>>>>>>>>>               disruption issue still exist. EVPN for DCI is an
>>>>>>>>>> important
>>>>>>>>>>               use case for EVPN, up to reception timer traffic
>>>>>>>>>>               disruption can't be tolerated for service
>>>>>>>>>>providers,
>>>>>>>>>> it
>>>>>>>>>>               should be improved.
>>>>>>>>>>
>>>>>>>>>>               Also for accuracy, i think handshaking state
>>>>>>>>>>machine
>>>>>>>>>> on
>>>>>>>>>>               each multi-homed PE is also needed. From solution
>>>>>>>>>>               perspective, in my draft, no inter-chassis message
>>>>>>>>>>is
>>>>>>>>>>               introduced, only one new extended community is
>>>>>>>>>> introduced,
>>>>>>>>>>               i think the process is comparatively simple than
>>>>>>>>>>your
>>>>>>>>>>               following draft.
>>>>>>>>>>
>>>>>>>>>>               Current EVPN DF election has some drawbacks, so
>>>>>>>>>>there
>>>>>>>>>> are
>>>>>>>>>>               three new drafts about DF election emerged. I
>>>>>>>>>>think
>>>>>>>>>> BESS
>>>>>>>>>>               WG can consider these three drafts in global view,
>>>>>>>>>>a
>>>>>>>>>>               single,comprehensive new DF election draft is
>>>>>>>>>>hoped.
>>>>>>>>>>
>>>>>>>>>>               thanks.
>>>>>>>>>>
>>>>>>>>>>               Thanks,
>>>>>>>>>>
>>>>>>>>>>               weiguo
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> 
>>>>>>>>>>-----------------------------------------------------------------
>>>>>>>>>>-
>>>>>>>>>>--
>>>>>>>>>> -
>>>>>>>>>> -
>>>>>>>>>> -
>>>>>>>>>> -
>>>>>>>>>>
>>>>>>>>>>               *From:*BESS [[email-masked]
>>>>>>>>>>               <mailto:[email-masked]>] on behalf of Ali
>>>>>>>>>> Sajassi
>>>>>>>>>>               (sajassi) [[email-masked]
>>>>>>>>>> <mailto:[email-masked]>]
>>>>>>>>>>               *Sent:* Thursday, March 26, 2015 0:21
>>>>>>>>>>               *To:* [email-masked] <mailto:[email-masked]>
>>>>>>>>>>               *Subject:* [bess] Handshaking among PEs in an EVPN
>>>>>>>>>>ES
>>>>>>>>>>               based on Paxos algorithm
>>>>>>>>>>
>>>>>>>>>>               FYI- First published July 4, 2011
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> 
>>>>>>>>>>https://datatracker.ietf.org/doc/draft-sajassi-l2vpn-evpn-segment
>>>>>>>>>>-
>>>>>>>>>>ro
>>>>>>>>>> u
>>>>>>>>>> t
>>>>>>>>>> e
>>>>>>>>>> /
>>>>>>>>>>
>>>>>>>>>>               -Ali
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> _______________________________________________
>>>>>>>>>> BESS mailing list
>>>>>>>>>> [email-masked]
>>>>>>>>>> https://www.ietf.org/mailman/listinfo/bess
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> 
>>>>>>>>>__________________________________________________________________
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>>>>>>>>>__
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>>>>>>>>> _
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>>>>>>>>> _
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>>This message and its attachments may contain confidential or privileged 
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