Hi Stewart, >> PEs can reserve some label ranges to be shared before they boot up. Then it >becomes easy for an RG to figure out a common range. > >Only if the equipment type is the same. h/w varies >as to label base and range.
At least we know that the proposal is feasible for PEs with the same h/w. For PEs with different h/w, it's still possible that they can find out a common block. If they cannot find a common block, the connection between them will end up with failure, then they have to fall back to the non-redundant mode. Thanks, Mingui >-----Original Message----- >From: Stewart Bryant [mailto:[email protected]] >Sent: Friday, November 22, 2013 5:56 PM >To: Mingui Zhang; Jakob Heitz; Eric Osborne (eosborne) >Cc: UTTARO, JAMES; [email protected] >Subject: Re: Why we consider the method of "label sharing for fast PE >protection" > >On 19/11/2013 10:01, Mingui Zhang wrote: >> Hi Stewart, >> >>> The authors need to take onboard the findings of the SPRING designers. >> I am not sure I've got the point. Are your still talking about the label >> allocation >issue? Could you please explain it more specifically? >Different equipment types and different s/w versions >use different label ranges for a specific purpose. > >So, you need the same h/w version and the same >s/w version and a co-ordination policy that may >well need to be domain wide to be able to use >an identical label on two separate PEs. >> >>> If the PE equipments are different the label ranges supported by h/w may be >>> disjoint. >> PEs can reserve some label ranges to be shared before they boot up. Then it >becomes easy for an RG to figure out a common range. > >Only if the equipment type is the same. h/w varies >as to label base and range. > >- Stewart > >> >> Thanks, >> Mingui >> >>> -----Original Message----- >>> From: Stewart Bryant [mailto:[email protected]] >>> Sent: Tuesday, November 19, 2013 2:41 AM >>> To: Jakob Heitz; Eric Osborne (eosborne) >>> Cc: UTTARO, JAMES; Mingui Zhang; [email protected] >>> Subject: Re: Why we consider the method of "label sharing for fast PE >>> protection" >>> >>> The authors need to take onboard the findings of the SPRING designers. >>> >>> If the PE equipments are different the label ranges supported by h/w may be >>> disjoint. >>> >>> Stewart >>> >>> On 18/11/2013 16:05, Jakob Heitz wrote: >>>> We are on the same page. >>>> I misinterpreted your :) >>>> >>>> I guess it could be done at small scale with certain restrictions. >>>> It's definitely not a generic solution. >>>> >>>> -- >>>> Jakob Heitz. >>>> >>>> >>>> On Nov 18, 2013, at 7:59 AM, "Eric Osborne (eosborne)" >>> <[email protected]> wrote: >>>>> Oh, yeah. I'm not actually proposing that there's a workable solution. >I'm >>> trying to point out that there isn't one. >>>>> The problem gets harder, too. >>>>> >>>>> PE1: VRF-A primary, VRF-B backup >>>>> PE2: VRF-B primary, VRF-C backup >>>>> PE3: VRF-C primary, VRF-A backup >>>>> >>>>> and so forth. >>>>> >>>>> >>>>> >>>>> >>>>> eric >>>>> >>>>>> -----Original Message----- >>>>>> From: Jakob Heitz [mailto:[email protected]] >>>>>> Sent: Monday, November 18, 2013 10:57 AM >>>>>> To: UTTARO, JAMES >>>>>> Cc: Eric Osborne (eosborne); Mingui Zhang; Stewart Bryant >>>>>> (stbryant); [email protected] >>>>>> Subject: Re: Why we consider the method of "label sharing for fast >>>>>> PE protection" >>>>>> >>>>>> "same algorithm" is not good enough on its own. If two routers using >>>>>> the same algorithm boot up at different times and/or with different >>>>>> neighbors, they still won't allocate the same labels. >>>>>> >>>>>> The algorithm cannot just be "same". It must be restricted in other >>>>>> ways. >>>>>> >>>>>> -- >>>>>> Jakob Heitz. >>>>>> >>>>>> >>>>>> On Nov 18, 2013, at 5:51 AM, "UTTARO, JAMES" <[email protected]> >wrote: >>>>>> >>>>>>> That sounds doable ;) >>>>>>> >>>>>>> -----Original Message----- >>>>>>> From: [email protected] [mailto:[email protected]] On >>>>>>> Behalf >>>>>> Of Eric Osborne (eosborne) >>>>>>> Sent: Monday, November 18, 2013 7:52 AM >>>>>>> To: Mingui Zhang; Stewart Bryant (stbryant); Jakob Heitz; >>>>>> [email protected] >>>>>>> Subject: RE: Why we consider the method of "label sharing for fast >>>>>>> PE >>>>>> protection" >>>>>>> It's not just the range, right? You have to allocate the same >>>>>>> label >>>>>> per VRF. So you either end up statically allocating labels or >>>>>> making sure you have the same label allocation algorithm on every >>>>>> pair of primary/backup PEs. >>>>>>> >>>>>>> >>>>>>> >>>>>>> eric >>>>>>> >>>>>>>> -----Original Message----- >>>>>>>> From: [email protected] [mailto:[email protected]] On >>>>>> Behalf >>>>>>>> Of Mingui Zhang >>>>>>>> Sent: Monday, November 18, 2013 4:34 AM >>>>>>>> To: Stewart Bryant (stbryant); Jakob Heitz; [email protected] >>>>>>>> Subject: RE: Why we consider the method of "label sharing for fast >>>>>>>> PE protection" >>>>>>>> >>>>>>>> Hi Stewart, >>>>>>>> >>>>>>>> Operators can configure the PEs in an RG to reserve the same label >>>>>> range >>>>>>>> for sharing. >>>>>>>> >>>>>>>> With the ICCP connection established between the primary and >>>>>>>> backup >>>>>> PE, >>>>>>>> the primary PE can mandate the sharing label range out of the >>>>>>>> intersection of the unused label space. >>>>>>>> >>>>>>>> Thanks, >>>>>>>> Mingui >>>>>>>> >>>>>>>>> -----Original Message----- >>>>>>>>> From: Stewart Bryant [mailto:[email protected]] >>>>>>>>> Sent: Thursday, November 14, 2013 9:52 PM >>>>>>>>> To: Jakob Heitz; Mingui Zhang; [email protected] >>>>>>>>> Subject: Re: Why we consider the method of "label sharing for >>>>>>>>> fast >>>>>> PE >>>>>>>>> protection" >>>>>>>>> >>>>>>>>> Isn't the normal problem that the two systems will be >>>>>>>>> independently >>>>>>>> allocating >>>>>>>>> labels from their default label table, possibly with different >>>>>> hardware >>>>>>>> base and >>>>>>>>> range, so there may not be a common label available that can be >>>>>>>> allocated by >>>>>>>>> both. >>>>>>>>> >>>>>>>>> - Stewart >>>>>>>>> >>>>>>>>> On 07/11/2013 21:50, Jakob Heitz wrote: >>>>>>>>> >>>>>>>>> >>>>>>>>> Several people at the mike asked this question: >>>>>>>>> How do you make sure that the PEs allocate the same label? >>>>>>>>> >>>>>>>>> This needs to be part of the document, because it is quite >>>>>>>> important. >>>>>>>>> If an external entity allocates the labels, the protocol >>>>>>>>> between the PEs and that entity needs to be standardized. >>>>>>>>> Since this is a feature that provides redundancy, the >>>>>>>>> label allocating entity also needs to be backed up by a >>>>>>>>> redundant entity. The protocol between the redundant >>>>>>>>> label allocators needs to be standardized. >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> -- >>>>>>>>> >>>>>>>>> Jakob Heitz. >>>>>>>>> >>>>>>>>> ________________________________ >>>>>>>>> >>>>>>>>> From: [email protected] [[email protected]] on >>>>>>>>> behalf >>>>>> of >>>>>>>>> Mingui Zhang [[email protected]] >>>>>>>>> Sent: Thursday, 07 November 2013 11:40 AM >>>>>>>>> To: [email protected] >>>>>>>>> Subject: Why we consider the method of "label sharing for fast >>>>>>>>> PE protection" >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> Hi, >>>>>>>>> >>>>>>>>> As a choice of fast PE protection, >>>>>>>>> >>>>>>>>> 1. This solution is simple and light-weight. We need not >>>>>> introduce >>>>>>>> the >>>>>>>>> complex context label table in PE routers. So label table need >>>>>>>>> not >>>>>> be >>>>>>>> stored >>>>>>>>> repeatedly on RG members. >>>>>>>>> >>>>>>>>> >>>>>>>>> 2. Also, it's easy to be deployed. It does not bring any >>>>>>>>> change >>>>>> to >>>>>>>> P routers >>>>>>>>> (control plane & data plane). It even does not change the data >>>>>>>>> plane >>>>>> of >>>>>>>> PE >>>>>>>>> routers. >>>>>>>>> >>>>>>>>> >>>>>>>>> 3. In addition, it does not bear the restriction of "no >>>>>>>>> penultimate-hop-popping". >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> Thanks, >>>>>>>>> Mingui >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> >>>>>>>>> -- >>>>>>>>> For corporate legal information go to: >>>>>>>>> >>>>>>>>> >http://www.cisco.com/web/about/doing_business/legal/cri/index.htm >>>>>>>>> l >>>> . >>>> >>> >>> -- >>> For corporate legal information go to: >>> >>> http://www.cisco.com/web/about/doing_business/legal/cri/index.html >> . >> > > >-- >For corporate legal information go to: > >http://www.cisco.com/web/about/doing_business/legal/cri/index.html
