Hi Jim & Jakob, I think you proposed a valid point. If we continue this proposal, we should include an operational section. I believe this point applies to all such kind of "fast egress PE node protection" schemes.
>What if the primary PE comes online after the backup? >What label should the backup use if it can not reach the primary? > >You need to think about partitioned networks too. If two PEs can reserved a label space to be used as the label range for sharing, the proposal is workable. However, we can slightly relax this constraint, i.e., PEs in an RG MUST reserve one label space for sharing. The PEs in an RG just need a common available label range, right? There are various ways to achieve this. For example, we can divide the label spaces into several blocks beforehand. Give them priorities. When PEs locally allocate labels, blocks with the higher priority will be used earlier. Then PEs in an RG can agree on those common blocks with lower priorities. This relaxation introduces flexibility. Imagine the case that an operator may be not sure about the size of the label space to be reserved at the beginning. In this way, even the primary come online after the backup, it can negotiate a label range for sharing with the backup. At last but not least, even if PEs cannot find a common label range in the worst case or the network is partitioned, the ICCP connection will not be established. In this case, the PEs just fall back to the non redundant mode. So the two scenarios proposed by Jakob can be handled. Anyway, I don't think there is no way to achieve such proposal. Thanks, Mingui >-----Original Message----- >From: L3VPN [mailto:[email protected]] On Behalf Of UTTARO, JAMES >Sent: Friday, November 22, 2013 4:17 AM >To: Jakob Heitz; Lizhenbin >Cc: [email protected]; Stewart Bryant (stbryant) >Subject: RE: Why we consider the method of "label sharing for fast PE >protection" > >As I stated before an operational section that anticipates running the network >would be useful in this discussion. I would like to see various scenarios, >restrictions, failure modes etc.. > >Jim Uttaro > >-----Original Message----- >From: Jakob Heitz [mailto:[email protected]] >Sent: Thursday, November 21, 2013 3:09 PM >To: Lizhenbin; UTTARO, JAMES >Cc: [email protected]; Stewart Bryant (stbryant) >Subject: RE: Why we consider the method of "label sharing for fast PE >protection" > >What if the primary PE comes online after the backup? >What label should the backup use if it can not reach the primary? > >You need to think about partitioned networks too. >It's not as simple as you think. > >-- Jakob. > >-----Original Message----- >From: Lizhenbin [mailto:[email protected]] > >It is not like this way. For the ICCP-based label allocation method, the >primary PE >is allocate the label for VPN by its own label allocation algorithm. The >backup PE >is just to allocate the label specified by the primary PE. The process is just >like >label backup. They need not use the same label allocation algorithm.
