I any PE is part of 2 RGs, then those RGs can not have overlapping label spaces.
-- Jakob Heitz. On Nov 28, 2013, at 6:16 PM, "Mingui Zhang" <[email protected]> wrote: > Hi Bruno, > > So you suppose the label used in an RG cannot be used again out of the RG. > That is not correct. > Please find my comments inline [Mingui]. > > <snip> >> [Bruno2] Let's assume: >> - 5 PE in the group, hence sharing the same range of labels (e.g., 1~1100). >> - 5 VPNs in connect to this group of PE, 2 of which being dual-homed (VPN1 & >> VPN2). >> >> With label sharing: >> Label:1 2 3 4 5 >> >> PE1 VPN1 x x x x >> PE2 VPN1 VPN2 x x x >> PE3 x VPN2 x x x >> PE4 x x VPN3 x x >> PE5 x x x VPN4 VPN5 >> >> All labels marked as "x" are burned/lost because of the label sharing. > > [Mingui] Not true. Where we got this constraint? For an explicitly example, > PE4 can well use label 1,2,4,5. > > [Mingui] I anticipate you assume PE1~PE5 are forming an RG, so that once a > label is used it is used across the RG. I need to point out that the unit of > "RG" is independent of PEs. It depends on the VPN connections. I saw Zhou > Peng has already given examples on this point. > > <snip> > >> [Bruno2] not always. There is public/ietf example for this: >> draft-l3vpn-legacy-rtc-00 > > [Mingui] It's designed to be incrementally deployable in the network. The > trick is confined in the RG. Other P and PE routers are unaware of the change. > > [Mingui] I guess you may change to imagine the scenario that operator need a > legacy PE and a label sharing PE form an RG. Let's consider the analogy that > the operator interconnects two switches using LAG while one of them does not > support LAG at all. :) > > [Mingui] Thanks for continuing the discussion. I think the discussion about > label ranges reservation in another thread is related to our discussion. To > my understanding, the conclusion is that it's not OK to require a label block > to be supported across multiple PEs. A possible escape is to resort to a > higher-layer authorized entity out of the RG to assign the label. > > Thanks, > Mingui
