Hi Tom, See comments inline:
On 1/7/11 5:17 PM, "Tom Taylor" <[email protected]> wrote: >Thanks for your comments. Responses below. BTW, we are going to follow a >suggestion to write this draft as a more general mechanism, to cover any >case where the host and the target network speak IPvx and the access >network between speaks IPvy. We'll try to frame it so the host-end >function (still trying to think of a name) can reside either in the CPE >or in the provider IP edge. [YL] Looking forward to it. >[PTT] You don't need a mapping for every v6 multicast group, only the >ones that someone in your network wants to join. So it's an engineering >issue -- how many addresses do you set aside in the address pool to >handle your demand? [YL] This will require provision in the TF which is an overhead. > >[PTT] No, the new protocol is used only to request a mapping from <S,G> >in the target network to <S',G'> in the access network. The 6rd CE does >indeed translate the MLDv2 to IGMP directly (you must have missed a step >in your reading), but it needs to know the access network view of the >address pair (i.e., <S',G'>) before doing so. [YL] Ok. I read the step now: "The 6rd CE interworks between the MLDv2 request it received and an IGMPv3 request." > >[PTT] Let's start with the <S,G> in the target network (IPv6 network, in >our current draft). S is wild-carded if the multicast session is >any-source (ASM). If the multicast session is specific-source (SSM), >then S in the target network is a unicast IPv6 address. The translator >maps that to an IPv4 unicast address S' from its pool, and the 6rd CE >uses S' in its IGMP request. [YL] Since the draft specified mentioned only IGMPv3, I thought it worked only on SSM. I think the text needed to update. > >[PTT] That's a point we hadn't thought of -- one of the details that >have to be sorted out, along with the question of how the PIM-Join finds >the 6rd-BR in the first place. For SSM, the answer is fairly simple: the >translator sets S' to the unicast address of the 6rd-BR, as you >suggested in an earlier comment. This doesn't work for ASM. [YL] One solution is to ask TF to give all the mappings to the BR (or the TF is collocated with the BR). For the get the PIMv4-Join question, you can make the BR the RP of the special v4 groups which are provisioned for v6 translation. Regards, Yiu _______________________________________________ Softwires mailing list [email protected] https://www.ietf.org/mailman/listinfo/softwires
