Re: [Softwires] 4rd Address Mapping - version-01

[Maoke <[e-mail]>]

hi Chunfa and Jacni,

thanks a lot for the corrections and clarifications. :)

2011/10/17 <[e-mail]>

>  I guess the second delegated prefix should be 2001:db8:1876:5400::/53
>
>    I guess the second delegated prefix should be 2011:db8:c3b2:a000::/53.
> Because the CE3 Rule IPv6 Prefix length is not mulitipe of 4 bits,it need
> calculate using Binary as follows.
>
>                                  v(/29)
>  --elipsis(0x2001 0db)--1000
>  (2011:db8::/29)
>  --elipsis(0x4020)------    000 1100 0011 1011 0
> (64.32.24.118)
>                                                                    010 1010
> 0 (PSID 0x54)
> --------------------------------------------------------------------------
> CE3 IPv6 prefix: 2001:db8:c3b2:a000::/53
>
> If the CE3 IPv4 address is 64.32.48.236, CE3 PSID is 0xa8, calculate as
> follows,
>                                  v(/29)
>  --elipsis(0x2001 0db)--1000
>  (2011:db8::/29)
>  --elipsis(0x4020)------    001 1000 0111 0110 0
> (64.32.48.236)
>                                                                    101 0100
> 0 (PSID 0xa8)
> --------------------------------------------------------------------------
> the CE3 IPv6 prefix is 2001:db9:8765:4000::/53
>
> I think this  should be not gonna happen, since the IPv6 address planing
> must be done natively
> considering nothing about the IPv4 address. As exclusiveness, each CE has
> unique CE IPv6 Prefix.
>
> As described in the example Maoke given, since "Rule IPv6 Prefix B" is
> contained in the "Rule IPv6 Prefix A",
> if the IPv6 addresses under Rule IPv6 Prefix A and the IPv6 address under
> Rule IPv6 prefix B are assigned independently
> and have any consideration each other, same CE IPv6 prefix assigning to
> different CEs may be happen. I think this MUST be
>  avoided when designing the mapping rules or setting the IPv6 assigning
> way(such as DHCPv6 etc.).
>
>
the consensus is keeping the exclusiveness of IPv4 address blocks in IPv6.
therefore, i understand the logic of address planning for CEs in 4rd could
be the following 4 steps:

1) list all mutually exclusive IPv4 networks to be involved in the residual
deployment, i.e., Rule IPv4 prefixes;
2) calculate IPv6 prefix length for each Rule IPv4 prefix, according to the
length of the prefix and the requirement like the PSID length and the CE
prefix length;
3) allocate the IPv6 address space into exclusive blocks, i.e.
rule_IPv6_prefixes, according to the prefix length requirements in 2), and
get the mapping rules;
4) assigning IPv6 address in each block for the CE.

am i right?

cheers,
maoke


> Cheers
>
> Chunfa
>
>
>
>>
>