Hi Qi,
> In case of MAP-E, IPv4 packet is encapsulated in IPv6. The above text is for
> check the validation of the received packet. In terms of IPv6 packet received
> at BR, the IPv6 source address should be based on the IPv6 prefix delegated
> to CE. Also, according to the MAP rule, IPv4 address and port number can be
> derived from the same delegated IPv6 prefix. So, BR can calculate CE IPv6
> address from the IPv4 source address and source port number in IPv4 packet
> encapsulated in the received IPv6 packet. If the calculation is failed, then
> the packet could be dropped. If the calculation is succeeded but the
> calculated CE IPv6 address is not matched to the source IPv6 address in the
> received IPv6 packet, then the packet could be dropped.
>
> [Qi Sun] I have 2 questions here.
> [Qi Sun] 1.My understanding is that the BR get the IPv4 related info from the
> IPv6 packet by reading the specific bits in the IPv6 packet, that is the IPv4
> address is put in the exact position in the IPv6 packet. Right?
> [Qi Sun] 2.You said,'If the calculation is failed, then the packet could be
> dropped.' I think this action may cause the data loss of normal IPv6 flow.
EA-bits can be gotten from IPv6 prefix. In case of MAP-E, it is based on the
encapsulation. Similar to other tunnel, IPv4 packet is encapsulated in IPv6.
As Ole mentioned, there is no difference than any other tunnel. Only if the
IPv6 packet can be terminated at a tunnel end-point address, the packet can be
processed as MAP-E packet. In other cases, the IPv6 packet can be processed
normally.
If the IPv6 packet is terminated at the tunnel end-point address, the packet
can be processed as MAP-E packet. At this time, if the encapsulated IPv4 packet
has invalid address as its source address, it could be a invalid MAP-E packet.
>> 2. If the received IPv6 packet is a normal one, instead of an
>> IPv4-encapsulated packet, what will the BR do? That is, dose the BR can act
>> as a normal router?
>
> In this case, BR should handle this IPv6 packet based on the normal IPv6
> routing because the next header is not IPv4 in this case.
>
> [Qi Sun] Agree :)
>> 3. What can cause the inequality between the derived CE IPv6 address and the
>> IPv6 source address in the received IPv6 packet? And what will BR do with
>> it, discard it ?
>
> It might depend on the implementation. But the derived CE IPv6 address must
> be same as the IPv6 source address in case of MAP-E because the derived CE
> IPv6 address should be the tunnel end-point address on the CE. So, the
> received packet should be discarded or not processed as MAP-E packet.
>
> [Qi Sun] You mean, in the MAP-E case, the inequality won't happen, right?
>
> My question is that whether the MAP-E nodes can be deployed with the normal
> IPv6 nodes. If can't, won't it cost too much to deploy brand new MAP-E
> domains for SP? If can, is it possible to be stated in the draft, with the
> considerations of BR handling non-MAP-E IPv6 packets ?
As Ole mentioned, if the IPv6 packet can not be terminated at the tunnel
end-point address of MAP-E, this packet can be processed as the normal IPv6
packet.
Thanks,
Tetsuya Murakami
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