Senthil,

[...]

>> The draft says that:
>> (a) The PSID is:
>> +--+---+---+---+---+---+---+---+---+
>> |PL|   8  16  24  32  40  48  56   |
>> +--+---+---+---+---+---+---+---+---+
>> |64| u | IPv4 address  |  PSID | 0 |
>> +--+---+---+---+---+---+---+---+---+
> 
> I believe this figure is misleading by placing the IPv4 address in a fixed
> location. Figure 3 and Figure 7
> In the draft shows that the IID is not in a fixed location. Also, the text
> surrounding the above figure 8, says
> "The Interface identifier format of a MAP node is based on the format
>   specified in section 2.2 of [RFC6052], with the added PSID field if
>   present, as shown in figure Figure 8."
> 
> 
> But RFC 6052 doesn¹t have the IPv4 address in a fixed location as per
> section 2.2. So I think this figure is misleading.

perhaps we should just remove the RFC6052 reference then?
with a 48 bits of PSID + IPv4 address.
I don't mind if it is just IPv4 address, but then someone need to drive that 
discussion.

> |     n bits         |  o bits   | s bits  |   128-n-o-s bits      |
>   +--------------------+-----------+---------+------------+----------+
>   |  Rule IPv6 prefix  |  EA bits  |subnet ID|     interface ID      |
>   +--------------------+-----------+---------+-----------------------+
> 
> 
>> (b) "If the End-user IPv6 prefix length is larger than 64, the most
>> significant parts of the interface identifier is overwritten by the
>> prefix."
>> 
>> This is particularly unclear:
> 
> True.
>> - What happens to the u octet?
> 
> I guess that needs to be made clear in the draft. We struggled with that
> in our implementation.

if we remove the 6052 reference, there is no u-octet.

>> - And to the IPv4 address if the prefix is longer than /68?
>> - ...
>> 
>> Of course, if a use case is provided where MAP-E would be actually used
>> with an IID shorter than 64 bits, it should be discussed. But:
>> - There is no such use case so far.
>> - Looking for one doesn't seem useful.
> 
> I would like to see the IPv4 address be present from bits 96-127, no need
> for the PSID to be repeated again. That would allow us to go upto /96 and
> being consistent with RFC 6052 which allows one to configure a prefix of
> upto /96.

just put the IPv4 address in the bottom bits, and allow it to be overwritten by 
the prefix.
it is just there for 'pretty printing' anyway.

cheers,
Ole
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