Re: [shara] [BEHAVE] TR: I-D Action:draft-boucadair-pppext-portrange-option-00.txt

[Rémi Després <[e-mail]>]

Mohamed,

Thanks for this draft.
It does contribute to the promotion of Port-Extended IPv4 addressing, which is the only known way to AVOID, during the IPv4-IPv6 coexistence period, that users MUST depend on CGNs .

Yet, the mask and value parameters which you propose, to express port ranges, are in my understanding, both too complex and too limited.
- too complex, because it's hard to imagine a practical use of non contiguous port ranges. (In particular I don't see where to use the chosen example of ports xxx0x1xxxxxxxxxx.)
- too limited, because it cannot express an IPv4-address extension based on dynamic ports, which, as I already discussed in various places, is IMO the most simple choice for a realistic deployment.

For example, no mask and value parameters can express 4-bits address extension based on dynamic ports (i.e. with ports 11EEEExxxxxxxxxx, where Es are the address extension bits).

If no need is identified for more complex solutions than dynamic-ports only, I then propose to amend the document so that parameters are simplified, e.g. but not necessarily to become:
   Port Prefix Length (6 in the above example).
   Port Prefix Value (11EEEE0000000000 in the above example).

Some other set of parameters could be proposed if  a good reason would be found to also use Well-Known ports and/or Registered ports. (I don't see such a reason, while avoiding interference with firewalls is an important reason  against),

Cheers,

RD