Hi, all,
1.
The translation-based stateless solution for IPv4 via IPv6 described in
draft-murakami-softwire-4v6-translation-00 seems to have a significant
limitation:
- When a 4V6T customer-edge node receives a packet from a CE of the same 4V6T
domain, it doesn't know whether it must treat it as a native IPv6 packet from
this CE or as an IPv4 packet that this CE has translated.
<-- 4V6T domain --> <-- IPv4 Internet --
(A) 4V6T CE |---->----.
|
V---- 4v6T-BR --- - - -
|
(B) 4V6T CE |----<----'
<= v4 or v6 ??
For instance, if the IPv4 address of (B) is shared, (B) doesn't know whether
received packets must go to its internal NAT44, or be treated a real IPv6
packet.
(Sending to the NAT44 packets whose ports are currently bound in the NAT44
wouldn't be satisfactory: all ports may be used in IPv6).
2.
Note that this problem doesn't apply to the encapsulation-based stateless
solution (4V6E):
- A 4V6E CE treats a received IPv6 packet as containing an IPv4 packet if, and
only if, its Next header is IP-in-IP, and the encapsulated packet is IPv4.
There is no ambiguity.
=> Unless something is wrong in the above, or a palliative is devised,
consideration of this should be added to the comparative analysis of 4V6T and
4V6E solutions (draft-dec-stateless-4v6).
Regards,
RD
_______________________________________________
Softwires mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/softwires
