Hi Reinaldo, all,
I read the updated version of draft-penno-softwire-sdnat. I like this new
version. Below some questions for clarification:
(1) draft-penno is converging to what is documented in
draft-cui-softwire-b4-translated-ds-lite:
(*) Question 1: It is not clear in text if there is a second NAT
in the AFTR or not. Could you please confirm/infirm a second NAT
is present?
(*) Question 2: If yes, is there any reason why you want to
maintain that second NAT?
(*) Question 3: If the public IP address assigned by the AFTR is
not known to the port-restricted CPE, some applications may fail
(referral). How the CPE will make a distinction between the
external IP address to be assigned in the WAN and the one used in
the AFTR? If UPnP is used, the WAN IP address should not be
returned.
(2) Unlike draft-penno-*, draft-cui-* does not mandate any proffered
provisioning means for port ranges; a list of alternatives is
provided in draft-cui-* without any preference (this is deployment-
specific):
o DHCPv4: the DHCPv4 protocol should be extended to support port-set
allocation
[I-D.bajko-pripaddrassign<http://tools.ietf.org/html/draft-cui-softwire-b4-translated-ds-lite-05#ref-I-D.bajko-pripaddrassign>].
Besides, the DHCP message
should send to the concentrator over IPv6. The concentrator can
be the DHCP server or DHCP relay
agent[I-D.ietf-dhc-dhcpv4-over-ipv6].
o PCP[I-D.ietf-pcp-base]: an initiator can launch multiple PCP
requests simultaneously to acquire a number ports within the same
IPv4 address, or use
[I-D.tsou-pcp-natcoord<http://tools.ietf.org/html/draft-cui-softwire-b4-translated-ds-lite-05#ref-I-D.tsou-pcp-natcoord>]
for one-time port-set
allocation.
o DHCPv6: the DHCPv6 protocol should be extended to support port-set
allocation
[I-D.boucadair-dhcpv6-shared-address-option<http://tools.ietf.org/html/draft-cui-softwire-b4-translated-ds-lite-05#ref-I-D.boucadair-dhcpv6-shared-address-option>].
o IPCP: IPCP should be extended to carry the port-set.
[RFC6431<http://tools.ietf.org/html/rfc6431>]
gives an example.
(*) Question 4: Given this list, is there really a need for the
proposed ICMP-based solution?
(*) Question 5: draft-penno-* says: "A stateless DS-Lite CPE MUST
implement the DHCPv4 client relay option defined in [I-D.ietf-dhc-
dhcpv4-over-ipv6] to learn is external IPv4 address.".
Question 5-1: Why "MUST"? IMHO, this is deployment-specific.
Question 5-2: By "external IPv4 address", do you mean the
address to be assigned in the AFTR (if any)? or the one to be
used in the WAN interface of the CPE?
(3) draft-penno-* advocates it is deterministic but this feature can
be enforced in any IPv4 address sharing technique:
(*) Question 6: Is there any particular reason draft-penno-* does
not mention draft-donley-behave-deterministic-cgn?
Cheers,
Med
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