Re: [Softwires] I-D Action: draft-ietf-softwire-dual-stack-lite-11.txt

[Daniel Roesen <[e-mail]>]

Hi,

maybe just nitpicking, but...

A.3.  High availability
[...]
   An important element in the design of the Dual-Stack Lite technology
   is the simplicity of implementation on the customer side.  An IP4-in-
   IPv6 tunnel and a default route over it in the B4 element are all is
   needed to get IPv4 connectivity.  It is assumed that high
   availability is the responsibility of the service provider, not the
   customer devices implementing Dual-Stack Lite.  As such, a single
   IPv6 address of the tunnel end-point is provided in the DHCPv6 option
   defined in [I-D.ietf-softwire-ds-lite-tunnel-option].
[...]

This ain't strictly correct.

Unfortunately[1], the DHCPv6 option was changed to provide an FQDN which
then has to be resolved to AAAAs by the B4 chosing one of them in an
unspecified way.

Best regards,
Daniel

[1] now you need working IPv6 DNS resolution to get IPv4 connectivity up
and running (ARGH!), adding unnecessary complexity in B4 initialization
and nondeterministic B4 behaviour in regard of AAAA choice, making any
load balancing mechanism based on returning multiple AAAA infeasible due
to possible biassing. While load balancing could have been achieved via
plain IPv6 address DHCPv6 option just fine, leaving it up to the DHCPv6
server issuing AFTR addresses in a balanced fashion.

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