Re: [Softwires] WG last call on draft-ietf-softwire-public-4over6-01

[Peng Wu <[e-mail]>]

Ole,


> btw, one thing that appears most complicated is provisioning; currently it looks like L4over6 suggests using 2 DHCP sessions and 3 DHCP options to get provisioned. firstly a RFC6334 exchange to get the DS-lite tunnel up, then a DHCPv6 option for the DHCPv4 server address, and then a DHCPv4 exchange to get the IPv4 address, and then a new DHCPv4 option to get the port set. that seems to me to be quite a few moving parts, and quiet a few corner cases to be specified when one or more of the above fails. in MAP you do all of that with one single DHCPv6 option...

Let me make it more precise.

In lw 4over6, It's one DHCPv6 exchange and one DHCPv4 exchange.
DHCPv6 exchange to get the concentrator address and DHCPv4 server
address, two options at the same time. And of course the DHCPv4 server
could be collocated with the concentrator.
DHCPv4 exchange to retrieve the address and port-set at the same time.

Now compared with MAP:
1) Concentrator address is also needed in provisioning.
2) DHCPv4 server address. This is only used when we want to separate
DHCPv4 server from the concentrator (For HA, redundancy...). With MAP
you cannot do this separation.
3) DHCPv4 is used to provision the address and port-set to the
intiator. Now with MAP you provide this as a rule in DHCPv6. That's
the most significant difference

So, I don't see lw4over6 provisioning more complicated than MAP...