Re: [dhcwg] WGLC for draft-ietf-dhc-dhcpv4-over-dhcpv6-03 - Respond by Dec 9, 2013

"Bernie Volz (volz)" <> Thu, 28 November 2013 14:13 UTC

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From: "Bernie Volz (volz)" <>
To: Cong Liu <>
Thread-Topic: [dhcwg] WGLC for draft-ietf-dhc-dhcpv4-over-dhcpv6-03 - Respond by Dec 9, 2013
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Date: Thu, 28 Nov 2013 14:13:14 +0000
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Subject: Re: [dhcwg] WGLC for draft-ietf-dhc-dhcpv4-over-dhcpv6-03 - Respond by Dec 9, 2013
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Cong, I don't understand this. Server-unicast option can only specify one address.

The 4o6 client has two lists - the "broadcast" list and the "unicast" list. When v4 packet is to be "broadcast", the "broadcast" list is used. When unicast and the unicast list is not empty, it is used; otherwise broadcast list is used. Broadcast list comes from new 4o6 option or the v6 multicast address. Unicast list is empty unless the server's v4 lease that was selected sent a server-unicast option.

Yes, if v4 client sends broadcast, packet could go to multiple servers but that's what happens with native v4.

Anyway, just a thought to reduce traffic for v4 unicast case.

- Bernie (from iPad)

On Nov 28, 2013, at 2:32 AM, "Cong Liu" <<>> wrote:

Hi Bernie,

2013/11/28 Bernie Volz (volz) <<>>
Here's a question we can also ponder ...

Should we perhaps allow the server to send back the Server-Unicast option to tell the 4o6 Client where it can send unicast (DHCPv4) packets to? This would allow DHCPv4 unicast packets to be sent directly to the server (of course inside a BOOTREQUESTV6 message).

Assume IPv6 lease time is 100s, and IPv4 lease time is 200s. Then the 4o6 Client receives a Server-Unicast option (which may contains 10 unicast addresses) every 100s, and a Server-Unicast option (which contains 1 unicast address) every 200s. I think it adds more complexity for client to deal with the same option from different servers (DHCPv6 / DHCP4o6).

Best Regards,
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