nanog mailing list archives

Re: DHCPv6-PD relay route injection - standard?


From: Tim Howe <tim.h () bendtel com>
Date: Fri, 17 May 2019 11:41:44 -0700

On Tue, 14 May 2019 22:27:09 -0400
Brandon Martin <lists.nanog () monmotha net> wrote:

Is there a standard that defines/recommends behavior for route injection 
of snooped DHCPv6-PD (or IA, I guess) assignments on routers running 
relay agents?  That is, snooping or otherwise examining a relayed DHCPv6 
response for a delegated prefix (or IA, if you want) and installing a 
quasi-static route toward the relevant next-hop based on the lifetime of 
the delegation.  Typical redistribution can then be used to put it in 
IGP if you want.

It seems to be a common feature - Cisco ("Relay Agent Notification" on 
IOS-XE), Juniper ("DHCPv6-PD Route injection" on JunOS), and Arista 
("ipv6 dhcp relay install routes" on EOS), and Ruckus ("Relay Agent 
Prefix Delegation Notification" on FastIron) all seem to support it.

Google has, however, failed me at finding any standard that defines or 
recommends corresponding behavior.  RFC 8415 punts on the issue:


        I went through that same search a little over a year ago.  I'm
curious if you got any off-list replies of interest.  We use dhcpv6
relay on Juniper ACX5048 (should be same on MX series).  It did not
work out of the box for me; Juniper had to fix a fundamental way it
worked in order to work with some clients (pretty much anything
Broadcom based at least).  I'm running working code now (17.4R2.4).  I
was very pleased Juniper took the problem so seriously and fixed it...
That hasn't been my experience with every vendor.

        I can provide some info about how it works and what "working"
looks like if you are curious.  Getting native dual-stack fully working
has been a long, strange road as a small ISP.  I'm thinking about
writing something up about my experience so far.

--TimH


Current thread: