[pcp] How to guarantee the same PCP/AFTR be selected in ip-in-ip anycast deployment

[Qiong <[e-mail]>]

Hi all,

I'm aware there was discussion on whether to use native IPv6 or ip-in-ip
for PCP. Sorry to re-open the discussion since  we have encountered real
problems when deploying anycast-based DS-Lite.

In our DS-Lite deployment, different AFTRs will be configured with the same
address to support load-balancing and announced with the same metric into
IGP. PCP server is co-located with AFTR, and there are multiple layer-3
hops between B4 and AFTR.

Currently, most intermediate routers along the path use 5-tuple by default
(source address, destination address, source port, destination port and
protocol) as the hashing index for native IPv6 PCP requests to determine
which PCP server will be selected. However, since the following data
traffic is ip-in-ip, the intermediate routers can not see the encapsulated
port numbers and they can only use 3-tupe (source address, destination
address, protocol) as the hashing index. In this case, there is no
guarantee that the same PCP/AFTR will be selected as the hashing index is
different, and therefore, the mapping will not consistent with different
AFTRs.

I'm hoping to find solutions to address this problem. Should we use
consistent PCP transportation as the following data traffic, e.g. ip-in-ip
in DS-Lite ?

Thanks in advance !

Best wishes
-- 
==============================================
Qiong Sun
China Telecom Beijing Research Institude


Open source code:
lightweight 4over6: *http://sourceforge.net/projects/laft6/*
PCP-natcoord:* http://sourceforge.net/projects/pcpportsetdemo/ *
===============================================