Subject: [DMM] Forwarding/Control Plane separation in AERO

From: "Templin, Fred L" <[email-masked]>
Date: Mon, 1 Jun 2015 16:57:14 +0000

Hi,

Much has been said about managing forwarding and control plane separation
in DMM. AERO now has a new method for doing this based on DHCPv6.

In AERO, the control plane is managed by the AERO Server. AERO Clients use
DHCPv6 PD messaging in order to register themselves with AERO Servers and
to update their access network addresses based on mobility events. The
AERO Server in turn maintains PD state for each AERO Client and also provides
default forwarding services for each Client. However, it would be desirable
for Servers to offload forwarding services to Forwarding Agents that can
handle high-speed data plane operations and therefore offload the Server.

In order to support this offload, when the AERO Server prepares a Reply to
a Client's DHCPv6 Request/Renew/Rebind/Release message, it forwards
the Reply to the Forwarding Agent instead of directly to the Client. The
Forwarding Agent then creates forwarding state and returns the Reply
to the Server, which then forwards the Reply to the Client. Now, the Server
and Forwarding Agent both have the necessary state synchronization, or
if any control messages are lost the Client will retransmit. Future data
packets can then flow through the Forwarding Agent without burdening
the Server.

This behavior now documented in Section 3.16 of the AERO spec:

https://datatracker.ietf.org/doc/draft-templin-aerolink/

With this behavior, the AERO Server and Forwarding Agent act as two halves
of a whole router, with the Server handling the control plane and the
Forwarding Agent handling the data plane. Each Server can further associate
with multiple Forwarding Agents if there is a desire to distribute the data
plane function to multiple agents.

This is a simple and effective solution for DMM forwarding and control
plane separation. I would be happy to talk more about this either on
the list or at the upcoming IETF. Comments?

Thanks - Fred
[email-masked]