Thank you for your liaison titled “MPLS-TP support for MCC and SCC”, dated
February 11, 2009.
In your liaison, you are asking Q14/15 “to communicate the entire set of
specific requirements for transport of MCC and SCC packets on the G-ACh”.
Please find a list of requirements below that the G-ACh
(draft-ietf-mpls-tp-gach-gal) together with the new Internet-Draft
draft-beller-mpls-tp-gach-dcn shall satisfy for building a Management
Communication Network (MCN) and a Signalling Communication Network (SCN):
1. A packet encapsulation mechanism must be provided to support the transport
of MCN and SCN packets over the G-ACh.
2. The G-ACh carrying the MCN and SCN packets shall support the following
a. The G-ACh interconnects two adjacent MPLS-TP nodes (used when the server
layer does not provide a Management Communication Channel (MCC) or a
Signalling Communication Channel (SCC)).
b. The G-ACh is carried by a MPLS-TP tunnel that traverses another operator’s
domain (carrier’s carrier scenario)
3. The G-ACh shall provide two independent channels: a MCC to build the MCN
and a SCC to build the SCN. The G-ACh packet header shall indicate whether the
packet is a MCC or an SCC packet in order to forward it to the management or
control plane application for processing.
4. The channel separation mechanism shall allow the use of separate rate
limiters and traffic shaping functions for each channel (MCC and SCC) ensuring
that the flows do not exceed their assigned traffic profile. The rate limiter
and traffic shaper are outside the scope of the MCC and SCC definition.
5. The G-ACh that carries the MCC and SCC shall be capable of carrying
different OSI layer 3 (network layer) PDUs. These shall include IPv4, IPv6,
and OSI PDUs. The G-ACh header of the MCC/SCC packet shall indicate which
layer 3 PDU is contained in the payload field of the packet such that the
packet can be forwarded to the related layer 3 process within the management
and control plane application, respectively, for further processing.
6. The G-ACh is not required to provide specific security mechanisms. However,
the management or control plane protocols that operate over the MCC or SCC are
required to provide adequate security mechanisms in order not to be
susceptible to security attacks.