Reply to MEF 27033-001 (From MEF NID)

The IEEE 802.1 Interworking Task Group thanks the MEF for the liaison, and encourages 802.1 members to continue to contribute to this work.

The question of the MIP has been considered by the Interworking
Task Group as a ballot comment on P802.1aj D3.1 at the IEEE 802
plenary meeting in Dallas, Texas, this week.  The purpose of
the default MIP is to permit a MEP in a non-TPMR to easily explore
an entire network, perhaps including chains of TPMRs, using an
802.1ag Linktrace Message.  The default configuration for an MEF
NID is, of course, a matter to be settled by the MEF.

The disposition of this comment is that Draft 3.2 of P802.1aj will
specify a default configuration for a TPMR Maintenance Domain at
MD Level 0, with MIPs enabled at MD Level 0 on both ports.  This
default configuration can always be overridden by explicit
reconfiguration of Connectivity Fault Management in a TPMR.

IEEE Std. 802.1ag-2007 Clause 22.1.7 addresses "Maintenance Points
and non-VLAN aware Bridges".  Figure 22-7 shows the position of
Maintenance Points on an 802.1D bridge, which is VLAN unaware, and
very similar to an 802.1aj TPMR.  This figure and the text of 22.1.7
indicate that:

  1. Up MEPs, MIPs, and Down MEPs can all be created above the
     Support of the MAC Service (Figure 22-7).

  2. Only Down MEPs can be created below the Support of the MAC
     Service.

The implication is that, since there are no VLAN tags, all Down MEPs
in the upper position are configured at higher MD
Levels than those in the lower position.

The next draft of P802.1aj, Draft 3.2, will include an explanation
of the relationship between the MAC Status shim and Maintenance
Point shims, along with one or more figures to clarify the
positions of Maintenance Points and the MAC Status shim in a
Two Port MAC Relay.

Thank you for pointing out these issues.