Ethernet OAM BCPs Please are there any yet???

[Adam Vitkovsky <adam.vitkovsky () swan sk>]

Hi
Are there any best common practices for the CFM levels use
Since my pure Ethernet aggregation layers are small I believe I only need
two CFM levels 
I plan on using Level 5 between CPEs managed by us and Level 4 between
Aggregation devices -that's where MPLS PWs kicks in
So leaving Level 7 and Level 6 for customers and carrier-customers
respectfully -would this be enough please?

I'm also interested on what's the rule of thumb for CCMs Frequency, Number
of Packets, Interpacket Interval, Packet Size and Lifetime for the
particular operation
Thanks a lot for any inputs


adam