[EFM] RE: Pause frame usage in transport networks
Based on 802.3 standard, the PAUSE frames may have an individual or multicast MAC address (including broadcast).
It seems to me if the ONU1 sends PAUSE frames with Dest MAC address of ONU2, then the OLT1 would
relay that to ONU2 (no matter if OLT1 behaves as a transparent box or as a bridge), while if the ONU1
sends a PAUSE frame with Dest MAC address of OLT1 or a multicast MAC address then the PAUSE frames
would be terminated at OLT1 if OLT1 behaves like a bridge.
Eth EOS Eth
In other words for end-to-end OAM, if we know that OLT1 does not terminate any OAM frames, then ONU1 may use either
Dest MAC address of ONU2 or a multicast address, but if we know that OLT1 terminates MAC, then ONU1 should use Dest MAC address of ONU2. To be is safe side it seems that for end-to-end OAM, it is best if ONU1 always sets the Dest MAC address to that of ONU2.