1. Optional FCS Retention for Ethernet, Frame Relay, and HDLC/PPP Port Mode
Current specifications leave payloads vulnerable to undetected accidental or deliberate alterations in the encapsulating network
Provide end customers a service where transparency and non-alteration of end-to-end frames is guaranteed
Security enhancement
Optional for vendors and service providers
Signaling is backward compatible with current drafts
Nothing comes for free; adds the overhead of transporting the FCS end-to-end in every frame

2. draft-malis-pwe3-fcs-retention-00.txt
From Andrew Malis, David Allan, Nick Del Regno
Distributed on mailing list this morning, will be submitted following Minneapolis meeting
Default behavior is that FCS is NOT retained
Defines a new VC element parameter ID, FCS Retention Indicator, used to signal the desire to retain the FCS when advertising a VC label
FCS is retained in either direction ONLY if the FCS Retention Indicator has been included in the label mapping messages for both directions on a pseudowire
Backwards compatible, since unknown parameter IDs are silently ignored