This value indicates the service to be carried over this VC, noting that the exact set of VC types was still being worked out by the working group at the time this MIB was written. This selects what kind of Layer 2 service the pseudowire actually emulates end to end, such as Ethernet, Frame Relay, or ATM, and getting it wrong means the two PE routers expect completely mismatched encapsulations, so a pseudowire configured with the wrong type on one end typically fails to pass traffic correctly even if every other parameter is set up perfectly. For example, configuring this as an Ethernet VC type on one PE while the matching pseudowire on the remote PE is configured for Frame Relay would result in a signaling mismatch or malformed traffic despite both ends otherwise pointing at each other correctly.