SONET/SDH Application
User Payload Identifier (UPI): An eight-bit field identifying the
type of payload conveyed in the GFP payload information field:
UPI
0000 0000
Reserved and not available Reserved
1111 1111
0000 0001
Mapped Ethernet Frame
0000 0010
Mapped PPP Frame
Next-Gen - Generic Framing Procedure (GFP)
Client Data
Glossary
Client Management
Client Signal Fail (Loss
of Client Signal)
Client Signal Fail (Loss
of Character
Synchronization)
655