EXFO IQS-8100 Series Transport Blazer for IQS-600 - Manual (Page 669)

Glossary
SONET/SDH Application 655
Next-Gen - Generic Framing Procedure (GFP)
³
User Payload Identifier (UPI): An eight-bit field identifying the
type of payload conveyed in the GFP payload information field:
UPI Client Data Client Management
0000 0000
1111 1111 Reserved and not available Reserved
0000 0001 Mapped Ethernet Frame Client Signal Fail (Loss
of Client Signal)
0000 0010 Mapped PPP Frame Client Signal Fail (Loss
of Character
Synchronization)