GFP-T vs GFP-F | Difference between GFP-T and GFP-F
This page compares GFP-T vs GFP-F and mentions difference between GFP-T and GFP-F modes. GFP is the short form of Generic Frame Protocol.
These are two adaptation modes used to carry client data in the GFP frames. GFP-F is applicable to most packet data types. GFP-T is applicable to 8B/10B coded signals.
GFP-F mode
• GFP-F maps each client frame into single GFP frame.
GFP-F is used where client signal is framed or
packetized by client protocol.
• GFP-F is the short form of Frame Mapped GFP.
• It is good for PDU-based protocols viz. ethernet, IP, MPLS or HDLC based protocols viz. PPP.
• Client PDU is placed in GFP payload field.
GFP-T mode
• GFP-T allows mapping of multiple 8B/10B
block coded client data streams into an efficient
64B/65B block code for transport within a GFP frame.
• GFP-T is the short form of Transparent GFP.
• It is good for protocols which exploit physical layer capabilities.
• GFP-T is transparent to codes such as 8B/10B, GbE, FICON, ESCON, DVB etc.
Moreover GFP-T need not require entire PDU to be received.

The figure-1 depicts GFP-F and GFP-T frame structures. Following table mentions comparison GFP-T and GFP-F modes.
Specifications | GFP-T | GFP-F |
---|---|---|
Full form | Transparent GFP | Frame mapped GFP |
Function | It maps bytes from frame to SONET frames. | It maps frames (such as ethernet) to SONET frames. |
Protocol transparency | High | Low |
Efficiency | Low | High |
Encapsulation protocol level | Layer-1 (PHY) | Layer-2 (PDU) |
Isocronic or delay sensitive | YES | NO |
Optimized for | SAN, DVB | Ethernet |
Statistical multiplexing of several client signals | NO | YES |
SAN transport | YES | NO |
Ethernet transport | POSSIBLE | OPTIMUM |
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