LAPF (Link Access Procedure for Frame Mode Services)

Pronounced lap ef. A bit-oriented pro-

tocol that is part of the frame relay protocol suite, LAPF is a subset High-level Data Link Control (HDLC) and runs at Layer 2, the Data Link Layer, of the OSI Reference Model. The LAPF frame comprises a header and trailer that frame the user payload. Figure L-3 illustrates the LAPF frame and its component fields.

1

2

0–4096

2

1 octets

Frame

Flag

Address

Information

Flag

check

(01111110)

field

field

(01111110)

sequence

DLCI (high order)

C/R

EA

DLCI (low order)

FECN

BECN

EA

DE

0/1

0

1

• 802.3ak
• 802.3an
• 802.3u
• 802.3z
• 802.4
• 802.4
• 802.5
• 802.5
• 802.6
• 802.7
• 802.8
• 802.9
• 850 Band
• 866
• 877
• 888
• 8B/10B (8 Bits/10 Bits)
• 8B/10B (8 Bits/10 Bits)
• 8B/10B (8 Bits/10 Bits)
• 8-level vestigial sideband (8-VSB)
• 8-Phase Shift Keying (8-PSK)
• 8-PSK (8-Phase Shift Keying)
• 8-VSB (8-level vestigial sideband)
• 9
• 900