HP 200 Series Services And Applications page 284

Linking Up with Frame Relay
Frame Relay Data-Link Interface
Frame Relay Data-Link Interface
Table 1 shows the structure of frames transmitted by HP routers on Frame
Relay networks. This frame structure was defined in the FRF's "Frame Relay
Specification". The frame structure was based upon CCITT Recommenda-
tion Q.921, "LAPD", and from work being done in the ISDN area and in the
ANSI committee T1S1. It was then standardized by ANSI in Standard T1.618
and by the CCITT in Recommendation Q.922. Q.922 is also referred to as
"Link Access Procedure to Frame Mode Bearer Service (LAPF)". In this
document, we will refer to the Frame Relay frame structure as Q.922.
Table 1. Q.922 Frame Structure
Octet 1
Octet 2
Octet 3
Octet 4
Octet 5
Octet 6
Octet 7
Octet N-3
Octet N-2
Octet N-1
Octet N
A standardized procedure for transmitting multiprotocol data over Frame
Relay was defined in Internet RFC 1294, "Multiprotocol Interconnect over
Frame Relay". The shaded fields in table 1 are defined by RFC 1294. RFC
1294 defines standard procedures for sending multiprotocol (connectionless
network-layer) data over Frame Relay networks. All popular LAN protocols
such as TCP/IP, Novell IPX, and AppleTalk have connectionless network
layers. RFC 1294 does not address interconnecting connection-oriented
protocols such as IBM's SNA over Frame Relay.
3-90
8 7 6 5 4
Flag (7E hex)
Q.922 Address
Q.922 Address
Control (UI=03 hex)
Optional Pads (00 hex)
NLPID
Data
Frame Check Sequence
Frame Check Sequence
Flag (7E hex)
3 2 1