Figure 22-8 Protocol Stack Operation - Cisco BPX-BXM-155-8DX Installation And Configuration Manual

Chapter 22 Configuring Frame Relay to ATM Network and Service Interworking

Figure 22-8 Protocol Stack Operation

Q.922 Fr Rly PDU
FR-SSCS PDU
CPCS PDU
SAR PDU
ATM PDU
(adds in 5-byte
header)
FFCI = ForeSight
Physical
(line framing, coding,
physical interface, etc.)
Release 9.3.0, Part Number 78-10674-01 Rev. D0, July 2001
8 7
DLCI upper
DLCI lower
Data field
8 7
DLCI upper
DLCI lower
Data
AAL5 PDU payload
N byte (1-65535)
48-byte PDU
8 7
HCF
00 = STI
VPI
VCI
Congestion
control
(bursty
data)
forward
congestion
indicator
53-byte
ATM cell
BTM Interworking and the ATM Protocol Stack
6 5 4 3
FLAG
FECN BECN
FLAG
6 5 4 3
FLAG
FECN BECN
PAD Length of user data
0-47 byte 2 byte
...........
48-byte PDU
6 5 4 3
VPI
VCI
Payload class
FFCI Re- PTI
served (payload type
indicator)
HEC
48 data byte
53-byte
...........
ATM cell
Cisco BPX 8600 Series Installation and Configuration
2 1
CR EA
DE EA
2 1
CR EA
DE EA
Trailer
CRC32
4 byte
48-byte PDU
2 1
5-byte
CLP
header
(cell
loss
prior-
ity)
53-byte
ATM cell
22-9