604 Chapter 8: WAN Protocols and Design
Figure 8-37
Cisco and RFC 1490/2427 Encapsulations
Figure 8-38 shows the use of LAPD versus PPP on ISDN BRI B channels.
Figure 8-38
LAPD and PPP on D and B Channels
LAPF
header
LAPF
trailer
Later added to
Q.933-E and T1.617-F;
includes Protocol Type
Field
RFC
1490
Packet
LAPF
header
CISCO
LAPF
trailer
Packet
Includes
DCLI
Fred
Fred
Barney
B0
B1
D
BRI
BRI
LAPD
B0
B1
D
BRI
LAPD
Call Setup
Flows
Call Setup
Flows
Call Setup
Flows
B0
B1
D
LAPD
B0
B1
D
BRI
LAPD
PPP
Barney
ch08.fm Page 604 Monday, March 20, 2000 5:17 PM