Pertemuan 24
Frame Relay Concepts
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Discussion Topics
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Introducing Frame Relay
Frame Relay terminology
Frame Relay stack layered support
Frame Relay bandwidth and flow control
Frame Relay address mapping/topology
Frame Relay LMI
Stages of Inverse ARP and LMI operation
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Frame Relay Operation
Frame Relay Switches
Frame Relay Concepts
Virtual Circuits
Local Significance of DLCIs
The data-link connection identifier (DLCI) is stored
in the Address field of every frame transmitted.
Terminology
• The connection through the Frame Relay network
between two DTEs is called a virtual circuit (VC).
• Virtual circuits may be established dynamically by
sending signaling messages to the network. In this
case they are called switched virtual circuits (SVCs).
• Virtual circuits can be configured manually through
the network. In this case they are called permanent
virtual circuits (PVCs).
Frame Relay Stack Layered
Support
Frame Relay Functions
Bandwidth and Flow Control
Bit counter Example 1
Frame Relay Concepts
Queue
Frame Relay Concepts
Frame Relay Concepts
Selecting a Frame Relay
Topology
Full Mesh
Partial Mesh
Star (Hub and Spoke)
LAPF Frame – Address Field
6-bits
4-bits
Data Link Control Identifier
• The 10-bit DLCI associates the frame with its virtual
circuit
• It is of local significance only - a frame will not generally
be delivered with the same DLCI with which it started
• Some DLCI’s are reserved
Local Management Interface
(LMI)
• Three types of LMIs are supported by Cisco routers:
– Cisco — The original LMI extensions
– Ansi — Corresponding to the ANSI standard
T1.617 Annex D
– q933a — Corresponding to the ITU standard
Q933 Annex A
LMI Frame Format
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Flag
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Address
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Control
PD
CR
MT
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LMI Message
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FCS Flag
Stages of Inverse ARP and
LMI Operation #1
Stages of Inverse ARP and
LMI Operation #2