CCNA 4 v3.0 Module 5
Frame Relay
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Objectives
• Frame Relay concepts
• Configuring Frame Relay
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Frame Relay Operation
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Frame Relay Switches
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Frame Relay Concepts
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Local Significance of DLCIs
The data-link connection identifier (DLCI) is stored
in the Address field of every frame transmitted.
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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).
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Frame Relay Stack Layered Support
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Frame Relay Functions
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Bandwidth and Flow Control
Bit counter Example 1
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Frame Relay Concepts
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LAPF Frame
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Full-Mesh Topology
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Frame Relay Mesh
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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
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Stages of Inverse ARP and
LMI Operation #1
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Stages of Inverse ARP and
LMI Operation #2
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Configuring Basic Frame Relay
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Configuring a Static Frame Relay Map
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Reachability Issues with Routing Updates
in NBMA
By default, a Frame Relay network provides nonbroadcast
multiaccess (NBMA) connectivity between remote sites.
An NBMA environment is treated like other multiaccess
media environments, where all the routers are on the
same subnet.
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Frame Relay Subinterfaces
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Configuring Point-to-Point Subinterfaces
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Verifying Frame Relay
• The show interfaces command displays
information regarding the encapsulation
and Layer 1 and Layer 2 status. It also
displays information about the following:
The LMI type
The LMI DLCI
The Frame Relay data terminal
equipment/data circuit-terminating
equipment (DTE/DCE) type
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The show frame-relay lmi Command
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The show frame-relay pvc Command
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The show frame-relay map Command
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Troubleshooting Frame Relay
• Use the debug frame-relay lmi
command to determine whether the router
and the Frame Relay switch are sending
and receiving LMI packets properly.
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