Wednesday, 26 June 2013

How to configure Frame Relay

How to configure Frame Relay

Configuring Frame Relay involves the following steps:

Change the encapsulation

Go in interface mode and select the Frame Relay encapsulation on the interface. There are two types of Frame Relay encapsulations: Cisco and IETF. Cisco is the default. Syntax to set your encapsulation is
 encapsulation frame-relay [ietf] 

Configure LMI type

The three LMI types are Cisco, Ansi, and Q933a. For IOS 11.2 and higher, the LMI type is automatically detected
 frame-relay lmi-type [cisco | ansi | 933a] 

Configure Frame Relay map

configuring a static Frame Relay map, is optional unless you are using subinterfaces. The Frame Relay map will map a Layer 3 address to a local DLCI. This step is optional because inverse-arp will automatically perform this map for you. The syntax for a Frame Relay map is as follows:
frame-relay map protocol address dlci [broadcast] [cisco | ietf]

Configure subinterfaces

If you are using a routing protocol in a hub-and-spoke topology, you will probably want to use subinterfaces to avoid the split-horizon problem. To configure a subinterface, remove the IP address off the main interface and put it under the subinterface. Configuring a subinterface involves assigning it a number and specifying the type. The following command creates point-to-point subinterface serial0/0.1
 Router(config)#interface serial0/0.1 point-to-point 
To create a multipoint subinterface, enter multipoint instead:
 Router(config)#interface serial0/0.1 multipoint 

Assign IP address to subinterface

After entering one of these commands you will be taken to the subinterface configuration mode where you can enter your IP address:
Router(config-subif)#ip address 
If you are using a multipoint subinterface, you will need to configure frame-relay maps and you cannot rely on inverse-arp.
If you are using a point-to-point subinterface, you will need to assign a DLCI to the subinterface. This is only for point-to-point subinterfaces; this is not needed on the main interface or on multipoint subinterfaces. To assign a DLCI to a point-to-point subinterface, enter the following command under the subinterface:
 frame-relay interface-dlci dlci 

Configuration of Frame Relay

Lets practically implement whatever you learn so far. Download this pre configured topology and load it in packet tracer.
Now first configure R1. Fast Ethernet port and hostname is already configured. Double click on R1 and configure serial port for frame relay encapsulation and further create sub interface for connecting R2, R3, R4. Configure also static route for connecting remaining network.

Configure R1

R1#configure terminal
R1(config)#interface serial 0/0/0
R1(config-if)#encapsulation frame-relay
R1(config-if)#no shutdown
R1(config-subif)#interface serial 0/0/0.102 point-to-point
R1(config-subif)#ip address
R1(config-subif)#frame-relay interface-dlci 102
R1(config)#interface serial 0/0/0.103 point-to-point
R1(config-subif)#ip address
R1(config-subif)#frame-relay interface-dlci 103
R1(config)#interface serial 0/0/0.104 point-to-point
R1(config-subif)#ip address
R1(config-subif)#frame-relay interface-dlci 104
R1(config)#ip route
R1(config)#ip route
R1(config)#ip route

configure R2

R2#configure terminal
R2(config)#interface serial 0/0/0
R2(config-if)#encapsulation frame-relay
R2(config-if)#no shutdown
R2(config)#interface serial 0/0/0.101 point-to-point
R2(config-subif)#ip address
R2(config-subif)#frame-relay interface-dlci 101
R2(config)#ip route

configure R3

R3#configure terminal
R3(config)#interface serial 0/0/0
R3(config-if)#encapsulation frame-relay
R3(config-if)#no shutdown
R3(config)#interface serial 0/0/0.101 point-to-point
R3(config-subif)#ip address
R3(config-subif)#frame-relay interface-dlci 101
R3(config)#ip route

configure R4

R4#configure terminal
R4(config)#interface serial 0/0/0
R4(config-if)#encapsulation frame-relay
R4(config-if)#no shutdown
R4(config)#interface serial 0/0/0.101 point-to-point
R4(config-subif)#ip address
R4(config-subif)#frame-relay interface-dlci 101
R4(config)#ip route
now verify by doing ping from pc0 to all pc. It should be ping successfully. I have uploaded a configured topology but use it as the final resort first try yourself to configure it.
Router(config)#interface serial 0/0/0
Enter in interface mode
Router(config-if)#encapsulation frame-relay
Turns on Frame Relay encapsulation with the default encapsulation type of cisco
Router(config-if)#frame-relay lmitype {ansi | cisco | q933a}
Depending on the option you select, this command sets the LMI type to the ANSI standard, the Cisco standard, or the ITU-T Q.933 Annex A standard.
Router(config-if)#frame-relay interface-dlci 110
Sets the DLCI number of 110 on the local interface and enters Frame Relay DLCI configuration mode
Returns to interface configuration mode
Router(config-if)#frame-relay map ip 110 broadcast
Maps the remote IP address ( to the local DLCI number (110). The optional broadcast keyword specifies that broadcasts across IP should be forwarded to this address. This is necessary when using dynamic routing protocols.
Router(config-if)#no frame-relay inverse arp
Turns off Inverse ARP.
Router#show frame-relay map
Displays IP/DLCI map entries
Router#show frame-relay pvc
Displays the status of all PVCs configured
Router#show frame-relay lmi
Displays LMI statistics
Router#clear frame-relay counters
Clears and resets all Frame Relay counters
Router#clear frame-relay inarp
Clears all Inverse ARP entries from the map table
Router#debug frame-relay lmi
Used to help determine whether a router and Frame Relay switch are exchanging LMI packets properly

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