What is Frame-Relay
Frame relay in computer
networks is a packet-switching technology that mainly operates at the data link
layer. Using virtual circuits. Frame-Relay is a WAN technology such as
Lease-line, Circuit-Switching (ISDN), and Packet Switching (Frame-Relay, ATM,
X.25, and MPLS). It is cheaper costs than leased lines and X.25. It is also
compatible with both MPLS and ATM, which are known as WAN technologies.
But now there are new
technologies like Ethernet, MPLS, VPN, DSL, and cable modems, which provide
higher bandwidth, better security, and greater flexibility, but are not widely used
today. However, some enterprises still use frame relay even though it is no
longer the most widely used WAN technology because they have traditional
hardware or applications that need it.
Frame-Relay Component:
DLCI (Data Link Connection Identifier): DLCI is a 10-bit space that indicates
the virtual circuit between the source and destination devices. DLCI no.
started from 16 to 1007 provided by the service provider for making virtual circuits
between two sites.
Committed Rate: The C/R field is a command/response bit that is used for
control frames.
Extended Address: When the DLCI value in the default Frame Relay header is
insufficient to identify a virtual circuit accurately, the Extended Address
field is utilized.
Congestion Control: It is divided into three parts-
- FECN: FECN (Forward explicit congestion notification)
is a bit that informs the destination devices about the congestion in the
network.
- BECN: BECN (Backward explicit congestion notification)
is a bit that informs the source device about the congestion in the
network.
- DE: (Discard eligibility) is the ability that indicates
whether a frame can be discarded or not during congestion in the network.
Flag: The flag field
is an 8-bit pattern that marks the beginning and end of a frame.
FCS: (Frame check sequence)
guarantees the integrity of the data that is transferred. The source device
computes this value to ensure transmission integrity, which the receiver then
verifies.
Frame-Relay Virtual Circuit types-
PVC (Permanent Virtual Circuit)- It is a permanent virtual circuit that provides logical connectivity between two devices. It provides low latency and better bandwidth.
SVC (Switch Virtual Circuit)- It is a temporary virtual circuit that provides logical connectivity between two devices. It is dynamically established on demand such as cell phone networks.
Frame-Relay Layers-
Data link- it is responsible for creating virtual circuits between devices so that DLCI can identify virtual connections. It is also responsible for creating frames and detecting errors and congestion.
Physical- it terminates physical connectivity between devices. It includes cable connection and raw bits of signals.
Frame-Relay Proc and Cons-
Frame-Relay is a cost-effective WAN technology. Better than X.25 and ATM protocol. Not providing flow control and not giving acknowledgment.
How to configure Frame-Relay
Learn how to configure Frame-Relay for Hub and Spoke network with Eigrp routing.
Watch YouTube video -
https://www.youtube.com/watch?v=R57yCHR5Kd4&t=1s
Steps to Configure Frame-Relay -
1. Assign IP to add to all router's serial and Fast Ethernet interface.
R1 Configuration
Router>enable
Router#configure terminal
Router(config)#interface FastEthernet0/0
Router(config-if)#ip address 10.0.0.1 255.0.0.0
Router(config-if)#interface Serial0/0
Router(config-if)#no ip address
Router(config-if)#encapsulation frame-relay
Router(config-if)#no shut
Router(config-if)#interface Serial0/0.1 point-to-point
Router(config-if)#ip address 1.1.1.1 255.255.255.0
Router(config-if)#frame-relay interface-dlci 102
Router(config-if)#interface Serial0/0.2 point-to-point
Router(config-if)#ip address 2.1.1.1 255.255.255.0
Router(config-if)#frame-relay interface-dlci 103
Router(config-if)#interface Serial0/0.3 point-to-point
Router(config-if)#ip address 3.1.1.1 255.255.255.0
Router(config-if)#frame-relay interface-dlci 104
Router(config-router)#router eigrp 10
Router(config-router)#network 10.0.0.0
Router(config-router)#network 1.0.0.0
Router(config-router)#network 2.0.0.0
Router(config-router)#network 3.0.0.0
Router(config-router)#no auto-summary
R2 Configuration
Router>en
Router#conf t
Router(config)#int se 0/0 po
Router(config)#int se 0/0
point-to-point
Router(config-if)#encapsulation
frame-relay
Router(config-if)#frame-relay
interface-dlci 201
Router(config-if)#ip add 1.1.1.2
255.255.255.0
Router(config-if)#no shut
Router(config-if)#ip add 20.0.0.1
255.0.0.0
Router(config-if)#no shut
Router(config-if)#do wr
Building configuration...
[OK]
Router(config-if)#do sh ip int br
Router(config-if)#router eigrp 10
Router(config-router)#net 20.0.0.0
Router(config-router)#net 1.0.0.0
Router(config-router)#no auto-summary
Router(config-router)#do wr
Building configuration...
[OK]
Router(config)#int se 0/0
point-to-point
Router(config-if)#encapsulation
frame-relay
Router(config-if)#frame-relay
interface-dlci 301
Router(config-if)#ip add 2.1.1.2
255.255.255.0
Router(config-if)#no shut
Router(config-if)#int fastethernet 0/0
Router(config-if)#ip add 30.0.0.1
255.0.0.0
Router(config-if)#no shut
Router(config-if)#do wr
Building configuration...
[OK]
Router(config-if)#do sh ip interface brief
Router(config-if)#router eigrp 10
Router(config-router)#net 30.0.0.0
Router(config-router)#net 2.0.0.0
Router(config-router)#no auto-summary
Router(config-router)#do wr
Building configuration...
[OK]
R4 Configuration
Router#configure terminal
Router(config)#int se 0/0 point-to-point
Router(config)#int se 0/0
point-to-point
Router(config-if)#encapsulation
frame-relay
Router(config-if)#frame-relay
interface-dlci 401
Router(config-if)#ip add 3.1.1.2
255.255.255.0
Router(config-if)#no shut
Router(config-if)#int fastethernet 0/0
Router(config-if)#ip add 40.0.0.1
255.0.0.0
Router(config-if)#no shut
Building configuration...
[OK]
Router(config-if)#do sh ip int br
Router(config-if)#router eigrp 10
Router(config-router)#net 40.0.0.0
Router(config-router)#net 3.0.0.0
Router(config-router)#no au
Router(config-router)#do wr
Building configuration...
[OK]
https://technical-rock.blogspot.com/2023/12/frame-relay-network.html
