Frame Relay

Frame Relay: 
A layer 2 WAN technology that sends frames over virtual circuits (VCs) that are identified by (DLCI) Data Link Connection Identifier number.

Virtual Circuit (VC): a logical connection between two ends.

Switched Virtual Circuits (SVC) 
A virtual circuit that is brought up on an as-needed basis

Permanent Virtual Circuit (PVC)
A virtual circuit that is always active

Data-Link Connection Identifier (DLCI)
A locally siginificant number that identifies a virtual circuit (VC)

Point-to-Point Circuit
A single VC interconnecting two endpoints, where both endpoints belong to the same IP subnet

Point-to-Multipoint Circuit
A connection from one end to one or more other endpoints, where all end points belong to the same IP subnet

Service Level Agreement
An agreement between a service provider and their customer, describing the level of  service the service provider guarantees  for a specific connection, which guarantee a minimum level of service

Committed Information Rate (CIR)
A bandwidth amount a service provider guarantees to be available, a certain percentage of the time, on a customer's virtual circuit.

Discard Eligibility (DE) bit
A bit in frame relay frame's header that indicates the frame was sent in excess of the CIR and can be discarded by the service provider if congestion is occurring

Backward Explicit Congestion Notification (BECN)
A bit in a frame relay frame's header used to tell a sender to slow down its transmission rate

Forward Explicit Congestion Notification (FECON)
A bit in a Frame relay frame's header used to tell a receiver to send a frame to the sender, which the service provider will mark with a BECN bit





























Frame_relay will be sending data over DLCI (Data Link connection Identifier) known as layer 2 addresses

Frame - LMI type
R3(config-if)#frame-relay lmi-type ?
cisco
ansi  
q933a

Configuring and verifying  Frame_Relay with GNS3

1. Frame_Switch(config)#frame-relay switching
2. Frame_Switch(config-if)#encapsulation frame-relay
3. Frame_Switch(config-if)#frame-relay intf-type dce 
4. Frame_Switch(config-if)#frame-relay route 102 interface serial 1/1 201
5. Frame_Switch(config-if)#frame-relay route 103 interface serial 1/2 301

1. R1(config-if)#encapsulation frame-relay
2. R1(config-if)#ip address 10.1.1.1 255.255.255.0
3. R1(config-if)#no shut

the same config goes for R2 and R3 

Frame_Switch(config-if)#frame-relay route 102 interface serial 1/1 201

frame-relay                  Set frame relay parameter

route                            frame relay route for pvc switching

<16-1007>                  input dlci to be switched

interface                      outgoing interface for pvc switching

<16-1007>                  output dlci to use when switching