- Packet-switching protocol
- DCLI’s are local – layer 2 addressing. Not advertised to other routers
- Permanent virtual circuit (PVC) – Dedicated circuit always up
- Switched virtual circuit (SVC) – Temporary circuit that is only up for example during a data transfer session
- Three LMI types cisoc, ansi and q933a
- Local Management Interface (LMI) – passes information about the status of the circuit. Must match on the DCE (Provider) and DTE end
- non-broadcast multi-access (NBMA) – broadcasts are not sent over frame-relay by default
- inverse ARP – Used to allow dynamic mapping. On by default can be turned off using no frame-relay inverse-arp
- Split horizon – Stops rouging updates such as RIP from being sent out of the same interface it was received on. Turning off split horizon may cause routing loops
- Sub-interfaces can overcome the split horizon by creating sub interfaces out of a serial interface. This gets around the problem of a routing update being sent and received out of the same interface. Sub-interfaces can either be point-to-point or multipoint
Show commands:
- show frame-relay map – Table of frame maps, shows dlci and lmi information
- show frame-relay lmi – Shows configured LMI type, if timeouts occur and increase could indiciate a lmi mis-match
- show frame-relay pvc – Shows BECN and FECN information
Debug commands:
- debug frame-relay lmi – myseq increments but yourseen doesn’t indicates lmi mismatch
Frame relay point-to-point
R1:
interface Serial2/0 no ip address encapsulation frame-relay interface Serial2/0.301 point-to-point ip address 10.0.1.1 255.255.255.0 frame-relay interface-dlci 301 interface Serial2/0.302 point-to-point ip address 10.0.3.1 255.255.255.0 frame-relay interface-dlci 302 router rip network 10.0.0.0
R2:
interface Serial2/0 no ip address encapsulation frame-relay interface Serial2/0.102 point-to-point ip address 10.0.2.2 255.255.255.0 frame-relay interface-dlci 102 interface Serial2/0.103 point-to-point ip address 10.0.1.2 255.255.255.0 frame-relay interface-dlci 103 router rip network 10.0.0.0 network 192.168.0.0
R3:
interface Serial2/0 no ip address encapsulation frame-relay interface Serial2/0.201 point-to-point ip address 10.0.2.1 255.255.255.0 frame-relay interface-dlci 201 interface Serial2/0.203 point-to-point ip address 10.0.3.2 255.255.255.0 frame-relay interface-dlci 203 router rip network 10.0.0.0 network 172.16.0.0
Frame relay multipoint
R1:
interface Serial2/0 ip address 10.0.1.1 255.255.255.0 encapsulation frame-relay frame-relay map ip 10.0.1.2 301 broadcast router rip network 10.0.0.0
R2:
interface Serial2/0 ip address 10.0.1.2 255.255.255.0 encapsulation frame-relay router rip network 10.0.0.0 network 192.168.0.0
R3:
interface Serial2/0 ip address 10.0.1.2 255.255.255.0 encapsulation frame-relay network 10.0.0.0 network 172.16.0.0