Frame Relay PVC Connection

by

Li , Sheng

104419

Wide-Area Network(WAN)

Wide-area Network

WAN connection type

Leased lines

Circuit switched

Packet switched

WAN connection typeLeased Lines—also known as a point-to-point or dedicated connection,provides a single preestablished WAN communications path from the customerpremises through a service provider network to a remote network .This connection is reserved by the service provider for the client’s private use. Leased lines are very fast but they are also costly.

WAN connection typeCircuit switched –circuit switched is a WAN switching method in which a dedicated circuit path must exist between sender and receiver for the duration of the call. Circuit-switched connection are commonly used in environments that require onlysporadic WAN usage. For example, It is used by service provider network when providing ISDN , and it is cheap one.

WAN connection typePacket switched—Packet switched is a WAN switching method in which networkdevices share a single point to point link to transport packets from a source to a destination across a carrier network. Packet switching offers services similar to Those of leased lines, except the line is shared, and the cost of the service is lower. But the cost of the service is higher than circuit switched connection types.

WAN connection type

Wan layer2 encapsulation type

Wan layer2 encapsulation type

Leased line : HDLC, PPP, SLIP

Circuit-Switched: HDLC, PPP, SLIP

Packet-Switched: X.25, Frame Relay,ATM

Frame Relay is a data link layer protocol that handles multiple

virtual circuits.

is an standard that defines the interconnection process between your router and service provider`s local access switching equipment.

is a connection-oriented data link technology that is streamline to provide high performance and efficiency.

Frame Relay overviewFrame relay only works at User’s DTE ( means Data terminal equipment) and provider’s DCE( data circuit –terminating equipment) or frame relay switch.

Frame Relay components

Frame Relay components

VC (Virtual Circuit) : Logical circuit created to ensure communication between two network devices. Include PVCPVC (permanently VC) and SVCSVC(switched VC);

DLCI (Data-link connection identifier): A number that identifies the logical circuit between the router and the frame relay switch.

Inverse ARP(Inverse Address Resolution Protocol): Method of dynamically associating a network layer address with a DLCI.

Frame Relay link initialization

Each router thought a CSU/DSU connects to theFrame Relay switch.

Frame Relay link initialization(1)

Frame Relay link initialization (2)

Step 5:Frame Relay address mapping

Step 6:Send Inverse ARP again

6Hello, I am 172.168.5.5

6Hello, I am 172.168.5.7

Step 7:Keepalive signaling

Frame Relay link initialization review

Step 1:

Step 2:

Step 3:

Step 4: Step 5: Frame Relay map Step 6: Step 7: Keepalives message(every 10 seconds)

csu/dsu

Status inquiry

Local DLCI number and status

Inverse ARP

Inverse ARP(every 60 seconds)

Connection Type Applications

Leased Lines High control, full bandwidth, high-cost enterprise networks, and last-mile access

Frame Relay Medium control, shared bandwidth, medium cost enterprise backbone; branch sites

ISDN Low control, shared bandwidth, more bandwidth than dialup

Asynchronous Dialup

Low control, shared bandwidth, variable cost-effectiveness for limited use connections like DDR

X.25 Low control, shared bandwidth, variable cost-effectiveness for limited use connections, high reliability

 WAN Connection Considerations

WAN Connection Considerations

References

Interconnecting Cisco network devices (Cisco press , Edited by Steve McQuerry)

Online version of the BCRAN (Cisco's e-learning )