Frame Relay

Frame relay is a uniformed Wide Area Network or known as WAN. It specifies the physical and logical link layers of digital telecommunications channels using a packet switching methodology. Originally designed for transport across Integrated Services Digital Network (ISDN) infrastructure. Frame relay aimed to provide a telecommunication service for cost effective or cheap data transmission for traffic between Local Area Networks or LAN and between end-points in a Wide Area Network or WAN. Frame Relay puts data in variable-size units called "frames" and leaves any necessary error-correction (such as re-transmission of data) up to the end-points.

Frame Relay is a layer-2 protocol used in wide area networking. It uses the

telecommunications provider's packet-switching infrastructure to move data. Frame Relay can provide speeds from 56kbps DS0 up to 43Mbps DS3 connections depending on the capability of the service provider's network.

These are some following terminologies used in Frame Relay:

CIR Committed Information Rate – the minimum level of throughput as

guaranteed by the service provider.

DCE Data Circuit-terminating Equipment – a device on the service provider's

network that connects to the customer's DTE.

DTE Data Terminal Equipment – a device at the customer's site that connects to the service provider's DCE.

DLCI Data Link Connection Identifier – a 10-bit number used to uniquely

identify a virtual circuit end-point on the customer's Frame Relay network.

HDLC High-level Data Link Control – a layer-2 protocol used to control data flow

and provide error detection.

LMI Line Management Interface – a protocol that provides line status and other

management information to the end user of a Frame Relay connection.

PPP Point-to-Point Protocol – an alternative to HDLC.

PVC Permanent Virtual Circuit – a connection between two nodes on a Frame

Relay cloud that allows the exchange of data.

Advantages of Frame Relay:

The main advantage of Frame Relay over point-to-point leased lines is cost.

Frame Relay can provide performance similar to that of a leased line, but with significantly less cost.

Disadvantages of Frame Relay

The two main disadvantages of Frame Relay are slow downs due to network congestion and difficulty ensuring Quality of Service (QoS).

Choosing Equipment

Some Frame Relay providers will include customer equipment like DTE's and routers in the overall package price. If not, Zippy's should plan to purchase equipment from a reputable hardware vendor. The DTE and router can be purchased as separate pieces or as an integrated solution. An integrated package, like a router with a plug-in WAN Interface Card (WIC), can offer easier management, space savings and on epoint of contact for any service related issues.