3.1 Technologies for WAN and Backbone Networks - Frame Relay

Here is the overview of the presented content for Frame Relay part.

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Frame Relay
Frame Relay Networks
Features
Example applications
Frame format
Frame size
Types of Virtual Circuits
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First of all, Frame Relay (FR) is a technology that enables encapsulation of voice and data into packets and transport to other interconnected networks within WAN. The connection is based on Virtual Circuit which operates on packet mode (packet switching).

Special features about FR is that it is
- high speed
- low error rate
- control is done through a seperate signalling VC as data transmission
- Multiplexing and switching of VC takes place at layer 2, thus its faster and simplier
- connection based. Works like lease line // inherit from VC
- Ability to handles bursty traffic because of its high speed
- High speed access >100Mbps


There are 3 types of VC for FR
- Switched VC
- Permanent VC
- Multicast VC

- Switched VC
- A sequence of digits is dialed and the cct is established if BW is available
- cct have different DLCI (identifier) for each link from origin to destination
- DLCI is made available for reuse after a call disconnect

- Permanent VC
- Works like a lease line

- Multicast VC
- have 1 to many relationship between source and destination. When sending a packet with DLCI that is for multicast VC, router will know who to send to.