Frame Relay

Features:

→ Data is transmitted in the form of the frame. (the access rate is 64 Kbps – 2 Mbps)

→ Bandwidth multiplexing and dynamic bandwidth allocation

→ As a type of simplified X.25 WAN protocol, it completes statistical MUX, transparent transmission of frames and error detection in the data link layer, but doesn't provide retransmission function

→ It provides a set of bandwidth management (CIR) and congestion prevention mechanism

→ FR adopts the connection-oriented switching technology, and provides SVC and PVC service

FR Interface Types

→ DTE : Data Terminal Equipment

→ DCE : Data Circuit-terminating Equipment

→ NNI : Network-to-Network Interface

→ DLCI : Data Link Connection Identifier [FR Network] → [range: 16-1007, DLCI 0-1023 for LMI]

Virtual Circuit : → max 1024 VC

→ PVC (Permanent Virtual Circuit) : Once the link is established, it will always be valid.

→ SVC (Switched Virtual Circuit) : automatically allocated by protocol. → transmit burst data

LMI (Local Management Interface) → monitor PVC status. [ANSI: T1.617 Annex D, ITU-T: Q.933 Annex A, non-standard]

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