Frame Relay - Frame Relay Versus X.25

Frame Relay Versus X.25

X.25 provides quality of service and error-free delivery, whereas, Frame Relay was designed to relay data as quickly as possible over low error networks. Frame Relay eliminates a number of the higher-level procedures and fields used in X.25. Frame Relay was designed for use on links with error-rates far lower than available when X.25 was designed.

X.25 prepares and sends packets, while Frame Relay prepares and sends frames. X.25 packets contain several fields used for error checking and flow control, most of which are not used by Frame Relay. The frames in Frame Relay contain an expanded link layer address field that enables Frame Relay nodes to direct frames to their destinations with minimal processing. The elimination of functions and fields over X.25 allows Frame Relay to move data more quickly, but leaves more room for errors and larger delays should data need to be retransmitted.

X.25 packet switched networks typically allocated a fixed bandwidth through the network for each X.25 access, regardless of the current load. This resource allocation approach, while apt for applications that require guaranteed quality of service, is inefficient for applications that are highly dynamic in their load characteristics or which would benefit from a more dynamic resource allocation. Frame Relay networks can dynamically allocate bandwidth at both the physical and logical channel level.