SDLC and derivatives (1)
SDLC - Synchronous Data Link Control
- IBM mid-1970s; link layer protocol
- synchronous, bit-oriented developed for SNA architecture
- 2 types of nodes:
- primary : control operation of secondaries
- secondary : can transmit data when primary grants permission
- supports variety of link types and topologies
- point-to-point (one primary, one secondary)
- multipoint (one primary, many secondaries)
- loop (one primary, many secondaries)
- hub go-ahead
- can be used with full-duplex and half-duplex; circuit switched and packet switched