cHDLC

Cisco HDLC data encapsulation

cHDLC is a Cisco variation of HDLC encapsulation, a bit-oriented synchronous data link layer protocol. HDLC specifies a data encapsulation method on synchronous serial links using frame characters and checksums. cHDLC also uses a control protocol to maintain serial link keep-alives. You can only configure Cisco HDLC on IES SAPs.