Question about SDLC, HDLC, LAPD, LAPF etc

ziggy

Hi all,

I am writing the CCNA cert tomorrow and I was doing some hard core studying all weekend.

I came across a statement in some extra material that states LAPD, LAPF, and HDLC are subsets of SDLC. I am confused. This was the first time I came acrosss SDLC (Synchronous Data Link Control).

All the Cisco material that I have been preparing with has stated:
The Layer 2 protocols include PPP and HDLC. That LAPD, LAPB, and LAPF are subsets of HDLC.

By default, a Cisco router serial interface has an encapsulation set as proprietary Cisco HDLC.

So I guess I have a couple questions in regards to the mumbling above....

1 - Does the cert have any reference to SDLC ?
2- If LAPD, LAPB, and LAPF are subsets of HDLC, is it standard HDLC or Cisco proprietary HDLC ?

Thanks