- Recall:
- The information frame of HDLC contains user data
- Structure of
the control field of
an I-frame:
Explanation:
- The bits
sss is a
3 bit send sequence number
- Each frame that
the sender
transmits, is
identified by
a send sequence number
(We will learn how this number is used a bit later)
- Each frame that
the sender
transmits, is
identified by
a send sequence number
- The bits
rrr is a
3 bit receive sequence number
- The receive sequence number is
used to
acknowledge
frames that the sender has
received (from the receiver)
(We will learn how this number is used a bit later)
- The receive sequence number is
used to
acknowledge
frames that the sender has
received (from the receiver)
- The bit p is
the poll bit
- When poll = 1, the sender is requesting an immediate response from the receiver
- The bits
sss is a
3 bit send sequence number