11.1
Chapter 11
Data Link Control
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11.2
11-1 FRAMING
11-1 FRAMING
The data link layer needs to pack bits into
The data link layer needs to pack bits into
frames
frames
, so
, so
that each frame is distinguishable from another. Our
that each frame is distinguishable from another. Our
postal system practices a type of framing. The simple
postal system practices a type of framing. The simple
act of inserting a letter into an envelope separates one
act of inserting a letter into an envelope separates one
piece of information from another; the envelope serves
piece of information from another; the envelope serves
as the delimiter.
as the delimiter.
Fixed-Size Framing
Variable-Size Framing
Topics discussed in this section:
Topics discussed in this section:
11.3
Figure 11.1 A frame in a character-oriented protocol
11.4
Figure 11.2 Byte stuffing and unstuffing
11.5
Byte stuffing is the process of adding 1
extra byte whenever there is a flag or
escape character in the text.
Note
