Lecture on Data Link Control
Goal : Conversion of a virtual bit pipe into an error free link.
Functions
Error Detection
Automatic Repeat Request (ARQ)
Framing

Sending DLC receives packets from Network layer.
Receiving DLC delivers packets to Network Lay
Finite M/M/1 queue
Consider an M/M/1 queue with finite waiting room.
(The previous result had infinite waiting room)
~
We can have up to N packets in the system.
After filling the system, packets are returned, or blocked.
Balance equations:
1
1
1
0
1
1
Lecture on Markov Chain
Definition : Markov Chain is a discrete time discrete alphabet random process
cfw_Xn, n>0 such that
Pr( X n1 j  X n i , X n 1 in 1 ,., X 0 i0 ) Pr( X n1 j  X n i )
X n is conditionally independent of X 0 , X 1 ,., X n 1 , given
Lecture on Multi Access Communication
For many applications (e.g.,satellite, radio broadcast, Ethernet), users share the same
channel. The received signal is the sum of the transmitted signal from the source that is
intended, the transmitted signals from
Routing in Communication Networks
Routing: Network layer protocol that guides information units to correct destinations. A
complex collection of decision rules that work somewhat independently.
 Determination of allowable path set for each origin  desti
esses.
For 1Gbps line, the search time has to be < 512 nano sec.
1000 prefixes
contiguous
more than 1M soon.
service differentiation, and
are strong drivers
a
s
s
Problems to Consider
What are the potential problems?
How do we improve the search algorit