Telecommunications Network Assignment II - Desklib

ELEC3500 TELECOMMUNICATIONS NETWORK
S2, 2018
ASSIGNMENT II
STUDENT NAME
STUDENT ID NUMBER
INSTITUTIONAL AFFILIATION
LOCATION (STATE, COUNTRY)
DATE OF SUBMISSION

PART A
Question 1
Link transmission rate --2.048mbps
Node separation --200km
Receiver buffer size --1.00mB
Information frame size --2500 bytes
Receiver informatino processing rate --10kbps
Xon/Xoff control packet size --80 bytes
(a) Value of P in a lossless communication while offering full utilization of the receiver
buffer.
(b) Calculate the time interval between the Xoff and Xon with signals transmitted by the
receiver when the buffer occupancy level goes down to 70% or below.
Solution
Every N downstream departure,
DD ( t 1 )=DD ( t 0 ) + N
CC =RTT∗Rpk + DD ( t−tf )−UD (t )
Question 2
1 frame length is used on the link is 400 bytes
20 byte header
ACK frame length is 20 bytes
2000 bytes 11 bits are corrupted due to the channel error
Solution
The transmission efficiency is given as,
α =
( 1− S0
Sf )
1+
( Sa
Sf ) + 2 ( t¿+t proc ) r
Sf
s0=sa=200

For the stop and wait efficiency,
s0 =sa=t proc=0
At a 50% transmission delay of the ACK,
r =4 kbps , t¿=20 ms
The ACK frame size with a header/CRC overhead = 1250 bytes
W s ≥ ( 2t¿ )∗r
Sf
=11bits for 1 frame
The emission delay for one frame,
¿ 1250 x 8
1 mbps =10 ms

The automatic repeat request and the positive acknowledgement with retransmission,
d= d 1
2
3 c
= 20 km
2e8
d∗2+safet y constant
T transmit = L
R = 200 kbppkt
10∗¿ 9 bps =2 μs
Delay=ttransmit + T¿+ Tqueue
The utilization shows the fraction of time the sender is busy sending,
U sender= ( L
R )
RTT + L
R
= 0.008
30.008 =0.0027