Nt1310 Unit 4 Assignment 2.1 Parity

Assignment 2

1. Parity bit:
A Parity bit is a single bit that is added to the data, during data transmission for error checking or data loss that may have occurred. The parity bit is either zero or one.

2. Internet checksum : 0A BC 78 9F 85 7E 5D BC.

Data at Sender: 0A BC 78 9F 85 7E 5D BC 00 00

Partial sum 0ABC + 789F
---------
835B_

Partial sum 835B + 857E --------- 108D9

Carry 08D9 + 1 -------- 08DA

Partial Sum 08DA + 5DBC --------- 6696

One’s Complement 9969

(a) Check sum calculation at sender

Data at receiver: 0A BC 78 9F 85 7E 5D BC 9969

Partial sum 0ABC + 789F
---------
835B_

Partial sum
i.e multiple signals are carried simultaneously on the same medium, by allocation each signal with different frequency band, by modulation. Multiplexing and modulation need different equipment, to do their jobs. They are used with analog signals.
Time Division Multiplexing:
It is a method of transmitting multiple signals, which differ in their timeslots, by allocating frames. i.e data is carried in repetitive blocks called frames, where each frame has a set of timeslots and each source is assigned to one or more timeslots. They are used with analog and digital signals.
Frequency Division Multiplexing (FDM) vs Frequency Division Duplex(FDD):
In FDM, the way of sharing the medium with multiple users, transmitting and receiving at the same time, with different frequency.
In FDD, is focused on single user, with transmission and reception on different frequency, on same time.

5. Division in spectrum of cable modems:
Cable modem handling upstream and downstream data, for each channel:
Spectrum of cable modems is divided into 3 ranges, to support both cable television programming and data channels.
- User to network data(upstream): 5 – 40 MHz
- Television delivery(downstream): 50- 550 MHz
- Network to user