# Basic CS-Networks (Hughes Papers): Sample Questions 1 - 3 of 3

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## Question number: 1

» Basic CS » Networks

Short Answer Question▾

### Write in Short

Which part of the IP header is used for the time limit of the packet?

### Explanation

• Time To Live (TTL) field relates number of hops that a packet is permitted to travel before being discarded by router. Once this time stamp is elapsed data is discarded from the computer networks.
• In the internet protocol, TTL field is of 8 bits and its maximum value is 255. In IPv4 this is measured in seconds. Every host that passes the datagram must reduce the TTL field by one, which was previously set by the sender. Thus, it is renamed as ‘hop limit’ in case of IPv6 header.

## Question number: 2

» Basic CS » Networks

Short Answer Question▾

### Write in Short

What is the channel capacity if the bandwidth is 500 Hz and there are 8 signal levels?

### Explanation

Nyquist criteria give the relation between channel capacity (C), Bandwidth (B) and signal levels (M), which is given as,

Substituting the values, B = 500 and M = 8 from the given information in the equation (i),

Channel capacity,

Channel capacity will be 3000 bits per second.

## Question number: 3

» Basic CS » Networks

Short Answer Question▾

### Write in Short

What will be the SNR if channel capacity is 50 mbps and bandwidth is 10 mbps?

### Explanation

• Shannon’s theorem gives relation between Channel capacity (C), Bandwidth (B) and Signal to Noise Ratio (SNR), which is given as,

• Substituting the values of channel capacity and bandwidth from given information into equation (i),