TCP

Question

A TCP segment consisting of 1500 bits of data and 160 bits of header is send to the IP layer ,which appends another 160 bits of header. This is then transmitted through two network,each of which uses 24-bit packet header. The destination network has a maximum packet size of 800 bits. How many bits,including headers,are delivered to the network layer protocol at the destination??

Answer 1

 

 

1. TCP segment: 1500 bits of data + 160 bits of TCP header = 1660 bits.
2. IP layer adds 160 bits of header to the TCP segment, making it 1660 + 160 = 1820 bits.

Now, the total size after passing through the first network:

3. First network adds a 24-bit header to the IP packet: 1820 + 24 = 1844 bits.

After passing through the second network:

4. Second network adds another 24-bit header: 1844 + 24 = 1868 bits.

Finally, at the destination:

5. The destination network has a maximum packet size of 800 bits, so the packet will be fragmented into multiple packets.

Let's calculate the number of packets needed and the size of the last packet:

Number of packets = ceil(1868 bits / 800 bits per packet) = 3 packets (rounded up)

Now, let's find the size of the last packet:

Size of the last packet = 1868 bits % 800 bits per packet = 268 bits

So, the total bits delivered to the network layer protocol at the destination would be:

Total bits = 2 * (800 bits) + 268 bits = 1868 bits