Question

Consider three networks A,B and C. Host $H_A$ in network A sends messages each containing 180 bytes of application data to a host $H_C$ in network C. The TCP layer prefixes a 20 byte header to the message. This passes through an intermediate network B. The maximum packet size, including 20 byte IP header, in each network is
A: 1000 bytes
B: 100 bytes
C: 1000 bytes
The network A and B are connected through a 1 Mbps link, while B and C are connected by a 512 Kbps link (bps=bits per second)

Assuming that the packets are correctly delivered, how many bytes, including headers, are delivered to the IP layer at the destination for one application message, in the best case? Consider only data packets.

• A. 200
• B. 240
• C. 220
• D. 260

Answer 1

The correct option is D 260

Network A sends a message of size 180 byte. Network B having the maximum packet size limit is 100 byte including 20 byte header. So the possible combination of sending packet form network A to C is
So the packet size = 100 +100 +60 = 260 byte