In a packet switching network, packets are routed from source to destination along a single path having two intermediate nodes. If the message size is 24 bytes and each packet contains a header of 3 bytes, then the optimum packet size is:

The maximum window size for data transmission using the selective reject protocol with n-bit frame sequence numbers is:

In a network of LANs connected by bridges, packets are sent from one LAN to another through intermediate bridges. Since more than one path may exist between two LANs, packets may have to be routed through multiple bridges. Why is the spanning tree algorithm used for bridge-routing?

Consider a three word machine instruction $$ADD$$ $$A$$ $$\left[ {{R_0}} \right],\,@\,B$$

The first operand (destination) ''$$A$$ $$\left[ {{R_0}} \right]''$$ uses indexed addressing mode with $${{R_0}}$$ as the index register. The second operand (source) $$''@B''$$ used indirect addressing mode. $$A$$ and $$B$$ are memory addresses residing at the second and the third words, respectively. The first word of the instruction specific the opcode, the index register designation and the source and destination addressing modes. During execution of $$ADD$$ instruction, the two operands are added and stored in the destination (first operand).

The number of memory cycles needed during the execution cycle of the instruction is