Longest Prefix Matching

Consider a datagram network using 8-bit host addresses.
Suppose a router uses longest-prefix matching, and has the following forwarding table:

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Question List

1. Suppose a datagram arrives at the router, with destination address 10000011. To which interface will this datagram be forwarded using longest-prefix matching?

2. Suppose a datagram arrives at the router, with destination address 00000110. To which interface will this datagram be forwarded using longest-prefix matching?

3. Suppose a datagram arrives at the router, with destination address 01100000. To which interface will this datagram be forwarded using longest-prefix matching?

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Solution

1. Since the address is 10000011, it will go to interface 4.

2. Since the address is 00000110, it will go to interface 1.

3. Since the address is 01100000, it will go to interface 5.

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That's incorrect

That's correct

The answer was: 4

Question 1 of 3

Suppose a datagram arrives at the router, with destination address 10000011. To which interface will this datagram be forwarded using longest-prefix matching?

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The answer was: 1

Question 2 of 3

Suppose a datagram arrives at the router, with destination address 00000110. To which interface will this datagram be forwarded using longest-prefix matching?

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The answer was: 5

Question 3 of 3

Suppose a datagram arrives at the router, with destination address 01100000. To which interface will this datagram be forwarded using longest-prefix matching?

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We greatly appreciate the work of John Broderick (UMass '21) in helping to develop these interactive problems.

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