Question

uppose that a datagram of 2,700 bytes (20 bytes of IP header plus 2,680 bytes of IP payload) arrives at a router and must be forwarded to a link with an MTU of 900 bytes. Also suppose that the original datagram is stamped with an identification number of 15. How many IP fragments will be created by the router to forward this packet

Answer 1

Four (4) IP fragments will be created by the router to forward this packet.

Step-by-step explanation:

Datagram = 2700 bytes

IP Header = 20 bytes

Maximum Transmission Unit = 900 bytes

Original datagram is stamped with an identification number of 15

Required number of fragments =
`(Datagram - IP header)/(MTU - IP header)`

⇒
`(2700 - 20)/(900 - 20)`

⇒ 2680 / 880 = 3.045

ceiling(3.045) = 4