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Mohamed G. Gouda                                		CS 386S
Spring 2009                                     		Quiz 8
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Design a packet filter that implements hop integrity over the subnetwork 
128.83.10.0/24. (Recall that the IP addresses on this subnetwork range from 
128.83.10.0 to 128.83.10.255.) This packet filter is to be installed in each 
router on this subnetwork. Assume that the MAC addresses for the routers on 
this subnetwork are m1, m2, .., m7. (Recall that each MAC address mi consists 
of 48 bits.)

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Student Name:
Student EID:
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Solution:

The hop integrity packet filter checks the following two fields in each 
received packet:

	src	: IP address of the "original source" of the packet
	hsrc	: MAC address of the "hop source" of the packet

This filter can be specified as follows:

hsrc in [m1, m1]      ^ src in [0, 2^32 - 1]			--> accept
...
hsrc in [m7, m7]      ^ src in [0, 2^32 - 1] 			--> accept
hsrc in [0, 2^48 - 1] ^ src in [128.83.10.0, 128.83.10.255]  	--> accept
hsrc in [0, 2^48 - 1] ^ src in [0, 2^32 - 1]			--> discard

Note that this filter has 9 rules.