Question : Problem: route summerization

Hi

can some one tell me a quick and easy way of working out what subnets are included in a summerized route. E.g 172.17.200.0 /12. I don't want the answer to this example only I want to know how you did it and how can I work out this information if I was given other summerized addresses of any class with any bit network mask. Thank you in advance

Answer : Problem: route summerization

The best way to work out what networks are included in a sumarised route is to look a the mask in binary, in your example /12 means that the first 12 bits of the mask are 1s and the rest are 0s so all addresses with the same first 12bits as your summarised one will be included. i.e.

Mask      11111111.11110000.00000000.00000000
Address  10101100.10010000.0.0 starting point (172.17.200.0)
Address  10101100.10011111.11111111.11111111 finsishing point (172.159.255.255)

Hope that helps

FatLad