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OSPF DR & BDR Calculations

andrewballard
Level 1
Level 1

What is the correct way to calculate the highest ip address? is it simply a case of adding up the octects or is there some sort of hierachy with the octets?

4 Replies 4

Kevin Dorrell
Level 10
Level 10

Don't add them up, just put them in numerical order according to normal conventions. The first octet is most significant, so compare those; if the first octet is the same, then compare the second, etc.

Kevin Dorrell

Luxembourg

Thanks, thats cleared things up a bit, just one thing, i'm guessing in this case the class is not important

That's right, the class is not important, nor is the mask. It is just a straight 32-bit number, expressed as 4 octets.

As a SID, it is not really an IP address any more. It is just a "random" number. OK, they derive that random number from the IP addresses because that way they have a fighting chance of being unique. But that's the only connection.

Kevin Dorrell

Luxembourg

Yes Andrew you are right class is not important in this case just need to compare octats to octats but if the situation is somewhat like 10.x.x.x and another 192.168.x.x it answers automatically.

Regards,

Ankur

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