Question about 223/8

Tue Apr 29 09:48:45 UTC 2003

>The reason I ask is that I was perusing RFC 3330 and noted that it 
>specifically stated that the basis for the reservation of 
>223.255.255.0/24 no longer applied and that the block was subject to 
>future allocation to a RIR. Yet there was an argument about it.

The argument was because it wasn't clear what the original basis was for 
the reservation nor was it clear how things had changed. 

Imagine you have a device that uses lots of addresses but considers them 
to be sequential numbers rather than bit patterns. For instance, this 
device could be configured with a starting number and then dole out 
sequential numbers to connections based on that starting number. This is 
how a lot of terminal servers work.

Imagine that you give the terminal server a number like 223.255.255.200 as 
the starting number to assign to dialup connections and that terminal 
server has a 32 port card installed. Then one day an engineer installs a 
second 32 port card. The terminal server continues to function just fine 
until one day when it tries to assign 223.255.255.255 to an incoming call 
followed by assigning 224.0.0.0 to the next call. Suddenly you have all 
kinds of wierdness breaking out with mysterious broadcast traffic and 
multicast traffic coming from the device. But it only happens for short 
bursts during the busiest times of the day. What the heck is going on!?

Could you debug that? Would you want to debug that?

Maybe that's why 223.255.255/24 should be forever reserved.

--Michael Dillon