Size of smallest allocations in CIDR blocks allocated by the RIPE NCC
                                      


                           Joao Luis Silva Damas
                                 RIPE NCC 
 


                             Document: ripe 211
                            Date: July 26, 2000
   



   This document contains the size of the minimum and default allocations
   made by the RIPE NCC to users from CIDR blocks assigned to the RIPE
   NCC by the IANA.
   
   ``Default allocation'' refers to the amount of addresses, in prefix
   notation, that are allocated to users by default.
   
   ``Smallest allocation'' refers to the size of the smallest allocation,
   in prefix notation, made by the RIPE NCC to a user.
   
   Allocations smaller than the default size have been made to users
   requesting Provider Independent (PI) address space.
   
   Routing decisions for blocks of address space are the sole
   responsibility of network operators.
   
   However, network operators taking routing decisions based on prefix
   length are requested and encouraged to route at least blocks of sizes
   corresponding to the ``default allocation'' and bigger.
   
   Users to whom small blocks (smaller than the default allocation size)
   of PI addresses are given out are always notified that network
   operators throughout the Internet may choose not to route, or may
   filter, small address blocks if they are not aggregated into bigger
   blocks. This is, as a matter of fact, common practice nowadays.
   
   CIDR block Default allocation Smallest allocation
       62/8          /19                /19
      193/8          /19                /29
      194/8          /19                /29
      195/8          /19                /29
      212/8          /19                /19
      213/8          /19                /19
      217/8          /20                 NA
   
   Table 1. Allocation sizes for CIDR blocks from which the RIPE NCC has
   made allocations.
     _________________________________________________________________