Smallest RIPE NCC Allocation /Assignment Sizes Joao Luis Silva Damas Nurani Nimpuno RIPE NCC Document ID: ripe-222 Date: 22 May 2001 Obsoletes: ripe-211 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 Internet Assigned Numbers Authority (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 or Assignments 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 larger. 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 larger blocks. This is, as a matter of fact, common practice nowadays. CIDR block Default RIPE NCC Smallest RIPE NCC Allocation Allocation / Assignment 62/8 /19 /19 80/8 /20 /20 81/8 /20 /20 193/8 /19 /29 194/8 /19 /29 195/8 /19 /29 212/8 /19 /19 213/8 /19 /19 217/8 /20 /20 Table 1. Allocation/Assignment sizes in CIDR blocks held by the RIPE NCC.