diff --git a/draft-nbourbaki-6man-classless-ipv6.xml b/draft-nbourbaki-6man-classless-ipv6.xml index 8427e40..18731b3 100644 --- a/draft-nbourbaki-6man-classless-ipv6.xml +++ b/draft-nbourbaki-6man-classless-ipv6.xml @@ -235,6 +235,36 @@ rate is low enough. +
+ + As IPv6 usage has evolved and grown over in recent years, it has + become evident that it faces several scaling and coordination problems. + These problems are analogous to allocation and coordination problems + that motivated IPv4 CIDR allocation and later abundant IPv4 PAT, they + include: + + + + + Address allocation models for specific counts of fixed length subnets + to downstream networks or devices from /48 down to /64 are based + on our imagination of how subnets are or should be allocated within + ipv4 networks. + + + Hierarchical allocation of fixed-length subnets requires coordination + between lower / intermediate / upper network elements and has implict + assumption that policies and size allocation at the top of the hierarchy + will accomidate all use cases with fixed lenth subnet allocation. + + + Coordination with upstream network elements for the allocation of + fixed length subnets reveals topology and intent that may be private + in scope and which amounts to permission to build a particular topology. + + +
+
IPv6 unicast interfaces may use any subnet length up to 128 except