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