32-bit address space, 4x10% capacity, "was then(1970s) believed to be adequate for all time 2.In1980s,the“ class based” structure was relaxed with“ subnetting”, Classless Inter-Domain routing(CIDR)", NATs, etc. 3. In late 1990s, the address space is rapidly exhausted, and it is estimated to be so by either 2005, or 2010 Truly the existing IPv4 will not work in the future, but is its capacity really exhausted? 35% remains unassigned and many assigned ones may be wasted) what happened to IPv4? Problems of ipv4 TSB7 TSB 1. 32-bit address space, 4x109 capacity, “was then (1970s) believed to be adequate for all time”; 2. In 1980s, the “class based” structure was relaxed with “subnetting”, “Classless Inter-Domain Routing (CIDR)”, NATs, etc. 3. In late 1990s, the address space is rapidly exhausted, and it is estimated to be so by either 2005, or 2010 _______________________________________________________________ Truly the existing IPv4 will not work in the future, but: ¾ is its capacity really exhausted? (35% remains unassigned and many assigned ones may be wasted) ¾ what happened to IPv4? Problems of IPv4