This is an extremely large address space. Even with the current expansion of the Internet, this should supply addresses for some time to come. Address space is not the only area being optimized. The 4-bit Priority field in the IPv6 header enables a source to identify the desired delivery priority of its packets, relative to other packets from the same source. In this way, time sensitive traffic can have priority over traffic that is not time sensitive.
Security is obviously a major concern for all Internet users.
IPng addresses security issues with two different header options. The IPng Authentication Header and the Encapsulating Security Header. Depending on the need, the two types of header security can be used together or separately. This allows for the flexibility that is needed when dealing with the multitudes of Internet users. The explosive growth of the internet has taught us many things, including mistakes that were made and places with room for improvement.