IP Next Generation Overview
Reviewer: Michael S. Liu
The arguments for the IPng in this paper are numerous. It does a great job of explaining
those benefits in a clear fashion and help to make the success of this new protocol more
likely. Hinden outlines the history, specifics, and benefits of the protocol and this is a
very effective method for aiding its rapid adoption. It looks like this protocol should be
rapidly adopted and implemented though it would be interesting to see a paper
outlining criticisms of the protocol. The main reasons that the protocol will succeed are
outlined clearly in the paper as:
1. Incremental upgrade and deployment. Individual IPv4 hosts and routers may be upgraded to
IPv6 one at a time without requiring any other hosts or routers to be upgraded at the same
time. New IPv6 hosts and routers can be installed one by one.
Though these reasons are all important, I feel the most important for its adoption will low
startup costs, minimal upgrade dependencies, and incremental upgrade and deployment. This
type of adoption strategy makes the most radical infrastructure changes easiest to bear and
most economically feasible. The adoption of the current internet came about in the same
manner and if the upgrade of the current IP structure follows suit, it will have a much
stronger chance of success. Once the new standards are adopted, in place, and actively
utilized, the most drastic but beneficial differences will already be in place and we will
begin to reap the full benefits of such an evolutionary and revolutionary shift.
2. Minimal upgrade dependencies. The only prerequisite to upgrading hosts to IPv6 is that
the DNS server must first be upgraded to handle IPv6 address records. There
are no pre-requisites to upgrading routers.
3. Easy Addressing. When existing installed IPv4 hosts or routers are upgraded to IPv6,
they may continue to use their existing address. They do not need to be
assigned new addresses. Administrators do not need to draft new addressing plans.
4. Low start-up costs. Little or no preparation work is needed in order to upgrade
existing IPv4 systems to IPv6, or to deploy new IPv6 systems. The mechanisms
employed by the IPng transition mechanisms include:
5. An IPv6 addressing structure that embeds IPv4 addresses within IPv6 addresses, and
encodes other information used by the transition mechanisms.
6. A model of deployment where all hosts and routers upgraded to IPv6 in the early
transition phase are "dual" capable (i.e. implement complete IPv4 and IPv6 protocol
7. The technique of encapsulating IPv6 packets within IPv4 headers to carry them over
segments of the end-to-end path where the routers have not yet been upgraded
8. The header translation technique to allow the eventual introduction of routing
topologies that route only IPv6 traffic, and the deployment of hosts that support only
IPv6. Use of this technique is optional, and would be used in the later phase of
transition if it is used at all.
The main need for IPng was of course to make the address space increase from 32 bits and 128
bits. This need is going to be more apparent as we head into the continuing growth of the
Internet and especially when we move to place all household appliances onto the net. It will no
longer be enough to assign an IP to each person but a whole range of IPs will be required for
each household. 2^128 will be definitely adequate as it is comparable to the number of particles
in the universe. Even in the most pessimistic estimates, it is 1,564 addresses/square meter,
which is still wholly adequate. It is best that we made enough preparations for this in our first
correction so that we wholly eliminate Y2K like scenario from ever happening in the address space
Another interesting improvement is the ability to distinguish packets based on the needs of the
data stream. This makes adjustments for high-bandwidth applications as well as other specialized
needs as we build in more functionality into the net. This is an interesting improvement because
it builds in a few of the benefits of stratification into the net though it was meant to be a
very simple universal system. We may get the benefits of ATM after all with the compatibility of
IP which made the Internet a success in the first place.