FNGi DHCPatriot Version 6, Руководство по эксплуатации

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You might be tempted to think that we are going to run out of IPv6 addresses in a hurry
if we setup each subnet as a /64. Currently, however, there are about 7 billion people
on the earth. That is somewhat less than 2
33
. There are 2
64
/64 subnets in the IPv6
space. This means that we could give every man woman and child on the earth 2
31
/64
subnets. So, each person on the earth could have approximately 2 billion subnets all to
themselves before we ran out of IPv6 addresses. Current population projections have
the world population growth leveling off around 9 billion. That is slightly more than 2
33
.
As you will learn later in the document, conventional wisdom states that we do use
DHCP to award each household/business a /48 for use on the local network. There are
2
48
(or 281,474,976,710,656) /48 subnets in the entire IPv6 space. That is still well
beyond the expected 9 billion people on the planet and far beyond the number of
households and businesses.
Here is a simple chart showing IPv6 size:
DHCPv6 Primer
Most current clients that support IPv6 will have at least two modes of operation that can
be set:
manual and automatic. When set to automatic, clients will receive network
information from the local router using a special procedure called Router
Announcements (RA). This information includes the network prefix to use, the default
gateway, and which method should be used to obtain or set an IP address on the
client’s connected interface.
At this point, the client has already established communication with the link local
network.
The link local network is a special network that each host becomes a part of
just by having IPv6 enabled. Addresses are created based on the MAC address on the
connected interface of machinery connected to the network. Systems on the network
can communicate with each other via these addresses. The gateway for the client will
Chapter 9: DHCPv6 Configuration and Maintenance 57
DHCPatriot Version 6 Operations Manual This document © 2017 First Network Group Inc. All Rights Reserved
Figure 9.1