Transcript Ch07

Chapter Overview
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IP (v4) Address
IPv6
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IPv4 Addresses
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Internet Protocol (IP) is the only network layer protocol with
its own addressing system and is design for a host on one
network to communicate with another host on a different
network, regardless the type of LAN
IP addresses are 32 bits long and have two parts: a network
identifier and a host identifier.
IP addresses are assigned to network
interface adapters, not to computers.
The Source IP Address field in the IP header always
identifies the computer that generated the packet.
The Destination IP Address field in the IP header always
identifies the packet’s final destination.
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ipconfig
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IP Address Assignments
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Every network interface adapter on a network
must have
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The same network identifier as the others on the
network
A unique host identifier
The Internet Assigned Numbers Authority (IANA)
assigns network identifiers, but you typically obtain
network addresses from an Internet service
provider (ISP).
Network administrators, or DHCP, assign host
identifiers.
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Dotted decimal
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For example,
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This is not one
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124.241.144.2
1.1.1.256
The binary and hexadecimal are not common
to say the least
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IP Address Classes
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IP Address Class First Bit/Byte Values
Class
First Bits
First Byte Values
A
B
0
10
1–127
128–191
C
110
192–223
Class D (224-239) and E (240-255)
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IP Address Class Network and Host
Bits
Class
Network
ID Bits
Host ID
Bits
Number of
Networks
Number of
Hosts
A
8
24
126
16,777,214
B
16
16
16,384
65,534
C
24
8
2,097,152
254
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Private Network Addresses
Class
Network Addresses
A
10.0.0.0 through 10.255.255.255
B
172.16.0.0 through 172.31.255.255
C
192.168.0.0 through 192.168.255.255
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IP Addressing Rules
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All the bits
to zeros.
All the bits
to ones.
All the bits
zeros.
All the bits
ones.
in the network identifier cannot be set
in the network identifier cannot be set
in the host identifier cannot be set to
in the host identifier cannot be set to
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Reserved IP addresses
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Automatic Private Internet Protocol
Addressing (APIPA)
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a common alternative to the use of DHCP to
request and retrieve an IP address for a host.
simplifies the assignment of IP address and
subnet-mask configuration information to hosts in
small networks.
When APIPA is used, the OS allows the assignment
of a unique IP address to each station on a small
LAN to avoids the administrative overhead of
running a DHCP server or manually setting IP
configuration information.
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Different types of broadcasts
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Layer 2 broadcast -- all nodes on a LAN
Broadcast (Layer 3) – to all hosts on the
network
Unicast – a node sends a message to
255.255.255.255 with port number 67 (BootP
server), router knows it is for DHCP asking
for an IP address, so forward to DHCP server
Multicast – one host to several hosts,
forwarded by router
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IPv6 Addressing
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Expands IP address space from 32 to 128 bits
Designed to prevent the depletion of IP addresses
and address-exhaustion crisis of IPv4, later
modified to add features for flexibility, efficiency,
capability, mobility, etc
Uses XX:XX:XX:XX:XX:XX:XX:XX notation, each X
is a pair of hexadecimals
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IPv6 Addressing (2)
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Global routing prefix – used by router for the network
A subset of a network
A host address
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IPv6 Addressing (3)
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You can only replace one contiguous block of
zeros in an address
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IPv6 Address Types
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Unicast – very much the same as IPv4 unicast
Global unicast – unicast, start with 001
Link-local address -- private, not to be routed
(FE80:: addresses) for point to point, not
forwarded
Unique local address -- FC00::/
Multicast – to all
Anycast -- to one
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Special address
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0:0:0:0:0:0:0:0 == :: same as 0.0.0.0 in IPv4 not for
communication
0:0:0:0:0:0:0:1 == ::1 same as 127.0.0.1 for loopback
0:0:0:0:0:0:192.168.100.1 mixing IPv4 with IPv6
200::/3 global unicast address range
FC00::/7 unique local unicast range
EF80::/10 link-local unicast range
FF00::/8 The multicast range
3FFF:FFFF::/32 and 2001:0DB8::/32 for examples and
document
2002::/16 for 6 to 4
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2002::/16 for 6 to 4
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For any 32-bit global IPv4 address, a 48-bit 6to4 IPv6
prefix can be constructed for use by that host (and if
applicable the network behind it) by prepending 2002 (hex)
to the IPv4 address.
For example, for192.0.2.42, the corresponding 6to4 prefix
would be 2002:c000:022a::/48.
This gives a prefix length of 48 bits, which leaves room for
a 16-bit subnet field and a 64 bit host address within the
subnet.
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