2. UNIVERSAL IDENTIFIERS
Universal Communication Service
Host identifiers are classified as
o Name - What
o Address - Where
o Route - How
3. IP ADDRESS
Each host on aTCP/IP internet is assigned a unique 32-bit internet address that
is used in all communication with that host.
Pair of [ netID, hostID ]
4. NETWORK CONNECTION
IP address does not specify individual computer, but a connection to the
network.
Multi-homed host & Multiple IP Addresses
7. ORIGINAL CLASSFUL ADDRESSING SCHEME
Class A : 7 bits to netid, 24 bits to hostid
Class B : 14 bits to netid, 16 bits to hostid
Class C : 21 bits to netid, 8 bits to hostid
Class D : Used for multicasting
Class E : reserved for future
8. CLASS RANGE
Class A Address: 1-126 | more than 65536 host
Class B Address: 128-191 | between 256 to 65534 hosts
Class C Address: 192-223 | less than 254 hosts
Class D Address: 224-239
Class E Address: 240-254
9. NETWORK ADDRESS
An address that has all bits of the hostID equal to 0 is reserved to refer to the
network.
eg. 130.5.0.0
10. DIRECTED BROADCAST
Any address with all bits of hostID equal to 1 is reserved for directed broadcast.
eg. 130.5.255.255
Sender can transmit a single packet that will be broadcasted on the specified
network.
11. LOCAL / LIMITED BROADCAST
IP Address : all 1
i.e. netID and hostID all 1
i.e. 255.255.255.255
A host may use the limited broadcast address as part of a start-up procedure
before it learns its IP address or the IP address prefix for the local network.
12. ALL-0s SOURCE ADDRESS
IP Address : all 0
i.e. netID and hostID all 0
i.e. 0.0.0.0 (non-routable address)
This address is used as a temporary source address at startup before a host
learns its IP address.
13. LOOPBACK ADDRESS
The network prefix 127.0.0.0/8, a value from the class A range, is reserved for
loopback.
eg. 127.0.0.1
It is intended for use in testingTCP/IP and for inter-process communication on
the local computer.
The computer processes the data without sending traffic across any network.
15. IP MULTICAST
Unicast : packet is delivered to one host
Broadcast: packet is delivered to all hosts
Multicast: packets is delivered to specific subnet of hosts
16. WEAKNESS IN INTERNET ADDRESSING
If a host computer moves from one network to another, its IP address must
change.
When network grows, it must move to higher class. Changing network addresses
can be incredibly time-consuming and difficult to debug.
And vice-versa.
17. WEAKNESS IN INTERNET ADDRESSING
Because routing uses the network portion of the IP address, the path taken by
packets traveling to a host with multiple IP addresses depends on the address
used.
18. NETWORK BYTE ODER
Not all architectures store 32-bit integers in the same way.
Two ways to store the data
o Big Endian
o Little Endian
19. NETWORK BYTE ODER
Integer: 64536
Binary: 11111100 00011000
o Most Significant Byte Least Significant Byte
o StartAddress+1 StartAddress
Big Endian stores Msbyte first
Little Endian stores Msbyte last
Big Endian is generally used.
20. NETWORK MASK
Helps you identify network and host
Put all 1 in place of netID and all 0 in place of hostID
Class A : 255.0.0.0
Class B : 255.255.0.0
Class C : 255.255.255.0
22. SUBNET AND CLASSLESS EXTENSIONS
Classless network: 204.17.5.0/27
i.e. 27 bits for network & 5 bits for host
In last octet
Using 3 bits we can create 8 subnets
Using 5 bits we can have 32 host addresses (30 of which can actually be assigned)
23. SUBNET AND CLASSLESS EXTENSIONS
204.17.5.0 255.255.255.224 assign host address range 1 to 30
204.17.5.32 255.255.255.224 assign host address range 33 to 62
204.17.5.64 255.255.255.224 assign host address range 65 to 94
204.17.5.96 255.255.255.224 assign host address range 97 to 126
204.17.5.128 255.255.255.224 assign host address range 129 to 158
204.17.5.160 255.255.255.224 assign host address range 161 to 190
204.17.5.192 255.255.255.224 assign host address range 193 to 222
204.17.5.224 255.255.255.224 assign host address range 225 to 254
