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Internet Addresses

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Right into parking lot. 5. Universal Identifiers. Why not use MAC address as universal identifier? ... Used during startup when don't know who to talk to. e.g. ... – PowerPoint PPT presentation

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Title: Internet Addresses


1
Internet Addresses
  • Chapter 4

2
TCP/IP Layers
Application
Telnet
FTP
SMTP
SNMP
Transport
TCP
UDP
Internet
IP
ICMP
ARP
Network Interface
Ethernet, FDDI, ATM, Frame Relay
Hardware
Wire, Coax, Fiber optic, Satellite
3
Universal Identifiers
  • Universal Communication Service
  • Allows any host to communicate with any other
    host
  • Host must have unique identifier
  • Host identifiers
  • Names
  • Addresses
  • Routes

4
Universal Identifiers
  • Frasch Hall
  • 201 South Grant Avenue
  • Route
  • 71 South to Broad Street Exit
  • West on Broad Street
  • South on Grant
  • Right on Rich Street
  • Right into parking lot

5
Universal Identifiers
  • Why not use MAC address as universal identifier?
  • May not be unique (depends on network technology)
  • Need to route message to host
  • Use phone number as address

6
Internet Addresses
  • Each host on a TCP/IP internet is assigned a
    unique 32 bit internet address that is used in
    all communication with that host
  • Three primary classes (two other)
  • Pair consisting of (network, host)
  • Easy (quick) to extract network id for routing

7
TCP/IP Model Boundaries
  • Application program as well as all protocol
    software from the Internet layer upward use only
    IP addresses the network interface layer handles
    physical addresses

8
TCP/IP Model Boundaries
Application
Transport
Internet
IP Address
Network Interface
MAC (Hardware) Address
Hardware
9
Internet Addresses
  • Two parts to identify address
  • Routing only cares about network part

Network
Host
10
Class A Address
  • 8 bit network id
  • 24 bit host id
  • Also called /8 address

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Network
0
Host
11
Class B Address
  • 16 bit network id
  • 16 bit host id
  • Also called a /16 address

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Network
10
Host
12
Class C Address
  • 24 bit network id
  • 8 bit host id
  • Also called a /24 address

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Network
110
Host
13
Class D address
  • Multicast address

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Multicast
1110
14
Class E Address
  • Reserved for future use

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Reserved for future use
11110
15
Network Size Limitations
16
Dotted Decimal Notation
  • 32 Bit strings of 0s and 1s difficult to read
  • Four decimal integers separated by dots
  • 11000000 01000110 11111100 00001000
  • 192.70.252.8

17
Address Ranges
  • Class A
  • 1.0.0.0 to 126.255.255.255
  • Class B
  • 128.0.0.0 to 191.255.255.255
  • Class C
  • 192.0.0.0 to 223.255.255.255

18
Special Addresses
  • Class A
  • Netid 0 reserved for default route
  • 0.0.0.0
  • Netid 127 reserved for loop-back
  • 127.x.x.x

19
Loop-back Address
  • Address of 127.x.x.x
  • Often 127.0.0.1
  • Used to test TCP/IP on a machine
  • Does not access network

20
Network Addresses
  • Network id ? 0 and Host id 0 refers to network
  • e.g.
  • 10.0.0.0
  • 129.42.0.0
  • 192.70.252.0

Network
000. . . . 000
21
Directed Broadcast
  • Host id of all 1s is directed broadcast
  • For example
  • 10.255.255.255
  • 129.42.255.255
  • 192.70.252.255
  • Maps to physical broadcast when possible

Network
111. . . . 111
22
Limited Broadcast
  • Address of all 1s (net and host)
  • Used during startup when dont know who to talk
    to
  • e.g. 255.255.255.255

111. . . . 111
111. . . . 111
23
Subnet Addressing
  • Use part of host id as sub-net identifier
  • More in Chapter 10

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
Network
10
Host
Subnet
24
Multi-homed Hosts
  • Host may have two or more connections
  • IP address specifies a connection to a network
  • Physical connection to N networks requires N
    IP addresses

Host
Network B
Network A
192.70.252.0
199.218.4.0
25
Weakness in Addressing
  • If number of hosts outgrows class, all hosts must
    get new addresses
  • If a host moves to a different network, it must
    get a new IP address
  • Route taken depends on IP address
  • Multi-homed hosts can cause problems

26
Multi-homed host problem
  • Two hosts - one multi-homed
  • One router

I1
I2
I3
Host A
Host B
Router
I4
I5
27
Internet Addressing Authority
  • Until 1998 Internet Assigned Number Authority
    (IANA)
  • After Jon Postels death, Internet Corporation
    For Assigned Names and Numbers (ICANN)
  • Asian Pacific Network Information Centre (APNIC)
  • American Registry for Internet Number (ARIN)
  • Réseaux IP Européens (RIPE NCC)

28
Internet Addressing Authority
  • Usually the ISP assigns address
  • Assigns IP network addresses
  • Site assigns host ids
  • Only if connected to global Internet

29
Reserved Addresses
  • A set of prefixes reserved for private networks
  • Non-routable addresses
  • 10.x.x.x
  • 172.16.x.x
  • 192.168.x.x
  • 169.254.x.x

30
Network Example
Router
65
192.70.252.0
8
6
125
35
Einstein
Euler
Linnaeus
Freud
31
Network Byte Order
  • Machines store numbers differently
  • Little Endian
  • Big Endian

104
103
102
101
101
102
103
104
100
Memory
101
102
103
104
105
32
Network Byte Order
  • TCP/IP network standard byte order
  • Big Endian
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