Networking Test Friday Online
Bell0216
chapter_6.1_powepoint.pdf
© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public 1
Addressing the Network – IPv4
Network Fundamentals – Chapter 6
Dr. C. BouSaba
2© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
IP addressing – works at
� OSI model layer 3
� TCP/IP model Internet layer
Application
Presentation
Session
Transport
Network
Data link
Physical
Application
Transport
Internet
Network Access
TCP, UDP
IP
Ethernet, WAN technologies
HTTP, FTP,
TFTP, SMTP etc
Segment
Packet
Frame
Bits
Data
stream
3© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Addressing topics
� Types of IP addresses
� Assigning addresses
� Network part and subnet masks
� Calculating addresses
� Ping and Traceroute Utilities
4© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
IPv4 address
00010001000101011010100011000000
1721.168.192.
octetoctet octet octet
network part host part
00000000111111111111111111111111
0255.255.255.
Prefix /24 Subnet mask:
• 24 bits for the network part
• 24 ones in the mask
5© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Find the network address
To find the network addressnetwork address, turn all host bits to 0s.
The router needs to do this for every packet.
00010001000101011010100011000000
1721.168.192.
00000000000101011010100011000000
021.168.192.
6© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Logical AND
00010001000101011010100011000000
1721.168.192.
00000000111111111111111111111111
0255.255.255.
Do a logical AND at each position
00000000000101011010100011000000
021.168.192.
AND: Λ
7© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Find the broadcast address
To find the broadcast addressbroadcast address, turn all host bits to 1s
The broadcast address is the last address in the
network.
00010001000101011010100011000000
1721.168.192.
11111111000101011010100011000000
25521.168.192.
8© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
3 Types of addresses
� Every network has:
� Network address – the first one
� Broadcast address – the last one
� Host addresses – everything in between
9© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Classful addressing
6053.17.10.
network part host part
A
20138.16.172.
network part host part
B
1721.168.192.
network part host part
C
10© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Classful addressing
� Easy to work out but very wasteful.
� Routers and hosts still assume class subnet masks by default
� Class A /8 255.0.0.0
� Class B /16 255.255.0.0
� Class C /24 255.255.255.0
11© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Classless addressing
� Any suitable prefix can be used
� We (and devices) need to know what the prefix is.
� More flexible, less wasteful.
12© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Classless addressing /16
� 172.16.0.0/16 mask 255.255.0.0
� Broadcast address 172.16.255.255
� Hosts 172.16.0.1 to 172.16.255.254
� 65534 host addresses
00000000000000000001000010101100
00.16.172.
13© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Classless addressing /24
� 172.16.0.0/24 mask 255.255.255.0
� Broadcast address 172.16.0.255
� Hosts 172.16.0.1 to 172.16.0.254
� 254 host addresses
00000000000000000001000010101100
00.16.172.
14© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Classless addressing /22
� 172.16.0.0/22 mask 255.255.252.0
� Broadcast address 172.16.3.255
� Hosts 172.16.0.1 to 172.16.3.254
� 1022 host addresses
00000000000000000001000010101100
00.16.172.
15© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Classless addressing /26
� 172.16.0.0/22 mask 255.255.255.192
� Broadcast address 172.16.0.63
� Hosts 172.16.0.1 to 172.16.0.62
� 62 host addresses
00000000000000000001000010101100
00.16.172.
16© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Classless addressing /28
� 172.16.0.0/28 mask 255.255.255.240
� Broadcast address 172.16.0.15
� Hosts 172.16.0.1 to 172.16.0.14
� 14 host addresses
00000000000000000001000010101100
00.16.172.
17© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Calculating addresses
� A host has IP address 192.168.1.70/24
� What is the subnet mask?
� What is the network address?
� What is the broadcast address?
� What is the range of host addresses in the network?
18© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
192.168.1.70/24 – fill in the table
Last host
First host
Broadcast
Network
Subnet mask
Host
FullLast octet decimal
Last octet binary
19© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
192.168.1.70/24
192.168.1.25425411111110Last host
192.168.1.1100000001First host
192.168.1.25525511111111Broadcast
192.168.1.0000000000Network
255.255.255.0000000000Subnet mask
192.168.1.707001000110Host
FullLast octet decimal
Last octet binary
20© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Calculating addresses
� A host has IP address 192.168.1.70/26
� What is the subnet mask?
� What is the network address?
� What is the broadcast address?
� What is the range of host addresses in the network?
21© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
192.168.1.70/26 fill in the table
Last host
First host
Broadcast
Network
Subnet mask
Host
FullLast octet decimal
Last octet binary
22© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
192.168.1.70/26
192.168.1.12612601111110Last host
192.168.1.656501000001First host
192.168.1.12712701111111Broadcast
192.168.1.646401000000Network
255.255.255.19219211000000Subnet mask
192.168.1.707001000110Host
FullLast octet decimal
Last octet binary
23© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Calculating addresses
� A host has IP address 192.168.1.70/28
� What is the subnet mask?
� What is the network address?
� What is the broadcast address?
� What is the range of host addresses in the network?
24© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
192.168.1.70/28 fill in the table
Last host
First host
Broadcast
Network
Subnet mask
Host
FullLast octet decimal
Last octet binary
25© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
192.168.1.70/28
192.168.1.787801001110Last host
192.168.1.656501000001First host
192.168.1.797901001111Broadcast
192.168.1.646401000000Network
255.255.255.24024011110000Subnet mask
192.168.1.707001000110Host
FullLast octet decimal
Last octet binary
26© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Unicast, Multicast, Broadcast
� Unicast – a message addressed to one host
� Broadcast – a message addressed to all hosts on a network. Uses network’s broadcast address or 255.255.255.255 locally
� Multicast – a message addressed to a group of hosts. Uses an address starting 224 - 239
27© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Private IP addresses
� Unrestricted use on private networks. Not routed across the Internet.
� 10.0.0.0 – 10.255.255.255 (10.0.0.0/8)
� 172.16.0.0 – 172.31.255.255 (172.16.0.0/20)
� 192.168.0.0 – 192.168.255.255 (192.168.0.0/24)
28© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Public IP addresses
� Routed over the Internet
� Master holder is IANA
� Assigned to regional registries and then to ISPs
� ISPs allocate them to organisations and individual users
� Use is strictly controlled as duplicate addresses are not allowed
29© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Special addresses
� 0.0.0.0 “all addresses” in default route. Hosts cannot be given addresses starting 0.
� 127.0.0.1 is loopback. Hosts cannot be given addresses starting 127.
� 240.0.0.0 and higher – reserved for experimental purposes.
� 169.254.0.0 - 169.254.255.255 local only
� 192.0.2.0 to 192.0.2.255 for teaching
30© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Network address translation
� A large number of hosts on a network use private addresses to communicate with each other.
� The ISP allocates one or a few public addresses.
� NAT allows the hosts to share the public addresses when they want to use the Internet
31© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Addressing hosts
� Static addressing – address is configured by an administrator
� Servers, printers, routers, switches need static addresses
� Dynamic addressing – address is allocated automatically by DHCP by leasing addresses from a pool
� Dynamic addressing is best for workstations
32© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Blocks of addresses
192.168.1.255Broadcast
192.168.1.254Router
192.168.1.224/27192.168.1.224 - 253Network devices
192.168.1.192/27192.168.1.192 - 223Peripherals
192.168.1.128/26192.168.1.128 - 191Servers
192.168.1.1-127User hosts
192.168.1.0/25192.168.1.0Network address
SummaryAddress rangeUse
33© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Subnetting 192.168.1.0/24
00000000255.255.255.0Subnet mask
00000000192.168.1.0Address
Last octet binary
Borrow 1 bit from host part, give it to network part, /25
10000000255.255.255.128Subnet mask
00000000 10000000
192.168.1.0 192.168.1.128
Addresses
34© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Subnetting 192.168.1.0/24
Borrow 2 bits from host part, give to network part, /26
11000000255.255.255.192Subnet mask
00000000 01000000 10000000 11000000
192.168.1.0 192.168.1.64 192.168.1.128 192.168.1.192
Addresses
35© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Subnetting 192.168.1.0/24
Borrow 3 bits from host part, give to network part, /27
11100000255.255.255.224Subnet mask
00000000 00100000 01000000 01100000 10000000 10100000 11000000 11100000
192.168.1.0 192.168.1.32 192.168.1.64 192.168.1.96 192.168.1.128 192.168.1.160 192.168.1.192 192.168.1.224
Addresses
36© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Subnetting 192.168.1.0/24
Borrow 4 bits from host part, give to network part, /28 192.168.1.128 192.168.1.144 192.168.1.160 192.168.1.176 192.168.1.192 192.168.1.208 192.168.1.224 192.168.1.240
Subnet mask 255.255.255.240 11110000
10000000 10010000 10100000 10110000 11000000 11010000 11100000 11110000
00000000 00010000 00100000 00110000 01000000 01010000 01100000 01110000
192.168.1.0 192.168.1.16 192.168.1.32 192.168.1.48 192.168.1.64 192.168.1.80 192.168.1.96 192.168.1.112
And so on…
37© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Subnetting 192.168.1.0/24
� Every time you borrow another bit you:
Double the number of subnets
Halve the size of the subnets
� Each subnet has a network address, a broadcast address, and everything in between is a host address.
� Here are some ways of visualising the process.
38© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Subnetting 192.168.1.0/24
252248240224192128Subnet mask
26143062126No of hosts
48163264128Bit value/ network size
/30/29/28/27/26/25Prefix
643216842No of networks
654321Bits borrowed
39© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Address space
� Make a spreadsheet or table with numbers 0 to 255
40© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Subnet chart
41© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Subnetting
� There are many subnet calculators, but you will not be able to use them in exams.
� Start with the biggest subnet and work down to the smallest.
� Make sure the subnets are valid sizes with valid subnet masks.
� Make sure that there are no overlaps.
42© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
Ping and traceroute
� Ping sends an ICMP message. If all is well, the destination replies. If not, a router may reply to say the destination is unreachable, or the ping may time out.
� Traceroute sends a series of messages so that each router along the path replies. You get a list of addresses of all the routers.
� ICMP: Internet Control Message Protocol
43© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
IPv6
� Development started in 1990s because of concerns about IPv4 addresses running out
� A whole new protocol suite – not just layer 3
� Uses 128-bit hierarchical addressing, written using hexadecimal
� Simpler header
� Integrated security – authentication, privacy
� Quality of service mechanisms
44© 2007 Cisco Systems, Inc. All rights reserved. Cisco Public
