In a network address, all the host bits are 0... In a broadcast address, all the host bits are 1... 3 types of address Every network has: Network address – the first one Broadcast addr
Trang 1Addressing the
network IPv4
CCNA Exploration Semester 1
CCNA Exploration Semester 1
Chapter 6
Trang 2IP addressing – works at
OSI model layer 3
TCP/IP model Internet layer
TCP, UDP
IP
Ethernet, WAN
HTTP, FTP, TFTP, SMTP etc
Segment
Packet
Frame Bits Data stream
Trang 4Binary and decimal
Convert to 8-bit binary
Trang 556 -32 24
120 -64 56
Trang 611 -8 3
59 -32 27
3 -2 1
Trang 789 to binary
0 1 0 1 1 0 0 1
89 -64 25
25 -16 9
9 -8 1
Trang 852
52
Trang 985
85
Trang 10207
Trang 11Binary and decimal
Convert to 8-bit binary
Trang 12IPv4 address
192 168 21 17
11000000 10101000 00010101 00010001
octet octet octet octet octet
network part host part
255 255 255 0
11111111 11111111 11111111 00000000
Prefix /24 Subnet mask:
Trang 13Find the network address
192 168 21 17
11000000 10101000 00010101 00010001
In a network address, all the host bits are 0.
In a network address, all the host bits are 0.
192 168 21 0
11000000 10101000 00010101 00000000
The router needs to do this for every packet.
Trang 15Find the broadcast address
192 168 21 17
11000000 10101000 00010101 00010001
In a broadcast address, all the host bits are 1.
In a broadcast address, all the host bits are 1.
192 168 21 255
11000000 10101000 00010101 11111111
The broadcast is the last address in the network.
Trang 163 types of address
Every network has:
Network address – the first one
Broadcast address – the last one
Host addresses – everything in between
Trang 18Classful 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 A /8 255.0.0.0
Class B /16 255.255.0.0
Class C /24 255.255.255.0
Trang 19Classless addressing
Any suitable prefix can be used
We (and devices) need to know what the prefix is
More flexible, less wasteful
More flexible, less wasteful
Trang 25Calculating 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?
Trang 26192.168.1.70/24 – fill in the table
Last octet binary
Last octet decimal
Trang 27Last octet binary
Last octet decimal
Full
Host 01000110 70 192.168.1.70 Subnet mask 00000000 0 255.255.255.0 Subnet mask 00000000 0 255.255.255.0 Network 00000000 0 192.168.1.0 Broadcast 11111111 255 192.168.1.255 First host 00000001 1 192.168.1.1
Trang 28Calculating 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?
Trang 29192.168.1.70/26 fill in the table
Last octet binary
Last octet decimal
Trang 30Last octet binary
Last octet decimal
Full
Host 01000110 70 192.168.1.70
Subnet mask 11000000 192 255.255.255.192 Subnet mask 11000000 192 255.255.255.192 Network 01000000 64 192.168.1.64
Broadcast 01111111 127 192.168.1.127 First host 01000001 65 192.168.1.65
Last host 01111110 126 192.168.1.126
Trang 31Calculating 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?
Trang 32192.168.1.70/28 fill in the table
Last octet binary
Last octet decimal
Trang 33Last octet binary
Last octet decimal
Full
Host 01000110 70 192.168.1.70
Subnet mask 11110000 240 255.255.255.240 Subnet mask 11110000 240 255.255.255.240 Network 01000000 64 192.168.1.64
Broadcast 01001111 79 192.168.1.79
First host 01000001 65 192.168.1.65
Trang 34Unicast, 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 locallybroadcast address or 255.255.255.255 locally
Multicast – a message addressed to a group
of hosts Uses an address starting 224 - 239
Trang 35Private IP addresses
Unrestricted use on private networks Not
routed across the Internet
Trang 36Public IP addresses
Routed over the Internet
Master holder is IANA
Assigned to regional registries and then to ISPs
ISPs
ISPs allocate them to organisations and
individual users
Use is strictly controlled as duplicate
addresses are not allowed
Trang 38Network 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
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
Trang 39Dynamic addressing is best for workstations
Trang 40Blocks of addresses
Use Address range Summary
Network address 192.168.1.0 192.168.1.0/25 User hosts 192.168.1.1-127
Servers 192.168.1.128 - 191 192.168.1.128/26 Servers 192.168.1.128 - 191 192.168.1.128/26 Peripherals 192.168.1.192 - 223 192.168.1.192/27 Network devices 192.168.1.224 - 253 192.168.1.224/27 Router 192.168.1.254
Broadcast 192.168.1.255
Trang 41Subnetting 192.168.1.0/24
Address 192.168.1.0 00000000 Subnet mask 255.255.255.0 00000000
Last octet binary
Borrow 1 bit from host part, give it to network part, /25
Addresses 192.168.1.0
192.168.1.128
00000000 10000000 Subnet mask 255.255.255.128 10000000
Trang 42Subnetting 192.168.1.0/24
Borrow 2 bits from host part, give to network part, /26
Addresses 192.168.1.0
192.168.1.64 192.168.1.128
00000000 01000000 10000000
192.168.1.128 192.168.1.192
10000000 11000000 Subnet mask 255.255.255.192 11000000
Trang 43Subnetting 192.168.1.0/24
Borrow 3 bits from host part, give to network part, /27
Addresses 192.168.1.0
192.168.1.32 192.168.1.64 192.168.1.96
00000000 00100000 01000000 01100000
192.168.1.96 192.168.1.128 192.168.1.160 192.168.1.192 192.168.1.224
01100000 10000000 10100000 11000000 11100000 Subnet mask 255.255.255.224 11100000
Trang 4400000000 00010000 00100000 00110000
10000000
10010000 10100000
00110000 01000000 01010000 01100000 01110000
10110000 11000000
11010000 11100000 11110000 Subnet mask 255.255.255.240 11110000
Trang 45Subnetting 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
Trang 46Subnetting 192.168.1.0/24
Bits borrowed 1 2 3 4 5 6
No of networks 2 4 8 16 32 64 Prefix /25 /26 /27 /28 /29 /30 Prefix /25 /26 /27 /28 /29 /30
Bit value/
network size
128 64 32 16 8 4
No of hosts 126 62 30 14 6 2 Subnet mask 128 192 224 240 248 252
Trang 48Subnet chart
Trang 50Ping 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
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
Trang 51Development started in 1990s because of
concerns about IPv4 addresses running out
A whole new protocol suite – not just layer 3Uses 128-bit hierarchical addressing, written
Uses 128-bit hierarchical addressing, written using hexadecimal
Simpler header
Integrated security – authentication, privacy
Quality of service mechanisms
Trang 52The End The End