1 26-Aug-15 S Ward Abingdon and Witney College CCNA Exploration Semester 1 Addressing the network IPv4 CCNA Exploration Semester 1 Chapter 6

226-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 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

326-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Addressing topics Binary and decimal Types of IP addresses Assigning addresses Network part and subnet masks Calculating addresses Ping and Traceroute Utilities

426-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Binary and decimal Convert to 8-bit binary Convert to decimal

526-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester to binary

626-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester to binary

726-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 89 to binary

826-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester to decimal

926-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester to decimal

1026-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester to decimal

1126-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Binary and decimal Convert to 8-bit binary Convert to decimal

1226-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 IPv4 address octet network parthost part Prefix /24 Subnet mask:

1326-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Find the network address In a network address, all the host bits are The router needs to do this for every packet.

1426-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Logical AND Do a logical AND at each position

1526-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Find the broadcast address In a broadcast address, all the host bits are The broadcast is the last address in the network.

1626-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 3 types of address Every network has: Network address – the first one Broadcast address – the last one Host addresses – everything in between

1726-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Classful addressing network parthost part A network parthost part B network parthost part C

1826-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Classful addressing Easy to work out but very wasteful. Routers and hosts still assume class subnet masks by default Class A/ Class B/ Class C/

1926-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Classless addressing Any suitable prefix can be used We (and devices) need to know what the prefix is. More flexible, less wasteful.

2026-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Classless addressing / /16 mask Broadcast address Hosts to host addresses

2126-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Classless addressing / /24 mask Broadcast address Hosts to host addresses

2226-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Classless addressing / /22 mask Broadcast address Hosts to host addresses

2326-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Classless addressing / /22 mask Broadcast address Hosts to host addresses

2426-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Classless addressing / /28 mask Broadcast address Hosts to host addresses

2526-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Calculating addresses A host has IP address /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?

2626-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester /24 – fill in the table Last octet binary Last octet decimal Full Host Subnet mask Network Broadcast First host Last host

2726-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester /24 Last octet binary Last octet decimal Full Host Subnet mask Network Broadcast First host Last host

2826-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Calculating addresses A host has IP address /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?

2926-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester /26 fill in the table Last octet binary Last octet decimal Full Host Subnet mask Network Broadcast First host Last host

3026-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester /26 Last octet binary Last octet decimal Full Host Subnet mask Network Broadcast First host Last host

3126-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Calculating addresses A host has IP address /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?

3226-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester /28 fill in the table Last octet binary Last octet decimal Full Host Subnet mask Network Broadcast First host Last host

3326-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester /28 Last octet binary Last octet decimal Full Host Subnet mask Network Broadcast First host Last host

3426-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 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 locally Multicast – a message addressed to a group of hosts. Uses an address starting

3526-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Private IP addresses Unrestricted use on private networks. Not routed across the Internet – ( /8) – ( /20) – ( /24)

3626-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 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

3726-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Special addresses “all addresses” in default route. Hosts cannot be given addresses starting is loopback. Hosts cannot be given addresses starting and higher – reserved for experimental purposes local only to for teaching

3826-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 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

3926-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 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

4026-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Blocks of addresses UseAddress rangeSummary Network address /25 User hosts Servers /26 Peripherals /27 Network devices /27 Router Broadcast

4126-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Subnetting /24 Address Subnet mask Last octet binary Borrow 1 bit from host part, give it to network part, /25 Addresses Subnet mask

4226-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Subnetting /24 Borrow 2 bits from host part, give to network part, /26 Addresses Subnet mask

4326-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Subnetting /24 Borrow 3 bits from host part, give to network part, /27 Addresses Subnet mask

4426-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Subnetting /24 Borrow 4 bits from host part, give to network part, / Subnet mask And so on…

4526-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Subnetting /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.

4626-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Subnetting /24 Bits borrowed No of networks Prefix/25/26/27/28/29/30 Bit value/ network size No of hosts Subnet mask

4726-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Address space Make a spreadsheet or table with numbers 0 to 255 Link to show table

4826-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 Subnet chart

4926-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 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.

5026-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 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.

5126-Aug-15S Ward Abingdon and Witney College CCNA Exploration Semester 1 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

52 26-Aug-15 S Ward Abingdon and Witney College CCNA Exploration Semester 1 The End