© 2007 Cisco Systems, Inc. All rights reserved.Cisco Public ITE PC v4.0 Chapter 1 1 Network Addressing Networking for Home and Small Businesses – Chapter 5

ITE PC v4.0 Chapter 1 2 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Purpose of an IP Address  A logical network address that identifies a host  A host (end-user) must have a NIC card – workstations – servers – printers – router interface  Each packet will contain a source and destination IP address Packet Tracer Activity – Section 2

ITE PC v4.0 Chapter 1 3 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public IP addresses  32 binary digits  4 octets  Dotted decimal notation  IP Version 4 – most common form of IP addresses  Over 4 billion possible IP addresses

ITE PC v4.0 Chapter 1 4 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Binary Numbers  The IP address is made up of binary numbers (1 or 0)  Humans must be able to talk computer language to send data  We do this by converting our numbering system (Base 10 to binary)  Let’s try some... Convert 140 to binary Convert 10 to binary Convert to Base 10 Convert to Base 10 Time to play a game -- Online Activity – Section 3

ITE PC v4.0 Chapter 1 5 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Parts of an IP Address  Hierarchial – made up of 2 parts network host – determined by IP class  Similar to your phone number – Area code = network – phone number = host

ITE PC v4.0 Chapter 1 6 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Purpose of the Subnet Mask  Helps identify network bits (all 1s) and host bits  Boolean math or “ANDING”  What happens if both source and destination IP are on the same network??

ITE PC v4.0 Chapter 1 7 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Types of IP Addresses  Class A – Range – N.H.H.H – First bit in octet will be a 0 – Default subnet mask – can create over 16 million host addresses 2 24 – 2 = 16,777,214 to be exact why do you subtract 2??? – Used in large organizations

ITE PC v4.0 Chapter 1 8 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Types of IP Addresses  Class B – Range – N.N.H.H – First bit in octet will be a 1 – Default subnet mask – can create over 65,000 host addresses 2 16 – 2 = 65,534 to be exact – Used in medium-sized organizations

ITE PC v4.0 Chapter 1 9 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Types of IP Addresses  Class C – Range – N.N.N.H – First two bits in octet will be a 11 – Default subnet mask – can create 254 hosts 2 8 – 2 = 254 to be exact – Used in small organizations

ITE PC v4.0 Chapter 1 10 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Types of IP Addresses  Class D – Range – used for multicasting – not for commercial use  Class E – Range – reserved for experimental use – not for commercial use

ITE PC v4.0 Chapter 1 11 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Private IP Addresses  Helps avoid the problem of limited IP addresses  Allows hosts to communicate locally without each device needing a public IP address  Not routed on the Internet; blocked by the ISP router  Private address ranges assigned by RFC 1918 – Request for comment – all classes can be used for any size network – most use Class A

ITE PC v4.0 Chapter 1 12 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Unicast Address  Most common type of address  Intended for a specific host  Must have both destination IP and MAC in the header

ITE PC v4.0 Chapter 1 13 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Broadcast Address  All ones in the host portion of the IP address – Class C address: (N.N.N.H) – Broadcast address:  MAC address all Fs – FF-FF-FF-FF-FF-FF

ITE PC v4.0 Chapter 1 14 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Multicast Address  Send packet to a group of devices  Must use multicast address range  Range –  Used for remote gaming  MAC address begins with: – E

ITE PC v4.0 Chapter 1 15 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Using Static IP Addressing  Manually configured by the network administrator  Advantages – useful for printers, servers, etc – increased control of resources (security)  Disadvantages – time consuming

ITE PC v4.0 Chapter 1 16 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Using Dynamic IP Addressing  Automatic assignment of IP addresses  Useful if frequent change in users (wireless hotspot)  Uses DHCP (Dynamic Host Configuration Protocol) server  IP addresses leased for a period of time – if host is removed from the network (turned off), the IP address goes back into the pool of IP address  Preferred method for large networks – reduces the burden of network support

ITE PC v4.0 Chapter 1 17 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Configuring DHCP  If host is configured as DHCP client, it will not have a – IP address – Subnet Mask – Default Gateway  Clients send a DHCP address – Broadcast IP and MAC only DHCP server replies  Server responds with DHCP offer of an IP address  Host/client sends DHCP request asking server to use the IP address  Server responds with DHCP acknowledgment

ITE PC v4.0 Chapter 1 18 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Obtaining an IP address from DHCP server  Multifunction device (Linksys Router) provides services to clients (SOHO network)  Configuring the DHCP server – Enter router default IP address and subnet mask for internal interface IP = Subnet Mask = –On DHCP screen check range number of users lease time (24 hours by default)

ITE PC v4.0 Chapter 1 19 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Purpose of a Gateway  Used by the router to provide the path through which hosts on one network can communicate with hosts on a different network  Default gateway address – IP address of the router interface  If DHCP is being used – the DHCP server will automatically send the correct IP interface to the host to use as the default gateway

ITE PC v4.0 Chapter 1 20 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Address Assignment  ISR (Integrated Services Router)  Default IP address – Class C Private Address – Configured on router interface  Internal hosts must be assigned addresses within the same network

ITE PC v4.0 Chapter 1 21 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Address Management  Direct Connection – direct connection from PC to ISP through modem – public address assigned to the host  Connection through Integrated Router – more than one host needs access to the Internet – modem connected to ISR  Connection through Gateway Device – ISR and modem in one unit – connect directly to ISP

ITE PC v4.0 Chapter 1 22 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public Using NAT with a Home or Small Business Network  NAT (Network Address Translation)  Translates private IP addresses into unique public address for Internet communication  Only packets destined for different network use NAT

ITE PC v4.0 Chapter 1 23 © 2007 Cisco Systems, Inc. All rights reserved.Cisco Public