IP AddressingIP Addressing

Lecture # 1Hassan Shuja01/31/2006

IP AddressingIP Addressing What is itWhat is it

– An IP address is an address used to uniquely An IP address is an address used to uniquely identify a device on an IP networkidentify a device on an IP network

– An address is a 32-bit numeric address written as An address is a 32-bit numeric address written as four numbers separated by periodsfour numbers separated by periods

– IPv4 is made up of 5 different classesIPv4 is made up of 5 different classes Class A,B,C,D,EClass A,B,C,D,E

– Class A,B,C are standard Internet and intranet Class A,B,C are standard Internet and intranet routable addressesroutable addresses

Private addresses are only intranet routablePrivate addresses are only intranet routable– Class D are Multicast addresses and class E are Class D are Multicast addresses and class E are

used for researchused for research

IP AddressingIP Addressing What is itWhat is it

– IP addresses are used by routers to route packets IP addresses are used by routers to route packets to destinationsto destinations

Class First Octet Network Bits Host BitsA 1 to 126 8 24B 128 to 191 16 16C 192 to 223 24 8D 224 to 239E 240 to 247

MulticastResearch

Private Addressing10.0.0.0 to 10.255.255.255 (10/8)172.16.0.0 to 172.31.255.255 (172.16/12)192.168.0.0 to 192.168.255.255 (192.168/16)

IP AddressingIP Addressing What is itWhat is it

– An address is made up of a network portion and a An address is made up of a network portion and a host portionhost portion

The network portion is used to identify the networkThe network portion is used to identify the network– Does not change within a network or subnetworkDoes not change within a network or subnetwork

The host portion is the range of addresses assigned The host portion is the range of addresses assigned to nodes on the networkto nodes on the network

– Standard Network & Host portion of Class A,B,C Standard Network & Host portion of Class A,B,C

Class AClass A nn h.h.hh.h.h

Class BClass B n.nn.n h.h h.h

Class CClass C n.n.nn.n.n h h

IP AddressingIP Addressing Obtaining IP AddressesObtaining IP Addresses

– IANA is the governing body for all IP addresses and IANA is the governing body for all IP addresses and has regional registry organizationshas regional registry organizations

American Registry for Internet Numbers (ARIN) American Registry for Internet Numbers (ARIN) supports North America regionsupports North America region

– IANA requires justification before they allocate a IANA requires justification before they allocate a range of IP addresses for somebody range of IP addresses for somebody

– Most IP addresses these days are obtained through Most IP addresses these days are obtained through ISPsISPs

IP AddressingIP Addressing Subnet MaskSubnet Mask

– A 32-bit value that is used to distinguish the A 32-bit value that is used to distinguish the network ID portion of the IP address from the host network ID portion of the IP address from the host

IDID – Subnet Masks determines size of local subnetSubnet Masks determines size of local subnet– Helps determine if two addresses are on the same Helps determine if two addresses are on the same

networknetwork

Default GatewayDefault Gateway– Default Gateway handles requests that are Default Gateway handles requests that are

destined for outside of the local subnetdestined for outside of the local subnet– The address of the router on the local subnetThe address of the router on the local subnet

IP AddressingIP Addressing SubnettingSubnetting

– A Method use to break up large networks into A Method use to break up large networks into smaller onessmaller ones

Splits the host field into a subnet and host sectionSplits the host field into a subnet and host section– This splitting is determined by the subnet maskThis splitting is determined by the subnet mask

The Network field remains unchangedThe Network field remains unchanged– Subnetting allows for ease of administration, Subnetting allows for ease of administration,

conservation of IP addresses, limit broadcast conservation of IP addresses, limit broadcast domains, and efficient use of resourcesdomains, and efficient use of resources

Converting Decimal to BinaryConverting Decimal to Binary– http://www.cuyamaca.net/curtis.sharon/pdf/http://www.cuyamaca.net/curtis.sharon/pdf/

CiscoLabs/lab_1_2_5.pdfCiscoLabs/lab_1_2_5.pdf