Chapter 5 IPv4 and IPv6 Address

NAT (Network Address Translation)

A feature available on routers that allows private IP addresses used within an organization to be translated into a pool of one or more publicly routable IP addresses.

What is a IPv4 address ?

A logical address consisting of 32 bits. written in dotted-decimal notation. each number represents a 8 bit part (Octet) of the 32 bit IP address.

DHCP (Dynamic Host Configuration Protocol)

A network service that provides automatic assignment of IP addresses and other TCP /IP configuration information.

NDP (Neighbor Discovery Protocol)

A protocol that is part of the IPv6 protocol suite, used to discover and exchange information about devices on the same subnet (neighbors). In particular, it replaces the IPv4 ARP protocol.

What are the Layer 3 Addressing Schemes.

Internet Protocol (IPv4 , IPv6). AppleTalk by Apple. Interwork Packet Exchange (IPX) by Novell.

Link-Local IP addresses (Zeroconf/APIPA)

Is a non-routable IP address usable only in a local subnet. APIPA and Zeroconf are examples of a technology that assigns link-local IP addresses.

formula for calculating the number of created subnets

Number of created subnets = 2s (exponent) S = number of borrowed bits to get number of borrowed bits (S): *borrowed bits (S)* = bits in custom subnet mask - bits in classful subnet mask

last available host address

One less than the broadcast address.

first available host address

One more than the network address.

APIPA (Automatic Private IP Addressing)

A Windows feature that allows a networked device to self assign an IP address from the 169.254.0.0 /16 (class b) private/intranet network if it isn't assigned a IP address from a DHCP server. Only usable on the device's local subnet /not routable

Binary Numbers

0s and 1s. Known as base2.

Octet

8 bits. Portion of IP address (32 bits).

What is a IP address composed of ?

An IP address is composed of 2 addresses. A network (left most part) and a host (right most part) address.

ICANN (Internet Corporation for Assigned Names and Numbers)

Assigns a block of IP Addresses to a regional internet registry. example: (ARIN & IANA)

Borrowed Bits

Bits added to a classful subnet mask. the number of borrowed bits used determines how many subnets are created and number of hosts available. *number of borrowed bits* = bits in custom subnet mask - bits in classful subnet mask

BOOTP

Boot Protocol/Bootstrap Protocol is a method of assigning IP addresses, Subnet mask and default gateway information to disk-less workstations. Cannot go beyond a local device's subnet because the requests are sent out as a broadcast. Requires a statically configured database of MAC to IP address mappings.

What are the default classful Masks ?

Class A = 255.0.0.0 or /8 Class B = 255.255.0.0 or /16 Class C = 255.255.255.0 or /24

Private IP networks

Class A Range: 10.0.0.0 - 10.255.255.255 subnet: 255.0.0.0 or /8 Class B Range: 172.16.0.0 - 172.31.255.255 subnet: 255.255.0.0 or /16 Class B Range: 169.254.0.0 - 169.254.255.255 subnet: 255.255.0.0 not routable used by APIPA (automatic private ip addressing). Class C Range: 192.168.0.0 - 192.168.255.255 subnet: 255.255.255.0 or /24

What are the IP addressing components needed by a network device ?

IP address Subnet Mask Default Gateway Server addresses

Dynamic IP configuration

IP configuration given dynamically by either BOOTP (Bootstrap Protocol) or DHCP (Dynamic Host Configuration Protocol)

IPv6 address types

Global Unicast Addresses - start with the first 4 hex characters 2000 to 3999 Link-local Addresses - begins with FE80 (local subnet address non routable) Multicast Addresses - begins with FF.

NDP ICMPv6 five packet types for important jobs

Router Solicitation: hosts inquire with router solicitation messages to locate routers on a attached link. Router Advertisement: Routers advertise their presence together with various link and internet parameters. either periodically or in response to a router solicitation message. Neighbor Solicitation: are used by nodes to determine the link layer address of a neighbor, or to verify that a neighbor is still reachable. Neighbor Advertisement: are used by nodes to respond to a neighbor solicitation message. Redirect: used by routers to inform of a better first-hop router for a destination.

Default Gateway

Routes traffic from the sender's subnet to the destination's subnet.

Locating network services (zeroconf)

SLP (Service Location Protocol) SSDP (Simple Service Discovery Protocol) by Microsoft DNS-SD (Domain Name Service - Service Discovery) by Apple. a feature of Zeroconf

EUI-64 (Extended Unique Identifier-64)

The IEEE standard defining 64-bit physical addresses. the Extended Unique Identifier (EUI-64) format can be used to cause a router to automatically populate the low-order (host bits) 64 bits of a IPv6 address based on the interface's MAC address.

Subnetting

The act of dividing a network into smaller logical sub-networks.

Block size

The block size can be calculated by subtracting the subnet mask value of the interesting octet from 256. helps determine by what increment you will be counting by in the interesting octet.

network address

The first address in the subnet.

NDP (Neighbor Discovery Protocol)

The protocol used to discover the network address and MAC address of neighbors on the same network (subnet). used by IPv6. replaces ARP of IPv4.

what are the 3 types of IPv6 data flows?

Unicast Multicast Anycast

Zero Configuration (Zeroconf)

Zeroconf is a technology supported on most modern operating systems that performs three functions. *Assigning Link-local IP addresses *Resolving computer names to IP addresses. *Locating network services. that allows network devices to communicate in a local subnet.

Subnet Mask

a 32 bit address that is used to show what part of the IP address belong to the network and which part belongs to the host. The 1s in the subnet mask signify the network part and the 0s signify the host part of a IPv4 address.

Static IP configuration

a manually assigned IP address (IP reservation) given to a network device.

intranet

a network designed for the exclusive use of computer users within an organization that cannot be accessed by users outside the organization.

IPv6 Unicast

a one to one communication flow.

IPv6 Multicast

a single IPv6 address can represent multiple devices on a network.

IPv6 Anycast

a single IPv6 address is assigned to multiple devices. it is a one-to-nearest communication flow (from the router's perspective).

What are the IP address classes ?

are ranges of the value given in the 1st octet that are categorized as follows : Class A: 1 - 126 range 255.0.0.0 Mask /8 prefix notation. Class B: 128 - 191 range 255.255.0.0 Mask /16 prefix notation. Class C: 192 - 223 range 255.255.255.0 Mask /24 prefix notation. Class D: 224 - 239 range used as destination addresses for Multicast networks. Class E 240 - 255 range are reserved for experimental use. Number 127 is used as a loop-back address that represents the device on the local network.

How is the default subnet mask determined for a given IP address ?

by the value of the IP address's first octet.

IPv6 address structure

contains hexdecimal digit in the range of 0 - F. 4 bits per digit (nibble) x 4 digits per field x 8 fields = 128 bits. -leading 0s in the field can be omitted. -contiguous fields containing all 0s can be represented with a double colon (can only be done once per address)

ARIN (American Registry for Internet Numbers)

is responsible for IP address assignment in North America.

IANA (Internet Assigned Numbers Authority)

is responsible for IP address assignment outside of North America.

Interesting Octet

is the octet containing the last 1 in the subnet mask.

broadcast address

last address in the subnet.

Resolving computer names to IP addresses (zeroconf)

mDNS (Multicast Domain Name Service) is a technology that can resolve computer names to their corresponding IP address on a local subnet. without the aid of DNS or WINS. a feature of Zeroconf

formula for calculating the number of available hosts

number of assignable IP addresses = 2h (exponent) - 2 H = number of host bits in subnet mask to get number of host bits (H): number of host bits (H) = 32 (IPv4 is made of 32 bits) - Number of bits in subnet mask.

CIDR (Classless Inter Domain Routing)

shortens a classful subnet mask by keeping the bits that are similar and removing the bits that differ. also called route aggregation.

VLSM (Variable Length Subnet Mask)

the act of taking your network address and dividing it into smaller sub-networks. by extending the number of network bits in the network's subnet mask.

IPv4 Unicast

traffic travels from a single source device to a single destination device.

IPv4 Broadcast

traffic travels from a single source device to all destinations on the network subnet (broadcast domain).

IPv4 Multicast

traffic travels from a single source to multiple yet specific destinations.

what are the 3 types of IPv4 data flows?

unicast broadcast multicast