CN2668 Routers and Switches Kemtis Kunanuraksapong MSIS with Distinction MCTS, MCDST, MCP, A+

Agenda Chapter 4: IP Addressing Exercise Quiz

Four methods are used to identify devices and programs ▫MAC Address ▫Using an IP address ▫Using character-based names  Such as domain names, host names, and NetBIOS names  Host names and NetBIOS names are often just called computer names ▫Using a port address Addressing on a Network

A number that uniquely identifies a device ▫Network ID – for the network segment to identifies the host network ▫Host ID – identifies the host within the network Consist of a 32-bit binary number Octet ▫Divided into four groupings of eight bits each = IP Address (IPv4)

Class A – to Class B to Class C to Class D to ▫Are used for multicasting to a group Class E to ▫Are reserved for experimental and future use Class D and E Are not assigned to individual devices The first and last of addresses of each class are reserved IP Address Classes

The first byte of the IP address must fall within the following ranges ▫1 through 126 ▫128 through 191 ▫192 through 223 IP addresses that begin with 0, 127, or 224 through 225 are invalid The host ID cannot be all binary 0s or 1s (all 0s or all 255s) No number in an IP address can be greater than 255 IP Address Validity

In your own network ▫ through ▫ through ▫ through ▫They will not be routable on the Internet ▫They use gateway to get out to Internet Private IP Ranges

Tells a TCP/IP host how to interpret IP address by defining what portion of the IP address is the network ID and host ID The default subnet masks ▫Class A: ▫Class B: ▫Class C: Classless interdomain routing (CIDR) notation ▫ /24 Network Addressing (Subnet Mask)

To determine whether a destination host is on the same or a different network ▫If on the remote network, it will use default gateway to communicate AND operation to determine network and host Classful subnet mask ▫Subnet masks that use either all ones or zeroes in an octet Subnet Masks

Broadcast Address If all the binary digits in the host identifier are ones ▫ /24 has as broadcast address ▫ /27 has as broadcast address Flooded broadcasts ( ) ▫Broadcasts for any subnet Directed broadcasts ▫Broadcasts for specific subnet

Subnet Masking To match the physical layout of the organization To match the administrative structure To plan for future growth To reduce network traffic See Table 4-3 on Page 96

Subnetting Formulas 2 y = # of usable subnets ▫Y is the number of bits borrowed 2 x -2 = # of usable hosts per subnet ▫X is the number of bits remaining in the host field after borrowing /28 (See Figure 4-13 on Page 100) ▫4 bits borrowed for the mask  16 usable subnets ▫4 bits left for host  14 usable hosts per subnet

Summarization (supernetting) To allow many IP subnets to be advertised as one. See Table 4-6 on Page 102 ▫All 4 subnets share the same left 22 bits ▫Routing table can aggregate it into /22 rather than 4 subnets

VLSM Variable Length Subnet Masking ▫a technique that allows network administrators to divide an IP address space to subnets of different sizes. ▫Commonly done with Class C address ▫RIP Version 1 and IGRP do not support  They do not carry subnet mask information in their routing table updates ▫With main IP address, you should start with the highest host required  See tech_note09186a00800a67f5.shtml#vlsmexample

VLSM (2) ▫netA: must support 14 hosts ▫netB: must support 28 hosts ▫netC: must support 2 hosts ▫netD: must support 7 hosts ▫netE: must support 28 host Calculate the subnet mask ▫netB: /27 host address range 1 to 30 ▫netE: /27 host address range 33 to 62 ▫netA: /28 host address range 65 to 78 ▫netD: /28 host address range 81 to 94 ▫netC: /30 host address range 97 to 98

Hexadecimal Numbers Base 16 (0 – F) Easiest way to convert any base number is ▫From X Base -> Binary -> X Base

IPv4 versus IPv6 128 bits and expressed as hexadecimal numbers 32 numbers divide into 8 groups of 4 numbers each 2001:702:21::/48 ▫The first 48 bits identify the network ▫:: means the rest are zeroes

IPv6 Transition Dual Stack ▫Enabling IPv6 on all routers, switches, and end nodes. ▫IPv4 is still enable Tunneling ▫Encapsulates IPv6 traffic inside IPv4 packets ▫To send IPv6 packets through the network that does not support IPv6 (v6 -> v4 -> v6)

Assignment Review Questions ▫1 – 24 Case Projects ▫2