CCNA Discovery 1 Module 5

1
CCNA Discovery 1 Module 5

• Network Addressing

2
Network Addresses

• IPv4
• Ipv6
• AppleTalk
• IPX

3
IP Address Purpose

• A host needs an IP address to communicate on the
  Internet
• The address must be unique and properly
  configured
• Packets traversing the Internet have a source and
  destination IP address specified within them
• The address is assigned to the NIC on the host

4
Base Conversions

• Binary is Base 2
• Decimal is Base 10
• Hexadecimal is Base 16

5
IP Address Structure

• 32 bits long
• Represented as four decimal numbers separated by
  a dot (dotted-decimal)?
• Each position in dotted-decimal notation
  represents eight bits, or one octet
• 32 bit addresses are specified by IPv4

6
Subnet Masks

• Determine which portion of an IP address
  identifies the host and which portion identifies
  the network
• Binary 1s in a subnet mask identify network bits
• Binary 0s in a subnet mask identify host bits
• May be written in dotted-decimal notation
  (255.255.0.0)?
• May be written in slash or CIDR notation (/16)?

7
Network Classes

• Determined by the first octet of the address
• 0-127 is Class A
• 128-191 is Class B
• 192-223 is Class C
• 224-239 is Class D (Multicasting)?
• 240-255 is Class E (Experimental Use)?
• Default Subnet Masks
• Class A is 255.0.0.0 or /8
• Class B is 255.255.0.0 or /16
• Class C is 255.255.255.0 or /24

8
Special Addresses

• Network ID
• Host portion of address is all 0s
• Broadcast
• Host portion of address is all 1s
• Multicast
• Class D Address
• Dest. MAC Address begins with 01-00-5E
• Dest. MAC Address ends with last 23 bits of IP
  address converted into hex.

9
Private Networks

• 127.0.0.0/8 is reserved for loopback testing
• 10.0.0.0/8 is a Class A private network
• 172.16.0.0/16 172.31.0.0/16 are 16 Class B
  private networks
• 192.168.0.0/24 192.168.255.0/24 are 256 Class C
  private networks
• 169.254.0.0/16 is a private Class B network for
  APIPA

10
Network Boundaries

• Network addresses must exist within confined
  regions
• Network boundaries are typically identified by
  router interfaces
• Remember that routers are also boundaries for
  broadcasts, thus DHCP is stopped at these
  boundaries without the use of a relay agent

11
Getting an IP Address

• Static Assignment
• The administrator configures the address manually
• DHCP
• Address are received from a Dynamic Host
  Configuration Protocol server
• APIPA
• Automatic Private IP Addressing, for use in
  networks configured for DHCP when no DHCP server
  is available

12
DHCP

• Host broadcasts a DHCP Discover to find available
  DHCP servers/addresses
• Server(s) unicast a DHCP Offer to the host with a
  suggested IP address
• Host unicasts a DHCP Request to the server,
  asking to use a specified IP address
• The server unicasts a DHCP Acknowledgment (ACK)
  to the host
• Under some circumstances, the server may unicast
  a DHCP Negative Acknowledgment (NACK), which
  rejects the host's DHCP Request

13
DHCP (cont'd)?

• DHCP can provide the following items to a host
• IP Address
• Subnet Mask
• Default Gateway
• DNS Server
• DNS Domain Name
• Many more...

14
NAT (Network Address Translation)?

• Used to translate addresses from one network to
  another
• Most commonly used to translate private addresses
  to public addresses