Work of DHCP Dynamic Host Configuration Protocol and PAT Port Address Translation

DHCP – Dynamic Host Configuration Protocol

• DHCP server is configured with a range of addresses
• Host 3 boots up and enters Initialize state
• It broadcasts a DHCP Discover message
• Then enters Select state
• DHCP servers send DHCP offer message
• Host 3 sends a DHCP request to one of the servers
• Host 3 enters the Request state
• DHCP server responds with a DHCP ack (with address)
• Host 3 enters the Bound state, accepting the lease

Network Address Translation – NAT

Operates at the edge of a company network, Converts the private IP addresses into one or more public addresses

Several flavours:

• Fixed private to public relationship – Static NAT
• Demand-based – when a private address needs external access, an address is taken from a pool of public ones and the conversion done at the edge router – Dynamic NAT
• Overload NAT – also called PAT – Port Address Translation

PAT – Port Address Translation

• User on IP Address ‘p’ and port ‘r’ sends packet for the outside
• Router converts this to IP address ‘w’ and port 36578
• Reply comes back for ‘w’ and 36578
• Router converts this to address ‘p’ and port ‘r’

• Mobile IP Procedures – Agent Discovery, Registration, Tunneling in Wimax

• Which OFDM Parameters Used in WiMAX

• Which is better AAC or SBC?

• Authentication and Access Control in Wimax

• Spatial multiplexing and Receive Diversity in Wimax