Ip Addresses

Published Date: 02 Nov 2017

When a client computer is added to a network or the internet the client has to have Dns and Dhcp or dynamic host configuration protocol this protocol uses client server architecture which are servers setup particularly set up to automate the process of assigning IP addresses within a network this is usually done using IPv4 and Dhcp version 4 usually when the computer sends a request to the server via a broadcast the Dhcp server sends a unicast acknowledgement to say that im here the client computer then requests an IP address and lease the Dhcp server broadcasts the address and lease time this is done so that other Dhcp servers hear this and don't give out the same addresses or lease time though the trouble with IPv4 and Dhcp4 are the limitations of the number of IP addresses aren't sufficient to sustain the growing number of IP addresses. IPv6 was invented to prevent IP addresses dwindling to nothing.

IP addressing requirements

The requirements for assigning IP addresses on a network is that "each computer and other hardware on the network should have its own unique IP address ,subnet mask on the network and default gateway "Microsoft 70-291 page 3 Gregg Bott Redmond Washington 2004" .boot p allows clients on the network to collect settings and information from the Dhcp server and to allow broadcasts to be passed through router interfaces.

Statefull static and stateless dynamic

"The difference between static and dynamic IP addressing in IPv6 is that static IP addressing is exactly what it suggests the IP address never changes this can be used for web servers that are used by the public to access a site, if you have an email server, ftp server or dns server for multiple sites . this is done by the administrator giving each client pc an address and reserving the address in address reservations this is done by configuring the server with the IP and mac address of the host you want to reserve the address for this will reserve the address and only give that client that address which is called stateful addressing dynamic stateless addressing or dynamic IP addressing. is done by solicitation messages sent by the server to client pc's the pcs respond and request that an IP address is given the server responds with an address the clients then respond by asking about the lease time and address the server responds with the address and lease time and the client responds with a reply of yes or no to the address.

Dynamic address assignment

There are many different ways to configure Dhcp v6 to give out IP addressing information "To function effectively, the server will need to be configured with an address pool, timing information, and any other information that needs to be distributed across the network."Address pools set an acceptable address range for clients by using address reservations which are static addresses for servers which have to have static addresses on the network so that they can be found easily on the network or webservers on the internet .the setup of the network is dependant on the size of the organization i.e for example a medium to large enterprise with more than one office and multiple subnets with hundreds of clients the server needs to have address pools configured which define what addresses can be given out as well as the lease times for T1 and E1 lines also you can configure address pools for trusted and non trusted networks for a medium to large organisation Dhcp relay agents may be required to be setup to send and receive messages on certain unicast addresses relay agents listening on client networks should be listening for multicast messages.there should be no need to use statefull addressing in this instance though nat and pat would be used to translate inside addresses to global addresses.

Method 1 Dynamic Addressing unicast addressing

Specific way is to use global unicast addresses "it is anticIPated that global unicast addressing will be used for internet based traffic ."the advantages of using global unicast addresses easier address allocation of addresses to each topological hierarchie, allows routers to be aggregated more easily this is good for small businesses because they can set the subnet bits to zero and have a flat internal structure, medium sized businesses could use all the subnet bits to perform subnetting and each subnet would be identified by its own subnet id this would allow 65,535 subnets which uses all 16 bits .larger organisations could use the bits to create hierarchical subnets. The prefixes used in global unicast addressing are n for the global routing prefix, m for the subnet identifier, the interface ID 128-n-m is used to uniquely identify the device on the network unicast addresses are globally reachable and identified by the prefix 001.

Method 2 Dynamic Addressing Multicast addressing

"Multicast addressing is used to allow a single device to send a datagram to multiple devices"

(http://www.tcpIPguide.com/free/t_IPv6MulticastandAnycastAddressing.htm") first 8 bits of the address are always 11111111 or ff in hexadecimal are used to state that the address is a multicast address . Multicasting sends 1 datagram to multiple clients internet protocol version 6 provides much better multicasting features and abilities than internet protocol version 4 and also provides more multicast addresses it provides groups of devices a multicast group that all nodes belong to.multicasting is very versatile because there are many different types of addresses there is multicasting on a local link or link local address or one that multicasts on a local site this allows router to predict how widely they can multicast and propagate datagrams across the network. Multicasting sends streams of data to agroup it is very efficient and optimises the network and reduces the load on the network. Multicasting is scalable over different sizes of networks and clients are given the option to listen or not .

Advantages of unicast addressing Unicasting is secure Unicasting has the biggest load of addresses flexibility for organisations to sub devide Greater meaning to IP addresses Globally unique addressing. Disadvantages of unicast addressing Possibility that duplicate addresses could be given out on 2 different network segments. Possibility that local addresses maybe leaked if border routers are not set. Connection timeouts are possible when two organisations dns servers both claim to be authoritive using different content this may cause a connection attempt to the closest host which may cause timeouts. Advantages of Multicast addressing near real time delivery of messages to host group. High scalability due to the reduction of the amount of services required. Less bandwidth is consumed using multicast addressing. IP multicasting is used to provide efficient multicast services to clients that are not on the same network segment. Disadvantages of multicast addressing Multicasting to many addresses is unreliable and may not send addressing information to all hosts. Routers must retain membersh IP information.