 I am working as assistant professor in computer science and engineering department at Walton Institute of Technology, Solopole. Today, in this lecture, we will going to discuss about the host configuration. Now, let us see the learning outcomes of host configuration. At the end of this session, the students will be able to explain the concept of DHCP protocol and second one is students will be able to explain the concept of DHCP protocol operations. This is agenda in this lecture, we will going to discuss about the DHCP protocol, DHCP packet format, DHCP configurations. This is about the DHCP protocol. So, DHCP is in dynamic host configuration protocol, it is a network management protocol used to dynamically assign an IP address to any devices or nodes on a network, so they can communicate using IP addresses. If the user want to assign dynamically some IP address to devices, in that time the user can use this IP address protocol. DHCP protocol automates and centrally manages these configurations rather than requiring network administrator to manually assign IP address to all networking devices. DHCP can be implemented on a small network as well as large enterprises network. It would not use in a larger LAN, VAN, MAN because it can in this protocol the user can manually assign some IP address to devices. This is a DHCP packet format, while transmitting the data from one device to another device, the user can send the data in the form of packet. If the user is sending the data in the form of packets, what are the different fields they have to enter? This DHCP packet format can contains operation code, hardware type, hardware length, hop count, transaction ID, number of seconds, flags, client IP address, your IP address, server IP address, gateway IP address, hardware addresses, server name, boot file name, lastly options. Now let us see in detail about each and every fields of DHCP protocol. Now first one is operation code. This is an 8-bit field defines the type of DHCP packet, while transmitting the packet from client to the server, if the packet contains one it is a type of request, if the packet contains two it is a reply. Second one is hardware type. This is an 8-bit field defining the type of physical network used while transmitting the packets. For example, Ethernet value is 1, Ethernet value Ethernet means this is a type of cable, the different types of cables are then Ethernet that are 10 base 2, 10 base 5, 10 base f, 10 base t, like these four different types of cables are there that physical cables we have to use for transmitting the packets from one device to the another devices. Next one is hardware length. This is an 8-bit field defining the length of the physical address in bytes. For example, Ethernet value is 6, hop count. This is an 8-bit field defining the maximum number of hops the packet can travel from communication from sending the data to one device to the another devices. Transaction ID. This is an 4-byte field carrying an integer while transmitting the data, how many transactions can be happened in both client side as well as server side, how to count in the transaction ID. Next one is number of second. This is an 16-bit field that indicates the number of seconds elapsed since the time the client started the board flags. This is an 16-bit field in which only the leftmost bit can be used and the rest of the bit should be set to 0. It means if the value is 0, it is an unicast, if the value is 1, it is broadcast. Client IP address. This is an 4-byte field that contains the client IP address. Your IP address, this is an 4-byte field that contains the client IP address. It is filled by the server at the request of the client. Next one is server IP address. This is an 4-byte field that contains the server IP address. It is filled by the server in a reply message. Gateway IP address. This is an 4-byte field that contains the IP address of router. It is filled by the server in a reply. If the user want to communicate in a different network, if the for example, if the client is there in one LAN, if the server is there in another LAN, then that time we have to use the concept of Gateway IP address. Because we have to convert from IP address from one unicast to broadcast and broadcast to the unicast. Client hardware address. This is a physical address of the client. Server hostname. This is 64-byte field that is optionally filled by the server in a reply message. This is an next boot file name. This is an 128-byte field that is optionally filled by the server in a reply packet. Option. This is an extra field available to the user to add any extra information in a packet. This is a 64-byte field with a dual purpose. It can carry either additional information or some other specific vendor information. That is if the user want to add some other information in a packet, they can use this option field to add the information. Now, this is a question-answer session. Think and write. This can contains two questions that are which protocol and port does DSCP can run. Second one is, what are the different characteristics of DSCP? Now, pass the video and answer the above questions. Now, let us see the answer for these two questions. First one is, protocol is UDP and port numbers 67 can be used in the server side and port number 68 can be used in a client side. Second question answer is, characteristics of DSCP protocol. All communications initiated by the client. Second one is, uses UDP port number 67 for the client and port number 68 for the server. This unicast when client has IP address, supports multiple servers, provides dynamic assignment, allows static assignments, doesn't interact with DNS services. DSCP configuration. Here it can contains two or three DSCP configurations that are static address allocation, dynamic address allocation and state transition. Now, let us see one by one in detail. First one is, static address allocation. DSCP server has a database that statically binds physical address to IP address. If the user want to assign some IP address to some machines in this static address allocation, if the user have assigned some IP address to some devices, it is fixed after assigning it is not possible to modify in a static address allocation. If the user want to assign already assigned IP address to some other machine, it means they can go to the dynamic address allocation. In the dynamic address allocation, DSCP has a second database with a pool of available IP addresses. The second database makes DSCP dynamic, it means if the client have send the one request to the server to assign some IP address to that request, then the client the server can search that IP address already stored in the server that stored IP address can manually assigns to the client request that IP address can be used in a client side. These are the different states of state transition of DSCP. First one is init state, initialization state, select state, requesting state, bound state, renewing state and then rebinding. Now, let us see in detail about the each states of DSCP protocol. First one is initialization. These are the different states can be used in a single diagram that is this one that is state transition diagram of DSCP protocol. In this diagram, first if the user started the booting, first they have to initialize the information. After initializing, it can discover some information related to the boot by using DSCP discover command. Then after initialization, they can go to the selecting state. In the selecting state, lots of options are available to the user for selecting some IP addresses that are already stored in a pool IP address database. And then after selecting and then select offer, they can go to the DSCP request. After requesting, they can go to the request state. And then the requesting state can go to the bound state. In the bound state, the user can wait until you get the acknowledgement from the server side. Then after getting the acknowledgement, they can get confirm that we have booted the system successfully. Here we have to use renewing and rebinding. If they can use for DSCP acknowledgement both in the renewing as well as rebinding, if it is not getting, then they can again they can go to the same procedure that is initializing, selecting, requesting and bound, renewing and binding. These are the different states we have to use in a stray transition diagram of DSCP protocol. These are the references have used for preparing this above PPT. Thank you.