BOOTP computer science for multiproc.ppt

BOOTP computer science for multiproc.ppt

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  Bootp Adeeba KH. Aboo PhD.student Seminarabout bootp supervised by: prof.D.Manar 1
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  2 introduction The information thatis held in each computer attached to a TCP/IP internet:  Its IP address  Its subnet mask  The IP address of a router  The IP address of a name server  The above information is usually stored in a configuration file and accessed by the computer during the bootstrap process  In the case of a diskless computer, the operating system and networking can be stored in ROM. But the above information cannot be stored in ROM.
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  BOOTP  BOOTP(Bootstrap Protocol)is client/server protocol designed to provide the information for a diskless computer or a computer that is booted for the first time  RARP provides only the IP address and not the other information  If we use BOOTP, we do not need RARP.  BOOTP is static.When a client workstation asks for the above info, it is retrieved from a fixed table. Every time the client asks for the info, it gets the same results. 3
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  BOOTP  UDP Ports BOOTP is the client’s use of the well-known port 68  if two hosts with same well-known port 68 use BOOTP at the same time in case of broadcasting the reply, both hosts receive the message. In this case, transaction ID is used  Using TFTP  If a client needs more information for booting, the client can use the pathname of a file sent by server which the client can find complete booting information.  The client can then use a TFTP message to get the rest of the needed information. TCP/IP Protocol Suite 4
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  5 Figure 1 Clientand server on the same network BOOTP places its packet inside a UDP packet (note that BOOTP is an application layer program).
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  Operation Steps involved inuse of the BOOTP protocol 1) BOOTP server uses UDP port 67 and waiting for a client 2) The client sends a BOOTP request message to the server. The client uses (0s )as the source address and all( 1s) as the destination address. 3) The server replies to the client with Either a broadcast or a unicast message using UDP destination port 68. 6
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  7 Figure 2 Clientand server on two different networks When client and server are on different networks, we need a relay agent, because client does not know IP address of server,. Relay agent knows the IP addr of the server.
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  Bootp Format 8
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  Bootp Format • Operationcode : request(1) or reply (0) • Transaction ID : set by the client and used to match a reply with the request • Number of seconds : indicating the number of seconds elapsed since the time the client started to boot • Your IP address : client address filled by server (in the client message) • Server IP address : in a reply message • Gateway IP address : IP address of a router in a reply message. 9
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  Bootp Format • Servername : the domain name of the server in a reply packet • Boot filename : the full pathname of the boot in a reply packet (128-byte) • Options : used in a reply message (64-byte) carrying either additional information (such as the network mask or default router address) or some specific information in case of magic cookie, options have following options. 10
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  Option format TCP/IP ProtocolSuite 11
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  Thank you TCP/IP ProtocolSuite 12