TCP IP Illustrated

The server responds with an rpc reply message across

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Unformatted text preview: he server registers each program, version, protocol, and port number by making a remote procedure call to the port mapper's PMAPPROC_SET procedure. 3. When the RPC client program starts, it calls the port mapper's PMAPPROC_GETPORT procedure to obtain the ephemeral port number for a given program, version, and protocol. 4. The client sends an RPC call message to the port number returned in step 3. If UDP is being used, the client just sends a UDP datagram containing an RPC call message (Figure 29.1) to the server's UDP port number. The server responds by sending a UDP datagram containing an RPC reply message (Figure 29.2) back to the client. If TCP is being used, the client does an active open to the server's TCP port number, and then sends an RPC call message across the connection. The server responds with an RPC reply message across the connection. The program rpcinfo(8) prints out the port mapper's current mappings. (It calls the port mapper's PMAPPROC_DUMP procedure.) Here is some typical output: sun % /usr/etc/rpcinfo -p program vers proto port 702 100005 1 tcp 699 100005 1 udp 702 100005 2 tcp 100005 2 udp 699 2049 100003 2 udp 709 100021 1 tcp 1036 100021 1 udp 721 100021 2 tcp 1039 100021 2 udp 100021 3 tcp 713 mount daemon for NFS mountd mountd mountd mountd NFS itself nfs niockmgr NFS lock manager niockmgr niockmgr niockmgr niockmgr file:///D|/Documents%20and%20Settings/bigini/Docu...homenet2run/tcpip/tcp-ip-illustrated/nfs_netw.htm (6 of 23) [12/09/2001 14.47.56] Chapter 29. NFS: Network File System 100021 3 udp 1037 niockmgr We see that some programs do support multiple versions, and each combination of a program number, version number, and protocol has its own port number mapping maintained by the port mapper. Both versions of the mount daemon are accessed through the same TCP port number (702) and the same UDP port number (699), but each version of the lock manager has its own port number. 29.5 NFS Protocol NFS provides transparent file access for clients to files and f...
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This test prep was uploaded on 04/04/2014 for the course ECE EL5373 taught by Professor Guoyang during the Spring '12 term at NYU Poly.

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