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Showing posts from January, 2008

TCP IP Topics

Coming here more on TCP/IP stuff... Keep watching TCP Buffer Sizing TCP uses what is called the "congestion window", or CWND, to determine how many packets can be sent at one time. The larger the congestion window size, the higher the throughput. The TCP "slow start" and "congestion avoidance" algorithms determine the size of the congestion window. The maximum congestion window is related to the amount of buffer space that the kernel allocates for each socket. For each socket, there is a default value for the buffer size, which can be changed by the program using a system library call just before opening the socket. There is also a kernel enforced maximum buffer size. The buffer size can be adjusted for both the send and receive ends of the socket. To get maximal throughput it is critical to use optimal TCP send and receive socket buffer sizes for the link you are using. If the buffers are too small, the TCP congestion window will never fully open up. I

Mobile IP and Simple IP in CDMA networks

What is Simple IP and Mobile IP? --------------------------------- The IS-2000 network using SO33 (see Packet Data Service Configurations ) for high speed packet data transmission supports connections to the public network or a private network using either mobile IP or simple IP protocol. A packet data session begins when the user invokes packet data service. A packet data session ends when the user or the network terminates packet data service. During a particular packet data session, the user may change locations (point of attachment). For simple IP protocol, a wireless device must obtain a new IP address (and lose existing connections) every time it changes its point of attachment. That is, moving from the coverage area of one PDSN to another PDSN constitutes a change in packet data session because a new IP address is assigned by the new PDSN. A packet data session and a PPP session are concurrent in simple IP, that is, the existence of the packet data session is dependent upon a PP