IEEE 802.21 MEDIA INDEPENDENT HANDOVER DCN: 21-08-0206-01-0000 Title: An Implementation Report on MIH Fragmentation Date Submitted: July 15, 2008 Presented at: Authors or Source(s):   Donald Baker (Telcordia) and Yoshihiro Ohba (Toshiba) Abstract: This document contains an implementation report for MIH fragmentation functionality 21-08-0206-01-0000

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Environment Two MIHFs on the same Windows XP PC run the MIH protocol using network socket CPU: Intel Pentium 4, Dual core 3.4 GHz Memory: 1.5G MIH Fragmentation : enabled MIH Acknowledgment: enabled Piggybacking ACK in response: disabled MIH Transport Protocol: UDP 21-08-0206-01-0000

Conditions aFragmentationThreshold = fragment size (except for the last fragment) = 1500 octets Message retransmission timer timeout value: 3000 ms, though not relevant Reassembly timeout timer value: 1000ms Number of fragments in a message: 1, 2, …, 20 To get larger fragments, an MIH_Get_Information request message was constructed with larger query strings Each data points represent 100 samples. No samples had dropped packets All times are milliseconds. All samples were collected in one execution of the program Sender and receiver are in the same address space which makes message transmit time negligible and may make "all packets sent" artificially low 21-08-0206-01-0000

Measured Data Data is based on "linearizing" the overall send process and taking time samples at key points in the process: 1) When the stack client (at the sender) has a message and begins the send Message call 2) Just before the first send packet is put on the socket 3) Just before the last packet is put on the socket. 4) Just after the last packet is received. 5) Just before the receiver sends the ack 6) Just after the sender receives the ack 7) When the stack client has the send message call return Series2 Series3 (1) Series1 (2) (3) (4) Series4 (5) Series5 (6) Series6 (7) Sender Message Processing Sender All Packets Sent Last Packet Transit Time Receiver Assembly Time ACK Transit Time Sender ACK Processing Time 21-08-0206-01-0000

Result (table view) 21-08-0206-01-0000 Frags Original size Sender Message Processing (ms) Sender All Packets Sent (ms) Last Packet Transit Time (ms) Receiver Assembly (ms) Ack Transmit Time (ms) Sender Ack Processing (ms) Total Send Time (ms) 1 52 0.22 0.00 0.17 0.77 0.13 0.87 2.17 2 2256 0.28 0.23 0.10 1.33 1.15 3.31 3 3356 0.35 0.39 1.39 3.32 4 4456 0.52 0.58 0.12 1.70 0.27 0.62 3.80 5 6656 0.80 2.03 0.29 4.46 6 7756 1.03 0.83 0.11 3.03 0.30 0.93 6.23 7 8856 0.98 0.94 0.09 0.33 0.43 4.94 8 11056 1.14 1.25 0.14 2.47 0.46 5.78 9 12156 1.31 2.32 0.34 0.45 5.76 10 13256 1.44 2.60 0.41 6.29 11 15456 1.56 1.61 2.52 6.56 12 16556 1.64 1.72 2.94 0.32 0.57 7.29 13 17656 1.87 1.80 3.36 0.37 7.82 14 19856 2.07 2.46 0.08 3.48 0.36 8.79 15 20956 2.28 2.04 3.60 0.49 8.84 16 22056 2.13 2.16 4.56 9.65 17 24256 2.21 0.07 4.09 0.38 9.11 18 25356 2.54 2.41 4.39 10.12 19 26456 3.02 2.92 4.68 11.41 20 28656 2.90 3.43 0.20 4.52 11.88 21-08-0206-01-0000

Result (graph view) 21-08-0206-01-0000

Analysis The sender message processing time goes up linearly, as expected due to the time it takes to fragment ever larger messages The sender all packets sent also goes up linearly at about the same rate. The packet transmit time and ack transmit time are constant, as expected. The receiver message processing time is the dominant cost and in this implementation, the cost is largely due to Java thread hand-offs The sender ack processing cost is relatively high due to thread handoffs in the implementation. 21-08-0206-01-0000