Changes between Version 1 and Version 2 of 2011/Projects/MobilityFirst/KaiSu


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Timestamp:
Aug 12, 2011, 10:30:58 AM (6 years ago)
Author:
kais
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  • 2011/Projects/MobilityFirst/KaiSu

    v1 v2  
    1 sk 
     1 
     2 
     3== What I'm working on? == 
     4Prototyping of data processing part in GSTAR routing protocol, namely, reliable hop-by-hop large chunk transfer. 
     5 
     6== Work Log == 
     7 
     8Jun 1st 
     9Got the host-router-host latency test configuration running, but still need to make sure click is handling all packets. 
     10Discussed about data process implementation with Kiran. 
     11 
     12Jun 8th 
     13Compiled the code for aggregator and segmentor with ACK. Testing it on orbit... 
     14 
     15Jun 13th 
     16tested: when packets get lost, sender can retransmit those packets.  
     17 
     18July 8th 
     19worked out sender-router-receiver configuration on Orbit. Sent a 1GB file from sender via two hops to receiver. 
     20 
     21 
     22== Comparison of !MobilityFirst vs. Hop protocol == 
     23 
     24||           || !MobilityFirst || Hop || 
     25|| Signaling || Chunk SYN msg  || separate signaling msg: BSYN || 
     26|| Chunk transfer || Yes, sending data in the unit of chunk || Yes|| 
     27|| Bitmap ACK || Yes || Yes || 
     28|| ACK loss handling || similar with Hop, CSYN || waiting for ACK timeouts, resend BSYN || 
     29|| When to ACK || received CSYN || received BSYN || 
     30|| What to ACK || bitmap of whole chunk or a portion of chunk || bitmap of whole chunk || 
     31|| Data caching (short-term) || Yes || Yes || 
     32|| Data caching (long-term) || Yes || No || 
     33|| Virtual retransmission ||  || Yes || 
     34|| ACK withholding || Yes || Yes ||  
     35|| Backpressure control || Yes || Yes || 
     36 
     37 
     38== Signaling process in one hop reliable data transfer == 
     39 
     40[[Image(Link_Layer_Reliability.png, 400px)]]   
     41 
     42''Signaling process for one hop reliability''                      
     43 
     44*Sender initiates chunk transfer by sending a CSYN message, receiver responds with an ACK with a bitmap identifying the receiving status 
     45 
     46*After receiving an ACK, sender begins sending a chunk of data packets, and then send another CSYN asking for ACK. 
     47 
     48*The transfer of this chunk terminates when the received bitmap says all packets are received. 
     49 
     50*Every time a CSYN is sent, a timer will be set. If an ACK is not received before the timeout, the CSYN will be resent. 
     51 
     52 
     53== One-hop file transfer evaluation == 
     54 
     55[[Image(FileTransferWithVariedChkSize.png, 600px)]]     
     56 
     57Notes: For the same file, a smaller chunk size corresponds to larger number of chunks, therefore more incurred latency on signaling. This suggests reducing signaling to improve performance (maybe doesn't need signaling for every chunk).