臺灣博碩士論文加值系統

兩台連結主機間的頻寬直接影響網路傳輸的效能．即使頻寬會因新技術的發展而不斷增加．不過，新技術的發展郤總是跟不上使用需求，新的網路應用程式是不斷在推出．隨著 802.11 無線區域網路的發展，對頻寬的需求也相對地越來越高．
Striping 是一個用來取得更多頻寬的方法．它的作法是把資料分散到不同的網路上傳送．在這碩士論文中，我們將提出一個在 802.11 無線區域網路上使用的 striping 演算法．我們將多張無線區域網路卡聚集在一起形成一個對外的 trunk．這個演算法將實作在 device driver 層．上層的應用程式將不會知道 striping 的存在，它只會感覺到得到底層可用的頻寬增加了．演算法使用 round robin 的方法和 sequence numbers 來運作．和其他的 striping 演算法比較起來，我們提出的演法可以得到最多的聚合頻寬．此外，在不良的網路環境下亦能運作良好．

The bandwidth between two connected hosts directly infects the performance of communications. Even though the increased bandwidth can be gotten by the new developed technology, the developing speed cannot always follow the growing bandwidth-requirement of applications. With the growth of the IEEE 802.11 wireless network, more communication bandwidth is needed.
Striping is a method used to obtain more bandwidth in network communications. This is done by splitting traffic over multiple network links. In this thesis, we proposed a new striping algorithm applied over the IEEE 802.11 wireless network. We aggregate multiple wireless adaptors to form a single trunk for communications. The striping algorithm is implemented at the device driver. The striping is transparent to high-level applications except that the increased bandwidth is realized. The algorithm uses a round robin scheme and sequence numbers embedded in packets. Compared with other striping algorithms, using our striping algorithm can obtain the maximum aggregated bandwidth. The algorithm can also performed well under bad network environments.

1 Introduction ............................................. 1
1.1 Striping over the Network Subsystem ................ 1
1.1.1 Introduction of Striping ......................... 1
1.1.2 Advantages of Striping ........................... 3
1.1.3 Problems of Striping ............................. 4
1.2 IEEE 802.11 Wireless Network ....................... 5
1.3 Motivation ......................................... 6
1.4 Organization ....................................... 8
2 Striping Algorithms ...................................... 9
2.1 Existing Striping Algorithms ....................... 9
2.1.1 SRR .......................................... 9
2.1.2 TRR ......................................... 14
2.2 TCP Fast Retransmit and Fast Recovery Algorithms .. 16
2.3 The Proposed New Striping Algorithm ............... 18
2.3.1 The System Architecture ..................... 18
2.3.2 Sequence Number ............................. 20
2.3.3 Reordering Timer ............................ 22
2.3.4 Load Balance ................................ 26
3 Performance Evaluations ................................. 29
3.1 Simulation Environment ............................ 29
3.2 Simulation Results ................................ 29
3.2.1 Throughput .................................. 30
3.2.1.1 Congestion ............................ 33
3.2.1.2 BER ................................... 38
3.2.1.3 Other Issues .......................... 41
3.2.1.4 Discussions ........................... 46
3.2.2 Scalability Issue ........................... 47
3.2.3 Latency ..................................... 48
3.2.4 Reordering Timer Issue ...................... 50
3.3 Result Discussions ................................ 52
4. Concluding Remarks ..................................... 54
References ................................................ 55

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[2] IEEE Std 802.11 Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications, June 1997.
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