没有合适的资源?快使用搜索试试~ 我知道了~
Topology Management in Rooftop Wireless Networks
需积分: 0 0 下载量 151 浏览量
2009-12-21
22:15:24
上传
评论
收藏 413KB PDF 举报
温馨提示
试读
54页
This report investigates existing wireless network technologies and mesh implementations and describes why they are unsuitable for use in a rural environment. Drawing on the experiences of these existing networks a protocol to create a wireless mesh network for use in rural areas is designed. The mesh network created by this protocol is different from existing mesh networks in a number of ways. Each node in the mesh network has multiple wireless interfaces and utilises directional antenna to reduce interference and increase communication range. Additionally the protocol creates a mesh network composed of many layer 2 wireless Ethernet links rather than a single link.
资源详情
资源评论
资源推荐
Topology Management in Rooftop Wireless
Networks
Matt Brown
Department of Computer Science
Hamilton, New Zealand
October 23, 2004
Abstract
The lack of access to broadband Internet services in rural areas of New Zealand has been identified as a
significant problem for rural businesses and households. The existing wired telephone network which is being
used for broadband delivery in urban areas is around fifty years old in most rural areas and is not capable
of sustaining the speeds required for broadband access. This problem has led to the idea of using wireless
technologies to provide broadband access to rural areas.
This report investigates existing wireless network technologies and mesh implementations and describes
why they are unsuitable for use in a rural environment. Drawing on the experiences of these existing networks
a protocol to create a wireless mesh network for use in rural areas is designed. The mesh network created
by this protocol is different from existing mesh networks in a number of ways. Each node in the mesh
network has multiple wireless interfaces and utilises directional antenna to reduce interference and increase
communication range. Additionally the protocol creates a mesh network composed of many layer 2 wireless
Ethernet links rather than a single link.
The successful implementation of this protocol within a framework that enables future research to be
easily performed is a significant achievement of this project. The results of evaluating this framework and the
mesh protocol in two test bed networks are also presented.
i
Acknowledgements
I would like to acknowledge the support and encouragement that I have received from the WAND group during
the course of this project. In particular I would like to thank my supervisor Murray Pearson for his guidance
and advice, particularly in the more complex areas of the project.
A big thank you also to Jamie Curtis and Perry Lorier for providing feedback on the mesh protocol and
assistance with debugging problems in the mesh framework. Finally lots of love and thanks to my fiancee,
Kat, for encouraging me to put my best effort into this project and for taking the time to proof read a long and
“boring” report.
ii
Contents
1 Introduction 1
1.1 Wireless Technologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Wireless Topologies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.1 Base Station Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.2.2 Mesh Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
1.3 CRCnet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4 A Wireless Mesh Network . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
1.5 Project Aims . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
1.6 Report Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2 Background 6
2.1 Introduction to 802.11b . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1.1 802.11b Channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1.2 802.11 MAC Layer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.1.3 802.11 Network Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.1.4 802.11b Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.2 Antenna Technology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2.3 Existing Mesh Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3.1 MIT Roofnet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
2.3.2 Locust World . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.4 Routing in Mesh Networks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
2.4.1 Shortest Path is Not Enough . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.4.2 Existing Wireless Metrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
2.4.3 Existing Routing Protocol Implementations . . . . . . . . . . . . . . . . . . . . . . . 13
2.5 Design Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
iii
3 Mesh Protocol 16
3.1 Protocol Aim . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.2 Protocol Tasks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
3.3 Hello Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.3.1 Hello Packets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
3.4 Link Database . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
3.5 Neighbour Discovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.5.1 802.11 Network Discovery . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.5.2 Scan Result Filtering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
3.6 Neighbour Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
3.6.1 Spanning Tree Based Neighbour Selection . . . . . . . . . . . . . . . . . . . . . . . 22
3.6.2 Redundant Links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
3.6.3 Channel Allocation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
3.7 Link Establishment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.7.1 Neighbour Synchronisation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
3.7.2 IP Addressing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
3.8 Routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
4 Implementation Framework 27
4.1 Implementation Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4.2 Implementation Language . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
4.2.1 Python Netlink Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
4.2.2 Python Wireless Tools Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.3 Mesh Framework Architecture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.3.1 Mesh Network Daemon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
4.3.2 Routing Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
4.4 Interface Threads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
5 Results 33
5.1 Indoor Mesh Test Bed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
5.2 Outdoor Mesh Test Bed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
6 Future Work 36
7 Conclusion 38
iv
剩余53页未读,继续阅读
jicanny
- 粉丝: 0
- 资源: 1
上传资源 快速赚钱
- 我的内容管理 展开
- 我的资源 快来上传第一个资源
- 我的收益 登录查看自己的收益
- 我的积分 登录查看自己的积分
- 我的C币 登录后查看C币余额
- 我的收藏
- 我的下载
- 下载帮助
安全验证
文档复制为VIP权益,开通VIP直接复制
信息提交成功
评论0