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IEEE 802.11ax_ High-Efficiency WLANs

IEEE 802.11ax_ High-Efficiency WLANs
IEEE 802.11ax_ High-Efficiency WLANs

a r X i v :1501.01496v 4 [c s .N I ] 28 J u l 2015IEEE 802.11ax:High-E?ciency WLANs ?

Boris Bellalta

Universitat Pompeu Fabra,Barcelona

Abstract

IEEE 802.11ax-2019will replace both IEEE 802.11n-2009and IEEE 802.11ac-2013as the next high-throughput Wireless Local Area Network (WLAN)amendment.In this paper,we review the expected future WLAN scenarios and use-cases that justify the push for a new PHY/MAC IEEE 802.11amendment.After that,we overview a set of new technical features that may be included in the IEEE 802.11ax-2019amendment and describe both their advantages and drawbacks.Finally,we discuss some of the network-level functionalities that are required to fully improve the user experience in next-generation WLANs and note their relation with other on-going IEEE 802.11amendments.

Keywords:IEEE 802.11ax,WLANs,High-e?ciency,Dense Networks 1Introduction IEEE 802.11Wireless Local Area Networks (WLANs)[1]are a cost-e?cient solution for wireless Internet access that can satisfy most current communication requirements in domestic,public and business scenarios.Similar to other wireless technologies,WLANs have evolved by integrating the latest techno-logical advances in the ?eld as soon as they have become su?ciently mature,aiming to continu-ously improving the spectrum utilization and the raw WLAN performance.IEEE 802.11n-2009adopted Single-user Multiple Input Multiple Output (SU-MIMO),channel bonding and packet aggregation.Those mechanisms were further extended in IEEE 802.11ac-2013,which also in-troduced Downlink Multi-user (MU)MIMO transmissions.In addition,new amendments such as the IEEE 802.11af-2013and the IEEE 802.11ah-2016are further expanding the application

scenarios of WLANs,which include cognitive radio,long-range communication,advanced power saving mechanisms,and support for Machine to Machine (M2M)devices.

Partly because of their own success,next-generation WLANs face two main challenges.First,they must address dense scenarios,which is motivated by the continuous deployment of new Access Points (APs)to cover new areas and provide higher transmission rates.Second,the current evolution of Internet usage towards real-time high-de?nition audio and video content will also signi?cantly increase users’throughput needs in the upcoming years.

To address those challenges,the High-E?ciency WLAN(HEW)Task Group[2]is currently working on a new high-throughput amendment named IEEE802.11ax-2019.This new amend-ment will develop new physical(PHY)and medium access control(MAC)layer enhancements to further improve the WLAN performance,with a focus on the throughput and battery duration. This article overviews some of those new enhancements and describes the potential bene?ts and drawbacks of each one.We have grouped these enhancements into four main categories:spatial reuse,temporal e?ciency,spectrum sharing and multiple-antenna technologies.Moreover,we also discuss several key system-level improvements for next-generation WLANs,as in addition to the IEEE802.11ax-2019amendment,they will likely implement other in-progress amend-ments such as IEEE802.11aq-2016(pre-association discovery of services),IEEE802.11ak-2017 (bridged networks)and IEEE802.11ai-2016(fast initial link setup time)to satisfy the created expectations.

2Scenarios,Use-cases and Requirements

The forecast number of devices and networks,the tra?c characteristics and user demands for the2020-2030decade motivate the development of a new PHY/MAC IEEE802.11amendment to cope with the new challenges and usages WLANs will face[2].

One of the most representative characteristics of WLANs is the use of Carrier Sense Multiple Access(CSMA/CA)as MAC protocol.It o?ers a reasonable trade-o?between performance, robustness and implementation https://www.doczj.com/doc/8e17622493.html,ing CSMA/CA,when a node has a packet ready for transmission,it listens to the channel.Once the channel has been detected free(i.e.,the energy level on the channel is lower than the CCA(Clear Channel Assessment)threshold,the node starts the backo?procedure by selecting a random initial value for the backo?counter.The node then starts decreasing the backo?counter while sensing the channel.Whenever a transmission, from either other nodes within the same WLAN or those belonging to other WLANs,is detected on the channel,the backo?counter will be paused until the channel is detected free again,at which point the countdown is resumed.When the backo?counter reaches zero,the node starts transmitting.Figure1(a)shows an example of the CSMA/CA operation.

2.1Dense WLAN scenarios

Providing high data rates in scenarios where the density of WLAN users is very high(e.g.,1 user/m2)requires the deployment of many APs placed close to each other(e.g.,within5-10m of one another).Figure1depicts and describes three of those scenarios:a)a stadium b)a train, and c)an apartment building.In these dense scenarios,most relevant challenges are related to interference issues,which increase the packet error rate and reduce the number of concurrent transmissions in a given area by preventing neighboring WLANs from accessing the channel. Additionally,the presence of many stations(STAs)in the same area increases the chances that the backo?counters of two or more STAs reach zero simultaneously,which results in a collision.

In the stadium scenario,many people are concentrated in small areas because of a fair,a

t

APs

Description

Stadium

(~12500m 2)>50000Train (~600m 2)

>1000Apartment building

-4?oors,6apart-

ments/?oor -(~2400

m 2)<

480

in these scenarios is to deploy,optimize and coordinate such a large number of APs and STAs.

Public transport is also a key scenario for next-generation WLANs because trains,buses and planes will o?er broadband Internet access.In these scenarios,the user density may be notably high,with several people per square meter.Then,a smart AP coordination can help improve the spatial reuse,and the use of an e?cient medium access protocol may help support many simultaneous contenders.

Finally,in the apartment building,we can?nd multiple autonomous and heterogeneous WLANs overlapping,including short-range WLANs that o?er high transmission rates in small spaces[3].In this scenario,each WLAN is primarily con?gured independently of the oth-ers,where the channel selection,channel width and transmission power are randomly set or are simply the pre-set values.Therefore,autonomous WLANs must be able to implement smart de-centralized self-con?guration and self-adaption mechanisms to minimize the interference among them.

WLANs must also coexist with other wireless networks that operate in the ISM band,such as Wireless Sensor Networks and Personal Area Networks.In addition,Long-Term Evolution (LTE)operators currently consider deploying LTE networks in the ISM band[4],which is known as LTE-Unlicensed,thus opening further coexistence challenges for WLANs.

2.2Future WLAN usages

Interactive and high-de?nition video applications are predicted to dominate future Internet us-age.Two examples of applications that require throughputs of several Gbps are high-de?nition multi-party video conferences in business environments,which can help avoid unnecessary travel and meetings,and virtual reality entertainment applications at home,which include culture,?lms and games.Additionally,web sur?ng is moving further towards a multimedia experi-ence,where rich text,images,audio and video content interact.Furthermore,?le storage, management and synchronization in the cloud are becoming the standard in terms of content management and generation.Those applications are bandwidth-demanding and require both reliability and limited delay.

2.3Requirements

Based on the aforementioned scenarios and expected use-cases,there are four key requirements for the IEEE802.11ax-2019amendment.

1.Coexistence:WLANs operate as unlicensed devices in the ISM(Industrial,Scienti?c

and Medical)bands.Therefore,the IEEE802.11ax-2019amendment has to include the required mechanisms to coexist both with the other wireless networks that also operate there and with the licensed devices.

2.Higher throughput:Improving both the system and user throughput requires the im-

proved use of channel resources.IEEE802.11ax-2019aims for a4-fold throughput increase compared with IEEE802.11ac-2013.To achieve this goal,some new wireless technologies

such as Dynamic CCA,OFDMA(Orthogonal Frequency Division Multiple Access),and advanced multiple-antenna techniques may be used.

3.Energy e?ciency:The target in IEEE802.11ax-2019is-at least-to not consume

more than the previous amendments,considering the aforementioned4-fold throughput increase,which requires both new low-power hardware architectures[5]and new low-power PHY/MAC functionalities.

4.Backward Compatibility:Because WLANs implementing IEEE802.11ax-2019must

also support devices using any previous IEEE802.11PHY/MAC amendments,mecha-nisms must also be implemented to make it backward compatible(i.e.,common frame headers and transmission rates),although it is a clear source of ine?ciency.

3New Features and Concepts

The IEEE802.11ax-2019amendment may include some new technical features compared with the IEEE802.11ac-2013amendment.We introduce them in this section,providing insight into their potential performance gains and limitations.All numerical results presented in this section are obtained using the analytical model and parameters from[6],unless otherwise is stated.

3.1Spatial reuse

In dense scenarios,the combined use of CSMA/CA,a conservative CCA and a high transmit power level may result in scenarios with limited spatial reuse.A conservative con?guration of both the CCA and transmit power levels minimizes the interference among the WLANs, which supports higher transmission rates.However,the number of concurrent transmissions is reduced,which may decrease the achievable area throughput.The alternatives that can be used to reach an optimal tradeo?between individual transmission rates and the number of concurrent transmissions that maximize the area throughput include adapting dynamically the transmit power level,the CCA level and the use of directional transmissions based on the observed network performance.

Figure2(a)shows three neighboring WLANs.The channels that each WLAN uses are shown in Figure2(b).Because WLANs A and C,and B and C,partially share their channels,they overlap.The three APs are inside the carrier sense range of the others as shown in Figure2(a), which pauses their backo?if either of the other two transmits.Although WLAN C uses the widest channel,it achieves the lowest throughput because it overlaps with WLANs A and B that are independent between them(Figure2(c)).

3.1.1Dynamic adaptation of the transmit power and CCA levels

Reducing the used transmission power in a WLAN reduces its in?uence area,which bene?ts the spatial reuse.However,it may result in a larger number of packet errors and lower transmission rates,as well as to increase the number of hidden nodes.

WLAN A

WLAN B

WLAN C

channels

(b)Channel used by each WLAN

3.2Temporal E?ciency

The backo?countdown,packet headers,interframe spaces,collisions and retransmissions are an intrinsic part of the CSMA/CA channel access scheme,but they signi?cantly decrease the e?ective time that a node spends transmitting data every time it accesses the channel.IEEE 802.11ax-2019may include several solutions to mitigate such overheads.

3.2.1Control Packets

The time consumed by the exchange of control packets may result in large overheads,partic-ularly because they are usually transmitted at a low https://www.doczj.com/doc/8e17622493.html,mon control packet exchanges between the AP and STAs include the RTS/CTS exchange to avoid hidden nodes and ACKs to acknowledge the reception of data packets.

Additionally,some of the new technical features described in next sections that enable multi-user transmissions may require a frequent exchange of control packets to synchronize all involved STAs,hence also increasing the control packets overheads.

3.2.2Packet Headers,Aggregation&Piggy-Backing

Packet aggregation was introduced in IEEE802.11n-2009to reduce temporal overheads by combining short packets into a longer https://www.doczj.com/doc/8e17622493.html,ing packet aggregation,multiple packets can be transmitted with a single backo?,DIFS,SIFS,PHY header and ACK.

The packet header overheads can be reduced by supporting variable size headers and using only the minimum required?elds for every packet.Additionally,the use of shorter identi?ers instead of the full MAC address is considered.

Moreover,the piggybacking of ACKs with DATA will improve the e?ciency,although some changes in the current setting of the Network Allocation Vector(NAV)are required because the full transmission duration is unknown to the transmission initiator.

3.2.3E?cient retransmissions

Packet errors are also a source of overhead because they currently require the full retransmission of the data packet.Further work about the use of incremental redundancy-based ARQs can reduce the time spent in retransmissions,although it implies some extra complexity in both transmitter and receiver?rmware.

3.2.4Simultaneous Transmit and Receive

By allowing the AP and a STA to simultaneously transmit and receive(STR),which is com-monly known as full-duplex communication,the channel capacity can be theoretically doubled [8].Using CSMA/CA,the only way they can have full duplex communication is if they?n-ish their backo?countdown simultaneously.Otherwise,one will start transmitting before the other,causing the latter to pause its backo?until the former?nishes its transmission.Only when the number of active STAs is low,they have bidirectional and saturated tra?c?ows and

To improve the spectrum usage e?ciency,two main approaches can be considered in IEEE 802.11ax-2019:dynamic channel bonding and OFDMA.

3.3.1Dynamic Channel Bonding

To adapt to the instantaneous channel occupancy,IEEE802.11ax-2019may consider to extend the Dynamic Bandwidth Channel Access(DBCA)scheme introduced in the IEEE802.11ac-2013 amendment[10].Using DBCA,only the available channel width is used at each transmission, which allows the WLANs to adapt to the instantaneous spectrum occupancy.This mechanism helps?ll most spectrum gaps and share them fairly among neighboring WLANs.

3.3.2OFDMA

The use of OFDMA adds a new degree of?exibility to the use of spectrum resources by dividing the channel width into multiple narrow channels.Then,these narrow channels can be used to transmit to multiple users in parallel[11].A basic implementation of OFDMA in WLANs may simply consider the use of multiple independent20MHz channels.This approach is shown in Figure4:when channel bonding is used,each20MHz subchannel can be independently allocated to a di?erent user.The RTS’packet has been extended to announce the subchannels allocation to the STAs.Additionally,OFDMA may enable the use of non-contiguous channel bonding and remove the requirement to use only20MHz consecutive channels.

Figure4(a)shows an example where Dynamic Channel Bonding and OFDMA operate to-gether.The upper part of Figure4(a)shows a snapshot of the spectrum occupancy for a group of neighboring WLANs.The lower part of Figure4(a)shows two transmissions:a node in the target WLAN transmits to a single user via a bonded channel of40MHz(left),and a node uses a bonded channel of80MHz and OFDMA to transmit to three di?erent users(right).Figure 4(b)shows the AP throughput when OFDMA is used to split a160MHz channel into multiple subchannels.The parallelization of temporal overheads clearly improves the throughput.

3.4Multiple Antennas

Spatial Multiplexing using multiple antennas at both AP and STAs remains one of the key technologies to achieve a high throughput in WLANs.IEEE802.11ax-2019will continue im-plementing both SU-MIMO and Downlink MU-MIMO,as in IEEE802.11ac-2013.However, it may also include or provide support for Uplink MU-MIMO,Massive MIMO and Network MIMO,as well as to support distributed antenna solutions.

3.4.1Multi-user MIMO

Multi-user MIMO enables multiple simultaneous transmissions to di?erent STAs from the AP in the downlink,and from multiple STAs to the AP in the uplink.A survey of MU-MIMO MAC protocols for WLANs is presented in[12],where the challenges and requirements to design a

(b)Achievable downlink throughput using a channel

width of160MHz and OFDMA.The RTS’size is

120+56·N tx bits,with N tx the number of OFDMA

subchannels

Figure4:Dynamic Spectrum Access with and without OFDMA.

MU-MIMO MAC protocol are introduced,and several uplink and downlink MAC proposals are reviewed.

In the downlink,a challenge for IEEE802.11ax-2019is to reduce the channel sounding over-heads given the same explicit approach as in IEEE802.11ac-2013is considered.The overhead caused by the explicit channel sounding protocol implemented depends on the channel sounding rate and number of sounded STAs,which can result in an unacceptable overhead in scenarios with many STAs.Solutions to reduce such a large overhead,apart from replacing the current channel sounding protocol with a more e?cient solution,will require the use of smart schedulers that consider the current tra?c patterns and the Quality of Service(QoS)demands from the users to decide when the CSI has to be requested,and from which STAs.

To support MU-MIMO transmissions in the uplink,the IEEE802.11ax-2019amendment

must also detail how the uplink CSI from each STA is obtained by the AP,introduce a mecha-nism to signal a group of STAs to simultaneously start a transmission,and include techniques to overcome channel calibration and timing issues in order to e?ciently decode all the simulta-neously received packets at the AP.

In both cases,using the collected CSI,the AP has to select the speci?c STAs that will take part in next MU-MIMO transmission.Therefore,the design of an e?cient mechanism to create groups of STAs with low spatial channel correlation and similar channel quality is still an open challenge.Failing on properly creating those groups may prevent next-generation WLANs to fully bene?t from MU-MIMO technology.

Figure5(a)shows an AP with three STAs.In the left side,we have three downlink MU-MIMO transmissions.The ones directed to STAs A,B and C contain four,two and one SU-MIMO spatial streams,respectively.To start a downlink transmission,the AP omnidirectionally sends the PHY header with information about the group of selected STAs and the number of spatial streams that are transmitted to each STA in SU-MIMO mode.On the right side,we show an uplink MU-MIMO transmission.In IEEE802.11ax-2019,because several STAs are unlikely to?nish their backo?countdowns at the same time,uplink MU-MIMO transmissions may be started by the AP using a special RTS”packet containing information about the STAs that can transmit in parallel.Then,the selected STAs will simply start transmitting at the same time and wait to receive the corresponding ACKs.This approach allows to synchronize all selected STAs but requires the knowledge of the STAs’s bu?er occupancy by the AP,which can be provided by the same STAs in previous transmissions.Figure5(b)shows the throughput achieved by the AP in two downlink MU-MIMO con?gurations(cases16:4:4and16:16:1). The obtained throughput values are compared with the case where a single spatial stream is transmitted to only one destination(case1:1:1).

3.4.2Massive MIMO

Massive MIMO refers to the case where the AP has many more antennas than STAs and uses them to create a nearly identical number of point-to-point links as the number of active STAs[13].In addition to the cost of APs,the extra processing complexity and higher energy consumption,other open challenges for massive MIMO include obtaining the CSI information; WLANs may require switching to an implicit channel feedback approach.

3.4.3Network MIMO

In coordinated WLAN deployments,network MIMO can be used to minimize the interference among simultaneous transmissions from di?erent APs.The idea behind network MIMO is that di?erent APs can coordinate the transmissions as if they were a large array of antennas, which reduces the inter-transmission interference and increases the spatial reuse[14].However, e?ectively solving the tight synchronization requirements among the APs remains an open challenge.

(b)Downlink Throughput.The AP is equipped with sixteen antennas.Each

con?guration is identi?ed by the code x:y:z,where x refers to the total number

of transmitted spatial streams,y to the number of destinations,and z to the

number of streams transmitted to each destination

Figure5:Multi-user spatial multiplexing.

4WLAN-Level Improvements

The user experience in next-generation WLANs will not be simply enhanced by increasing the achievable network and user throughput as previous technical features do.To achieve that goal,

Amendment

IEEE802.11ai-2016

D2D/WI-FI Direct STAs with D2D capability can de-

cide to create their own WLAN to

communicate directly.

IEEE802.11ak-2017

Video Tra?c Di?erentiation Stream prioritization and groupcast

mechanisms.

IEEE802.11aq-2018

Figure6:Upcoming IEEE802.11amendments.

apart from the IEEE802.11ax-2019amendment,there are other IEEE802.11amendments in progress.Figure6shows the most signi?cant ones,including the new features they are targeting.

In scenarios where multiple APs are used to o?er a large coverage area and higher data rates by deploying multiple WLANs nearby,a mechanism that enables a fast hand-o?among the APs is required because the current large delays when a STA switches to a new AP are

unacceptable.The IEEE802.11ai-2016amendment targets this challenge.It aims to provide a hando?duration below100msecs by implementing preemptive channel sensing and user authentication.Alternatives based on network virtualization and software de?ned networks are also an interesting option as they are able to centralize all decisions,including the hando?between overlapping APs.Probably,future IEEE amendments will consider such an approach.

Device-to-device(D2D)communications,which are also known as Wi-Fi Direct in the IEEE WLAN context,will also be a key element in next-generation WLANs[15].Examples of D2D communications are?le synchronization with an external hard disk and instantaneous?le ex-change between a mobile phone and a projector/smart television.The use of D2D commu-nications will reduce the amount of airtime required for each transmission by allowing higher data rates and avoiding the use of the AP as a relay.Beamforming is an interesting feature for D2D communication because it may allow concurrent transmissions inside the same WLAN by di?erent groups of nodes.

IEEE802.11ax-2019aims to operate in the2.4and5GHz bands,by superseding and integrating the IEEE802.11n-2009and IEEE802.11ac-2013amendments.In a few years,every single AP will most likely implement two IEEE802.11ax-2019instances that independently operate at2.4and5GHz,with a IEEE802.11ah-2016instance at1GHz for M2M and long-range communications and one IEEE802.11ad-2012(or the future IEEE802.11ay-202x)at60 GHz for very fast millimeter Wave communications.In this situation,the STAs of any of those networks should be able to communicate with the STAs in any of the other WLANs.This is in the aim of the IEEE802.11ak-2017amendment,which focuses on adding bridging capabilities to WLANs.

Finally,next-generation WLANs will use tra?c di?erentiation,?ow admission control and groupcast mechanisms from the IEEE802.11e-2007,IEEE802.11ae-2012and IEEE802.11aa-2012amendments to support multimedia tra?c with the required QoS.Also,further advances in Power Saving Mechanisms are expected to keep the WLAN energy consumption as low as possible.

5Conclusion

We have reviewed some technological options that could be included in the IEEE802.11ax-2019 amendment for next-generation WLANs.Individually,all those solutions o?er some perfor-mance gains by improving the spatial reuse and the spectrum utilization.However,the analysis of the actual performance gains when several of those solutions are combined and used simul-taneously is still an open challenge requiring signi?cant research e?orts in the next years.For instance,for a given transmission power,multiplexing di?erent users in a single transmission using channel bonding and spatial multiplexing reduces the received power per Hertz and user, which may require the selection of lower order modulation schemes and coding rates,and the theoretical gain in throughput obtained by the combined use of spatial multiplexing and channel bonding may be lost by the larger transmission delay.

Finally,in addition to the higher achievable throughput provided by IEEE802.11ax-2019

PHY/MAC features,we believe that the most disruptive performance and user experience improvements in next-generation WLANs will be also related to the development and imple-mentation of the other recently approved or ongoing amendments,and by developing e?cient and smart mechanisms to improve the coexistence and cooperation among WLANs.

Acknowledgements

This work was partially supported by the Spanish and Catalan governments through the projects TEC2012-32354and SGR-2014-1173respectively.

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宿舍楼无线网建设方案

宿舍楼无线网建设方案 1.项目概述 利用WLAN来覆盖学生宿舍楼,从而使每个宿舍能更好的链网络。 2.需求分析 (1)场景描述及需求分析 宿舍楼是人群密集区域。用户数较多、数据流量较大,WLAN业务需求量较大,WLAN建设应同时兼顾覆盖和容量,对GSM/TD也有较大业务需求。 宿舍楼的建筑结构一般有走廊单边宿舍、走廊双边宿舍以及小区套间结构。建筑材质一般以钢筋混凝土为主,屏蔽效应较强,无线信号从走廊穿透宿舍难度较大,无线网络覆盖重点是宿舍区每个房间。 (2)场景覆盖方案 WLAN宿舍楼场景一般采用室内分布系统合路和室内放装两种建设方式。室内分布系统合路: 宿舍楼覆盖一般需要考虑网络容量,应根据并发用户数需求,确定每台AP安装位置和覆盖区域,合理设计分布系统的主干和分支。设备一般安装在宿舍楼每层机房、弱电井或走廊;天线一般安装在走廊的顶部,如条件允许,可将天线延伸至房间内。

对于房间信号穿透损耗较小(如采用木质门、有窗户等)的宿舍,可采用全向吸顶天线;对于房间信号穿透损耗较大(如铁质门、无窗户、实心水泥墙体等)的宿舍,可采用定向板状天线;建议信号只穿透一堵墙为宜。 以某宿舍楼为例,房间为钢筋混凝土结构的走廊双边宿舍,木门,有窗户。每层有24间宿舍,共96人,并发用户需求24人。 平层有2个支路,每支路合路1台500mW AP,共采用6个全向吸顶天线,每个天线覆盖4个房间。整栋楼由POE交换机集中供电,AP 安装在楼层中多媒体壁挂箱内。 实施要点: 由于宿舍楼用户容量较大,在建设时要充分考虑容量需求,合理选取合路点,避免2个AP合路到1个支路中。 在宿舍区域做室分合路方式时,需注意宿舍楼建筑材质和结构,合理采用全向和定向天线。 室内放装

XX医院网络项目设计实施方案

XX医院网络项目设计方案

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网络设计方案 2009-3-20

目录 第一部分需求分析 (5) 第一章调研 (5) 1. 医院楼房分布 (5) 2. 科室分布情况 (5) 3. 现有网络的物理布局及信息点数统计 (5) 4. 现有网络情况 (7) 5. 现有网络的主要问题 (7) 第二章建网需求 (7) 第二部分网络设计 (8) 第三章网络设计 (8) 1. 网络设计概述 (8) 2. 网络拓扑 (8) 3. 设备选型及链路选型 (8) 4. 网络资源规划 (9) (1) 新增设备主机名、loopback/管理IP和管理VLAN (9) (2) 链路互联及端口IP表 (10) (3) 本部业务VLAN及IP (10) (4) B区门诊楼业务VLAN及IP (11) (5) C区干休所业务VLAN及IP (11) 5. 详细技术方案 (11) (1) 技术方案概述 (11) (2) 本部LAN技术模块 (11) (3) B区门楼技术模块 (11) (4) C区干休所技术模块 (12) (5) 本部与B区、C区互联技术模块 (12) 6. 实施方案 (12) 7. 测试方案 (14) 第三部分设备介绍 (15) 1. RSR20-04 (15) 2. RSR10-02 (16) 3. RG-S3760-24 (17) 4. RG-S2126S (19)

第一部分需求分析 第一章调研 1. 医院楼房分布 A区(本部):医院主楼、住院楼、门诊楼 B区:门诊部(4F) C区:干休所(3F) 2. 科室分布情况 12个临床科室:普内科(含消化内科、神经内科、血液内科、中毒急救、肾脏病内科、内分泌等)、心内科(心脏和支气管肺病)、普外科(肝胆、泌尿、烧伤等)、骨外科、神经外科、妇产科、小儿科(含新生儿科)、 五官科、中医科、传染病区、急诊科、120急救中心 6个医技科室:检验科、放射科、功能科等 16个行管职能科室:办公室、人事股、医务科等 3. 现有网络的物理布局及信息点数统计 大楼之间的距离:本部各大楼之间都在200m以内,本部与两个分部之间均相隔在5公里以上,10KM以下 A区主楼:

校园无线网络建设方案

校园无线网络建设方案 一、现状 随着信息时代的到来,各个学校意识到校内网络建设的重要性,只有实现高度的信息共享,建设完善的校园网络平台,才能够发展成为一所现代化的学校。现在学校办学条件的日趋完善,近年来实现了与 Internet互联,同时建成了校园网络,实现校内外信息的共享、传递,而网络信息的普及,而学校的建成时间较早,没有网络综合布线设计,类似的原因制约了学校现代化办学的指导思想,伴随着IEEE802.11标准的出台,解决这一矛盾在无线技术发展成熟的今天已不是问题,同时,无线局域网(WLAN)还拥有传统网络所不能比拟的扩容性和移动性,在校园内采用无线局域网技术实施校园网络工程,最大限度地满足教师学生上网需求,对于创建较早的学校来说,年代较久的教室不宜拉网布线,理想的解决方案就是布署无线局域网。 二、需求 在校园无线网络建设需求中,主要存在四种典型的应用: 1、实现以地区教育局为中心的整个地区教育系统的无线网络连接; 2、校园内的户外公共区域覆盖; 3、局部开放的室内大环境,如典型公共教室、图书阅览室等无线覆盖; 4、用户数量不多但分布较散的楼宇,如教室、教师宿舍等的无线网络覆 三、应用方案 1、室内覆盖:在室内根据覆盖需要,放置若干个无线局域网访问点,用户在移动时,系统会自动漫游,在不同的访问点之间进行信号的切换。这些访问点连接到各楼的校园骨干网。也就是将多个AP形成的各自的无线信号覆盖区域进行交叉覆盖,各覆盖区域之间无缝连接。所有AP通过双绞线与有线骨干网络相连,形成以有线网络为基础,无线覆盖为延伸的大面积服务区域。所有无线终端

通过就近的AP接入网络,访问整个网络资源。 采用高灵敏度的无线AP设备,配合吸顶天线,以一个AP配合一个天线,或一个AP配合多个天线,以保障高质量的无线信号能够覆盖更远的距离,同时增强设备在干扰较大的频率环境中使用的能力,从而完成室内区域的完全覆盖要求。 2、室外覆盖: 室外区域覆盖一般包涵,体育场地,校内花园,教学区等。根据需覆盖的室外区域的实际情况,选择不同。 (1)设备的选择:AP、全向天线. (2)室外考虑因素:环境、天气。

毕业设计-----医院的网络规划与设计

毕业设计-----医院的网络规划与设计 -CAL-FENGHAI-(2020YEAR-YICAI)_JINGBIAN

题目莒南县医院的网络规划与设计 系 计算机科学技术系(院) 专业计算机网络技术 班级2009级2班 学生姓名 学号 指导教师 职称讲师 二〇一二年五月八日

莒南县医院的网络规划与设计 摘要 随着网络技术,信息通信领域的长足发展,网络经济,知识经济再不是IT等高科技行业的专利。作为传统行业之一的医疗卫生行业,如何面对网络时代带来的冲击,如何利用网络技术提高我们医疗卫生行业的管理水平和服务质量,是无法回避的问题。随着网络硬件性能的不断提高,成本不断降低,目前新建的局域网基本上都采用了性能先进的快速以太网技术,其核心交换机采用三层交换机,能很好地支持VLAN。本方案提供了丰富、全面的系统安全设计。整个方案考虑了用户层面、设备、数据和管理的各个层面的安全需求,并进行了整体安全的设计。设备方面,采用的各个层次的设备都支持了对自身负责层面的安全功能,从接入层、汇聚层到核心层,都进行了安全方面的考虑和设计;如接入层面提供的VLAN保护接入层面数据和用户的安全。防ARP功能和常见的蠕虫、冲击波等病毒的防范。数据层面,对数据在各个系统层面的传输都考虑的安全方面的设计。 关键词:网络性能;网络安全;网络配置;VLAN Network Planning and Design of the Junan County Hospital Abstract

With the rapid development of network technology, information communications, network economy, knowledge economy, not the IT high-tech industry patents. As one of the traditional industries of the health care industry, and how to deal with the impact of the Internet age, how to use network technology to improve the management level and service quality of our health care industry, is an unavoidable problem. The program provides a rich and comprehensive system security design. Equipment, at all levels of equipment support level is responsible for their own security features, from the access layer, convergence layer to the core layer, all the security considerations and design; such as access level VLAN to protect access to entry-level data and user security. Prevention of the virus of anti-ARP feature, common worms, such as shock waves. Data level, the safety aspects are considered by the transmission of data in each system level design. Keywords: Network Performance; Network Security; Network Configuration; VLAN

高校无线校园WLAN方案V1

高校WLAN组网方案 方案背景: XXX无线校园网解决方案能够帮助高教、普教、职教师生通过Wi-Fi便捷快速的接入校园网络,共享校园资源,提供更安全、更快速的接入体验,真正的做到教师安全办公,学生高速无线畅游。 目标客户:高教、普教、职教等教育行业客户。 问题及挑战 1、业务终端的高密和高速接入:校园公开区域部署无线,学生、教职工可以在任何区域都可以上网或共享教学资源,但人数众多,无线网络的接入容量是上网体验的瓶颈。 A、高密接入,所有学生通过移动终端接入无线网络,在一间教室内60个终端并行接入,给无线网络带来了很大的压力。 B、高速接入,所有学生通过终端去访问教学系统,比如教学视频,也给无线网络带来了很大的压力。 2、有线无线认证复杂繁多:原有校园有线网络认证系统与现在无线网络认证方式不同,导致管理复杂,认证繁琐。 3、认证权限难以管理:校园WiFi有不同的人员接入、不同的区域接入、不同的终端接入那么如何区分基于位置,基于角色,基于终端的访问权限是一个很复杂的问题。 4、高校学生宿舍一号多用:学校按照学生账号运营无线网络,需禁止学生账号被多人共享使用。 方案价值

更快速便捷: ●射频优化 对于无线用户密集的区域,可智能实时的根据用户数和流量调整分配到不同的接入点,平衡负载压力,极大的提高无线网络的容量和连接可用性。依据不同环境,可自动进行射频调整、信道调整,有效避开干扰。 ●流量管理 基于应用的精准流控,保证关键应用的带宽资源,有效提高带宽利用率。例如,电子书包应用中,可保障关键教学应用系统的带宽。 ●协议栈加速 针对协议栈加速,改善传统TCP协议传输机制,提升传输效率。解决无线网络由于干扰导致的无线传输速率低、丢包等网络质量问题。 更安全可靠: 端到端安全

医院网络建设方案

目录 一.医院网络建设需求 (2) 1.1整体需求概述 (2) 1.2内网需求 (2) 1.3外网需求 (2) 二.医院业务应用分析 (3) 2.1医院业务划分 (3) 2.2医院业务系统的需求 (3) 三.医院网络组建 (4) 3.1 网络拓扑 (4) 3.2网络组建分析 (4) 3.3核心层设计 (5) 3.4接入层设计 (5) 3.5网络可扩展性 (5) 四.产品概述 (5) 4.1 S7500E产品概述 (5) 4.2 S5120-24P-EI产品概述 (7)

一.医院网络建设需求 1.1整体需求概述 1、为HIS、PACS等应用系统提供一个强有力的网络支撑平台; 2、网络设计不仅要体现当前网络多业务服务的发展趋势,同时需要具有最灵活的适应、扩展能力; 3、一体化网络平台:整合数据、语音和图像等多业务的端到端、以IP 为基础的统一的一体化网络平台,支持多协议、多业务、安全策略、流量管理、服务质量管理、资源管理; 4、数据存储安全:医院信息系统的数据存储需要具有存储量大、扩充性强的特点。 5、医疗信息的安全保护,也是组要的环节,网络的设计不仅要考虑用户与服务器之间的互联互通,更要保护关键服务器的安全和内部用户的安全。 1.2内网需求 内网是医院核心网络系统,用于开展日常医疗业务(HIS、LIS、PACS、财务、体检系统等)的内部局域网,系统应稳定、实用和安全,具有高宽带、大容量和高速率等特点,并具备将来扩容和带宽升级的条件。 ●网络设计要求: 1、主干网络一台7503E,全局MSTP链路冗余,千兆接入交换机实现千兆到桌面。 2、配备的网管软件应提供可视的形象化的图形界面,对整个网络中网络产品的全部端口进行监视和管理;(可选) 3、交换机互连采用多条链路捆绑,防止链路瓶颈,并提供链路冗余。 由于医疗行业的特殊性,医护人员和病患者之间需要频繁地在院内移动、同时处理大量的信息,要求网络具备可移动性、传输速率高等特点。同时考虑到医院业务量的增加,网络需要留出足够余地扩容而不影响医院正常的工作。 ●网络应用设计要求: 1、院内核心网络系统HIS、PACS和LIS、体检系统等应用分别单独组网。以子网的形式组成医院的整体网络。各网络功能独立应用,信息互通,资源共享;当任何一个子网出现故障,都不会影响到其他子网的使用。 2、新建的网络系统应充分考虑跟现有网络系统的平滑接入,不影响现有系统的正常运行,并考虑和现有网络系统实现网络冗余。 4、传输动态图像的部门有:放射影像科、PET/CT、核磁共振MRI、介入放射科DSA、B超室、心超室、脑超室、心电图室、肌电图室、胃肠镜室、内窥镜室、重症监护室(ICU、CCU等)、手术室、麻醉科、视频示教室和会议室等。 5、医保(包括省医保、市医保、区医保以及市公费医疗)是专线接入。须配置医院内网与专线网的接口。 6、为了更好地服务于医疗科研工作,需要将各类监护治疗仪器上的各项生命体征等信息以数字化手段采集并且保存下来,在需要时,可随时还原。因此,须考虑将医院所有的监护仪器和大型设备都联网。 1.3外网需求

高校无线网络建设方案设计设计

高校无线网络建设方案 1 校园网络建设背景 目前校园网为学校和运营商共同运营,运营商提供宿舍网维护、出口带宽。目前整个校园网有线部分已经比较完善,但是由于建设年限比较旧,星锋航建议可以逐步进行替换,将原有百兆更换为千兆接入到桌面。 校园网有线接入接入交换机,每台接入交换机都需要管理人员进行配置,网络面临着设备管理难得问题,需要进行将整体网络扁平集中认证。 校园内部也有WIFI,但是WIFI单独独立于校园网,学生移动终端使用越来越频繁,只有有线网络的校园网很难以应对日益增长的移动终端使用需求。 2 高校无线网络需求 ◆实现室内、室外整个校区内的无线全覆盖。 ◆有线、无线网络采用统一的管理系统,以提高网络安全性和便利性。 3 校园网络总体目标 校园网络项目总体目标如下: 利用先进的无线网络技术进一步扩展校园网的覆盖范围,使全校师生能够随时随地、方便高效地使用校园网络; 满足校内日益增长的移动终端如PDA、手机、平板电脑对互联网访问的需求; 改善现有有线网络的网络体验; 提升校园网络环境,提高管理水平和效率,推动学校信息化建设,服务无所不在且安全优质,建立校企合作的运营模式,实现校企双方的双赢战略; 3.1 具体目标 建设一个高可用、高安全、高稳定、易使用、易管理、易扩展的无线校园网络与基础设施平台,通过支持802.11N标准,实现无线网络的无缝、高速覆盖,为网络资源的充分利用和共享提供强有力的保障,为学校的全面信息化奠定坚实的基础。网络基础设施完善,基本形成覆盖全校的高速无线网络。在网络规模、技术水平、性能、稳定性和安全性方面,达到省内一流水平,为学校各类应用系统和公共资源服务提供一个高速、安全、可靠的无线基础平台。 全面进行多种灵活接入方式建设,通过完善的高速无线网络来实现整个校园范围内无盲点区域的网络覆盖,学校拥有对全校(包括无线网络在内)的所有网络设备完全管理权限,以保证整个校园网络的可用、可管;在校内可以提供各运营商的无线网络WLAN接入等。3.2 项目建设目标 星锋航方案侧重实际应用,覆盖校园内大部分区域(包括宿舍楼、教学楼),为教学和学习生活提供切实可用的无线网络环境; 采取通行的网络协议标准:目前无线局域网普遍采用802.11系列标准,因此校园无线局域网将主要支持802.11n/802.11ac标准,从而提供可供实际应用的相对稳定的网络通讯服务; 全面的无线网络支撑系统(包括无线网管、无线安全,无线计费等),以避免无线设备及软件之间的不兼容性或网络管理的混乱而导致的问题; 保证网络访问的安全性,支持Web登陆、pppoe、专用客户端、radius认证、pptp_vpn,支持微软系统自带的vpn及Android、iOS系统自带VPN拨入认证多种认证方式;并且此次需要实现有线网和无线网的统一认证; 集安全、管控、优化于一体的网络出口解决策略;

高校无线网建设方案

附件2 学院无线网络建设方案

1 校园网络建设背景 目前校园网为学校和电信运营商共同运营,电信运营商提供宿舍网维护、出口带宽。目前整个校园网有线部分已经比较完善,但是由于建设年限比较旧,建议可以逐步进行替换,将原有百兆更换为千兆接入到桌面。 校园网有线接入认证NAS均在接入交换机,每台接入交换机都需要管理人员进行配置,网络面临了设备管理难得问题,需要进行将整体网络扁平集中认证。 校园内部也有移动WIFI,但是移动WIFI单独独立于校园网,学生移动终端使用原来越频繁,学校无法监控到学生日常上网行为。只有有线网络的校园网很难以应对日益增长的移动终端使用需求。

2 校园网络总体目标校园网络项目总体目标如下: 利用先进的无线网络技术进一步扩展校园网的覆盖范围,使全校师生能够随时随地、方便高效 地使用校园网络; 满足校内日益增长的移动终端如PDA、手机、平板电脑对互联网访问的需求; 改善现有有线网络的网络体验; 提升校园网络环境,提高管理水平和效率,推动学校信息化建设,服务无所不在且安全优质, 建立校企合作的运营模式,实现校企双方的双赢战略; 2.1 项目建设目标 侧重实际应用,覆盖校园内大部分区域(包括宿舍楼、教学楼),为教学和学习生活提供切实 可用的无线网络环境; 采取通行的网络协议标准:目前无线局域网普遍采用802.11系列标准,因此校园无线局域网 将主要支持802.11n/802.11ac标准,从而提供可供实际应用的相对稳定的网络通讯服务; 全面的无线网络支撑系统(包括无线网管、无线安全,无线计费等),以避免无线设备及软件 之间的不兼容性或网络管理的混乱而导致的问题; 保证网络访问的安全性,支持802.1x、web-portal、MAC快速认证、pppoe认证等方式;并且 此次需要实现有线网和无线网的统一认证; 集安全、管控、优化于一体的网络出口解决策略; 采用扁平化的网络构架、方便管理和扩展,迎合未来网络的发展趋势。

医院网络架构设计与实现

医院网络架构设计与实现 [摘要]随着医院信息化进程的深入,医院信息平台的运行将越来越依赖基础网络的建设。网络成为医院各种关键数据的信息进行交互和传递的重要途径。多种网络架构拥有各自的优势与不足,下面就我对其的认识作出阐述和选择一种合适的网络基础架构。 [关键字] 内外网融合,内外网分离,结合 医院的网络基础架构发展至今,主要分为三种架构,分别是内外网融合的网络架构、内外网分离的网络架构、以及最近几年刚刚兴起的基于业务的无线网络平台架构,这是和医疗信息化的发展阶段分不开的。(内网外网的概念为逻辑上的划分,两种实际的物理架构中,逻辑上均包含内网和外网两部分。划分主要根据业务系统的对内对外服务属性,医疗核心业务相关度等特性来进行。) 首先先来简单认识一下内外网融合的网络架构、内外网分离的网络架构和无线网络平台架构和基于业务的无线网络平台架构以及他们的优缺点比较。 内外网融合的物理架构:就是医院的内网业务以及办公业务都在一张基础网络上运行,在这一网络架构之上,无论是数据的类型、重要程度,还是对网络的要求,以及数据流方向都不尽相同,使得网络数据复杂度提高而可控性下降。从介绍可知,所有业务都在一张基础网上,缺点明显可知,两网仅逻辑隔离,外网对设备的攻击可能引起

内外网络全面瘫痪。优点则是:可以保护投资,并且可以根据需要让某部分终端可以同时访问两个区域,而且内外网融合所需设备相对较少,在维护和购买设备方面都很大程度上减少了成本。 内外网分离的网络架构:就是将医院的内网和外网业务分别放在一张单独建立的网络上来运行,两网物理隔离,最大限度的保障内网业务及数据的安全。内网主要承载医疗核心业务,如HIS、PACS 等。外网作为行政办公、对外发布、互联网医学资料查询的主要平台,对于稳定性和保密的性的要求低于内网,并且接入终端及数据流特点也更为复杂。优点:内外网无共用设备和链路,两网之间互不影响。此种网络架构设计,能够最大程度保证内网安全。缺点:由于内外网完全物理隔离,两张网络单独建设,投资规模增大;灵活性稍弱,一台终端只属于一张网,不能同时对两网资源进行访问,也不能自由切换;需要管理两张网络,增加管理成本 无线网络与上述两种相比大大不同,它是采用无线传输媒介的计算机网络,结合了最新的计算机网络技术和无线通信技术。首先,无线局域网是有线局域网的延伸。使用无线技术来发送和接收数据,减少了用户的连线需求。由于采用无线信号通讯,在网络接入方面就更加灵活了,只要有信号就可以通过无线网卡完成网络接入的目的;同时网络管理者也不用再担心交换机或路由器端口数量不足而无法完成扩容工作了。但是无线网络初次建设成本较高,很多条件不是很好的医院都无法实现;部署时需要改动现有网络结构,对原网络进行调整,增加初次部署复杂度,随着无线网络带宽以及传输数据

医院的网络的设计和实施方案设计

医院计算机网络系统改造工程方案的设计随着医院信息化管理的不断深入,医疗设备数字化处理技术的不断发展,要求医院计算机网络系统要有更大的容量、更快的速度,更合理的布局。因此,在医院原有网络系统已不能满足医院发展需求的情况下,对医院网络系统进行整体的结构化设计改造,使之适应医院信息化建设发展的需要,已成为医院建设的一个重要组成部分。 我院计算机网络系统于1997年建成,整个网络共有302个信息点,主要分布在院内七栋大楼,楼宇之间采用多模光纤连接。网络核心交换机采用Intel ES 10/100 Switch,为100Mbps交换结构,10Mbps到桌面。网络总体布局是根据“医院信息管理系统”软件开发提供的系统管理架构而确定。由于受当时客观条件的限制,网络站点设置及工作带宽已严重不适应医院业务发展的需要。 当前网络存在以下缺陷: 1、网络布局不合理,不能有效复盖院区; 2、信息点严重不足,制约信息资源的利用; 3、网络骨干的带宽过窄,无法满足大数据量的传输要求; 4、核心网络设备不具备容错功能; 5、核心网络设备的可扩展性、可管理性差; 6、用户端10Mbps接入已无法满足应用需要。 1 网络架构改造方案 网络是医院信息系统(HIS)得以稳定、快速运行的基础,网络建设不但要考虑目前系统的要求,更要为今后发展保留足够的可扩充余地。既要满足门诊、

住院等系统的数据量传输需求,又要为PACS等大数据量传输的系统作好准备。针对我院目前的网络状况,结合医院信息化建设的发展趋势,网络改造采用流行的三层网络架构方案,全面升级为1000M交换式以太网。 1.1 网络结构设计 1.1.1 网络核心层 通过更换网络中心交换机和楼宇交换机构成医院的网络核心层。网络主干线布设可有两种方案: (1) 利用原有的光纤进行升级。核心层部署1000M网络交换设备,提高网络传输速率的带宽; (2) 重新铺设网络中心至各楼宇1000M光纤,全面提升为1000Mbps快速以太网。 1.1.2 网络分布层 楼宇的层间视为网络分布层,楼宇交换机采用1000M光纤接入。根椐实际情况决定楼宇交换机至楼层交换机的连接,楼层信息点多、可采用1000M光纤引入各楼层交换机,反之,可采用超五类双绞线100M引入到楼层交换机。 1.1.3 网络访问层 根据医院规划和各建筑物的医疗功能布局,全面扩容访问层网络信息点,采用1000M光纤接入楼层交换机,通过水平布线系统100M交换到桌面。为保护利用原有资源,对于访问数据量不大的信息点可以考虑采用10M HUB或10M SWITCH到桌面。

校园无线网络设计方案

潍坊学院计算机工程学院 课程设计说明书 课程名称:网络系统集成综合设计 设计项目:无线校园网方案设计 学生姓名:潘彬彬 学号: 专业:网络工程 班级:2011级2班 指导教师:赵艳杰 2014 年9 月 一、任务与具体要求 设计一套较为完整的无线网络,以满足学校师生教学、办公、娱乐以及无线应急等项目。 二、设计说明书包括的内容 1、需求分析 2、无线网络的具体设计与实现 3、网络安全防护措施 三、应完成的图纸 四、评语及成绩 指导教师(签字)_____________ ________年____月____日

目录 一、前言...................................................... 1.1概述 ............................................................................................................................................... 1.2需求分析 ....................................................................................................................................... 1.2.1建设背景............................................................................................................................. 1.2.2总体建设目标..................................................................................................................... 1.2.3具体实施目标..................................................................................................................... 1.3校园无线网在教育中的发展与应用............................................................................................ 1.3.1教学网络............................................................................................................................. 1.3.2图书馆网络......................................................................................................................... 1.3.3行政办公网络..................................................................................................................... 1.3.4教工、学生宿舍网络......................................................................................................... 1.3.5无线应急网络..................................................................................................................... 二、校园无线网的设计方案...................................... 2.1概述 ............................................................................................................................................... 2.2 WLAN 的工作机制...................................................................................................................... 2.3硬件设备的选购............................................................................................................................ 2.3.1核心交换机的选购............................................................................................................. 2.3.2 POE交换机的选购 ............................................................................................................ 2.3.3光纤收发器的选购............................................................................................................. 2.3.4服务器的选购..................................................................................................................... 2.3.5无线路由器的选购............................................................................................................. 2.4校园无线网设计分析.................................................................................................................... 2.4.1设计原则............................................................................................................................. 2.5设计方案 ....................................................................................................................................... 2.5.1主要拓朴图......................................................................................................................... 2.5.2校园无线网络的三种典型应用及解决方案..................................................................... 三、安全防范.................................................. 3.1概述 ............................................................................................................................................... 3.2无线局域网的安全认证................................................................................................................ 3.2.1开放认证............................................................................................................................. 3.2.2共享密钥认证..................................................................................................................... 3.3安全运维管理................................................................................................................................ 3.4无线安全问题及对应策略............................................................................................................ 四、结束语.................................................... 五、参考文献..................................................

高校学生宿舍楼无线网络建设方案解析

高校学生宿舍楼无线网络建设方案 1、项目概述 利用WLAN 来覆盖高校学生宿舍楼,从而使每个宿舍能更好的链接网络。 2、需求分析 (1)场景描述及需求分析 高校宿舍楼是高校人群密集区域。用户数较多、数据流量较大,WLAN 业务需求量较大, WLAN 建设应同时兼顾覆盖和容量,对GSM/TD也有较大业务需求。 高校宿舍楼的建筑结构一般有走廊单边宿舍、走廊双边宿舍以及小区套间结构。建筑材质一般以钢筋混凝土为主,屏蔽效应较强,无线信号从走廊穿透宿舍难度较大,无线网络覆盖重点是宿舍区每个房间。(2)场景覆盖方案 WLAN 宿舍楼场景一般采用室内分布系统合路和室内放装两种建设方式。室内分布系统合路 高校宿舍楼覆盖一般需要考虑网络容量,应根据并发用户数需求,确定每台AP 安装位置和覆盖区域,合理设计分布系统的主干和分支。设备一般安装在宿舍楼每层机房、弱电井或走廊;天线一般安装在走廊的顶部,如条件允许,可将天线延伸至房间内。 对于房间信号穿透损耗较小(如采用木质门、有窗户等)的宿舍,可采用全向吸顶天线;对于房间信号穿透损耗较大(如铁质门、无窗户、实心水泥墙体等)的宿舍,可采用定向板状天线;建议信号只穿透一堵墙为宜。 以某高校宿舍楼为例,房间为钢筋混凝土结构的走廊双边宿舍,木门,有窗户。每层有24间宿舍,共96人,并发用户需求24人。

平层有2个支路,每支路合路1台500mW AP,共采用6个全向吸顶天线,每个天线覆盖4个房间。整栋楼由POE 交换机集中供电,AP 安装在楼层中多媒体壁挂箱内。 实施要点: 由于宿舍楼用户容量较大,在建设时要充分考虑容量需求,合理选取合路点,避免2个AP 合路到1个支路中。 在宿舍区域做室分合路方式时,需注意宿舍楼建筑材质和结构,合理采用全向和定向天线。 室内放装 在高校高容量需求的情况下,应根据并发用户数需求,确定每台AP 安装位置和覆盖区域。设备一般安装在宿舍走廊;天线一般安装在走廊的顶部,如条件允许,可将天线延伸至房间中。 对于房间信号穿透损耗较小(如采用木质门、有窗户等)的宿舍,可采用 AP+自带鞭状天线;对于房间信号穿透损耗较大(如铁质门、无窗户、实心水泥墙体等)的宿舍,可采用AP+定向板状天线方式。建议信号只穿透一堵墙为宜。

无线网络建设方案

一、无线网络建设目标 仓库部署无线网络及移动终端系统,建成无线扫码、无线仓储系统后,可以主要实现以下目标: 1.入库管理:入库单即时通过无线网络提交给后台系统,管理员及时获取入库数据; 2.出库管理:当理货员到仓库领取图书时,仓库管理员在移动终端上通过无线网络下传出库单据并输入待出库的图书数量,主机数据库就会自动更改商品库存; 3.库存盘点:理货员手持移动终端,直接在货架上扫描商品条码,即时通过无线网络环境提交库存信息; 4.其它作业:人员调度管理、系统管理等。 无线扫码作业、无线仓储系统中,投标商必须保证仓库无线网络环境全覆盖,并确保高效稳定的网络环境。 二、无线网络建方式 2.1瘦AP组建方式 传统FAT无线网络的部署需要网络管理员对网络中的每一个AP进行逐一配置,对其进行配置的话,工作量巨大,且容易出错,因此,不建议用户大规模部署使用。建议采用“无线控制器(AC)+瘦AP(FIT AP)+POE交换机+无线网络管理”的FIT AP组网方式,无线控制器(AC)必须使用单独的机架式硬件设备,瘦AP实现无线信号的处理,而用户管理、加密、漫游、AP管理等功能全部集中到AC进行,这样可以简化整个网络的管理,提高设备的工作效率。AP的供电采用以太网供电(Power Over Ethernet,PoE),通过以太网线来汇聚AP的流量,同时为AP提供电源,这样可以简化布线,同时减少故障点,提高网络的可靠性。本次FIT AP无线网络部署模式,是将所有的配置在AC上统一实现,AP本身零配置,可实现无缝漫游,适合大规模无线组网。

服务器 路由器控制器 汇聚交换机 移动手持终端无线AP 无线AP 无线AP 移动手持终端移动手持终端移动手持终端 无线AP POE 交换机POE 交换机POE 交换机 (瘦AP 无线组建网络拓扑图) 无线定点图—初步

医院网络规划建议

北京大学人民医院网络规划建议 人民医院在HIS系统升级的同时有必要进行网络的全面升级,以保证全系统的稳定、可靠、安全运行,避免由于网络瘫痪和延时造成HIS系统的不稳定。 在网络的设计方面我们提出的设计模型,其设计思想是建立在保证网络稳定性与可靠性及冗余备份基础之上的,并充分利用了Cisco网络设备的领先技术,可以为HIS软件系统提供稳定的运行环境以及可扩展的高带宽传输。以下是就网络模型的简单描述: 该网络的核心采用两台Cisco Catalyst 6509交换机,建立冗余的核心路由、交换矩阵,其配置根据HIS系统业务流量选择平衡(相同配置的双机)结构。由于人民医院HIS系统配有大量服务器,平衡配置的双核心交换机将使业务流量均衡的分配在其上,这样将充分利用两台核心的处理能力,也会使下联汇聚层交换机的链路带宽得到充分的发挥,因此选择平衡配置的双核心交换机,并利用GigaChannel技术在两交换机之间建立8G~16G(4~8条线路)的无阻塞通道,保证两台核心交换机之间的大量数据的传输。 网络汇聚层根据级联设备的数量以及流量分配有选择的配置三层交换机。对于关键业务以及数据传输量较大的部门除配置普通Cisco Catalyst 2950系列二层接入交换机以外还可配置一台Cisco Catalyst 3550系列路由交换机,通过千兆光纤分别连接两台核心交换机,这样不仅可以提供2G的传输带宽,而且当任一核心交换机宕机时接入交换机仍然可以连接HIS系统主机,以此有效的保证全院PC机与HIS数据库之间的不间断访问。

网络中的HIS主机集群系统同时连接两台核心交换机,可以避免系统主机和网络核心单点故障的同时发生,使全系统具备更高的可靠性,保证医院关键业务的无间断处理能力。其它专业应用服务器可根据使用情况直接接入核心交换机,以提供较高的访问带宽。 通过如上网络结构的设计不仅可以使本院网络系统更加可靠、稳定,而且可为今后的医疗信息化改造建立坚实的网络基础。网络核心Cisco Catalyst 6509交换机可以提供720G 的背板带宽以及400M的包转发率,完全可以满足日后PACS系统应用的要求;对于服务器不断扩容的需求,该交换机还可提供七层内容交换模块,起到负载均衡的作用,使三层结构HIS系统中的中间件服务器运行更加稳定;同样对于医疗信息系统将要面对的海量存储问题,该交换机也可以提供包括CWDM和10G Ethernet技术在内的全面解决方案,保证系统对在/近线存储的带宽要求。汇聚层Cisco Catalyst 3550三层交换机可以灵活的为网络提供多种服务,包括访问控制列表(ACL)、QoS、802.1X、EtherChannel等技术,对于保证网络的安全、带宽等都具有实际应用价值,并为今后网络系统扩容提供对投资保护。 北京大学人民医院网络系统升级的主要技术优势可以概括如下: 一、核心双机网络拓扑结构优势: 1、双机网络系统具备更高的可靠性; 2、双机可根据业务量需求提供负载分担; 3、网络系统扩展可以更加灵活; 二、汇聚层引入三层交换机的优势: 1、在汇聚层和核心层可以启用动态路由(如:RIP或OSPF),这样可以提高收敛速度(动态路由协议收敛速度小于15秒,而SPANNING-TREE协议的收敛速度为60-120秒); 2、通过路由策略使汇聚层的三层交换机分担部分VLAN间流量,以减轻核心交换机的负载; 3、汇聚层三层交换机可以有效防止广播风暴,并部分阻断类似BLASTER病毒所造成的大流量端口攻击;

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