Manuale d’uso / di manutenzione del prodotto 7920 del fabbricante Cisco Systems
Vai alla pagina of 48
Corporate He adquarters Cisc o Syst ems , Inc . 170 West Ta sman Drive San Jos e, CA 95 134-1706 USA http://www.ci sco.com Tel: 408 526-4000 800 553- NETS (638 7) Fax: 408 526-4100 Site Sur v e y Guid.
THE SPECIFICATIONS AND INFORMATION REGARDING TH E PRODUCTS IN THIS MANUAL ARE SUBJE CT TO CHANGE WITHOUT NO TICE. ALL STATEMENT S, INFORMATI ON, AND RECOMMENDA TIONS IN T HIS MANUAL ARE BELIEVED TO BE ACCURATE BU T ARE PRESEN TED WITHOUT WARRANTY OF ANY KIND, EXPRE SS OR IMPLIED.
iii Site Sur vey Guide fo r Deploying C isco 7920 IP Pho nes OL-6315-01 CONTENTS Preface v CHAPTER 1 Overview 1- 1 Recommenda tion s for Succe ssful VoI P Surveys 1-1 Gettin g star ted 1-2 Minimum Req.
Cont ent s iv Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01.
v Site Sur vey Guide fo r Deploying C isco 7920 IP Pho nes OL-6315-01 Preface This doc ument provides inst ructio ns and guidelin es for condu cting a site su rvey for wir eless LA Ns using V oice over IP (V oIP) o n Cis co 79 20 IP Phon es.
vi Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Preface.
C HAPTER 1-1 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 1 Overview This documen t be gins by identif ying the spec ific radi o en vironmenta l v alue s that ar e ne eded fo r a successful voice de ployment.
1-2 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Ch apter 1 Over vi ew Recomme ndations for Success ful VoIP Survey s degr adation.
1-3 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 Chapter 1 Ov erview Recommen dations f or Succ essful Vo IP Surveys Figur e 1 -1 ACU Site Surv e y Window Noise is def ined as a 2.4-GHz signal that is not in an 802 .11 DSSS format bu t is in the frequency range of the access p oint’s conf igure d ch anne l.
1-4 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Ch apter 1 Over vi ew Recomme ndations for Success ful VoIP Survey s Figur e 1 -2 Signal to Noise Ratio Minimum Require ments for WIP T Cells Ta b l e 1 - 1 lists the minimum v alues for v oice and data cells.
1-5 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 Chapter 1 Ov erview Recommen dations f or Succ essful Vo IP Surveys difference in transm itter power an d receiver sensitivity that ma tters beca use the gai n of an an tenna i s recip rocal.
1-6 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Ch apter 1 Over vi ew Recomme ndations for Success ful VoIP Survey s Figure 1-4 also illustrates the recommended o ver lap of 15 to 20 percent for WIPT cells ( larger than the 10 to 15 p ercent for data cells).
1-7 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 Chapter 1 Ov erview Recommen dations f or Succ essful Vo IP Surveys The char acteristic s of V oIP r equire a met iculous WIPT site sur vey . T o av oid a c all with ji tter , th e delay variation betwe en packets shoul d not exceed 30 ms.
1-8 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Ch apter 1 Over vi ew Recomme ndations for Success ful VoIP Survey s Compariso n of a M anual Surve y and an A utomated S urvey Figure 1-6 sh ows an act ual ho spital survey done using Ai rMag net Surveyor wit h an 8 02.
1-9 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 Chapter 1 Ov erview Recommen dations f or Succ essful Vo IP Surveys Fi g u re 1-7 Ho s p i ta l F l oo r Su r vey by a S u r vey.
1-10 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Ch apter 1 Over vi ew Recomme ndations for Success ful VoIP Survey s.
C HAPTER 2-1 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 2 Survey Tools AirM agnet offers ma ny tools f or an alyzi ng 80 2.11 perform ance at a site . Fi gure 2-1 sh ows the AirMagn et Survey tool. Cisco reco mmend s AirMagne t for data an d WIPT surveys.
2-2 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Chapter 2 Su rvey Too ls Figur e 2-2 AirMagnet P a ck et Decode T ool The 7920 survey tool rep orts the signal stren gth of the sign al from the a ccess poi nt as an RSSI value. Most client c ard utilitie s report signal str ength as dBm or per cent of signal str ength.
2-3 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 Chapter 2 Survey Tools The d ata in Ta b l e 2 - 1 was c reated fr om live tests. Each tool an d card combi nation data po int was taken at the sam e time from the same dis tance.
2-4 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Chapter 2 Su rvey Too ls The Cisc o CB21 ADU repor ts signal st rength in dBm . Figur e 2-4 shows the ADU Adv anced Status windo w .
2-5 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 Chapter 2 Survey Tools Figur e 2-5 AirMagnet Surve y T ool.
2-6 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Chapter 2 Su rvey Too ls The Air Magnet Survey packet de code tool shows signal strengt h in dBm.
2-7 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 Chapter 2 Survey Tools Figur e 2-7 Air oP eek Windo w AiroPeek has options to show real-t ime graphs of current signal strengt h and current noise le vels both in dBm and pe rcen tages, but it does not have a surve y tool like A CU or AirM agne t.
2-8 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Chapter 2 Su rvey Too ls Figur e 2-8 Air oP eek dBm and Signa l P er centag e Real-Time Graph s Snif fer Pro fr om Network A ssociates sho ws th e signal strength in a perce nt v alue.
2-9 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 Chapter 2 Survey Tools The Cisc o access point displ ays the signa l strength of the packets fr om the client.
2-10 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Chapter 2 Su rvey Too ls Figure 2-11 shows that the 7920 hears th ree acce ss points an d the RSSI values of those access points ar e 18, 31, and 48. Figur e 2-1 1 Cisco 79 20 IP Phone Surv ey Scr een Y ou can also use Air Magnet Su rveyor to de termine chann el s eparation.
2-11 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 Chapter 2 Survey Tools Survey Too ls for Pa cket Jit ter Survey Tools for Packet Jitter T ypicall y , voice pac kets ar e sent every 20 ms.
2-12 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Chapter 2 Su rvey Too ls Survey To ols for Packet J itter Figur e 2-1 4 AirMagnet Jit te r T ool in an Ent er pr ise Off ice with High 8 02.
2-13 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 Chapter 2 Survey Tools Survey Too ls for Pa cket Jit ter Home off ice u tiliz ation is 2 .18 p ercent and t he throughp ut i s 246 kbps for 1 1 Mbp s-onl y calls, wit h a single act iv e WIPT call, but utiliz ation is 15.
2-14 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Chapter 2 Su rvey Too ls Survey To ols for Packet J itter.
C HAPTER 3-1 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 3 Surveying for Cell Capacity an d Channel Re-Use This chap ter de scribe s ho w to perfo rm a site sur ve y to de sign a wirele ss LAN for cel l capaci ty and chan nel re -use.
3-2 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Chapt er 3 Surveying f or Cell Capacit y and Channel Re -Use Survey Des ign for Cell Capac ity Note If the Cisco acces s point is configured to di sable data rates 1, 2, and 5. 5, clients ar e not requi red to transmit on ly at 11 Mbps.
C HAPTER 4-3 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 4 Conducting a WIPT Survey This chapter describes specific steps for performing a site survey for WIPT .
4-4 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Chapter 4 C onducting a WIP T Survey How To Surve y for the WIPT Figur e 4-1 Ideal WIPT En vir onment Channel R e-Use Figure 4-2 shows the typica l chan nel r e-use fo r 802.1 1b and 802.
4-5 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 Chapter 4 Condu cting a WIPT Surv ey How To Survey for the WIPT Manual Su rvey for the WIP T Y o u can use passive or activ e mode w hen you use A CU to run a si te survey . Figur e 4-3 shows the A CU Site Surv ey windo ws.
4-6 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Chapter 4 C onducting a WIP T Survey How To Surve y for the WIPT Figur e 4-4 ACU Site Surv e y Activ e Mode Click OK to retu rn to the Site Surve y screen. Click Start to start the site surv ey in acti v e mode.
4-7 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 Chapter 4 Condu cting a WIPT Surv ey How To Survey for the WIPT The AirMagnet su rve yor works v ery well for surv e ying a site with an in stalled WLAN or for surv e ying a site wit hout a WLAN.
4-8 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Chapter 4 C onducting a WIP T Survey How To Surve y for the WIPT Figur e 4-6 AirMagnet Surv e y Activ e Mode T o survey a group of acc ess point s using the A ctive Mode tool, configur e the too l with an SSID that is configured on the access points.
4-9 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 Chapter 4 Condu cting a WIPT Surv ey How To Survey for the WIPT Figur e 4-7 AirMagnet Client W alkabout When you selec t display mode on the bottom tool bar, SiteV iewer displays da ta collec ted during t he surve y .
4-10 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Chapter 4 C onducting a WIP T Survey How To Surve y for the WIPT Figur e 4-8 AirMagnet Sho win g Acce ss P o ints and Mer g ed Displ ay Figure 4-9 sh ows Site V iewer’ s four-p anel display .
4-11 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 Chapter 4 Condu cting a WIPT Surv ey How To Survey for the WIPT Figur e 4-9 AirMagnet Four -P anel Displa y.
4-12 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Chapter 4 C onducting a WIP T Survey How To Surve y for the WIPT.
C HAPTER 5-1 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 5 Positioning Access Points and Ante nnas for Site Surveys When you perform a site surve y , it is important to position wire less equipmen t for opti mal co verage. This chap ter de scribe s best practic es for p osition ing access p oints and antennas.
5-2 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Chapter 5 Positioning Access Points and Antennas for Site Surveys Antenn as and Ant enna Posit ioning The access point in Figure 5- 2 provides b etter c overage beca use the re flecte d sig nal prod uces fewer nul ls and less multipa th than the I-beam pl acement.
5-3 Site Sur vey Guide fo r Deployin g Cisco 792 0 IP Phones OL-6315-01 Chapter 5 Positioning Access Po ints and A ntennas f or Site Surve ys Ant ennas an d Ante nna Pos itioni ng Figure 5-4 shows a p atch ante nna mount ed on a wa ll. The ant enna cab les are ro uted ab ov e the sus pende d ceili ng and are attach ed to a hi dden acc ess poi nt.
5-4 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Chapter 5 Positioning Access Points and Antennas for Site Surveys Antenn as and Ant enna Posit ioning Figure 5-6 shows a pat ch ant enna m ounted o n a suspe nded cei ling. The cable s are h idden an d are routed abov e the cei ling to the access point.
A- 1 Site Sur vey Guide fo r Deploying C isco 7920 IP Pho nes OL-6315-01 APPEND IX A Additional Sources of Information This a ppendix lists docume nts th at provi de addit ional i nfor mation about si te su rveys: • Cisco W ir eless IP Phone 7 920 D eploym ent Rec ommendat ions http://www .
A- 2 Site Survey Guid e for Depl oying Cisco 7920 IP Phones OL-6315-01 Appendix A Additional Sources of Information.
Un punto importante, dopo l’acquisto del dispositivo (o anche prima di acquisto) è quello di leggere il manuale. Dobbiamo farlo per diversi motivi semplici:
Se non hai ancora comprato il Cisco Systems 7920 è un buon momento per familiarizzare con i dati di base del prodotto. Prime consultare le pagine iniziali del manuale d’uso, che si trova al di sopra. Dovresti trovare lì i dati tecnici più importanti del Cisco Systems 7920 - in questo modo è possibile verificare se l’apparecchio soddisfa le tue esigenze. Esplorando le pagine segenti del manuali d’uso Cisco Systems 7920 imparerai tutte le caratteristiche del prodotto e le informazioni sul suo funzionamento. Le informazioni sul Cisco Systems 7920 ti aiuteranno sicuramente a prendere una decisione relativa all’acquisto.
In una situazione in cui hai già il Cisco Systems 7920, ma non hai ancora letto il manuale d’uso, dovresti farlo per le ragioni sopra descritte. Saprai quindi se hai correttamente usato le funzioni disponibili, e se hai commesso errori che possono ridurre la durata di vita del Cisco Systems 7920.
Tuttavia, uno dei ruoli più importanti per l’utente svolti dal manuale d’uso è quello di aiutare a risolvere i problemi con il Cisco Systems 7920. Quasi sempre, ci troverai Troubleshooting, cioè i guasti più frequenti e malfunzionamenti del dispositivo Cisco Systems 7920 insieme con le istruzioni su come risolverli. Anche se non si riesci a risolvere il problema, il manuale d’uso ti mostrerà il percorso di ulteriori procedimenti – il contatto con il centro servizio clienti o il servizio più vicino.
