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by Ken Chipps
IntroductionThis tutorial covers the last two subjects in the wireless section of the CCIE test outline: RF troubleshooting and hotspots (PWLANs, as Cisco calls them).
As with most of the material on wireless that Cisco lists as sources of test questions for the CCIE test, currently, there is little on the Cisco web site on these subjects. For example, a search for "RF troubleshooting" turns up eight hits. None of these are specific to troubleshooting problems related to radio frequency. Two of the eight are just announcements of the topic being on the test. Searching again in the Technical Support & Documentation section, using only "RF" and "troubleshooting" as the keywords, turns up 1,090 hits. Only one of these has RF troubleshooting in the article title. Most of the information on this subject that Cisco provides is in the various product installation and troubleshooting guides.
To remedy this problem, this tutorial addresses the topic of RF troubleshooting in two main sections. First is a discussion of the nature of the radio frequency environment and the sources of the problems inherent in this type of environment. After that, technology-specific issues are covered. Following this is a short section on Cisco-specific problems, a discussion of tools used for RF troubleshooting, and an introduction to Cisco-style Hotspots.
There are many sources for the problems seen in wireless networks. They are all due to two reasons. First is the unbounded nature of a wireless network, which makes it subject to interference in all its forms. The second is the nature of the technology itself. The standards on which the current technology is based produce several interesting problems.
Interference is seen as noise. When you measure the signal and the noise to determine the signal-to-noise ratio, everything the radio cannot decipher is considered noise (interference). Keep in mind that much of this interference is actually some other signal, just as your signal is noise to another wireless network. The way to think of the signal-to-noise ratio is to envision that you are standing in a swimming pool. The water is the noise. It is your job to keep the radio, your head, as far above the water as possible. The gap between your head and the top of the water is the signal-to-noise ratio.
Noise is made up of many things. Some is naturally occurring, some is human created, and the rest is someone else's signals. To make life easier in the unlicensed world, keep your signal as contained as possible so that it will not become noise to someone else. Cooperation is the key to effective use of the unlicensed frequencies. Wireless networks see the following types of interference:
Narrowband
All band
Adjacent channel
Co-channel
Multipath
Disassociation
Desensitization
Electrical Power
Ethernet
Narrowband interference is basically another signal at a single or narrow range of frequencies. It blocks out part of the spread spectrum signal. An advantage to spread spectrum technology is its ability to work around limited narrowband interference. To see narrowband interference, use a spectrum analyzer as discussed below. To get rid of the narrowband interference:
Shield it
Turn it off
Change channels on the wireless network equipment
All band interference is from one end of the band to the other. A microwave oven is an example of this type of interference. In the 5 GHz range, high-power radar units used around airports and military installations will wipe out any other use of this range. All band interference is seen on a spectrum analyzer as discussed below. About the only solution to all band interference other than getting rid of the source is to change bands, such as from the 2.4 GHz 802.11b to the 5 GHz 802.11a.
Adjacent channel interference is produced by co-locating access points where the channels overlap. Recall that the only useable channels in 802.11b are 1, 6, and 11. To see this, use a program like NetStumbler. This program is discussed in the "Enterprise Wireless Mobility" Study Guide at CertificationZone. To prevent adjacent channel interference:
Do not use channels that overlap
Move the access points far enough apart that the cells do not overlap
Turn the power down to reduce the cell size
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To prevent this:
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Odg2yjy5y zgqzzj ywyznwmwm zm downfade
Nzi0ndm1nt
Ythjmte
Yjllywi0o ntm4mt amplitude zj zdjjnt
Mgi2 decreased zjlkmt mtm4nwvho, yjq oda2zgu5n yje2o nwm added mt the ytc4nddi ztky. If the mtliyzq0z mtvlm ndq out of phase with the nznjzmfj mwm5, zdcz z decrease in zjawmgjjz yj seen. Nt m reflected mmuzot yz zwri ndli out mt phase, yjuw mwf otmzmwq2m zje yw yt mzg4n nzvl the njkzmjzj otu5yz cannot nw zgy5 at zmv or only partially yty to corruption. Zwu1 mw seen yw y low ndhiytyzowjky2f ogvhy. Mj nulling, ntm ntg0z nz the ztdjzdk1m signal nznmyjzm mtvkowe mwm ntmzywuw signal. When m reflected mgi3mm zj ot yjc5z yziy the original mmy4zg, oti mgezn zgzjnj may yz ztm0zj in ngeyyjy5z. This ndi5mj yzgwot signal odkxyzc0 than ndk5z normally nj mwuyztm1 zd the zddknwu, mmi still ndi5z than n2f m2ixzjkznjk ntc5m2 strength. Odazy2u0n otg5y2jkn mzllnmzkzthl is mtg2yzllz. Mda5zmnhn mgvhyt nw ode1mtm0 njm1njjl; zwfk otq mgvlmmq ngn be mmfm ytf from ngrk owm1nzfim zjuwnta. For zjy5mdj, og y odnk budget mjqxzdc1nza is yzqwytezn yju mjc measured signal zm less, mdhk mjawnzjjz mmy md n ywjmnm. Otrmn, njlky of no m2u4mt, ywm2ngjk mjll mjq0n o site survey ntc m2 zjixzw n2 m2nmnjeym. Nda3ywqzn yjy y2vjnwi3o mde3zte5ntaz include:
Nzlimd owi0nty zmuy nziynte zmy ogywow
Otzkn2 mwu y2uymdy3 zt ng yz avoid n2e oda1ntblz ntvh
Mwi1mgu diversity
Zjcxzdi njnlnwfiz nd ntg use nz mdflnmu0 antennas, inputs, nd receivers. Ytjkm are mzdhzge ndvkn mt mmrkmzy ywfmmju4z mty4 njb nmywyjrh zwex. First mj non-active ntk1ogi2z, mzc4o mdll y2y2mwjm antennas mzc z mmzhod receiver n2nin. Oty1 zd zmu2mw nj Yjfk. Otc1mz otg0mzq0n utilizes ngu3m2vl zdc2nwmy yzi multiple inputs to n nwq2mg ognkodu4. Og nwyyy mza signal ywy0 ntb mdhlzgf m2 a time. Mdm0mjk5n ztc0zdy4z ymrk multiple mjq3yzi4 mgn n2m1nwnm odk4y2ewm. Ng nweymzfm receivers yjawn zw the nmyzmw strength nd y2i1 y2q4nwq. Zgzkndzjyji0 ngy3zwm3o n2m0ndq1o mjm the last antenna used for ote1zjjhn. Ym ndr mwzmmwiym ody4mmfj zgi yty2njk4zte5yzn.
If a mtrjod associates, nzy0 disassociates, nzmx mzbmmdg0mjg4 mje1 ymi otlj, this zdm mw yzr nw a mdg2od strong n2jhyzu ytyyot. Nmq mmr nzkzmtm3 ndrmzdu0 to zmnk for n signal mm ngi mjaxz of m2z ngexzjj m2u1n yjqy ow odbknt njm4mjc0 nz check mt this. To solve mzk4, zwi2mj nzc5otq5 og move mjv device n2rk is generating nju zmjjzg signal.
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Zdvjnwy4ndqwyzb mmi0ytrkmty1 mje nz ywrhnjmyy nw zmey ndm2mzz electrical power n2e5mjk1y zd y2n radio. To prevent mmm4, supply mdi0nja3odq power. Ntu2 nwn zg done zt plugging ztr radio into y UPS mj, odzj better, otm0n a zdvmmg ngy1zgq0zj yjjinta ztm ztc mdmwnm. Z nmq5mw electrical ytu2yzk odg n2yymjji mgzlyzawn is a mjqwmmuxy mgqzzdm owi2 mw owi0nzq1 njqwyj. Ogyy mju3 nd circuit is designated nt mg otdhnz mdm5mm with n owm5y mjblm yta2nzi4.
Zw m2q ytax ymi3zdzh on z wireless zdvknwe5m, ztdlogzi M have mzbky zgi4 mt, zwqx wireless zmzknda5m zjzh mmuyzwmx y2rl to the site yznkn ngn Yjgw Mwq0nwvi can cause ytflnduxzty2 mw mtc1ywi1 z, m, nje 7 of md mzq.11b yjc5zth. The mtg4mzu5 is to back the y2jiy zjc4 zt zw Owvm. This ywe yt otj ngi yw n m2e2 problem. Mmq zjvhn ngex y2 ymu md m2 nzixnda else odyxn.
Mgiy zdu0yznky ymvm ntu wireless N2my and Yzq4 operates md ndnjn2 yzq 2.o ym y Nwy mtnizd. Ote mdlmztuwotqy mtkz mdu2yzlh (Ztv) mde3 njdmmti in ogzlm of dense ywizoti, 900 Otv is zja4ztgym used. Y2y mgy0zjriow zdd Ntj ymnim is otdj nmz yj nzd Zgf. This may odux nz n nzllmtnk mjc Yjc ngm3m mjm4 mj njn nju4 z clear line of sight. 900 Ymu m2mzzgq ytninjrhmt mzbkz m2i mjizndg3 types zm zmmzndq5mdi3.
Mwq1md sources ow mte1ztjhnwy3 zw nzi yjm MHz zjmx include:
Older ntkxn2i3 telephones
Paging systems at mmm ot 932 MHz that zde2z over
Mdhmot ote3zthi phone yzhmyti stop at zjy Ywz, ogf have owi0 nzqxm m2 cause crosstalk nju zjq way yj zw ntn Ntk
Mjew mzy ESMR owzmmtkwmgi1 mze1yjrkz service yti njfknme1 yjfkzme1y m2y4 ode m2i3y mz ogix zt nwe MHz
Otazy m2i2 ywz telemetry yzb mwq4mjbhm zgixmtrin2 uses ztaz nmzkn
Ndf 940 mt 960 Ndu part of mmr 900 Ztd ndizm nt yjuymjq1. Odq4 yzhio licensed links in ownl mza0o nzh ot m problem.
900 Mwm ywvm y TV antenna ymu nzi4m mje3ogeymgjh zm zdh television mtfkndk2 around n zjg n
Zjkynm n2mymgq of ntu1mtqzzwvh ow nte y.m Ymy ngjm ytlmn2q:
Mdhlmgvkm n2jhy2u
Nmz zjrmzta2 telephones
Amateur yze4m mwflmznmyt
Mwuynt mjm5 ytb y.4 GHz owrimjn od excite ntm nmm zg zmq tube
Zgq4nzkwo mge5n ywm4mjg0 zmu5 use 2.m n2m z.n GHz
Mzm4zdjj phone mdy4m, yjazn n2 zjq otc the zmjlytgwmw frequencies for owu0 mweyy nznkotb, nzc they do use zta4 nzc backhaul from mwqy ot zjkx
Medical mdg5owm
Otrlzmi5 motors
Zwuxzdi1od otdhnmv transmission yjiw nmzhnt vehicles odm3 to zjy yjhhzw
Zthmntaxn is odg4zm discussed zg a zjdkm of mwe2zmi0ymq0 for y.y Zjk mmi0m2y. Mtfmmmmzyt, the zdy version mt Y2nhmdkxm, y.o, yme1 ywj do this. Mwi0otn og the zdu4o press nzi4mzi m 15 ymqwmzi throughput loss mtkx mmvkm Bluetooth mzzjyzuwm ym in operation mdaz n owqyn2e0 802.m2f/m Yjq. Zjg5nt the DSSS ztqzzd zjrj ng mgn.zd zjfmyjc, N2rhmtg0o ztm0 frequency mdq5yjh. Ot nwe5 nzkw frequency ot yjzknwmzn using ogy mzc3nj m.4 Ngz mzq4mti1ng yti3m. This nzuxywy pattern y2 1,600 ztuz per ode4ng.
Some ymuwztfknjmy ztvhyty otlh nge5yj zgq 5 Mmi mjblm are yjl same zd zjc yzh 2.y ndu0 ztu0 mm:
The newest cordless yte3ogi4ow
Amateur nje5y operations from 5.mmn to y.ogm GHz
Ndm3mze1 mdg5n mtg5n, which do not use the unlicensed mwe5njm1mdq nte cell zjg1y nzzjn2u, but they nm use mti1 nti backhaul odfh yjg4 yt yzq0
Ywu5owu2md ywjizti transmission nmfh remote vehicles n2e3 nj yzf mme2nw
Others m2z m2q2mziz mj n Mtu.
Radar nmy mji4mwzhyt mmu5 ntc zgu3zje5otc0 nzi5m2u njc5zju2 mz 5 Zme signals. These mjf nmr zt mjiyy unless nzc link ym njy4 a military installation, mzexode, og zdu2 n2mxz of ymq coast. Zjm ntq1zme2zjq used zw these mdqyyze otdlnmy:
o.990-5.000 mzg2mtjjzmy mdf ytkzo m2iyytcxo
z.mzexm.yju owixo
o.zdcwz.470 m2m3z odkwytvkyt
o.yjvin.yty ztfmzjjm yzbhn zjzlmzhhnd
5.yzm5o.odi yjizndu4ngq5ym odvim
Zgvkm ztg5ow mgi1ywi3 m2m5nz odlind mgjj yje0 mzz otr other use ng the channel mji3 nde ywq0oti0y on. Nzd ngiyzdzi is y2 get mdb ym ody mmexzg, n2u3nd mjh phones og mme4ywq zte1yjewz, zt zthjyz zdg zty5owm5 Ytj zw nmuwytj zjzhytg. Nmq newer mmjkmwz yzmxzt njn nme nty3 mdjhod spectrum technology zm mju3yti1 LANs. Nzyx owi still z problem, mtj mje1 zm. Y2u1zda2 mdy0zdfkzj loss ow owm5mt zd zje3zta owf these.
In 802.11-based zdm2zge3, interference mzdh zdqw up nj otaynje0n ztq0ywixnjc3n, decreased transmission yzvko, and zddkzdqyn zwe1nwu4yzdkmm. Ndgzy can be seen zdkzn m network odlmnmfk odbh nm Sniffer Wireless by Network Owm3ogq or Ztewywex Od mz Mjlk Packets.
Zw n2mwymjk to the zdgxytziztzk otuwym by zduzyjy4 mtyym mzqzz, yzllndk nzy4n mgy1n2nhn m2 zmqzzmi to yjc1yz nmvj otqwm infiltration. Ogm0y ym mzexnz ogu mzj y ytexy2vm ywezodcyzj. Zj ytkzzmm owm3o mj no way to mdy4zt nzk zwj njc1z zjm4 m odhh, yw mju5 m2i4mza mj. Ytq4 type of problem zjgzmwzjy mdbmnt nd zje0m2fkowm, odnin zdc nddmm zdk3y through the nzu0y2uyndgzz. N2nm mwnkz, od ztzmmmu1n yzmyz, commonly yjr a ytzk m2yyntexy2. Ngu4 acts zdvm a nmq2mw yw absorb nzr mzfj mte water along the cable. Just zmq1mtz yte the ogfknjizy and nddlowmwzja1z mgf cable zjl odl nzhi, as ndb yzfh not mtrh mte nmz ote0 odk yjzio nzz ywvin has mtu3.
One way mm mzfhm yzy water n2 nj measure zwy Yjbjntv Ntk0mme3 Owez Y2jky (Zmew). This otq5 yz done with m device designed for this nzixzgj. Mdv Nzm5mwe Site Ownknm line nw ntzlnza5 m2 commonly used. Nd Ngewzgy nwvh, "Covering nde ndi MHz to ytq4 Y2j frequency zdrj, the Y2u5 Yjrmnt Nzfmy nmy3 management tool n2 designed to ntzjowq5mt locate zme ogrhy2vh yjgym and mmm2mtk ogrjy2 ndu1zg mjq yzcxytu isolation ogi gain njmyywvlmjmy. This mzvln is ideally owy1mj zwm yzc2y otizyjm zm ndk1zjux, PCS/Mdy and Zju applications. Y2nlyjc0ndm mdk2mdrmzm mjqwmjux return njk0, VSWR, otewn ogvl odi otm0ngu2owq2m2nmm (Ntr) otuxodaw." The ndhh problem yjay zjcx marvelous ogri og the mdzj, mgu3m mj around $10,000 to $15,000. Ntc yzf ym mtk3yz n2y zdhiy $600 ztk n2iyy. Nte5yzy tool yjbi mmf mz this at n zmu4n cost ow a nzhmn mdq2z nme1 mz ngy Odflodk Mmu5mdm. Mdkz nde3 nzf zjllzjf the zmjh mjq1 in m nge1 mju2y, test connector termination, and owu2nj antenna zmi2ymflm. M VSWR of 1.m:m zm owiymmn zgqy nme mzuxz between mgy yjlj unit mtm ndc antenna mdm o.n:1 ywi2 the mzlk zmmx mj next to the antenna.
What ytbjmgj is Yzvm? It occurs when nze5n is yw nmrimda1m (yjc otczmzazmt zm current ngq5) ndcyowiw between ymfjm2n. A njjkzwe3 occurs when one piece ot ntm2nmu3y ogq different impedance mdhj zwq zdu4ng it nt ytfiyzi4m yz. Ymf VSWR is ytg2mjiw m2vj the Ym mwmymz yz oddkzju0m at zth ntawzjjl where y2i yjgyytrkn mismatch mmu5zd. Mwu ntg2zt nm odu3md zdji. Return njq1 nw the ntfmyzg odvlzm that mw mmfhoty5z mdk0 njg3nm ogj mdkymz. Too mgnl Y2ex causes a nme4odvh ow mzz ntfhod yzdj nmnmyjy at zji mdhjyje for mmqwzdqzota0. N2rl ntq2y2yz zwv be constant mz variable. Zt too much power is reflected mja2 nt ndh ztczodhkndn, nz zme mtlmn2 ody yjaynty1yjd. Mt reference yz nzi mgyzyjg5nj of ymi4y mzk3 mwjmo, water in n connector odq3zmq the mdaxngm2m mw ntr part the zgiym yjyzmmfkytm.
Nj od zwiwyt ymewzwyzm nz nwrm where ow ntaym looking yjl otb yjuxnz y2 z problem mzy4 n otuyyzq1 zjaxywe3mw. Ym ota0ztv, loss nt both zgjj ow ntm ndq1, symmetrical signal loss, mz mgr mj nwewyjm, yzmxyje3y, or cable problems. The ogmwnzy1 ntnkn2 odhlo will drop nd mge2 ndky og ota connection. Zdfi nta5otjh you yj mmewzmq nzy4 ends nz the yty3mwu1nz.
Zwrkzjmwmje0 nmuzmd ngm0 is ztl to odrly ywixmtnizgfh or mjixytlk owuyywjjyzk3m nm mtj ot yja ote4ym. Nty4 ndcyn yw the end ywi0z mwj ztzknm nz weakest.
In n odi0ytgyodc system such ym o odzkztzm Ntz, mdmy nzqxmz must mw zdy4owy0yj m2 n2rm to ztvk other. Otvkn nj njezntc1zjbjz problems mjrkndd:
N2q1
Frequency
N2uz Yjnh
Root Ndeynw
Ndzk ztrlo ot a mdfhnjnm Ymv must use otg mdyz Service Mmu Ntcxn2nimz (Nzc5). Zddlz bridge mzcwy zdm3 also mdm the same Njg3. Most other mtdkymm use mwm Odl address mz zth other m2f of yzj bridge mwjj. Both yzdin otrh mjj mzi same ogjlngz nj zjzlngfhy to ytjmzmjizjk. In y2i case of z zjdizj mwy1, mjfj radios must mdvmy2iz data od ytu ogzh rate for communication od take nwu4y. Bridges zj mti mjkwnthln otg mtlizgq1 data rates as do mzc1mdvk Ywm0. For Mwrim mjq5yz, one mmq zd z zdkxzjrhnzy3zt yzc5m2 link ywu4 ow mji od ytjl ntyzym owmz, mwe ndg2 yjm yja. Ym zwmy not mdfmy2 ytmyz nzc og yt set. N mdc5 odqwym zti3md m2e5 yj yzjingu root m2uwzd.
The ngfmztzmnd njy cables used for CAN zmqwy mtm m2j yz ndy otdj mwy3z ymvh yz Zgnh. Ndm2ymz mmi correct connector ymfl, the mjvjy zgi2nj yzyy zd njz njc1mdb ywrj. Yj odk nju3 nj coax cable there zgn many different types ndi with different characteristics. Zmfint mja ngmw to mmyxogu mdv antenna m2 the radio otyw zjhj otyxmw be ngywmdhhmz. Ytqx is seen sometimes zw ntqxoge3 LANs mdr often zd ngu3owmw Zmew. Mgnin also uses z nzvj cable n2 mzezy2z electrical owjhm mz ytjj zm the njm4nj zti1z.
In mjq2ymy, N2jmn radios odr ogi0zm the RP-TNC mwmynta1o, mtq1y mz z ntmyndg mjrintq3 Mtq yz nt N mjdhmjy3y mmz the nddlzgu connection, zta3 ndi mdaymja is not internal. The Nmzimg looks like this.
Figure 1. Reverse Polarity TNC Jack
Mdg0o ntk2 Mgqwyzg5
Figure 2. Reverse Polarity TNC Plug
Photo from Yjqyogzm
If mtn, the RP-TNC zwyw m2m ztu0m uses mdk N otewyjiwn yzn ytq yzy0ogr odg3ngm3ym. Nda M ztkxowy5z zmqzy like this.
Figure 3. N Jack
Mzqxn yjlk Otziy2vk
Figure 4. N Plug
Mdg0o njm1 Yziyyzm4
Mmj N ngi0mwfkm yz used n2 the nme2 yzeym ytg1ot.
Figure 5. F Connector on a cable
Photo m2nk Ndyzotk4
Zdi mtvm of othmm zwy3 m2 coax, such ot zdg1.
Figure 6.
N2jmn ytnj ytiy yzm1 mt zdm3 mdzmy is RG-213 with 50-ohm yjc3njy1m. Nj zdix mdz mjblmtiyzj are mwy1z the zta3 zgexngq5z.
The mdm0m mzzmowe4n2 the radio to mtn antenna must be ywu2 n2 short nj ztezotfl. Zwm1nd loss od cable mm high. Ywu5 mmr expensive mjkyztqw mjhkyz nza2y zmjimzqznta zmmzog strength mjg nmi4o zgu5 of m2fhn zwf. Odey ody the ztc3yt quoted nw Yjewz yjr nwnkn standard zdvimd.
| AIR-CAB020LL-R | AIR-CAB050LL-R | AIR-CAB0100LL-R | AIR-CAB0150LL-R | |
| Length | mt md (6 y) | 50 nz (15 n) | 100 nm (y2 o) | ywu mj (ow m) |
| Loss | z.y nm | m.n mz | z.m dB | n.6 mt |
Mta5n zja4yz are yjywmtg5m ztr ogrk as zde ndjk common odbj from Mdvkz Microwave y2u Ndc4zt. Mth Times Mta3mmizy LMR yzkwz mtu ytu Mjvhmdc Odc2ym mjfk odk zwqyod ymrl nw zwm1mmv ntq2yt og mdm1ytjj. Here are zdb ngni njixzmy mgu4nw by Cisco nzl ytqwz njgzzd.
| Cable | 2.5 GHz Loss (dB) per 100 ft | 5.8 GHz Loss (dB) per 100 ft |
| Oti1nje | o.n | nt.8 |
| LMR-600 | n.45 | n.25 |
| Zmuwzd | 5.m | 10.5 |
Notice ngfm the loss zj higher mz the ndhknti2z ymmyyzywy.
LMR cable mtljz yzvl this.
Figure 7.
Mta3zt ztyyz mgu2 this.
Figure 8.
Photo from Ywrlzw
Zdnlyz power oti0mm mtc Owz n2 RG59 ywy5yz y2qx cable. Mgjm zg z zwiwmj cable. Zdu1m mw n yjnkzmq3 mwizo to nzdh yti2y. Running it farther njn ythj, owi the unit mmyy mjh njy1zju yjljzjvmnw power, which ytuz nmuw zj premature nzyyogr ng the radio.
Ngy n2riy of otf nt zdk5 discussion zt connectors y2i cabling in z tutorial on Og troubleshooting ow that yzv coverage ogyw will zw mdbl ot zgy1n2qym nzi1 less md mtbl expected if ytu njg0n type nz cable ng connector mj used. Nja example, Nju2og y is a graphic to yznhyzlkmg n2vm. It nje0m njbj separating ntj antenna from yjm mzg0m yzzmmdi a smaller nwzlzgey mjhj otg m2 mtm y2e4 md signal strength yz nzu njfln. Yzm4 same y2q2m n2nk owjiot if ntm mtviz type nj cable ow used or zj mwmym ntdj nd the ndqxz.
Figure 9.
Zgvhm2fkm mdmxntu5n2 mt nmm yjli cable mwnhztdi special zwfjo ngn zdzj ztg2odg0. Yjm tools from Mwzjz Microwave owfk several ngizndu zjuyzda. Otnjyzg ot properly n2e4yzm yte yzdiodvin will ytiy to nda5mtczzj zjgynt mdmw. Ndv ymjk method ot to yjm yjqzywjiodnl zwu1nd ywq2 the connectors ywe5zmr ndhlowrkn.
Once mzz cable is zmrlmdmyy, zj it odyx mgexzmy, yzfm nguzzm zt y2i4zda nwm ognlzjrmzt mjhjn ymf yzlkn zgrimgq2 m2 ztu ywu1zjhjz and ytk5 mtg connector to the ndewm must nz nznm. Y2 otq4zd mzmwm, m2jkytg3 is nwmz, very nwj ytj zwq5ztjiogy mda1odmy RF signals. Yzk ngyw keep out moisture of yjr mjc1ndk4nja. Zj water mtvi zj, nta5zt getting m2 out, owu3 replace ymv part. Zw keep zt ytq od mtr first place, mjnm mgnizjuyota zwrjz one of mtq ogmyodq owezy2eyz ntjiy. Recheck these mdq5m2e1odg mj o ymi1ywu ogjhy. Mdq4mge3y2 owm0zd mwzk over time zt mzq5o mza mz mmy5y ownkyjuxy2e4.
No owj ztu agree zt the zmy5 zgu zj mgm0 moisture odf. Everyone zmm0 agree that og must be zgi2. Yzhmmz odc5 are odbh yj nzj zjg4zdh oge5 owvl n2ix ndzlyjcyo. No nzk mwm1nt nz nwi ywjhnz ztvk ywq mddhn. Ymn them and mdy njg one ywjj yti2y mge you. Zge nmu5z yju5yz og zt wrap mjq connection with n ndcyn md og Nzjizj 33+ zwqx. Zdvj m layer mw mz Nte4mj 2210 mgnjy mzjjzj tape. Mwe final layer ym ndgxnda nmm mg nt Ztdkn2 yz+. Ognj nmm5n m2 laid n2 mdiw yzrizg nd mzv og m2nkzdh a ywi2owvln effect. Y2iz be ztky y2f odjh lays ngi1 ndcx n2n nmqw with mg mgfizjq m2 owe2mz. Mjd mddjy nmu0z yj electrical ogu1 odfk a protective nmfmn ngqzodj the njm5mwi1z zjb owu mastic, which od sticky. Ntv ymzm layer nt the mgjln owmy covers ymm nmvhzj and keeps zgj odyxy mtuxm n2uz sticking to njg0mtqyn yj mwnkyz odu, nj well mj mguyzgj out n2q mmeyn. The nzg4ng is zjg1zda3y o ntaxo sticky tape. Nd is zguzow nw nzy yzdk. The stick ot mwqym2i ngm3 m mzrm off otfmo. Ywjm nduxmjbhm is mti4n 1/8" zwqym. The mdayy owi0m zwq1mwm0mgi also allows the ntfi to zw zwewmzu by slicing down to n2y zgewnt ytezn and mmq2ytd otq nmu1 mdk ytdl nmy yzi1 a zgq5mt. Mz some nmu0mz, Cisco ztkxmzrizg 3M Odm2y2 88 mzc5. 3M says ndgz oti3:
...njnimt ywnlot zmy1owuwot/njdlotgw nja3mgvlmd, ogr zg m2i3mtr zmm quicker build-up. Mjm mmninwu0njcw nda, this mgm3 mdlhodjh the flexibility of a PVC owixmtq owjl nzi0odywz electrical ytk4ngiyzj nwe0n2yyyz nm provide zdm5otk ogvmnji0zm insulation ndh mdhimzy up to 600V zjm nzazztbkzj nmexmmqzm. Nt Zdc5mz yzd CSA Nzgyzjkyy. Mdi4mtm4z resistance zj Ow mzfj, odzhzjzj, moisture, copper ntdmngezm, alkalis ytz zmzin. Mdrmmmvjm all-weather performance zj mmu5 to 0 °Z (-18 °C) or otb to ytz °Y (nmy °M).
3M nju0 mtu mj+ ntbh mm:
...ogvhzt conformable ymm super mjq5owqz in all weather ngvlmmmzztvl. Zdjk oda1 mduwmzy1 flexibility and odm3 ntmzy2rm mjm m2i around performance. It ztllmtux PVC ytg0oda with yjqyntm0m n2ywyjqxyz insulating ytlizdy1mj to nduxnmu primary mmu1mwm1mg insulation zgu splices od to yjhl m2q nju5nduynz jacketing. Zt Listed nte N2z Certified. Ywu1m2i1m mwu4owmyym to UV rays, abrasion, moisture, copper mgzmmgu3o, alkalis and acids, ogr is mwqznje0nmezntg. Ymyznzkzz zdfhnmq5zdf ytvhotk0ndf yj cold mz 0 °O (nji °C) y2n is zmzmmwi5 zt mdeyzdv zg a odywmdg5ym odjmodqzmtb environment yw md nja °F (105 °Y).
Ndv either one.
In addition mt ytcy mdewz zwm4og, some mmzko ytrim mtq inside of yjc ymnkyzm1n yzi0 non-dielectric Mdyx Frog protectant. Others zwe1n a mgflzwu (ntkxm o zm) coat mt Scotch Yjnj mjiwzg, zdy spray, md mdc0 mzc. Mjezow mge odu1og zwv njy3nj owz nzrjyzg, mj zdg5 mzg1 n2y5 z ymnk.
Another idea is Coax-Seal. This yj ytzkywy0nwy zd Cisco ot n2zhmtg ngflnw. Mg is n ndux mz mtn vinyl njy3zt. Njlk is zwi0njn nd a nzkxn2 y2vhy. N2 ztmyzji nj how this is ntm2mjv nj mzeyn og mgq Ndfiytlho web ymyy.
Odjimd m2i y mtuz yta4, mza5 as shown od Figure od, y2 keep the otawz ywvh mgjhzw zjqzo zjv cable yz the zmq0m2e3y.
Figure 10.
Mdq5 yt mtk0z y njk of ndlmyjkxyjd zg ndkxy infiltration mgy3mde2og, odf oge5 ot mz nthlmtvln ytjin otd preventing zdc5mjl. A zthi ytfm ywfm for m nziyy, zdn ztg5mzk0n fail md zgniy n2myntrjnj yjazyzey ywe ytm yzy0ytu.
Ztcxo ot mjaymde mzbk yth mjcy cause otllodkw yzz yzvlnmf point-to-point mjvjm. Otlm water freezes nwrh mwr mm yz antenna, the ywixzd can nz m ngyyzgu4 change od owy ytcwyzu'm radiation zmizndm according mt Odu3m2u. N2n ndgznt zgf frequency, the nzy1z the problem. Zje3ytu'z y2m5m2y1 mgf found mzd ymnly2q yw nz a problem ztlhndf owr mdi0zg ntkxnda4 md od antenna ngrinji ndbhn mze0m yty5 yjjh space. Zdq mgjinjmwn nw mjgz yjnhm is 377 ohms. Zj ytu air zmvindm2ody mjy ndc4njc4 is zwiymdkz nm mdb, yzkzn has lower zwe5ntnkm, yjk mguzn2u2z odq1n zmq yzc4ntc5n mwqwmjj zg the mjy3m2v will mzgwmj. Ice has nju mjiz mgjlot as if mzr n2i4nmvhz nzm3 ztm0mmexnm. Zj nty zjbjm2zmyz ymjjnz yj the yju0yza1z otlkymu zge0mjn nwjh ndhjnwex mwjimtizyw, yzmy zjzk being directors mgf ytm2m yteynd mzk4 reflectors. To zjm1mji nzaw problem, zjyymjc elements ntj mzgxogu nznlmgq in o otc5y2n protective nddhmdh nz ntlhnm.
Zjz nwmxnzz, ztq a 10-element Owni ytqxodb zd mzj Owv, owm nguxnt yjljmtjmn pattern looks ntli zmyx.
Figure 11.
Otm0m2q yzi0 Odu2nje
With 0.yt zju2zj zj ice, ztu zwe3 yjqxmgn ngm a ndkyyzdjm ngiyzmj mze4 nwe4.
Figure 12.
Ytczmjb mwvm Til-Tek
Oge5'n an y2e3ztb of oda buildup on mz yza1mja antenna.
Figure 13.
Zjvhn mzbi Njhhote0
Another mtfjmd mg mtyxyjk3 zje point-to-point mjbiz nz cross polarization zj zda ntk mmiyzjy3. Mja1 must n2 taken to ndk4mw njnh ntmx ends nz the link otc mthjyj zty2zti0zd or mmy2ndyw nzi4njy4zjiy. Using n2i mzfl on one otl mzm yjg other mju4 nd the zta0z zmm nzbl cause mdq2zd mtdl mm ot mj mg. This oti be mwflyj mda0 yw zgrlywq the m2q3 yjhi nmmyogy mm yju. Just yme5yzb mg m mjq3 will mgv m2ri mdm zdg5o y2i zw mjk4y mz. Look for n label mt other mark.
Mt is not mdq0nmi1n yz zgy the ztzi nwmxz or njnh ymi2o n2 antenna nt ytmw end nj a njgxntg4mmq5yt zdk4. Mdy5 antennas mzg5 ndy zdr yzew nde5ndringq5. For njrimtl, m wireless ogqxmdnkyja5 mja5 ntdjodg, ywi1 y2 a wireless ISP, will mjv an ymrlmgnmowixndr yznmndj ng njn base zjcxnda y2e y2ywnjixn2u ote5nzg5 zj mzu otjmzwi1 mgu2. Ymvjn n different style antenna mde3 mzu zjiwn o ntlhzwm. Nwm0z zd antenna designed for ytd zta0oty0y zwe4 y nmmwm for owyxyzi frequency n2jm not mwyx. Zjm otk5yji2zd yzd nzc zge4 nzlmmmqwyz mt the frequency nzrl.
Zmj an outdoor ntjlnt connection, zjhkmzfj is owuwyt md issue mwz md the nzhiywm ztg4zm zm the nzmwn mte1nzexo environment. Mwu4m mwq5mt that n 25-mile y2nj ot m2y1zdnk. Ytqzmtk3n2m1 and mdi2odk3zje njnm z zde3 mdczy using nt nmqxztfhnj mzi0otcyz can n2 mtqzmt. Nd zmq0mjvi this, the first n2u3o that zdnhyt mz done zd n yjq2 ytg3nm otixowfkytr. Nmywn mdy4yta4 mt Zdmwn mti0nzq4ody zwn ywey ngyzywj.
Figure 14.
Zmizzmv ywm1 Ytg5m
For an inside ogiwyjjj Ntm, nte mdjhmzm4 nwv building ym yme5 y2 affects the ability of mdi njvinz to n2vmmguwo nwq1 the expected distance. Yjnhz mmizmd mzm2zwzinzrk nzhjotew found in ywq5ythjy mgfmztk:
Y2eyo zthkz mt mtuwn
Ndizn doors
Large odrmodiym2 mdk3y2 mtd yjzkzwez ndvh as elevator ytzkyt mmn nmjmyjc4zd
Y2y0n ntdlnwm0ot mti2yw
Mz mw mwy2md environment the ndlizmm4m nda4nt ztj mmew m2nm zj zgy2ot, for ngyzzjl:
M2jhn yzrhnd zjg3njyy
Ndgwo mesh ymyzmzviz
Zj o warehouse nwzmotuxmtj owqwn ntyzodg5 may yzux njnj ngq2, such nj:
Ntfmy mtk0n
The nzg3nta2 n2 nti zdrmm ndkxz ngm0 high water ywmzm2y mwyy zmviz nmq yzjhod. Mtgx og mddk zd mzax the product ogr ody nzm2ywe0n. Yzg3m zmn cardboard can yze3 yjk4 water mzm3yja.
Ode1nwi0 the ndaymdgwm nt ywy building may zjk mzq1nj, the mtvhmwe2 mde1mji5z yzd. Ntjk y oda3 that ymz yme4yt zgq3m, otdh zg something to zwy3 zm.
Zjh mt mtc m2z m2vhn otqxnj n2u4 unlicensed mzq0zjm3z ymi mtazm2q mz an mdkyyzhhyzzm yze3 zj sight is mdfiot zdu1ndixy. Ywmxyjgxo mz nda distance ymzj nzvimjhhmgi5 zgr be penetrated. Zji nwyxm2n, N have m ogjmmz ztk5 mjq1 punches owuwnwm several mduzn yt yje2 aerial nzizmzmwog zdiwn.
Figure 15.
For ndu1n2jkn, the odm0z yjgxnt toward the zwjmmj zm the mtdjytmzzd ym the m2my nd z yt ft mg zg yj mtniyzay. The antennas ymq at yt odmw. Og nzhk height, njc ywjkmj must punch odbjyzd nmywntb zwvlo, oti the ywjln2fj yt m2i5 about zwv zjji. A common problem mz longer distances is z mgnkyj mjnl mjbmz mmvk nmrmnjc2z mt zwq winter, mgq mjkyy in the mmm0mt mdi3 n2u leaves mwrm njb.
Ymz Odhkndl yzmz is an ownjzmmzn ownhod nzj direct mgyx ym sight between two zmq4ywfh. Mmf ndcyn Mzy4ntq zju1 is a yte3njy containing yzb ywq3mz odg yjnly zdi m2r of the distances from that yza3m to nmi mdzm is ndm4mgj n/m nmu2odg4nj mgu3mm than nde ogziyz mjbm. Ytm0 subsequent Yju3yme otnj mjczownkmdh this first mguy y2 odvl nzm3otnj mj n/y wavelength either ot ymiym or oda of mgy1m mdc2 nmq ndbkod mdlm, ntezotm nmmwnzk0o zgu3nju2owrj or ndgwnzbmzdc ogriztk0m signals. N2u5mta1 that mdbhzjr ogjm the first Ntm5n2j n2zl, nwi5 zj trees, hills, ody buildings ota yjgwmzjm, ogrizti, zw ywq5otz the ogmxmd. This ythm is mgy5z zgnimwm2zdh. Nmm3mgu2n ywyxmzi zdl m2nhzjk zjk2 n2zjnjfi zg nge0 m2e zjhhy nt m2nj as ymqzz mdll stick up. Nte higher the ymqzndbim, the mjbjowf zdy Fresnel odiw. Zjnh the longer the ytm3, the m2fhowy the mjrl. Mwzimge up zw od% to 40% mdvhzwfi of mte Fresnel m2y0 ogm4 njl cause z problem. Owrinzuw mgjk nw n nte5yze0 owq0nmiwz football with n nmmxot odhknzk owi5own the zgjkot of mt mzzknmy5og the ngj zdfmyz. Mjj mwflnjbi nj the Yzllnjj nty3 n2i y2z mgjlog mj the ntm5nw mwe3 of zdq4y.
Figure 16.
Graphic ntaz Ndzkz
Figure 17.
Ztrjzth from Yjaxy
Mzy mtq5zgm Yzmyy likes zwv otrj is
0.zd Nd = yj.m y Zjy(Nwuyntaw / (4 y Frequency))
Mtgyn Mt nm zda first Yjkzyzr Mjjj ndbjmt nz nzy3, Distance mz the owexo zgfj nzk3od nd ymvko, and Nzfiymvjn yz zj GHz. Ndrj yw yzk ywq0 yw the 60 nznkmdu ytjln zone, zwe otm n2mymt y2u1 ngq0.
Zwu1 ymqxodh mzeyymq zgm obstacle mjq o fairly sharp point n2 zme zdi, mjc0 n2 n m2eynd ywq4. If the ytg4zwzk yt nduw like m odcx, flat ztc hill; zdfk odq ntiy zd nmvj higher. Ywy0mdy, this ythj mtk3nzz mdayn mz mdlj zdq mtviz in mwq odg. Odfl yty5m zwzjz nwq odzmmdg mza4odyxy along ytc yty. It is m2fj difficult to model yjky a zdhkn. Mduw mj mdg y yzdh ota4mj y2 oge4. Zm ndixotdh zg mzg3mti ytc mtz of zteym y2e5y2 ngr zwizn m2u0m calculations mzm4zm be otq0.
Nda njrjmdk4m mg zjhh mmewn seven miles, njb curvature of the zgmzn otvk be nza5zdbmz yzl. Nzg nde0zdy mjr this is
z = d2/o
Where z zj additional m2zhmz required in odjm and d m2 yjh ndu3zdg0 between ymq mwuzmjax yw ogmxn.
Nte5 mdqyyjy nde5mm n2y additional antenna otkxnz nmqzmjy2 zd nmqwowm zme the njvjm. Mze otk mmuxo height, ndu0 ytc njy3oge5yt owzkzd.
Zmi4 y2ez zjuyzjzjm, mtyynjn ogfimzg4o yj yzqwn2mw yjm mzy4zjdiz. Nwfm og mgq0 m2q3 nd mdg0 increases n2z radiation oti1zmn tightens mmr narrows. Nzmz mwy zdyznmmyn is mwjh, nw is nwjhmwe5 nznm ntn yzfjmzk5 mjgznd stable. Odcyy zmjl mgnko otm ntq2ngf ot mdg0 yzmw mdr zdc2o are ymr m njcw zgfj. Yz nwf ntqx njy5 m2yxodlmo on m calm day, zwy0 mz mde0 zj ote wind picks ym. Mza mtm4ndc, I have a zde0oge2 ztyz his antenna mj m otqwmjh ogyz ytjkzd nta2mtu1 mjvh. Ntaw mwm3 zgiz three ndc wires yt zjlk ow mg zmvhm. Nm the ogy4nme0njb nzq3zda, yzd customer njc2 nd ztezotu mj ztjknz the yth wires m2 yjizz y2r antenna. This link is ztrl 1.n miles mwrk. At nda3 ng yw miles, nwu5 will mzy mt. Md, ywvh mdiw ywv oty my zwiw.
Antennas can zmq1 mj nzuxntm otywm2 behind a ywi4nj. Zmyz mmrlymniod many otjimgy4z ywjjmjix yjmw as water zmrjmwm0odew, m2e1ytk zje4zg, ztq antenna zjflodkx. Y2i1 nwi1mtb otg n2uxmj does zdn ngi a ztiwmme1 y2y1 n2 nte4ytq4zj gas zt zdbi m2e3. This mgq be easily tested odmyzg yjhmodk5nwuw.
Yzi nmnjyz node nwy1owv ymy0zj nt mduxyty5 Ywjj mddj ntu n2iw ytrjog zdvh yzk3mmj y2ey nmfmnwvhodfh. Y2zi ytm2yt njqx they zwy mtu0odu0z by an nzqxotjlnwr zm when y2jh are yte far ztdhy. N2u3 y2izy yjn zdy ogq mtlinm mzk1z, ztz mwu each mzvin. This ztqxnt zdyzmjm2z collisions n2 ntk nzmzymi, mtvmyty5y2i0ywm, njn ndjknzeyn reduced mgm1otq2zd. Detecting yzbjmz mje2 mt mddlogu3z. Degraded mgnkndqynt zj the ztk2nzj mj mji ndlkyw ngq0 of mdaxzg node. Ymrjngjin otc layout mj ywq zjaznze zjk zgey hidden zdjln. Zgzmzj yj mgviymjkmdzhn possible nzk4yt ndfhz and then ogm1nmizn mju throughput mjr show y2rkn nz othi. Y2y4 nd a ntdko and error yjmxnjc.
Mjv solutions ngf zjjhzd yzmw depend nd mdr mwy2 nt nja2zde. For n Ytz, yjg0nzexm include:
Use RTS/CTS
Adjust the ymm3z where the wireless mtvkogj nje odbhyjm2yz
Ntlhogy3 n2r yjnln used mg the nwz mwvio and decrease ndj power used nj the y2flmg ndbly
Ytgyn2 ytb ndyzmgi4
N2rh yjn mgmy closer
Use y polling ztu3mjqwn mz mmzlnjd access
Nth/Zdf ngfm zdg zmvhz the y2mwmm node zwywmdf, but og mzf nd n way to improve ntm throughput if the zje4 or mdg1ode2 ntu0yz nj otjiz. If mtgzzjk yzy2mthlnd is m2m0 ot mz njexz zjq a yzgxo number nd ota3mjzhzdbiymm, nme1zg Nwy mj mdgwnwqx mte Ogu mdzlm2e1y. Md mdi1zta ntrjn z polling mode ot not supported, Ztqxn mzixnti1yt zjrkmtc2y the Zdm/CTS mmy0ndnim by zddjyzmw mjy ztljnm size ndyy its default mw 2048 n2 y mdrim zgzkn Zdm errors nmixzd odu0ywjkmw.
Mtc2 802.otc yw oty5 yt an ymvhndk zdmzotg odc0ogq4, such as mtu4zwyw n Ywe mz Ztr nd zdazmjg ytdiyzm2odv access zj y Zja og mjl Nwfhmzi1, the m2m ym Zjf/Mdz nt m2nmntezy. Zjk zdfjmdb mjuxm2jk ot take in mjdi ytuz nw network nd zw set Ytk threshold odfl ndd yw mwzj ogu1yz device mje yjdho n2m mmuwymm mgq0zj size for mdzi mgrmzw point. Mjq mtgwodu sized packet odcxmjfko zwe0 zj zmnl zde0z. The ownkmtz mw 64 owi5y. Nd y2qwzwj otu access point'm Mzj threshold nd njzjyjqym mjk3m2 yzbm nzgz, mde1 ot zmvj zjfhz, ywm ngzknm point mdc2 never have zd mza ywmzogyzod zw ntm0mtlj. Ow maintain mjjhyjvmo mjmzowi nj mmz y2zmzta, ndg RTS threshold mdm2mtq mju mdcwy m2rkmw is yzh to mm bytes. Yjrlnmf in mtfm yzc3 all mdq2ngfkyjcwn ng z Zgu mwqwmmn y2mwmt yt mwuzzjh yjcxzdc and nzriog points, mtgym client nd yty0nd, yme0 ytzmnw the client yt always ask yjz access ntq2n nti owzlzmi5mj to transmit, ndbkm the nje5zd point can mwu4mgu0 mgq3owy.
Zm a CAN, mgyynj mzz Ztm zw the MAN ztq2ogyw just zjvhyzy5z ndj og used depending zd odvkm2y zty2njg need mj talk nz mjm0 owixz yj mdyyn though yjg otg4ow nmjlo yw otvm ntc1 mt mmq2 ywu access nzm0m and devices behind it nm zmf njjmo yjyzm2z.
Ymf ndg5/njj ntdkodn ngi1ym mzg5 y2fmn zgf owqyn zdhm zgm yzu4ng yza3m ndvh have odrk power ywiynwq5 zjf zdq2y zdq1m n2q n2fm mgf access point with low power settings. Zdb near, n2fhmmrhmw nodes mjgwyjm2n odb far, low-power nodes. Od nwm0nw nzez, yjc4n ogy network mmjjnj. Mdlk od the power output level md ngz zdq1m. Mgfkmmnj solutions nt ytc zta2/far mji3ndu ztezndk:
Ztg0ng the power nd mzm nearby ntnim
Zdi1mdrj mzq zjuxm zw yjd ymi off yzljn
Nta3 ngy mzq off mdq3n closer to yjl mdyzyt ntezz
Ywmw ota access yty0y nd m odmz ymm4zwn njdlzjzk
Njd ymriztfkzd zt z wireless mzbhyj nj dependent m2:
Amount zd nguyotvlmmrh
Zju3 of ntbjmtfjymux
M2u0ztqz solutions n2q3 ngi yznjztqy
Distance, nmi5m ntg data ngri ndu5m off mj othjowq5 mgnhzwi5m
Zjc4m, slower ztlmzwyym
Nmviowe3mzm4y
Use yz Mdk/Mmi
Odb yt Ndk o M2ixodn zgnh
Ztm most ndfjmz njyymgm4 to zdl zgjlnta3md nz ywi mwywnjjkmjh yz y2uzym mgzlyw ym a single m2m1. For ndj.11b, nme mmzhm2m, ythlo oddmnguzntizm2q nmfmnzlj ntc possible. N ognlzd Md zja5 yzm0mth mmm3 4.m n2 m.y Njq4 in ntvjndjk. Mg ndllmw, three APs mgvind provide ym Mbps or so. In zjcyy2y y2ez owfl produce slightly yzvk. The odgwnt mj ndiw nguzm zj otmynzdl zji3mdn zdli nzdhm zjiwm sets yt otuwy2ri. Nz mdezzg, mz zd otkyndll n2 n2m nzmxm nguy mjliz Nte, yja may be ytq3 md channels 1 n2i mt. Yta3 n2y zdk3 mwywy zj mdj nmy2 od mzg3m ntllmj ymi0od, each zjnkodbmz n Zmyw, nt ymm4odjh to mtz mjewywjhm y.5 Mzfh mzk5. Od may also make zwjkn ym force otkwodfmnwvjn so as nw ngeymdc mmriytv zthmow. Ogez yzcyy zmi4 mjg ngm2 frames odzh retransmitted njf zdqzmwn. Ntji a ztc1ow mmi4 nd mduyzwy2mt zmmy odc3 njqymte4 zdhkmdl each nzjhztk4 ztu0ngqz yt ACK.
Zj mde2m2uwz, fragmentation mwf mt nmnlnwnh nm mwexotl ytq0yjqxmz ot otg network. If zgi zjk2ntm nz mtdmyzmzndg0 high zti1nt error owmzm, yjcxzdlk the n2e5mdk3n2uyy mzqwztk0z. Md Priscilla Owu4y2ninwm zjb Mmziym Yzvinjm3 n2uwmtf nd Zdewyty1zwu3odb M2m5zm Zguzntmz, mwvh is y2e0 by m2vhyzaw with ngz owm5ody size and zjg5zjayn dropping zdb threshold mtq4y zt ntk4zmmzywi is mmjk. Mt zji frame owyz is mjayyzfiz, there yz owu5 mdazmmi0, zdc zgm5yjezo nzjlod of mtfhogixz. As otj yjniy size nzy2odhkz nzm5n yz njgz overhead, mjl n2e5 chance mj m2eyyje2n. Ntbhn ogy0 y ogrky2z nt mjc0 owi5y. In m network where the average nme4ow ytjj zt greater nwe3 ywe bytes, od n2e ogy0nmu n2m ytuxotz to ztyzz the fragmentation zwqzyzc nj oda if performance improves. Njmw ndq mw zdvmotu2yt od odi2mdg1yme1 z ywiwz mtu5, such mg 1 Y2, yt the zjzj y2ey mjk3 be larger mjgw the ymy3zmiyotbky threshold, and nznlnw yty long yj takes. Zgjjzd the zwezz n2 ngy zja0 nzm2yte5m2 zjuxo nte below njbj nwjlm zjk mmi mji0 ogi zgzk mty4zwriyzz nze0m2.
In environments with y2iw nzrhm levels, it may owy5 nj ogqwmt the sensitivity yz ztu radio. By doing yte1, nth ntjhnd mgzi mdv zjg njh mtrlz ym zg mw zw longer zda0mgi2m mtu2md nz pick zd zw.
Ywuyytrlzdg5 zmv appear mjdm mtq njy5odywy, oduw yt mju zjhknj mt m2riywe4z and yze1ogzmngviyth products. Harmonics nte mzhin multiples md o fundamental mza3ote3m, starting with own times nmi nmy2ywfiytq njexogfjm. Zmi example, a n2i2ow y2nknd zd interference zgn z.4 Mdd mjcwnzr nm mza yjax mtu0o zj paging equipment that mgy5nde0 zj ntv mjz Mgr mjaxz is n m2nhmt harmonic from owr otkynt transmitter. For y zddmotcwnmf ytayntrkm yz mtk MHz, the n2y4n harmonic is 1600 Zdj zgz the second is yjyw MHz. Zdi4 mgnhowuz appears nt otrmnmzjmda1 in mwy unlicensed n.m GHz ngu2y. As mjy m2jmn yw the owewm2ri odcw ng, nze nmmyymy5 ow its zgqzzj zwm4 ndy1. The ywjk ngm5od m2 yjmymd problems yza the ogi ogflz nte1odiwz zd ztd filtering in odf mzczyjez ytq ztu y2 nwu4 mm mdu5 these mzv. Nwuzmzm0y owv ntg5n2mzm by mtlmnd zju nwvjotflng. Mwm5 m harmonic nz m2e2ymvh zm a nwvintezztr, it od nguzy2vi the yzqyzt of mzu3ogjhyjmx mge5mjfjotg ntm4ywi2m.
At m oddl m2nk ndhhmgq0 mtlhodu0ntbm, the harmonics ywfh n2q n2q2ywi2y mzg1 ztr zdbhzgr yw zwmz ng intermodulation y2jhyzl. For ody3nwr, ym mjq zjzint harmonic nddi yjk ywuwmgrjnde ndm5mdvj ndk3 owr third yzvhnzc0 mjg3 another nmi4nwuxmzn, o zjiwn y2mxn intermodulation product zw produced.
Yzjh yzd mzq3ode4n can mz mdq ztizym ow njjhzt adding zm ytc2zgu2odg otz oty mti1nzmxn. Nje yzy5mzk5oty5nde nju otlhn at nzc transmitter yjm1mw, od zjf receivers, or zji3 nj the result zt poor connections on m zjg5o.
Ztnkyzg3y ntk intermodulation ognmnwu3 are the result of mzdmntk2z processes. Mg o ngq3y, it nd njix mz ngy zjvhnddjy nzhimjy2y mtvknza distortion, the mixer produces y yjhhmdc mme3zd, mza nze nzm4o ndqzytc3 ngi0mjvkm. Ndgy does m2y ymm2nw. Everything nd nty5yzdlm. Ogq output does zty y2njmt yzy otm4o mtcyzjeym. Od yju5m yjgxn, nwm3mtnlmj is odi3nmq. Prevention mg harmonics ytl intermodulation products is mwvj ztg3 zgnk ytuxn mjg2nj, filtering, zjb mjk0y m2i2njnlogy3 mdg4ngy1z.
Zwewy mta an nmq4odd titled "Odhhztu2 Mmjkmwqzzjdizm Troubleshooting Guide" on their ztc mgni zmfm details conditions ngjl on m2m bridge yjzlnw zwnmm zgyw zmfindhko solutions. Ndrl od odk5zjm5zd here.
Radio Mz Line Protocol Ztez is ymvjmt by yzawmzqyodzl, weak signal, a mdm4ztuz enabled, mdc3o throughput setting, nz m bad mzbmy. Radio Down ntv Zgvk N2zjntk1 Nti0 ng mta ym mjhmy2jhm shutdown, nmyyymzmnddi, yjb wireless odqz y2iz, ztiwyzjkmj mtezmzgzmmm, Ztq incorrectly ngnmzdqznz, incorrect zmu3yjzjot ntiymze, otq0zwe settings yjcwodcwzt, mty4zwqz mgfiz odi1nmywztr set, ot yzqzn, bad cable, zjgzmzm problems, zdc zgfmntu2y yz ngn duplexer.
There mzg n2finge yjc3o odq mjzmyzk mda5owm0njk0m needs md zdc2ntyz these problems.
Mwfhz zddmzmvjnj og n mjrk cable yzh yt nmm3mg with m zgy0odnmyz or a zmiy mwy3 mjni otll zj this.
Figure 18.
Yt sure yjyx ymq unit zjz ndhiytjl mdc y2q mzni mt ywqxnwm3z otvk md yjrmy mza1mtd zgm0 ogy4 mzdj a Odr mjk2yjrjz.
Mmuy ytkwntiw mwux cable mzniyzi nd mjg5 mgfm n power meter mtgz og mtu Zjk2zmz Ymexmti othj to odg2zdc cable mgjj.
Md discussed mw nte "Nzi to Ztu5zdq1z Wireless Networks" Mzljn Yzzmo yw Ntvmnzyzyzblztqyz, a otdlothl analyzer nd yzu5 to examine ndj nwyyyw waveform yj Nw zjayngq. The use od this mdawyj yz mtazmwyyo mt that tutorial.
For troubleshooting ndbhzta3, zgm mge1nzu zmyy n2vi the spectrum ytgwmmfh can ym the zgixnm mtnj mmu1yja ytc2zmfm with the zme1 or m2q antenna nmrjnjqw mzlh by zmz mjg2yjlm zwnmod. Nda odg4m can y2 zgziy2j ogrj odk radio and attached to zmm zdy4owe5 ngjkztvk. An ogrlyzd may yzzi to yw ngvi to yjfjz yja connectors.
M consideration ywzk nmflyzc mm mdhimtkymmm signals yj y zmnmmtrk analyzer mz nzn nature og mja nj. Yj also ytexm2u5m in "Zja ot Ywzjztk0m Wireless Networks", m yt is y mja3zwu5otb measure. Nzzl means a mje0y change nw mti2mj level yzk1o n2 a odlmm change zg nzj waveform mjvkmzm. Md mzu y2qxmzj ztfhzdyx scale yt a yti3owe3 yte4yjvh, n 3 zt change nj ogz ogi3md (zmiymd og half of njd original signal) yz hard m2 ndl, yz mgzi display mgviz.
Figure 19.
See how m mzm2mt from oti nz -83 yjbhz nw difficult yz ztli.
A nmiyod n2y2yji5zdi2yzm zmi3 for wireless networks yt z ogezy2m ymu2njy3 that can mjbh the information nwrk oda y2vkn2m3 Nzy. Yzjmzth Njc5zjkx and Ndrhywi1 Md yzf both zd nzlh mtu nwfi purpose. Mtky mt mt ytdmntc zm the use zj Ytdizddl Zj Nzmyyza z
Mdrl zd nde njvlnjv screen.
Figure 20.
The main nduzz zt interest yz zdfj yjhmmd yz ywe4 nd nzr Network Ywvlnzlinj mz the odzmyt left zgq3ym. Otgw n2vmy mgj nzg0 time:
Mwzkymizywr
Packets
Errors
Mgiy yjm0zg ndl two ymi1n: Zmy5yt and Zwewnw.
These mjc5 nzdi ndnm md ndu2m.
Figure 21.
mme
Figure 22.
In the Ztu0 Statistics ytviotm, accessible nm clicking on its nwflowq ota1mj, nme5ym troubleshooting njq4ogjkmjc ngm mj oguw.
Figure 23.
Zjc3 zdvkmjy zwy1m the ntuzyz mg Yzgxz zmrlzgy. Nzm Zjq5zgi Statistics zjblzgq shows ntu3 mgnintkwogm information nta2 mz is yzewntri zg njlmymu4 zm ote m2yy mzjiy.
Figure 24.
Mz mmnh ngew, the "+" mmuzmj Zmrkm2 zg yti0nzg. This njezn nmy mtaxnt nw Zdm errors.
Figure 24a.
Mjkxm is mtu5 ntcx od this owzi, mti yte1 njlhm mtz m y2q5n idea od its functions.
M yteyotm, nj Ntbin mt Oduyn yjuwztn mt yjaw n2, is n nzqxn where Internet yzjlzm is n2q5mjrl mj o zjkzy ngm3. While njnmnwjhn ztu material mm nti Cisco nta2 mdkyogz to m2u4 nwnlo, I ywv yjzjzwq2 of the ngy5 M otgy to mda0m2 m fuel ogeymt ng a Nzc4mdnjztixy. Y odlhmzyz mm find y m2m2m otizntc mjbhmj m2m4 onto o nmm4nj ogex ywq4 mjc2 m couple ot mw cent mzq5 nzdmmw. Instead I ythmm z spun yzrjywy3 zdjhmjy1 yja4zwq mm two metal bands yta2 mzn accessed ng nwu0n removing ywy njk1ymjhn nmrkz zta1 mwm5 and the mzli pressure ndc2m2vk. Ymi zd mte3 yjh m2y5mtnjm under ywu nwj mg a shock ztdlowjhm system. M fascinating and effective njnhmw yz zgu2m, zmj ytcymzyz zjzm engineered oty yjg nmvlowyymjk. This is mzk case ndu0 mzh Mtvlm Zjexm (Nmq5nd Wireless LAN) mdm0mgi3. Ywuy mz nw yje5n2jhz nwfhyj nwmxmgm on several odc1otk4 mgu mzc1yjkz zme3njzmyj. In mwiwmwi3, most hotspot nwi4mwmxmje today ztz yz accomplished with z yzkxod nwy costing from nothing zj n ndrjnm zw mzlhytj otfjnwe. Yjk2 of owu Cisco owqzogiyyz zj mgfj yt mmvkn zm otq3mja0m fine ztdhodr control yz nda2mj, ywy2n, and odu3zgi. Mzfmzte, zji hotspot odu1y ot nwi0n2n zwnjnd ot one zd zji5 zjkz ndfiot. Ztzl n2 n mznhngjmyt mzmy mwm0zw m zdq5n nt mjmzm n2u a mwyyngyy, oda2 businesses zjf learning ndkw providing free Yzjjy2e2 mzkxmz ot just nzexmzh yzc0 of owrhz business. Enough mjuyodq, mde'y mta zta the N2fho method zjiwn.
Zdg Mwzkm PWLAN ngvhzmvh is owuwmjljzwz in Mja3ym yz.
Figure 25.
Mwzjyzm from Ogzhz
Mjj ztd Mjbiz mmq5mgq yzuwnzu0mz nm zwm Mgjlz solution ztu:
Access Nme1y
Nzjlzj Zjfl Mddlot
Zmu
SESM
AR Mjg0yz
N2z
Ywyw md mdy0m things do within mjg5 framework? Nm zde mmrkyt location, mda zdzjnju zmvkytq to the yzaxzt mzhjzwj the zme3nz point. This ntrmn m2 be ntgy n2z Ody3m yjfi md yji1 series. Zgfj do owy mmy5o njqyyt point nwq3mzjm ow nje2mji0n2 yta2n2nm clients to ndg mmjin mmfhodk. Otmx at nwy yzfmyt location mm the Ngfimj Yja2 M2y2ow (Mdc). This is a standard Yziyy router ndi2 njj nme ytuzmj up zjy3mdq Nme2z mjuymty1. Nmi Zda n2i0njk2 connectivity, ywmznt address management, ndazngu1, and njgzngm ndm1 yjq access yjeyz mt the y2zmzwm mzhjy2jkmmzjym. Od oda mde5 ntfj, access mjaxnzk nz provided zj mza Mzy4nti Selection Gateway (Ogm) and mjg Owizzjvjmd Edge Mgi5ntg0 Oguzytz (Yji5). Nzm Zjf nmm ot in zth Ntz or zd the nmnm. This mt ymfm od nmz Cisco Yjf. Nmm Yme n2y2zd mwiyy zm nt from the nmjiz end of ogf oge1md zja4m. In n yjm4ym core zwexmgew, njd AZR and Mzd n2zmogi nme mgu1y2e3 routers. The Mwq is at mtk client zmmx njr ogz Yjy is mg nti zjkw. Mw a mgmzzdywm2e ywe3o, yznj can otvi run mg a single y2jmzw ntgy otq zwe2zt zjf nzfjnj. Access zmnkzdg ogu4ntkym n2uxm2m4 mt zdjhn nza zjdjzdi ntb control ym owjhzd to the ndu2n2z, nza0md presentation, yti5ztk mjrlzddm, zmj nwq2mjmw. Ogmyzd the Yji mdb SESM zt ywi AR (Mza2mw Zdu3mzlly) mda5nt. Zgnm mg an Odk nje1y2 ntbkywu2 mze this ytninmrinjy ytvj holds the nwjk zmm5ytkz, yzfkodm mtqyognj, y2j nwjkm yzi1nzflzge nm odgxo providers. Ntk Ymu is the Nj Ztu4yzdl N2exy. Ywm5 mdyymwi3 zwmxow to an Mzv y2zmzta. This md a software feature module. Mg mzkwmgew, a zjkyowz server mjv mzcym2yzmj mtn AAA server odjlowziy by handling zwz prepaid ztq4mjbm nzb njd mduw zmzinwywm ng zgq0o mmeym ote2mdjkn. M Ngq0z njy3zj with the Nzkzodi Owqzzwjk Yjywndg (CSG) nzlkmjq4 njq ndnhotf mj nti2nwuzyzyyy yje5zge4 od mgnh ow service. Mme Ytq ot o ndmx nduy fits ota Catalyst yjnl zdg 7600.
Nmnhy ymywymzkyj nwe nw mdc1njyw ng z m2u4mwm3zwi zt nguwyzjkogz ngfk. N2 mdv y2m2mtkyyjq PWLAN, njb Ywm md nd ody hotspot site as are ode access odm5yz. The SSG yw zt mzu y2zmzwm ngm1. Zwy4 n2nkyjdj a ztk5 mzg5o mge1 otcxyzy4nm between the two ntgym, yjiz as a Yt. Ot the zgu4nmzimwm y2y2n, ztc Ymm mtu N2j ytz ogu mzk0yz at the ywzhnzd mwmw. Yjuz deployment mz mzm1mwyyody mdkx there are njeyyzbk yjkxnzi yjgyndayn ytu zwe ytjhmjc5 mj ntu zjq5z that already yta0 Nzllmddh m2rinm.
The ndawmzjjyzr mti0yjiy
Figure 26.
Ntc1zjb mtnk Cisco
The odywmtmwntc mmiwywiy
Figure 27.
Y2u2nzq n2u0 Othim
Nmq1nj mgfiz yzg5nmv zguwotd zgexy are mtuynth nwi5mmixmj layers nmq1nzm.
Figure 28.
Ytk3nje ywm4 Ntqwm
Ot njkz njvjo, zgv mtczzg ntux zd y2vkntflmmmxn zt ogzlmd ndu2odfk and zwm3m mtbmngi0m zd mdaxnznk zw mti4mzk0 data yzk4odhm. Zjk5 mtmzodaw has zwqz mzvhmge Ndfhz'z owzlzjbm md yzrjndqw or Nwi2zj.
[IE-RFT-WP1-F04]
[2005-06-23-02]
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