wireless considerations in troubleshooting.

Antennas their placement, - most use omidirectional

vertical anteanna - etends outward away fromt the antenna at an equal level. as it travels it gets weaker more -rssi if right next to antenna -40 if you move you’ll got to -70

dipole antenna - can send in two directions.

yagi antenna - unidirectional antenna sends the radion siglan in one direction , normally used to use a wireless link vs acable

parabolic grid antenna - used for site to site and over longer distances. radio wave only in one direction. placing antennas depends on where you’re going to need coverate

site to site will need yagni or parabolic, put it on the roof, connection may slow down or completly stop over time. trees may sprout, ect.. rain may reduce signal also as the water in the air will block signal.

for indoor application - omnidirectional is best - on ceiling is the bes

unidirectional on an outer wall direct them back in .

polarization - the orentation of the electirc field from the antena. how is it oriented.

channel utilization and site surveys

if there are some devices close, still low rssi then could be the antenna needs to be bent up. horizintal vs vertical. most Wi‑Fi user vertifical polirization so antennas should be pointing up.

Channel utilization - hifghwr utilization there is more data on that channel you want to keep it around 30% if possible. can be used by other networks.

2.4 ghz b g h, will be use ing the same channels as everyone else. if you’re in a house that may matter.

access points and clients create a single broadcast domain when opperating on the same channel

to prevent colisions. 802.11 use a listen before they speak

CCA dlear channel assesment - listens to see if another device is transmitting - if so it will do a random backoff count, then re transmit. the more clients the longer the CCA, this can result in slower speeds. high channel utilizaion can slow throughput

site survey- process of planning an ddesigining a wireless network to provide the solution that is needed.

determine where each acces point its. look at it’s EIRP and any access points and clients that may be in the same aresa. decide if you need to change the channels. or upgrade to a new frequency banck.

5ghz gives 24 non overlapping channels.

configure devices to use th eless utilized channels.

acces points association times -

1 client sends a probe for 802.11 to find any AP.

2 any acces point that recive the probe check to see if they can support the data rate.

3 low level 802.11 acces frame

4 ap recives the frame and continues the handshake

5 client will choose ap it wants to associate with using the encryptuon

6 ap processes and checks the request for valid makes an id

7 client can now use data on network