802 standards Flashcards
802.3ad
Link Aggregation: combines multiple physical connections into single connections to minimise congestion
802.3 af
Power over Ethernet (15.4 watts)
requires CAT or higher copper cable
802.3at
power over ethernet + (up tp 25.5 watts)
802.1x
user authentication: requires users to authenticate before accessing the network
– Port-based Network Access Control (NAC)
802.1X integrates with EAP (Extensible Authentication Protocol) and RADIUS
Supplicant –> Authenticator –> AAA server
802.1q
VLAN Trunking: 4 byte identifier TPI / TCI
- -> Extra tag on a frame to help the switch identify which VLAN it belongs to
- -> also used for QoS to prioritise traffic (voip on a different plan)
VLANS 0 & 4,095 are reserved
1 - 1005 normal range, 1006 - 4,094 extended range
802.1D
STP: Spanning Tree Protocol (or SPB shortest path bridging for larger networks)
802.11 | CSMA/CA
Wireless uses collision avoidance [RST request to send / CTS clear to send]
(vs. CSMA/CD for wired N.)
Wireless Standard | Frequency | Throughput | MIMO
- 11a | 5 Ghz | 54 Mbit/s | none
- 11b | 2.4 Ghz | 11 Mbit/s | none
- 11g | 2.4 Ghz | 54 Mbit/s | none
- 11n (Wifi4) | 2.4 & 5 Ghz | 600 Mbit/s | 4 X MIMO
- 11ac (Wifi5) | 5 Ghz. | 6.9 Gbit/s | 8 x DL MU-MIMO
- 11ax (Wifi6) | 2.4 & 5 Ghz | 9.6 Gbit/s | 4 X DL & UL MU-MIMO
*WIFI 6E operates on 6 Ghz
3 wireless frequencies
DSSS: modulates data over a range of frequencies using chips (old)
FHSS: allows devices to hop between pre determined frequencies
OFDM: simultaneous transmission over different data streams
Non overlapping channels on 2.4 Ghz
11 20 Mhz channels: non overlapping 1, 6, 11
Non overlapping channels on 5 Ghz
24 20 Mhz channels: 24 non overlapping
channel bonding: bond frequencies together
Wireless encryption
WEP: IV
WPA: TKIP & RC4
WPA2: CCMP & AES
WPA3: GCMP & SAE
Wireless networks reach (distance in m) indoor | outdoor
TYPE
802.11 a/b/g
