Misc Terms Flashcards
(70 cards)
SCADA / ICS
Supervisory Control and Data Acquisition system
- large scale, multisite Industrial Control System
distributed control systems for equipment managed by a PC
- power generation, refining, manufacturing equipment, etc.
Must be segmented so no access from outside
RIP
Routing Information Protocol
-distance vector routing
-decides how many ‘hop’ away another network is
EIGRP
Enhanced Interior Gateway Routing Protocol
-distance vector routing
-decides how many ‘hops’ away another network is
OSPF
Open Shortest Path First
-link state routing
-info passed between routers is related to the current connectivity
(if its up you can get there. If its down you cant)
BGP
Border Gateway Protocol
-determines route based on paths, network policies, or configured pre-set rules
CSMA / CD
CS - Carrier Sense
-is there a carrier? is anyone communicating?
MA - Multiple Access
-more than one device on the network
CD - Collision Detection
-collision - two stations talking at once
-identify when data gets garbled
CSMA / CD operation
Listen for an opening (dont transmit if the network is busy)
Send a frame of data (send data whenever you can, no queue)
If a collision occurs, transmit a jam signal letting everyone know a collision occurred and wait a random amount of time then resend
NDP
Neighbor Discovery Protocol
-operated using multicast with ICMPv6
-neighbor MAC discovery (replaces IPv4 ARP)
-SLAAC (Stateless Address AutoConfig) congifs IP without DHCP server
802.3af
PoE
15 watts of DC power
max current of 350 mA
802.3at
PoE+
25.5 watts of DC power
max current of 600 mA
802.1Q
trunking
adding a VLAN header to an Ethernet frame
VLAN IDs are 12 bits long
STP
Spanning Tree Protocol
-loop protection with switches
STP port states
blocking - not forwarding to prevent loop
listening - not forwarding and cleaning the MAC table
learning - not forwarding and adding to the MAC table
forwarding - data passes through and is fully operational
disabled - admin has turned off the port
LAG
Link AGgregation
-multiple interfaces act like one big interface
LACP
Link Aggregation Control Protocol
- adds additional automation and management
jumbo frames
ethernet frames with more than 1500 bytes of payload
- up to 9216 bytes
-ethernet devices must support jumbo frames
MDI
Media Dependent Interface
- network interface card
MDI-X
Media Dependent Interface Crossover
-network switch
Antenna performance is measured in ___
dB
- double power every 3dB of gain
Yagi antenna
very directional and high gain
Parabolic antenna
focus the signal to a single point
Route Poisoning
-method to prevent a router from sending packets through a route that has become invalid with computer networks
-achieved through changing the route’s metric to a value that exceeds the max allowable hop count so that the route is advertised as unavailable
Split Horizon
-route advertisement
-method of preventing routing loops in distance vector routing protocols by prohibiting a router from advertising a route back onto the interface from which it learned
Can browsers have group policy block lists?
yes
they can block access to a domain via a given URL
not the whole domain because other parts might be fine - like a particular repository on GitHub may be bad, but the entirety of GitHub is not bad