Network Implementations Flashcards
Layer 2 Switch
Directs network traffic to specific machine (unicast). Works at Layer 2 of OSI model (frames).
Layer 3 capable switch
A switch that has routing capabilities
Router
Used to connect different LANs
Hub
Repeater - broadcasts incoming frames to all ports
Access point
Wireless device to allow connection to LAN
Bridge
Joins two network segments into a single network
Wireless LAN controller
Manages wireless access points, etc.
Load balancer
Helps balance the amount of traffic flowing through specific network devices
Proxy server
Retrieves data from a source on behalf of a user
Cable modem
Connects a LAN to cable internet
DSL modem
Connects a LAN to DSL internet
Repeater
Rebroadcasts wireless signal to help it reach remote areas
IPS
Intrusion Prevention System
IDS
Intrusion detection device
Firewall
regulates incoming/outgoing traffic based on a set of rules
VPN headend
A central point that allows devices to connect through a VPN
Dynamic routing
automatically configured routing
RIP
Routing Information
Protocol - (Interior protocol) - routers periodically (fixed time interval) exchange routing tables; focuses on hop count
OSPF
Open Shortest Path First (Interior protocol) - Uses an Area ID. One router in each area is selected as the “designated router.” Routers send info about each link separately instead of the entire routing table. Convergence is quick
EIGRP
An enhanced dynamic routing protocol that uses a combination of parameters to calculate metric
BGP
Border Gateway Protocol - The internet is broken into Autonomous Systems. Because routing tables are too big, BGP only tracks how to get to other Autonomous Systems.
Link state
Information passed between routers is related to the current connectivity (up/down, speed)
Distance vector
Information passed between routers contains network details: how many “hops”
Static routing
routes are entered manually
Default route
When no other route exists, send it here.
Administrative Distance
An arbitrarily-assigned value that represents how preferred a route is
Exterior vs Interior (routing)
Exterior refers to routing to remote networks
Time to live
A value given to packets to keep them from circulating endlessly on the Internet. Starts at a certain number and decrements each time it hits a router. When it hits zero, the packet is dropped and a message is sent to the source.
Traffic shaping
The act of optimizing available bandwidth according to priorities
Quality of Service
Prioritizing traffic to ensure best performance
Voice VLAN
Separate VLANs are often created for VoIP traffic so it can be given priority.
Port tagging
A tag in the frame header designates which VLAN the frame belongs to (802.1Q Header)
802.1Q
A standard that allows VLANs.
Trunking allows VLANs to be used across multiple switches - a connection on each switch is reserved to use for all VLANs
Port aggregation/LACP
Multiple interfaces can be “bundled” into a single interface with higher bandwidth
Port duplex settings
Half - can ONLY send OR receive
Full - can send AND receive at the same time
Port speed
Speed/duplex settings on both sides of a connection MUST match.
Port flow control
Port mirroring
An interface can be configured to “mirror” traffic from one or more interfaces on the switch for monitoring
Port security
Prevents unauthorized users from connecting to a switch interface based on the MAC address. Each port can be configured seperately.
Jumbo frames
A frame that is larger than 1500 bytes. 9000 is the accepted norm. In order to use these, all devices must be configured to use them.
MDI
Media Dependent Interface
Workstation
Router
MDI-X
Media Dependent Interface Crossover
Switch
MAC address tables
Switches maintain a list of MAC addresses and to which interfaces they are connected; Switches build this table by examining the SOURCE MAC on incoming frames; if an entry is not found in the table, the frame will be BROADCAST
PoE/PoE+
Power over Ethernet
PoE - 15.4W 350mA
PoE+ - 25.5W 600mA
STP
Spanning Tree Protocol - this keeps loops from being created in switched networks.
STP Port Designations
Root port - the port closest to the “network root”
Designated port - ports that are allowed to forward traffic
Blocked port - these ports are blocked if a potential loop is identified
CSMA/CD
CS - Carrier Sense: is there a carrier? is there a signal available?
MA - Multiple Access - more than one device on the network
CD - Collision Detection: Devices can detect data collisions and will wait a random amount of time to resend data
ONLY USEFUL ON HALF-DUPLEX
ARP
Address Resolution Protocol - used to associate MAC addresses with IP addresses
NDP
Neighbor Discovery Protocol - the IPv6 version of ARP. Uses multicast instead of broadcast (there are no broadcasts in IPv6)
802.11a
5 GHz range
54 Mbit/s
Small range (generally 1/3 the range of 2.4 GHz)
802.11b
2.4 GHz range
11 Mbit/s
Longer range
More frequency conflict
802.11g
(upgrade from 802.11b)
2.4 GHz range
54 Mbit/s
Backwards-compatible with 802.11b
802.11n (WiFi 4)
Operates at both 2.4 and 5 GHz ranges
600 Mbit/s
Introduces MIMO
802.11ac (WiFi 5)
5 GHz range only
7 Gbit/s
MU-MIMO
802.11ax (WiFi 6)
2.4 and 5 GHz
Introduces bidirectional MU-MIMO streams (1201 Mbit/s per channel)
9.6 Gbit/s
WiFi Channels
Groups of frequencies, numbered by the IEEE. Best to use non-overlapping channels
Can range in frequency
Channel bonding
Ability to combine two separate wireless channels into a single data stream
Basic Service Set
The hardware address of an access point (not the SSID)
Extended Service Set
A shared network name across access points
Independent Basic Service Set (Ad-hoc)
Two stations can communicate directly, with no access point required.
Roaming
Automatically switching from one AP to another
Omnidirectional Antenna
Signal is evenly distributed evenly on all sides of the antenna
Directional Antenna
Signal is focused on a single direction
WPA/WPA2 Personal
Uses pre-shared keys for authentication - everyone on the network uses the same key
WPA/WPA2 Enterprise
Uses separate authentication for all users on the network - requires an authentication server
CDMA
Used by Verizon and Sprint
GSM
Originally an EU standard, used globally (AT&T and T-Mobile in the US).
LTE
Converged GSM and CDMA. Based on GSM and EDGE
MIMO
Multiple Input Multiple Output - Sending multiple streams of data over the same frequency at the same time (can only do this with one user at a time)
MU-MIMO
Multi-User Multiple Input Multiple Output - MIMO but can split the stream to multiple devices
