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53 Cards in this Set
- Front
- Back
Switch: |
Layer 2/3 device Uses MAC/IP addr. Routes frames/packets |
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Switch functions: |
(Like Bridge) Filters/Forwards/Learns Creates Redundant Paths Isolates device traffic Creates separate collision domains |
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How exactly do switches learn? |
stores own device address/port in mem table |
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Init. step a new router always takes: |
Broadcasts addr. request to all connected devices |
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Router vs. Bridge |
Rt : dedicated data lanes per each device/segment
Brg: single lane for all devices/Segs Ltd. shared bandwidth |
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Switches have two kinds of transmission |
Port switch: supports single net device
Segment switch : connects network segment |
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Router purchase considerations: |
Bandwidth multiplocation = is bandwidth per port or overall
Full/half-duplexing |
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Router vs. Layer 3 Switch |
Switch faster cuz different behavior and internals Both filter/forward packets |
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802.11 = |
Wireless Standard Creates interfaces tween devices or device and base Specifies MAC and phys layer protocols |
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802.11a vs. 802.11b |
Both phys layer. A is faster Compat with Ethernet & DLL, not each other |
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802.11a |
Common in Eurasia 5.7 GHz For radio; single/multichannel Impeded by walls Frequency hopping = more secure |
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802.11b |
Common for office wireless nets 2.4 GHz Low enough freq = pass through walls Direct sequence = reduced interference |
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802.11g |
Best of a and b A's speed with B's freq. (Pass walls)
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802.11n |
802.11g but with more antennas for data transmish MiMo functional - multi-input/multi-output |
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WLAN configs: |
All Wireless Wireless Link Mobile net |
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Bluetooth = |
Short access range For personal devices Creates PAN Uses radio |
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Adapters = |
Lets compie interface to a net Found in compie expansion NICs or as onboard circuit chip |
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Network Converters |
Layer 1 hardware Convert signals tween diff transmish media: coax -> FO or -> UTP |
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802.15 |
Bluetooth wireless stds. 2.4 GHz |
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How bluetooth keeps comms secure? |
Shorter data packets Uses frequency hopping spread spectrum Encryption for sure Maybe reqs authentication |
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All wireless = |
Every device connects wireless, but may be stationary
(All wireless != mobile net) |
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Mobile net |
When devices (laptops) in net move around and connect wirelessly |
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Wireless Linked = |
Devices on each sep. seg wired to a base hub w/wireless capability
Removes need for inter-building cabling |
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Frequency hopping spread spectrum: |
Each transceiver must know pseudorandomly generated freq. To chat |
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Direct sequence spread spectrum: |
Reduces outside interference whether intentional or not |
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Why pick an all wireless LAN? |
For aesthetic and safety in buildings with no beneath wall/floor space |
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802.11 characteristics |
unlicensed band usage = free use as long as on freq.) |
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Repeaters: |
Device that extends a segment, repeats signals signals passed and supplies power to sigs |
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Repeater does not: |
Filter, evaluate, or change signals |
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Diff tween what analog and digital repeaters do? |
Analog just amplifies signal / make loud
Digi takes sig, regenerates the bits, and passes it along |
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When no use repeater? |
On heavy use net Between two networks/ net segs |
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What do digi repeaters introduce to a net and why? Why bad |
Introduces delays to a net because sig regen takes time
Bad cuz throws off network clock |
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5-4-3 rule |
Rule for repeaters Max of 5 segs connected with 4 repeaters between each Only 3 of 5 segs allowed to be to split off more than 1 way |
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Hubs = |
Central unifying point that extends segment and allows adding multi devices to net |
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Repeater limits |
Use in small geo areas/small lans Extend no more than 100m |
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Hubs do not ___ but instead __ as far as data transmish |
Filter info, just repeats what's received to all other nodes including sender Dumb |
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Hubs are logically a what? |
Shared bus/multi-repeater |
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Collision domain: |
Area where data packets can collide Nodes compete to talk One talks, all hear Can include multiple hubs |
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Example of bad collision domain: |
2 net hubs connected w/out bridge: If node of one hub broadcasts, it'll every node on both hubs |
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Network segment |
Group of nodes that all talk over same phys layer devices Segs separated by hubs, routers, and switches |
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Hubs pka? |
Wiring Concentrator |
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Collision domain size based on |
# of nodes |
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Repeaters and hubs are: |
Phys layer devices |
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Bridges: |
Device that separates collision domains Filters data and forwards to proper location |
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Most common hub: |
Ethernet hub |
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Simplest bridge found where: |
Inside a NIC |
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Bridge can meet how many networks/segs |
2 |
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Bridges learn how? |
Create and retain bridging table of which devices on which side as the devices send message |
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Like switch cache, how are bridging tables created? |
Broadcast to all users "where are you" |
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2 bridges to same net seg/node bad why? |
Can result in active loop where bridges send info in circle cuz of messed up ports |
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Bridges separating collision domains help: |
Increase net performance and offer connectivity tween LANs for WAN |
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Bridging domain: |
Encompasses any layer 2 devices of net seg |
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Bridges and specific switches are |
Layer 2 devices |