< All CompTIA Network+ Notes

Tobraham | CompTIA Network+ | Module 1.4

By: Tobraham | Related Course: CompTIA Network+ | Published: February 5, 2018 | Modified: February 6, 2018
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Routers move data to *other* networks, as opposed to internal ones.

  • allow segmentation and subnetting
  • manage traffic flow

Manage Routing Tables

  • where to pass data (where is Google.com?) when the destination is outside of your local network
  • keep tack of networks  we have and where it needs to query if it doesn’t have the answer
  • knows the fastest way to get data from A to B
  • static or dynamic
    • static – you manually update the tables yourself
    • dynamic – auto update 
  • Protocols: OSPF, EIGRP, RIP, RIPv2, etc. These provide diff algorithms for assessing the best path from A to  B
  • Default Gateway
    • only deals with packets sent directly to the router (no broadcast packets are accepted). 
    • If a computer doesn’t know where to send a packet (packets for locations outside the network), it will send it to the default gateway. So we set our routers up as the default gateway. 

NotepadRouting and Switching (part 2)

MultiLayer Switches

  • can perform routing (L3) AND switching (L2)

Bridges– connect network segments 

  • segments could be devices on diff floors of a building that can’t be connected due to the length of cable necessary
  • rather than connect via switches, we connect via bridges
  • can break up and segment traffic
  • Layer 2 – Data link only – doesn’t route traffic . Does manage by MAC address.
  • can be wired or wireless

Repeaters – increase a signal

  • long cable runs lose signal over distance
  • repeaters are in-line signal amplifiers
  • typically built into smaller devices
  • on large scale scenarios, these would be stand-alone
  • can amplify a signal (boosting power) or regenerate a signal (clean it up)

NotepadRouting and Switching Pt 1

Routing / Switching – allows for connecting devices

  • Switching – connecting within the same network
    • Layer 2: hubs, switches, MAC addresses
  • Routing – connecting to other networks
    • Layer 3


  • Hubs – network diagram is a single arrow: ->
    • sends/receives to anyone connected to it
    • ”dumb” glorified repeaters – take data from one port and send it out to the rest of the hosts without inspecting destination
    • cleans and amplifies when necessary
    • *insecure – anyone can listen in to the traffic by plugging in to the hub
    • can plug in to monitor all traffic for diagnostic purposes
  • Switches – ”smart hubs”
    • track MAC addresses and what ports they’re on
    • the first few seconds you fire up a switch, it acts like a hub, trying to figure out which MAC address is on which port and building a table
    • more secure because destinations are unique
    • minimizes network traffic and ’collisions’
    • can set up ”port mirroring” to allow monitoring of traffic meant for a different port
  • Routers
  • Repeaters – simply cleans and boosts the signal to allow it to continue
  • Multilayer switches
  • Bridges

    * see diagram symbols here

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