Router’s role in network
Explained by OSI model (Open System Interconnection Model )
-an abstraction for communication layers/network protocol
Routers are a “layer 3 network device.”
Layer 1- Physical layer(cables and devices like repeaters and hubs)
Layer 2- Data link layer(Provides MAC addresses to identify network nodes, and is a
means for data to use the physical layer with packets(ex: bridges and switches))
Layer 3- Network layer- Controls routing of data across network segments
Layer 4- Transport- for successful delivery of packets of data.
Layer 5- Session- Creates sessions between network applications.
Layer 6- Presentation- Translates/converts data that each system can understand.
Layer 1 just hardware
Layer 2-6 hardware/software, increasingly software with higher layer
Internal Router Components
Controller - function control
LAN ports- for wired connections
WAN port – connects to DSL or cable modem
Transmitter/Reciever – provides signal connection
RAM- used as buffer
ROM- stores firmware
Flash- software updates
Voltage Regulator- control voltage from source
Main Circuit Board
Contains most functional components
Or “router chip.”
Acts as CPU for router.
Controls many router functions.
- Datapath control
Home routers-typically 4 LANs, 1 WAN
Antenna(s) (radio signal)
Not to be confused
with antenna(e) (biology)
Wifi- term synonomous with
IEEE 802.11 technology(WLAN)
Frequencies 2.4, 3.6 and 5 GHz
RAM(Random Access Memory)
Provides a connected computer ability to maintain its
data transfer rate by storing data.
Acts as a buffer that helps maintain this transfer rate.
Holds Routing table, config files.
Contents in this memory lost when router turned
ROM(Read-Only Memory), usually 8 to 16 MBs
Controls diagnostics and bootup, provides OS.
Contains the firmware(router’s configuration) that
directs the controller on how to perform its tasks.
Contains the router’s firmware.
Firewall for security
Reprogrammable memory, used for updating router
Memory that persists when router turned
Usually 4 to 8 MB.
No picture here(also a black square).
Steps the voltage from the external power supply to the
Prevents excess voltage to go through the components
of the chips, which would cause overheating in the
Signals carried to and from router based on Ethernet technology
Modem(internet source) usually connects to WAN port.
Ethernet is an LAN(Local Area Network) technology
Router links these networks using a configuration table stored in its
Transfers information that is broken up into wrapped, 1500 byte
Router Sending/Receiving Info
Information that is wrapped in packets is sent to the proper
destination, based on the receiver address.
Packet information includes the data to be sent, sender and receiver
address, and the location where the data is within the package.
Breaking into packets allows good load balance and greater
Thank you and good night.