Transcript Introduction to networking

Introduction to networking
Devices
Objectives
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Be able to describe the common networking devices and
their functionality, including:
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Repeaters
Hubs
Switches
Bridges
Routers
Icons
Repeater
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This receives a signal from the network and then repeats it
After a distance an electrical signal will lose power
(attenuation)
This node increases the power of the signal again
Hub
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Multi-port repeater
Shares bandwidth
Prone to collisions
Uses the Ethernet CSMACD technique to govern
communication
Cheap
Generally non-configurable
Switch
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Based on the Ethernet MAC address this node will forward
the data to the correct host/machine
Creates micro-segments
Avoids the CSMACD issues of collision
Bandwidth is not divided between connected hosts
Provides Virtual LAN’s
Can be very basic and very advanced
Advanced models highly configurable
Bridge
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Connects two segments of a network together
Only allows data to pass if the destination host/machine is
located on the other segment
Preserves bandwidth
Routers
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Similar to a bridge
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Based on the IP Address this node will forward the data to the
correct host/machine
Calculates the ‘best path’
Also performs a switching function
Uses routing tables
Convergence
Uses routing protocols
Uses ACL’s (Access Control Lists) for security
‘Knows’ the network
Can be very advanced, highly configurable
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Routers
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Internal components
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D/RAM: storing routing tables, ARP cache, temporary and
running memory for the config file
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Loses data when powered down
NVRAM: stores backup/startup config file
Flash: EPROM, hold OS image, allows OS to be updated, can
contain multiple OS’s
ROM: POST, bootstrap and basic OS
Interface: where packets enter and exit router
Routers
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Routers can operate at all 7 levels of OSI, but mainly at
levels 1-3
Communication via level 1 and 2 refer to the routers
switching function
Routes identify routes via layer 3
Routers are quite simple physically, but very complicated
logically due to its routing logic
Router internal components
You will mostly experience the I/O interfaces and the IOS
(the configuration file)
Router functions
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One physical path must exist between source and
destination
Having and using a path are not the same thing!
Source and destination must speak the same language
(routed protocol), routers should also speak the same
language (routing protocol), and agree on path
Functions therefore are:
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Physical interconnectivity
Logical interconnectivity
Route calculation and maintenance
security
Internal components of a 2600 router
Router external connections (2600)
WAN interfaces
LAN interfaces
Management ports
WAN connections provide connections through a service
Provider to a distant site or the Internet, often a CSU/DSU is
required
Management ports
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Text based CLI configuration and troubleshooting
Console and auxiliary are used for this (EIA-232
asynchronous serial ports)
Console is the preferred method of configuring as an
administrator has access to router despite what state it is
in and it allows the administrator to see and start-up
messages
Terminal console connection
HyperTerminal settings
Summary
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The main devices you will use are:
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Switches
Routers
Hosts
Relevant cabling
Cisco Switches and Routers for the CCNA are very
advanced and highly configurable
Questions...
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...are there any?