Institute of Technology Sligo - Dept of Computing LAN Maps & Symbols Topologies & Devices Paul Flynn

Institute of Technology Sligo - Dept of Computing

LAN Maps & SymbolsLAN Maps & Symbols

Topologies & DevicesTopologies & Devices

Paul Flynn


By the end of this Chapter, you will be

able to name and describe all the symbols in this

diagram.


Physical & Logical TopologiesPhysical & Logical Topologies

Physical TopologiesPhysical Topologies define the actual define the actual layout of the wire (media).layout of the wire (media). For example, this classroom’s wiring is For example, this classroom’s wiring is

laid out in an extended starlaid out in an extended star Logical TopologiesLogical Topologies define how the define how the

media is accessed by the hosts.media is accessed by the hosts. For example, in this classroom hosts For example, in this classroom hosts

access the media on a first come, first access the media on a first come, first served basisserved basis


Physical TopologiesPhysical Topologies

Bus

Ring

Star

ExtendedStar

Hierarchical

Mesh


Bus TopologyBus Topology

Single backboneSingle backbone

All hosts directly All hosts directly connected to backboneconnected to backbone

Each end of the bus Each end of the bus must be properly must be properly terminatedterminated


Ring TopologyRing Topology

No backboneNo backbone

A host is directly A host is directly connected to each of its connected to each of its neighborsneighbors

Used for token passing Used for token passing logical topologieslogical topologies


Star TopologyStar Topology

All devices connected to All devices connected to a central pointa central point

Center of star is usually Center of star is usually a hub or a switcha hub or a switch

Used for Ethernet Used for Ethernet technologiestechnologies


Extended Star TopologyExtended Star Topology

Connects individual star Connects individual star topologies together.topologies together.

At the center of the star At the center of the star is a hub or a switch.is a hub or a switch.

Extends the length and Extends the length and size of the network.size of the network.

This is the topology we This is the topology we are using in our lab!are using in our lab!


Hierarchical TopologyHierarchical Topology

Like the extended star Like the extended star except a computer except a computer controls traffic—not a controls traffic—not a hub or a switch.hub or a switch.

Server


Mesh TopologyMesh Topology

Each host has its own Each host has its own connection to every connection to every other hostother host

Used in situations where Used in situations where communication communication must notmust not be interrupted.be interrupted.


Logical TopologiesLogical Topologies

Broadcast TopologyBroadcast Topology Each host on the LAN sends its data (or Each host on the LAN sends its data (or

broadcasts its data) to every other host.broadcasts its data) to every other host. Access to media is based of “first-come, Access to media is based of “first-come,

first-serve.” (Ethernet works this way)first-serve.” (Ethernet works this way) Token Passing TopologyToken Passing Topology

Access to media is controlled by an Access to media is controlled by an electronic token.electronic token.

Possession of the token gives the host the Possession of the token gives the host the right to pass data to its destination.right to pass data to its destination.


LAN Media SymbolsLAN Media Symbols

TokenRing

FDDIRing

EthernetLine

SerialLine


LAN Device Symbols—Layer LAN Device Symbols—Layer 11

Transceiver

Hub

Repeater


LAYER 1—RepeaterLAYER 1—Repeater

Cleans up (regenerates) and repeats the Cleans up (regenerates) and repeats the signal.signal.

Used when a network’s cabling extends Used when a network’s cabling extends beyond its capability.beyond its capability.


LAYER 1—TransceiverLAYER 1—Transceiver

TransTransmitter and Remitter and Receiverceiver of electronic of electronic signals—specialized repeater.signals—specialized repeater.

Connects different media technologiesConnects different media technologies

Also called a MAU (Media Attachment Also called a MAU (Media Attachment Unit)Unit)

FiberCat 5 UTP


LAYER 1—HubLAYER 1—Hub

Simply a multi-port repeater.Simply a multi-port repeater.

Used to connect multiple devices to the Used to connect multiple devices to the same network drop.same network drop.

The Cloud



Bridge

Switch


LAYER 2—BridgeLAYER 2—Bridge

Connects two LAN segments.Connects two LAN segments.

Keeps traffic local by filtering traffic Keeps traffic local by filtering traffic based on MAC Addresses.based on MAC Addresses.


LAYER 2—SwitchLAYER 2—Switch

Connects multiple LAN segments.Connects multiple LAN segments.

Can be called a multi-port bridge.Can be called a multi-port bridge.

Provides full bandwidth out each port.Provides full bandwidth out each port.

The Cloud



Router


LAYER 3—RouterLAYER 3—Router

Can be used to connect different Layer 2 Can be used to connect different Layer 2 devices and different topologies.devices and different topologies.

Makes decisions based on network addresses Makes decisions based on network addresses (IP Addresses).(IP Addresses).

What are the routers two main functions?What are the routers two main functions?

The Cloud


Router’s Two Main FunctionsRouter’s Two Main Functions

Path DeterminationPath Determination

Packet SwitchingPacket Switching



Path Determination is the

process of evaluating a packet’s

destination IP address so that the

router can decide which port to

send out the packet.



In Packet Switching, the router re-

encapsulates the packet in the

protocol needed for the specified

port and then switches the packet

out that port.


The CloudThe Cloud

The cloud is a collection of devices that The cloud is a collection of devices that operate at all levels (7-1) of the OSI model.operate at all levels (7-1) of the OSI model.

The cloud is used to represent a large group The cloud is used to represent a large group of details that are not pertinent to a situation of details that are not pertinent to a situation or description, at a given time.or description, at a given time.

The cloud helps remind us that our The cloud helps remind us that our discussions are about various parts of a discussions are about various parts of a larger interconnected network—The Internet!larger interconnected network—The Internet!

The Cloud


Engineering Journal AssignmentEngineering Journal Assignment

Draw freehand the Teaching Topology found in the second graphic on Screen 3.1.1 (shown below). As you draw it, test your knowledge about the various topologies and devices.

Documents

Institute of Technology Sligo - Dept of Computing LAN Maps & Symbols Topologies & Devices Paul Flynn