CCNA Routing and Switching Lesson 04 - Topology & Design - Eric Vanderburg

1. Network Topology & Design
Chapter 4
Networking Essentials – Eric Vanderburg © 2005

2. Bus topology
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Bus topology advantages
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Inexpensive
Easy to design
Easy to implement
Bus topology disadvantages
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Difficult to troubleshoot
Requires termination

3. Star topology
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Star topology advantages
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Break in one cable does not
affect other devices (except up links)
Easy to locate problems
Easy to install
Does not require termination like bus
topology
Star topology disadvantages
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Center of star topology device (hub) can be
expensive
Hub failure can affect entire topology
Amount of cable is expensive

4. Ring topology

Ring topology advantages
Prevents network collisions
 Each station acts like a repeater
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Ring topology disadvantages
Cable break can affect all devices
 Temporarily shut down network to add a
new station
 Maintenance and monitoring is difficult


5. Network Architecture

IEEE 802
CSMA/CD (802.3)
 Token Ring (802.5)

 NADN (Nearest Active Downstream
Neighbor)
 NAUN (Nearest Active Upstream Neighbor)
 Node with the token can send data
 Predictable send/receive time
Wireless Technologies (802.11)
 FDDI (Fiber Distributed Data Interface)


6. Media

Twisted-Pair cabling have the following
in common
Copper based data transmission
 Copper wires come in pairs
 Each Wire of a pair is twisted around each
other to protect against NEXT (Near End
Crosstalk)
 Copper wires are enclosed in a sheath
 All wire pairs are enclosed in a sheath


7. Media (continued)
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UTP (Unshielded twisted-pair)

Advantages of UTP cable
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Disadvantages of UTP cable
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Thin and flexible
Easy to install
Many modern buildings come with CAT 5 installed
Small size does not fill up wiring ducts fast
Inexpensive per foot
Susceptible to interference
Cable length is 100 meters or 328 feet
RJ (Register Jacks)

RJ-45

8. Media (continued)

9. Media (continued)

STP (Shielded twisted-pair)

Advantages of STP cable
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Greater protection from interference
Thin and flexible
Overall it is easy to install
Disadvantages of STP cable
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Inexpensive per foot but more than UTP
STP must be grounded, problems exists if not grounded
properly
More difficult to install than UTP
Small size but does fill up wiring ducts faster than UTP

10. Media (continued)

Coaxial cabling (Thicknet and Thinnet)

Advantages of coaxial cabling
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Cable lengths are longer than UTP/STP
Less susceptible to interference than UTP
Hubs are not required, direct connection
Disadvantages of coaxial cabling
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Thicknet is very difficult to install
More expensive than UTP
Difficult to troubleshoot

11. Media (continued)

Thinnet and Thicknet Connectors
RG-58 cabling
 BNC
 AUI (Attachment unit interface)
 Barrel connectors
 T-connectors
 Terminators


12. Media (continued)

Fiber-Optic cable

Advantages of fiberoptic cabling
Transmit data over long
distances
 Not susceptible to EMI
 High transmission rates
 Not susceptible to
eavesdropping
 Small cable size
Disadvantages of fiber-optic cabling

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Expensive
Cable can be easily damaged during install making installations more
difficult
Manual termination of ends is time consuming

13. Fiber Optic Connectors
ST (Straight Tip)
LC (Link Control)
SC (Straight
Connection)
MIC (Medium Interface Connector)
MT-RJ
two cables in one
RJ-45 clone
SMA (Subminiature Type A)

14. Signal Degradation (continued)

Reduce EMI/RFI

Do not place copper media next to
 Fluorescent
lights
 Generators/motors
 High-voltage electrical wire
Proper installation
 Use quality cable
 Use shielded cabling
 Use repeaters to strengthen signal on long
cable runs


15. Cabling
Horizontal Cabling – cables going from
the wiring closet to end nodes
 Vertical Cabling – Backbone of the
network


16. Wiring Closets


MDF (Main distribution
facility) – Central wiring
closet when more than
one is used
IDF (Intermediate
distribution facility) –
wiring closets off the
MDF

17. LAN Design Models

Two basic design strategies

Mesh
 all routers are peers,
interconnected, and
exchanging information
 Easy to set up

Hierarchical
 Easy
to troubleshoot
 Easier to manage
 Can scale better
 Can obtain better performance data

18. LAN Design Models

Three-layer network model
Core – WAN connectivity between sites
(usually owned by the ISP)
 Distribution – Connects buildings on the
LAN or wiring closets in a building
 Access layer – Connects nodes into the
network


19. Acronyms
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AC, Alternating Current
AUI, Attachment Unit Interface
CMIP, Common Management Information
Protocol
EIA, Electronic Industries Alliance
TIA, Telecommunications Industry Association
FDDI, Fiber Distributed Data Interface
IDF, Intermediate Distribution Facility
MDF, Main Distribution Facility
MID, Management Information base

20. Acronyms
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MAU, Multistation Access Unit
NEXT, Near End Crosstalk
NADN, Nearest Active Downstream Neighbor
NAUN, Nearest Active Upstream Neighbor
POP, Point of Presence
SAP, Service Access Point
STP, Shielded Twisted Pair
TDR, Time Domain Reflectometer
UTP, Unshielded Twisted Pair