Campus Network Design Steps:
Develop a cabling plant design
Select the types of cabling
Select the data-link-layer technologies
Select internetworking devices
Meet with vendors
Cabling Plant Design Considerations
Campus and building cabling topologies
The types and lengths of cables between buildings
Within buildings
The location of telecommunications closets and cross-connect rooms
The types and lengths of cables for vertical cabling between floors
The types and lengths of cables for horizontal cabling within floors
The types and lengths of cables for work-area cabling going from telecommunications closets to workstations
Centralized Versus Distributed Cabling Topologies
A centralized cabling scheme terminates most or all of the cable runs in one area of the design environment. A star topology is an example of a centralized system.
A distributed cabling scheme terminates cable runs throughout the design environment. Ring, bus, and tree topologies are examples of distributed systems
Types of Media Used in Campus Networks
Copper media
Optical media
Wireless media
Copper Media Advantages
Conducts electric current well
Does not rust
Can be drawn into thin wires
Easy to shape
Coaxial Cable
Solid copper conductor, surrounded by:
Flexible plastic insulation
Braided copper shielding
Outer jacket
Can be run without as many boosts from repeaters, for longer distances between network nodes, than either STP or UTP cable
Nonetheless, it’s no longer widely used
Twisted-Pair Cabling
A “twisted pair” consists of two copper conductors twisted together
Each conductor has plastic insulation
Shielded Twisted Pair (STP)
Has metal foil or braided-mesh covering that encases each pair
Unshielded Twisted Pair (UTP)
No metal foil or braided-mesh covering around pairs, so it’s less expensive
UTP Categories
Category 1. Used for voice communication
Category 2. Used for voice and data, up to 4 Mbps
Category 3. Used for data, up to 10 Mbps
Required to have at least 3 twists per foot
Standard cable for most telephone systems
Also used in 10-Mbps Ethernet (10Base-T Ethernet)
Category 4. Used afor data, up to 16 Mbps
Must also have at least 3 twists per foot as well as other features
Category 5. Used for data, up to 100 Mbps
Must have 3 twists per inch!
Category 5e. Used in Gigabit Ethernet
Category 6. Used in Gigabit Ethernet and future technologies
Copper Vs Fiber-Optic Cabling
Twisted-pair and coax cable transmit network signals in the form of current
Fiber-optic cable transmits network signals in the form of light
Fiber-optic cable is made of glass
Not susceptible to electromagnetic or radio frequency interference
Not as susceptible to attenuation, which means longer cables are possible
Supports very high bandwidth (10 Gbps or greater)
For long distances, fiber costs less than copper
Wireless Media
IEEE 802.11a, b, g, n
Laser
Microwave
Cellular
Satellite
Cabling Guideline
At the access layer use
Copper UTP rated for Category 5 or 5e, unless there is a good reason not to
To future proof the network
Use 5e instead of 5
Install UTP Category 6 rated cable and terminate the cable with Cat 5 or 5e connectors
Then only the connectors need to be changed to move up in speed
In special cases
Use MMF for bandwidth intensive applications
Or install fiber along with the copper
Cabling Guidelines
At the distribution layer use
MMF if distance allows
SMF otherwise
Unless unusual circumstances occur and cable cannot be run, then use a wireless method
To future proof the network
Run both MMF and SMF
LAN Technologies
Half-duplex Ethernet (becoming obsolete)
Full-duplex Ethernet
10-Mbps Ethernet (becoming obsolete)
100-Mbps Ethernet
1000-Mbps (1-Gbps or Gigabit) Ethernet
10-Gbps Ethernet
Metro Ethernet
Long Range Ethernet (LRE)
Cisco’s EtherChannel
Metro Ethernet
Service offered by providers and carriers that traditionally had only classic WAN offerings
The customer can use a standard Ethernet interface to reach a MAN or WAN
The customer can add bandwidth as needed with a simple configuration change
More Selection Criteria for Internetworking Devices
Cost
Ease of configuration and management
MTBF and MTTR
Support for hot-swappable components
Support for redundant power supplies
Quality of technical support, documentation, and training
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