Transcript Networks

CIT 470: Advanced Network and
System Administration
Networks
CIT 470: Advanced Network and System Administration
Slide #1
Topics
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Network Topology
Structured Cabling
Simple Host Routing
Overlay Networks
Monitoring
CIT 470: Advanced Network and System Administration
Slide #2
Network Topology
Arrangement of network elements, showing
physical or logical interconnections between
nodes. Does not include info about:
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Distance
Transmission rates
Protocols
Cabling types
CIT 470: Advanced Network and System Administration
Slide #3
Star Topology
• Network connected to
a central node using a
single link.
• All data transmitted
between nodes goes
through central node.
• Easy to understand,
simple, affordable.
• Single point of failure.
CIT 470: Advanced Network and System Administration
Slide #4
Ring Topology
• Each node is connected
to two other nodes, with
first and last node
connected to each other.
• All devices have two
connections to network,
so any link can fail w/o
causing a problem.
• Dual ring has two
connections to each
node.
CIT 470: Advanced Network and System Administration
Slide #5
Structured Cabling
Telecom cabling infrastructure consisting of
 Entrance facilities: where building interfaces to ouside
world.
 Equipment room: more complex equipment (routers,
major cable terminations.)
 Building backbone: star topology providing access to
all wiring closets, equipment rooms, and entrance
facilities.
 Telecom closet: wiring closet where horizontal cable for
floor is terminated.
 Horizontal cabling: extends from telecom closet to end
user devices in the work area.
 Work area: office space, labs, etc. where computers and
other equipment are located.
CIT 470: Advanced Network and System Administration
Slide #6
Wiring Closets
Small room where
cables are connected
from main network to
local devices, a/k/a
a distribution frame.
Needs:
 Reliable power
 A/C
 Physical security
CIT 470: Advanced Network and System Administration
Slide #7
IDFs and MDFs
Intermediate Distribution Frame (IDF)
– One per floor.
– Connects end users to network.
Main Distribution Frame (MDF)
– Connects all the MDFs.
– Often located in data center.
CIT 470: Advanced Network and System Administration
Slide #8
Patch Panel
A panel that houses cable connections.
– Front: short patch cables.
– Back: longer permanent cables.
Allows you to change cable path w/o new cables.
CIT 470: Advanced Network and System Administration
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Patch Panel
CIT 470: Advanced Network and System Administration
Slide #10
Star Topology Cabling
CIT 470: Advanced Network and System Administration
Slide #11
Star Topology Wiring Advantages
1. Central wiring hubs make it easier to move,
add, or change cabling.
2. Central cabling points allow faster
troubleshooting.
3. Independent point to point links prevent
cable problems from affecting other links.
4. Central wiring hubs can allow easier
upgrades to new technologies.
CIT 470: Advanced Network and System Administration
Slide #12
Cabling Contractors
• Cabling an entire building is a major project.
• Cable contractors know how
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Plan cabling for an entire building
Estimate cabling and install hosts
Structured cable standards
Electrical safety standards
Fire safety standards
CIT 470: Advanced Network and System Administration
Slide #13
Documentation
• Logical map
– Logical network topology
– Network numbers, names, speeds
• Labeling
– Label both ends of each cable.
– Cables can be difficult to label, but
manufacturers will print serial numbers.
– Include text comment on each interface in
router/switch software.
CIT 470: Advanced Network and System Administration
Slide #14
Simple Host Routing
Machines with one NIC only need two routes:
– Local subnet: direct connection.
– Everything else goes to local gateway router.
Don’t enable routing protocols on PCs.
– Makes networking more complex.
– Decreases network performance w/ broadcasts.
– Badly configured PC can send bad routes to
other PCs and routers, breaking network.
CIT 470: Advanced Network and System Administration
Slide #15
Overlay Networks
A logical topology on top of physical topology.
– VPN: connect remote users/sites to main site as
if a single secure WAN existed over Internet.
– VLAN: treat any connection as belonging to any
subnet, no matter what the physical cabling is
like. Eliminates need to recable to move
machines to different subnets.
CIT 470: Advanced Network and System Administration
Slide #16
Monitoring
Need two types of monitoring
– Real-time alerts: alert when network interface
goes up or down, heavy load, security, etc.
– Historical trends: record overall network usage
in order to plan for future capacity and detect
behavorial abnormalities before they become
problems.
CIT 470: Advanced Network and System Administration
Slide #17
References
1. Thomas A. Limoncelli, The Practice of
System and Network Administration, 2nd ed,
Addison-Wesley, 2007.
2. Kennedy Clark and Kevin Hamilton, Cisco
LAN Switching, Cisco Press, 1999.
3. Charles E. Spurgeon, Ethernet: The
Definitive Guide, O’Reilly, 2000.
4. John Vacca, The Cabling Handbook, 2nd ed,
Pearson PTR, 2000.
CIT 470: Advanced Network and System Administration
Slide #18