Download Troubleshooting Your Network

Help Desk
Working at a Small-to-Medium Business or ISP –
Chapter 2
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2.1.1 ISP Help Desk Organization

Level 1 is for immediate support handled by junior-level help
desk technicians.

Level 2 handles calls that are escalated to more experienced
telephone support.

Level 3 is for calls that cannot be resolved by phone support and
require a visit by an on-site technician.
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2.1.1 ISP Help Desk Organization

can consist of one person that performs all three levels of support

can be a comprehensive call center with elaborate call routing
facilities and escalation rules

contracted to a third-party call center company, which provides the
services of Level 1 and Level 2
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2.1.2 Roles of ISP Technicians
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2.1.2 Roles of ISP Technicians
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2.1.2 Roles of ISP Technicians
usually in accordance with a Service
Level Agreement (SLA) - resembles an
insurance policy, because it provides
coverage or service if there is a computer
or network problem
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2.1.3 Interacting with Customers
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2.2.1 Using the OSI Model
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2.2.1 Using the OSI Model
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2.2.1 Using the OSI Model
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2.2.1 Using the OSI Model
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2.2.2 Using the OSI Model
Step 1: Upper layers create the data.
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2.2.2 Using the OSI Model
Step 2: Layer 4 packages the data for end-to-end transport.
Step 3: Layer 3 adds the network IP address information.
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2.2.2 Using the OSI Model
Step 4: Layer 2 adds the data link layer header and trailer.
Step 5: Layer 1 converts the data to bits for transmission.
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2.2.2 Using the OSI Model
Activity 2.2.2.4 – Let’s do this activity together!
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2.2.2 Using the OSI Model
Activity 2.2.2.4
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2.2.3.1 Troubleshooting the OSI Model
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2.2.3.3 Troubleshooting the OSI Model
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2.2.3.3 Troubleshooting the OSI Model
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2.2.3.4 Troubleshooting the OSI Model
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2.2.3.5 Troubleshooting the OSI Model
Activity 2.2.3.5
Let’s do this together!
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2.2.3.5 Troubleshooting the OSI Model
Activity 2.2.3.5
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Planning a Network
Upgrade
Working at a Small-to-Medium Business or ISP –
Chapter 3
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Purpose of a Site Survey

Documents existing network structure
– Shows physical layout to determine if new equipment can be
installed

Will also help show . . .
– What is already on site
– What type of equipment may be needed
– Floor plan of structure

Determine obvious issues
– Unlabeled cables
– Poor physical security
– Lack of power
– Lack of UPS
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Perform a Customer Site Survey
 What does the technician look for . . .
– Number of hosts or users
• how many will be added over the next 12 months
• how many network servers and/or printers are needed
– Internet Service and Equipment
• if upgrading speed, may need to upgrade equipment
– Existing network devices
• type of network equipment installed
• configurations loaded on devices
– Security
• are additional firewalls needed
– Applications
• VoIP or video conferencing
– Wireless or Wired
• amount of square feet between access points
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Determine the Topologies
 Physical topology
– actual physical layout of devices
 Logical topology
– documents what paths are taken through the network
– includes:
• IP addresses
• device names
– workstations
– routers
– servers
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Perform a Customer Site Survey
 Documentation on current hosts and devices
 Includes:
– device name
– location
– brand and/or model
– operating system
– IP addressing
– connectivity method
– security
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Physical Topologies
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Coming up with a Game Plan
 A good plan will help identify the following:
– Strengths
– Weaknesses
– Opportunities
– Threats
 AKA SWOT
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Phases of the Network Upgrade
 Requirements Gathering
– analyze data from on-site visit to determine network requirements
– done by the design team
• creates Analysis Report
 Selection and Design
– selection of devices & cabling
– weaknesses of design are identified and addressed here
– creation of a prototype
 Implementation
– overlooked tasks are corrected
– constant customer communication is CRITICAL
 Operation
 Review and Evaluation
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Examining the Physical Environment
 Examine existing facilities and existing cabling
 Find MDF (Main Distribution Facility)
– houses network devices
– all network cable concentrate here
– may also contain POP of ISP
 Any IDFs? (Intermediate Distribution Facility)
– additional wiring closets
– connect to MDF
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Cabling Considerations
 Check cable types needed
– STP
– UTP
– Coaxial
– Fiber
 Check cable specifications
– Straight Through
– Crossover
– Rollover
– Serial
 TIA/EIA 568A/568B standard
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Check Out the Cabling
 Patch Cable
– from PC to wall plate
 Horizontal cable
– from wall plate to IDF
 Vertical cable
– from IDF to MDF
 Backbone cable
– handles major traffic
 Wiring closet location
 Cable management system
– protects cables/cable runs
 Cable labeling
 Electrical
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Purchasing Equipment for the Network
 Managed services
– equipment obtained from ISP through a lease
– all updates, maintenance, etc. of equipment are the
responsibility of the ISP
 In-house services
– all responsibility falls on the customer
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Selection of Network Devices
 Selection of LAN devices
– hubs could be used with smaller LANs
– switches more efficient
• managed switch – control over individual ports
• which is better? (one 24 port switch or 2-12 port switches)
 Selection of a WAN device (router)
– fixed or modular expansion?
• fixed – specific number/type of ports
• modular – includes expansion slots
– breaks up collision and broadcast domains
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Cisco Devices
 Router
– 1841 ISR (Integrated Services Router)
– used for medium-sized business
– different connectivity options
 Switch
– 2960 switch
– used for Fast Ethernet and Gigabit connectivity
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Network Reliability and Availability
 Reliability
– can be achieved by adding redundancy to the network
– use of two routers instead of one
 Five-9’s of availability
– network operational 99.999% of time
 Use of fault tolerance helps to ensure reliability
– a network will continue operating properly in the event of a failure
– Use of the following devices will help ensure fault tolerance
• UPS
• multiple power supplies
• hot-swappable devices
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IP Addressing Plan
 The following devices will need IP addresses
– user PCs
– servers
– printers, IP phones
– router LAN interfaces
– router WAN (serial interfaces)
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Summary
 A site survey including extensive documentation of both
physical and logical network information must be
performed before a network upgrade can be planned.
 The five phases of a network upgrade include
requirements gathering, selection and design,
implementation, operation, and review and evaluation.
 Structured cabling deals with the placement of cables,
location of wiring closets, cable management, and
electrical considerations.
 Cost and expandability are important considerations
when planning equipment upgrades.
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