Networking Essentials - PowerPoint by wulinqing

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									Networking Essentials

   Chapter 18 – Network
 Design and Implementation


        RVCC - CISY 219 - Fall 2004 - TWE   1
         The Process
Network Design is a Process of many
steps
The time to completion varies with
the size of the organization, size and
complexity of the network
The Process will require a team of
diverse people
Documentation of each phase and
overall project is vital
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        Seven Step Process
1.   Statement of Requirements
2.   Investigation of Alternatives
3.   Design of the Network
4.   Selection of Equipment
5.   Planning for Implementation
6.   Implementation
7.   Cutover

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   Required Documentation

Requirements
Alternatives Research: what, choices,
why
Estimated Cost of Implementation
Timetable (Project Plan)
Implementation Plan Results/Key
findings
Summary Document (success of
cutover)    RVCC - CISY 219 - Fall 2004 - TWE   4
    1. Requirements Phase

Document will differ based on New
Network or Upgrade to existing network
New network – very unlikely today;
most companies of any size have a
network with Internet access
Upgrade – this may include expansion
or downsizing to save cost
This plan MUST have Management
Approval and backing
            RVCC - CISY 219 - Fall 2004 - TWE   5
Examples Requiring Upgrade

Fix existing problems (congestion,
performance, …)
Company merger requiring integration
of disparate networks (common)
Capacity Problems (internal, Internet
Access, WAN access, VPN access)
New Technology (wireless, VoIP, VPN)
Expanding Territory (branch locations,
new countries,…)
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    2. Investigating Alternatives

Objective: Consider all relevant
alternatives and eliminate inappropriate
options
This is NOT equipment selection; it is
done at a higher level and may include:
   Private vs. Leased circuits
   In-house vs. contract
   Vendor RFI (request for information)
   Reuse existing technology? New? Both?
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 2. Investigating Alternatives
 Team needed (if not already formed)
     Tech specialist (networking)
     Users (best source of information)
     Management (part of the process)
 Experience is useful but can have
  blind spots for new
  solutions/technology/services
 Rough Cost Estimates useful for
  narrowing down the vendor proposals
                RVCC - CISY 219 - Fall 2004 - TWE   8
   3. Network Design Phase
 Two main methods: (1) modeling
  and simulation, and (2) brute force
 For relatively small, in-house LAN
  design or upgrades, brute force
  works well
 For inter-location or international
  networks, simulation works best


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   3. Network Design Phase
 Simulators require an excellent
  knowledge of the design and traffic
  flows and volumes PLUS in-depth
  knowledge of how to use the
  simulation software
 Simulators don’t design the network;
  they test your designs with the
  relevant traffic data and desired
  performance goals.
             RVCC - CISY 219 - Fall 2004 - TWE   10
Figure 18-1   A wiring diagram of a small office building.




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Figure 18-2   A map showing the geographic scope of a U.S.-based WAN.




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   3. Network Design Phase
 WAN’s are more difficult to design
  because there needs to be a
  balance between performance and
  cost
 Need to calculate performance of
  every WAN circuit
 Amount of queuing will vary from
  design to design

             RVCC - CISY 219 - Fall 2004 - TWE   13
   3. Network Design Phase
 Simulators allow you to vary the
  variables in real time and
  measure the results immediately
 You may end up with several
  designs that go into the next
  phase



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      4. Selection Phase
Most often, the design phase will
produce alternatives that are all viable
Selection, therefore, may require a
refinement of design or a proposal to
management for their help on
selecting the final options


            RVCC - CISY 219 - Fall 2004 - TWE   15
     4. Selection Phase
Vendor information was already
collected (RFI) which allowed some
vendors to be rejected
Remaining vendors should now
receive an RFP (Request For
Proposal) which will define cost and
timelines

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Figure 18-4   The items to be included in an RFP document.




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Figure 18-5   The typical kind of information included in a vendor’s
response to an RFP.




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      4. Selection Phase
RFP Review is a Crucial Team Exercise
Someone needs to verify the financial
viability of the potential vendors
The team needs to prepare an objective
checklist for vendor comparison by
major categories (cost, time, material,
equipment, software, …)

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     Cost Calculation
Vendors may do it all in the RFP
Their costs need to be merged
with your costs to give a
complete picture
Many factors here, but basically
the cost needs to reflect all
parties and services required to
implement the plan
          RVCC - CISY 219 - Fall 2004 - TWE   20
   Major Cost Categories
Circuit Costs (leased and/or private)
Network Equipment (new, upgrades,
maintenance)
Other Hardware Required (Servers,
Network monitors,…)
Software Costs (new or upgrades,
maintenance costs as well)
Personnel Costs to manage the final
product (not this project)
             RVCC - CISY 219 - Fall 2004 - TWE   21
      Benefit Analysis
Improved Customer Service?
Increased Sales?
New Markets?
Reduction in costs?
Improved employee morale?
New services (VPN, VoIP,…)?


           RVCC - CISY 219 - Fall 2004 - TWE   22
    Output of Selection Phase
Proposal for Management Review
and Commitment
   Cost/benefit analysis\
   Team recommendation and why
   Implementation Plan preview
Proposal may be accepted,
rejected, or sent back for more
study
             RVCC - CISY 219 - Fall 2004 - TWE   23
 5. Implementation Planning
Phase and 6. Implementation
Assumes an approved
recommendation and funding
commitment
Needs Physical Planning – where the
equipment is located, HVAC and
security concerns, power, …
Physical Plans need to be drawn
Order equipment, delivery schedule,
dates verified to be within plan

            RVCC - CISY 219 - Fall 2004 - TWE   24
              Testing
Component, segment, subnetwork,
entire network
All equipment must be tested;
workstation access to all servers;
Internet Access; VPN access
Stress Testing – artificial loads
generated using a workload generator;
looking for bottlenecks, breaking
points

            RVCC - CISY 219 - Fall 2004 - TWE   25
               Testing
Error Recovery Testing – “break”
things and measure network response;
make sure equipment works as
advertised
For initial phases of testing, make sure
the vendor is on sight or at least on call



             RVCC - CISY 219 - Fall 2004 - TWE   26
             Training
A MUST!
User training (new equipment, new
services, changes in methods,…)
Network Support Staff (usually given by
vendors prior to or during installation)
Network Managers (varies)
All training should be hands-on!


            RVCC - CISY 219 - Fall 2004 - TWE   27
       7. Cutover Phase
New Network – this can usually occur
anytime since there is nothing to
interrupt
Major Upgrades – over breaks or
weekends; vendors on call; a few users
at each location
Goal: Cutover is transparent to users
as much as possible

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      7. Cutover Phase
Final update of Documentation –
because nothing ever goes
completely as planned!
Celebrate!!




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WAN Design Considerations
Geographic distances present complex
issues at all phases of the project
May need to deal with multiple
communication carriers – a coordination
issue
Lead time for circuits may vary from
state to state and country to country
Traffic must be carefully calculated
Recognize that error rates will be higher
            RVCC - CISY 219 - Fall 2004 - TWE   30
LAN Design Considerations
Higher Speed that WAN; relatively easy
to upgrade
Determine heaviest traffic patterns
(e.g., between clients and servers) and
plan alternate routes or multiple routes\
Consider future growth in terms of
more access and higher speeds
Consider switching in the LAN from the
start
             RVCC - CISY 219 - Fall 2004 - TWE   31
        Internetwork Design
           Considerations
Multiple media, multiple protocols,
WANs
Hierarchical Approach:
   Backbone for network connection
   Major services layer
   Organizational LANs (VLANs)
Design as much fault tolerance as
possible, including load balancing

               RVCC - CISY 219 - Fall 2004 - TWE   32

								
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