Enterprise Network Design and Management

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Enterprise Network Requirement

Definition

1. Network is connect to other LANs

2. Interconnected LANs

3. A whole network of the enterprise

4. All kinds of message, such as voice, fax, video and data are transfered in this

Approach to  network design

1. Top-down

a. Essential for new networks

b. Easy to scale

c. Earlier to find the bottleneck

d. Helpful to execute the rules

2. Buttom-up

a. Upgrade of existing networks

b. Rapidly set up

c. small size

d. short term plan

e. specific application foucs

Design Criteria

1. media specs: for LANs and access

2. protocols: LANs and WANs

3. N. O .S

4. HW specs-servers, client nodes

5. switch / router specs (capabilities of the product)

6. Interface specs for the above components

7. application consideration: types, licensing (site, client/server, standalone)

8. technology choices (routing/L3, ATM type, addressing, QOS)

9. No of users etc.. leads us to work out the usr requirements

Major Steps

1. Analysis process

a. Requirements analysis

b. Flow analysis

2. Design process

a. logical design

b. physical design

c. developing of addressing & routing for the design

Standard of Network Design:

1. Capacity

2. Delay

3. RMA: Reliability, Maintainability and availability

Separation of Requirements

1. Requirements gathered and derived from Users, Management, Staff

2. Analysis of requirements

2.1. Identifying, Gathering & Understanding requirements & their characteristics

2.2. Developing thresholds for performance

2.3. Determine specific services for network

2.4. Catagory the requirements

2.4.1 Catagory level

a. Core Requirements for the network

b. Features for the network

c. Requirements for future revisions/upgrades

d. Rejected requirements

e. Informational requirements

2.4.2 Catagory Method

a. Must/Shall/Required --> core requirements

b. Must not/Shall not --> core requirements

c. Should/Recommended --> features or future requirements

d. Should not/Not Recommended --> features or future requirements

e. May/Optional --> features or future requirements, or be rejected

2.4.3  Benefit of Requirement Analysis

a. More objective, informed choices of network technologies and services

b. The ability to apply technology and topology candidates to networks

c. Networks and elements properly sized to users and appliations

d. A better understanding of where and how to apply services in the network

2.5 Requirements Types

a. User                    Highest Level, Least Technical

b. Application

c. Device

d. Network             Lowest Level, Most Technical

2.5.1 User Requirements

a. Timeliness --> tolerable time frame --> bulk file / image transfer

b. Interactivity --> response time, delay --> remote device access, web use, visualization

c. Reliability --> all performance characteristics (delay, RMA, capacity)

d. Presentation Quality --> all performance characteristics (delay, RMA, capacity)

e. Adaptability --> wireless  

f. Security --> reliability, impact capacity and delay

g. Affordability --> overall budget perspective

h. Functionality --> application requirement

i. Supportability --> maintenance of the network

j. Future Growth --> user/device/application add into network

2.5.2 Application Requirements

a. Application Types

i. Mission Critical --> RMA  --> airline reservation / credit card processing applications

ii. Rate-critical Apps --> Capacity --> voice / non-buffered video

iii. Real Time --> Delay --> real-time / interactive burst / interactive bulk / asynchronous

                                               telephone / telnet / backup / email

b. Application Groups

i. Command & Control Group --> Mission Critical

ii. Visualisation Apps --> 2D and 3D viewing of objects 

iii. Distributed Computing Apps --> Clustered computing / Parallel processing

iv. Web Access, Development & Use Apps --> Remote access / Interactive --> delay sensitive

v. Bulk Data Transfer --> FTP / BACKUP --> less interaction / not High-performance

vi. Tele Service apps --> voip apps / video conferencing apps --> high-performance

vii. Operation, Admin and Maintenance (OAM) apps --> DNS/DHCP/SMTP/NNTP/All address resolution/Network monitoring/Net security/system accounting --> high reliability, not delay sensitive

viii. Client-Server apps --> ERP / SCM / CRM

c. Application Locations

2.5.3 Device Requirements

a. Device Types

i. Generic --> desktop / laptop

ii. Servers --> computer servers, storage servers....

iii. Special equipment

Device Type	NIC Type	Processor	OS	Applications
Low-End PC	100M Ethernet	i3	Win 7	Word, PP, Finance
High-End PC	100/1G Ethernet	i5	Win 7	Word, PP, DB, Graphics
Generic PC	100/1G Ethernet	i7	Win 2008 / Linux / Unix	Word, PP, DB, Graphics
Workstation	100/1G Ethernet	i5	Win 7 / Linux	DB, Graphic, CAD, SC
Laptop	144M Ethernet	i3	Win 7	Word, PP, Others
PP—Powerpoint		CAD—Computer-Aided Drawing
DB—Database		SC—Scientific SW

b. Performance Characteristics

i. Storage performance - disk drive seek time

ii. Memory performance - access time

iii. Bus performance - cap arbitration

iv. OS performance - (protocol stack effect, APIs sup, load on CPU)

v. Device driver performance

c. Location info

i. Helps in establishing realtionship bet. users, apps & networks

ii. Outsourcing of sys components as for admin/config from remote site

2.5.4 Network Requirements

a. Type

i. Constraints from existing networks

ii. Expected scaling of existing networks

iii. Interoperability between networks

iv. Existing network and support services

v. Existing architectural and design guidelines

b. Tasks

i. Existing network integration, migration

ii. Functional requirements including network management & security

monitoring / event notification / net configuration / trouble shooting / monitoring for metrics planning

iii. Network broadcasts

2.5.5 Financial Requirements

a. Fixed

i. Desigh

ii. Deployment of HW/SW + Initial Installation & Establishment of services

b. Recurring

i. Net. administration

ii. Upgrades (including SW licensing)

iii. Security

iv. BW cost(external/WAN)

Requirements Analysis Process

1. Gathering and listing requirements

1.1 Determining Initial Conditions

Type of Network Project

1. New network

2. Modification of an existing network

3. Analysis of network problems

4. Outsourcing

5. Consolidation

6. Upgrade

Scope of Network Project

1. Network size

2. Number of sites

3. Distance between sites

Initial Architecture/Design Goals

1. Upgrade technology/vendor

2. Improve preformance to part or all of network

3. Support new users, applications, or devices

4. Solve perceived problems within system

5. Increase security

6. Support a new capability in system

1.2 Setting Customer Expectations

1. a rapid, initial evaluation of the problem

2. estimating resoureces and schedule

1.3 Working with users

1. gather requirements

2. interact with users

1.4 Taking Performance Measurements

Use test environment or existing environment to get the performance information

1.5 Tracking and Managing Requirements

List down all the requirement in a form like below to track

1.6 Mapping Location Information

1.7 Developing Service Metrics

1.7.1 RMA

1. Reliability: MTBF(mean time between failures) and MTBCF(mean time between mission-critical failures)

2. Maintainability: MTTR(mean time to repair)

3. Availability: (MTBCF)/(MTBCF+MTTR) or (MTBF)/(MTBF+MTTR)

4. Optionally, uptime, downtime

% Uptime	Amount of Allowed Downtime (Hours [h],Minutes [m], or Seconds [s] per Time Period)
	Yearly	Monthly	Weekly	Daily
99%	87.6 h	7.3 h	1.68 h	14.4 m
99.9%	8.76 h	44 m	10 m	1.4 m
99.99%	53 m	4.4 m	1 m	8.6 s
99.999%	5.3 m	26.3 s	6 s	0.86 s

100% --> 99.999%

Year --> 365 * 24 * 60

Monthly --> 30 * 24 * 60

Weekly --> 7 * 24 * 60

Daily --> 24 * 60

Description:

1. 99.99% --> measured weekly, measured at every router interface and user device in the network

2. 99.999% --> measured weekly, for access to ther server farm network, measured at the router interface at the server farm, at server NICs. The application ping will also be used to test connectivity between user LAN and the server LAN.

3. Note that these requirements do not apply to scheduled downtime period for maintenance

1.7.2 Capacity

1. Data rates: PDR(peak data rate), SDR(sustained data rate), MDR(minimum data rate)

2. Data size: burst size, durations

1.7.3 Delay

1. Interaction Deily(INTD): how long a user is willing to wait for a response from the system--> Web/File Transfer/Database Proceing --> 10 - 30 seconds

2. Human Response Time(HRT): a time threshold which user begin to perceive delay in the system--> Visualization --> 100ms

3. Network Propagation Delay: how long it takes for a signal to cross a physical medium or link --> 10ms ~ 500ms

4. End-to-end delay: PING

1.8 Behavior

1. User: work times and durations

2. Application: data size/frequency/flow directions/broadcast