UNIT - III

OBJECTIVES:

This chapter introduces flows andflow concepts, data sources anddata sinks, and flow models will helpus to identify, size, and describeflows.

FLOWS: Flows also known as network flowsor traffic flows or data flows.

It provides the traffic movement inthe network.

A sequence of packets sent from aparticular source to a particular(unicast or multicast) destination.

FLOWS ANALYSIS: Flow analysis is the process of describing/characterizing traffic flows for anetwork.

Where they are likely 2take place/occur. What levels of performance they willrequire.

BENEFITS: Provides hierarchy (arrangement) levels. In choosing interconnection strategiessuch as (switching, routing and hybrid)mechanisms.

Flows are represented as Unidirectional or Bidirectional performance.

Bidirectional :

Unidirectional:

It is represented as single anddouble sided arrows.

Most flows are Bi-Directionalarrows.

Flows are important in analysis,architecture and design process.

TRAFFIC FLOW:

Traffic flow is the study ofinteractions between trafficcontrol devices and minimaltraffic congestion(packet loss)problems.

Flow attributes, such as Source/Destination address, Type of information, PORT numbers like,

▪ 21 FTP (File Transfer Protocol)▪ 25 SMTP (Send Mail Transfer Protocol)▪ 68 DHCP (Dynamic Host Control Protocol)▪ 80 HTTP (Hyper-Text Transfer Protocol)▪ 161 SNMP (Simple Network Management Protocol)

▪ 8080 HTTP

Composite

flows

Individual

flows

Flows

It is an One-Way delay/application requirement for a single session.

Requirements are left with individual flowand not consolidated with otherrequirements.

Uni-directional (UPSTREAM).

Single applications of flows that share acommon link, path or network.

It has guaranteed requirements.

The combination of requirementsfrom multiple applications ofindividual flows that share acommon link, path or network.

Bi-directional (UPSTREAM/DOWNSTREAM).

Most flows in a network arecomposites.

It requires high or guaranteedperformance that are operate/control the architecture and design.

Example: Mission critical(MTBF,MTBCF) Rate critical(PDR,SDR) Real critical.

An activity, device, service or systemwhose failure or problems whichinterrupt an event will cause afailure in business operations.

For example, an online business'smission critical.

Mission critical refers to any factor of a system like,

equipment, process, procedure, Software whose failure will result in the failure of business operations.

Critical rate is an attribute of your character that determines how often you make a critical attack.

For example, if your critical rate is 40% then on average 4 out of every 10 attacks will be a critical attack.

Focusing on particular application Developing a profile Choosing the top N applications

Focusing on an application Application group Device / functions.

Profile or template can be developed for applications.

Each flow fits the profile identified with profile tag.

Profiles are used to simplify information.

Top 5 Applications Web browsing E-mail File Transfer Word processing DB transaction The purpose, determine which application represent the most important requirements for the network.

Data sources: It is used to generate the data flow. Represented as circle with cross(star/asterisk).

Two dimensional plane, arrow coming out.

Data sinks: It is used to terminate the data flow.

The group of flows publicly display the consistent behavior characteristics is called as ‘flow models’.

Useful to identify and categorize flows in an Environment peer-to-peer client-server hierarchical client-server and distributed computing.

FLOW PRIORITIZATION Flows can be prioritized according to

importance, based on the characteristics. To determine which flows get the most

resources or which flows get resources first. Some prioritizations include:

▪ Business objectives▪ Political objectives▪ RMA and QoS▪ Security Requirements▪ The numbers of users, applications and devices.

It is a mechanism to combine these performance requirements (capacity, delay and RMA).

To describe the optimal composite performance for that flow or group of flows.

Example: Building and device locations ▪ Requirement analysis▪ Flow models▪ Flow map

THANK YOU