UNIT – 4

SYSTEMS ARCHITECTURE

It is a conceptual model that defines the structure, behavior, and more views of a system.

Also known as ‘Enterprise Architecture’It is a superset of network architecture. It consists of following functions:

ClientsApplicationsStorageNetworkServersDatabases.

SYSTEMS ARCHITECTURE

relationships clients

applications

storage

network

Servers Databases

Systems ArchitectureRelationships

Network architecture is an identifier used to locate a device(host) on the network.

IP address dotted decimal notation.Example :

192.168.155.0 192.168.155.0

Addressing Fundamentals

addresses

Local

GlobalPrivate

Public

Temporary

Permanent/

persistent

Address Type

Address Type Meaning

Local Address Identify locally – LAN/ SUBNET/ETHERNET

Global Address Identify Globally/World Wide – WAN network

Private Address Used in NAT – Network Address Translation(individual)

Public Address Used in Public Internet(static/dynamic)

Temporary Address

Assigned for short term duration of time.

Persistent Address

Assigned for long term duration of time.

Addressing Fundamentals

Routing is the process of selecting best paths in a network.

the process of moving a packet of data from source to destination

Example :Routing Protocols:

RIP – Routing Information ProtocolRIP v2 - Routing Information Protocol Version 2.0OSPF – Open Shortest Path – FirstBGP – Border Gateway Protocol.

ROUTING FUNDAMENTALS

Routing traffic source to destination

Sub-netting & Super-netting,Variable-length Sub-netting,Dynamic Addressing,Private Addressing,Virtual Lans (Vlans),Ipv6, AndNetwork Address Translation (Nat).

ADDRESSING MECHANISMS

Switching And Routing,Classless Inter-Domain Routing (CIDR):

Multicasts,Mobile IP,Route

Filtering/Peering/Routing/policiesConfederations( IGP, EGP)

ROUTING MECHANISMS

CLASSFULL ADDRESSING :

Class A,B,C,D,E.

ADDRESSING MECHANISMS

To Scale the network Addressing we will use the number of Functional areas within the network.Workgroups within each function areaSubnets within each workgroupTotal numbers of subnets(current & future)

OrganizationTotal Number of Devices(current & future)

ADDRESSING STRATEGIES

Routing strategies Such as Process of timesProtocol overheads: (Static And Dynamic

protocol)In terms of capacity(bandwidth)CPU – UtilizationMemory - UtilizationStability.

ROUTING STRATEGIES

Some Recommendations for choosing and applying routing protocols for the network.

These recommendations are:

Minimize the number of routing protocols used in the network.

Start with the routing mechanism/ protocol.Routing choices of routing protocols increase.Revaluated the previous decisions.

Chossing And Applying Routing Protocol

NETWORK MANAGEMENT MECHANISMS:There are two major network management

protocols:The Simple Network Management

Protocol(SNMP).The Common Management Information

Protocol(CMIP).These two protocols provide the mechanism

for RETRIEVING , CHANGING(MODIFY) AND

TRANSPORT the network management data across the network.

Network management architecuture

Monitoring is obtaining values for • End to End.• Per Link• Per Element.

Monitoring process involves

• Collecting data.• Processing data.• Storing data.

MONITORING MECHANISMS

Instrumentation is the set of tools and utilities needed to monitor and management the data.

Instrumentation mechanisms are:Access to network management data VIA

SNMP(MIB).Monitoring tools(Ping, Traceroute, TCPdump)

(remote)Direct Access(TelNet,FTP)Instrumentation can be coupled with MONITORING,

DISPLAY, PROCESSING AND STORAGE to form a complete management system.

INSTRUMENTATION MECHANISMS

• Configuration is setting parameters in a network device.

• Used to Operation and control the element.

• Configuration mechanisms:• Includes

• DIRECT ACCESS to devices,• REMOTE ACCESS to devices,• DOWNLOADING configuration files.

CONFIGURATION MECHANISM

• Downloading Configuration Files:

• Use of FTP to download configuration files.• SNMP set commands.• Telnet and command line interface (CLI) Access.• Access via HTTP.• Access Via CORBA(Common Object Request Architecture)

Telnet is a network protocol used on the Internet or Local Area Networks.To provide a bidirectional interactive text-oriented

communication facility using a virtual terminal connection.

CONFIGURATION MECHANISM

PERFORMANCE ARCHITECTURE:To provide

single – Tier performance.Multi – Tier performance in a network.

These mechanisms provide the means • to identify traffic flows, groups of flows.• Measure temporal characteristics.

PERFORMANCE ARCHITECTURE

It is the overall performance of a computer network, particularly the performance seen by the users of the network.

QoS, is determining, setting, and acting upon priority l

Quality Of Service:

(SLAs) are informal or formal contracts between a Service - provider and Service – Requester.

Policies are sets (formal or informal) of high-level statements about how network Resources / Services /Access Permissions are to be allocated among users.

SERVICE-LEVEL AGREEMENTS

The heart of providing performance in a network.

These mechanisms are usually implemented in network devices such as ROUTERS AND SWITCHES

PRIORITIZATION, TRAFFIC MANAGEMENT, SCHEDULING AND QUEUING

It is process of determining which user , application, device, flow or connection gets service.

Or Gets a higher level of service.It begins during the requirements and flow

analysis process.

PRIORITIZATION:

It consists of two mechanisms:admission control:

Ability to refuse/restrict access to network resources.

traffic conditioning: It is a set of mechanisms that

modify(increase/decrease) performance to traffic flows.

VOIP : voice over IPSIP : Session Initiation protocol.

TRAFFIC MANAGEMENT

Scheduling is the mechanism Determines the order in which traffic is

processed for transmission.It is applied at network devices throughout a

network.Network Devices such as : Switches/ Routers.

Algorithms:Weighted Fair Queuing(WFQ)Class Based Queuing(CBQ)

SCHEDULING

Sorting IP packets within a network device while they waif for processing.

The queuing mechanisms are:First In First Out(FIFO)- packets stored in a single

queue.Weighted Fair Queuing(WFQ)-Assigns priorities to

queues.Class Based Queuing(CBQ) - multiple queues with

differing priorities are maintained.Random early detect(RED)- Drop packets early.Weighted RED(WRED)- supports multiple levels for

dropping packets.

QUEUING

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