NETWORK MANAGEMENT ELECTIVE SUBJECT FOR CS AND IT STUDENTS OF VII SEMESTER

NETWORK MANAGEMENT BOOKS TO BE USED Computer Networking with Internet Protocols and Technology by William Stallings Management of Network Systems by N I I T Internetworking with TCP/IP by Douglas Comer COMPUTER NETWORKS by Uyless Black

NETWORK MANAGEMENT Definition Network management refers to the activities, methods, procedures, and tools that pertain to the operation, administration, maintenance, and provisioning of networked systems.

NETWORK MANAGEMENT Operation Operation deals with keeping the network (and the services that the network provides) up and running smoothly.

NETWORK MANAGEMENT Administration Administration deals with keeping track of resources in the network and how they are assigned. It includes all the "housekeeping" that is necessary to keep the network under control.

NETWORK MANAGEMENT Maintenance Maintenance is concerned with performing repairs and upgrades - for example, when equipment must be replaced, when a router needs a patch for an operating system image, when a new switch is added to a network.

NETWORK MANAGEMENT Provisioning Provisioning is concerned with configuring resources in the network to support a given service. For example, this might include setting up the network so that a new customer can receive voice service.

NETWORK MANAGEMENT A common way of characterizing network management functions is FCAPS - Fault, Configuration, Accounting, Performance and Security.

NETWORK MANAGEMENT History In the early 1980's the term FCAPS was introduced within the first Working Drafts (N1719) of ISO 10040, the Open Systems Interconnection (OSI) Systems Management Overview (SMO) standard. At that time the intention was to define five separate protocol standards, one for each functional area. Since initial experiences showed that these protocols would become very similar, the ISO working group responsible for the development of these protocols (ISO/TC97/SC16/WG4, later renamed into ISO-IEC/JTC1/SC21/WG4) decided to create a single protocol for all five areas instead. This protocol is called Common management information protocol (CMIP). In the 1990's the ITU-T, as part of their work on Telecommunications Management Network (TMN), further refined the FCAPS as part of the TMN recommendation on Management Functions (M.3400). The idea of FCAPS turned out to be very useful for teaching network management functions; most text books therefore start with a section that explains the FCAPS.

NETWORK MANAGEMENT Fault management The goal of fault management is to recognize, isolate, correct and log faults that occur in the network.

NETWORK MANAGEMENT Configuration management The goals of configuration management include: to gather and store configurations from network devices (this can be done locally or remotely). to simplify the configuration of the device to track changes which are made to the configuration to configure ('provision') circuits or paths through non-switched networks [edit]

NETWORK MANAGEMENT Accounting management Accounting is often referred to as billing management. The goal is to gather usage statistics for users.

NETWORK MANAGEMENT Performance management Performance management enables the manager to prepare the network for the future, as well as to determine the efficiency of the current network, for example, in relation to the investments done to set it up. The network performance addresses the throughput, percentage utilization, error rates and response times areas.

NETWORK MANAGEMENT Security management Security management is the process of controlling access to assets in the network. Data security can be achieved mainly with authentication and encryption. Authorization to it configured with OS and DBMS access control settings.

NETWORK MANAGEMENT PROTOCOL The need for a Protocol Architecture The source system must either activate the direct data communication path or inform the communication network of the identity of the desired destination system. The source system must ascertain that the destination system is prepared to receive data. The file transfer application on the source system must ascertain that the file management program on the destination system is prepared to accept and store the file for this particular user. If the file formats used on the two systems are incompatible, one or the other system must perform a format translation function.

NETWORK MANAGEMENT A high Degree of cooperation between two computer systems. The task is broken up into sub tasks. Each task implemented separately. Protocol Architecture the modules are arranged in a vertical stack. Each layer in stack performs a related subset of the functions.. Communication is achieved by having the corresponding or peer, layer in two systems communicate. The peer layers communicate by means of formatted blocks of data that obey a set of rules or conventions known as a protocol.

NETWORK MANAGEMENT The key features of a protocol are Syntax: Concerns the format of data blocks. Semantics: Includes control information for coordination and error handling. Timing: Includes speed matching and sequencing.

NETWORK MANAGEMENT Instead of a single module for performing communications, there is a structured set of modules that implements the communication function. This structure is referred to as a protocol architecture. A simple example of file transfer is shown in the next slide.

NETWORK MANAGEMENT

Communication can be said to involve three agents.: Applications Computers Network Thus, the transfer of data from one application to another involves first gathering the data to the computer in which the application resides and then getting it to the intended application within computer. With these concepts in mind, it appears natural to organize the communication task into three relatively independent layers: network access layer, transport layer, and application layer.

NETWORK MANAGEMENT NETWORK ACCESS LAYER Exchange of data between the computer and the network Sending computer provides address of destination May invoke levels of service Dependent on type of network used (LAN, packet switched etc.)‏

NETWORK MANAGEMENT TRANSPORT LAYER Reliable data exchange Independent of network being used Independent of application

NETWORK MANAGEMENT Application layer Contains the logic needed to support the various user applications. For each different type of application, such as file transfer, a separate module is needed that is peculiar to that application

NETWORK MANAGEMENT

Addressing Requirements Two levels of addressing required Each computer needs unique network address Each application on a (multi-tasking) computer needs a unique address within the computer The service access point or SAP The port on TCP/IP stacks

NETWORK MANAGEMENT To control the operation, control information,as well as user data, must be transmitted as shown in the diagram in next slide

NETWORK MANAGEMENT

At each layer, protocols are used to communicate Control information is added to user data at each layer Transport layer may fragment user data Each fragment has a transport header added Destination SAP Sequence number Error detection code This gives a transport protocol data unit

NETWORK MANAGEMENT At each layer, protocols are used to communicate Control information is added to user data at each layer Transport layer may fragment user data Each fragment has a transport header added Destination SAP Sequence number Error detection code This gives a transport protocol data unitAt each layer, protocols are used to communicate Control information is added to user data at each layer Transport layer may fragment user data Each fragment has a transport header added Destination SAP Sequence number Error detection code This gives a transport protocol data unit

NETWORK MANAGEMENT Network PDU Adds network header network address for destination computer Facilities requests

NETWORK MANAGEMENT Operation of a Protocol Architecture

NETWORK MANAGEMENT Required for devices to communicate Vendors have more marketable products Customers can insist on standards based equipment Two standards: OSI Reference model Never lived up to early promises TCP/IP protocol suite Most widely used Also: IBM Systems Network Architecture (SNA)‏ Standardized Protocol Architectures

NETWORK MANAGEMENT Open Systems Interconnection Developed by the International Organization for Standardization (ISO)‏ Seven layers A theoretical system delivered too late! TCP/IP is the de facto standard OSI

NETWORK MANAGEMENT

The OSI Environment

NETWORK MANAGEMENT OSI as Framework for Standardization

NETWORK MANAGEMENT Layer Specific Standards

NETWORK MANAGEMENT Protocol specification: Two entities at the same layer in different systems cooperate and interact by means of a protocol. Protocols must be specified precisely. This should include the format of protocol data units exchanged, the semantics of all the fields and the allowable sequences of PDUs. Service definition: Standards are needed ofr the services that each layer provides to the next higher layer. Addressing: Each layer provides services to entities at the next higher layer. Network service access point ( NSAP ) indicates a transport entity that is a user of network service.

NETWORK MANAGEMENT Services between adjacent layers expressed in terms of primitives and parameters Primitives specify function to be performed Parameters pass data and control info Service Primitives and Parameters

NETWORK MANAGEMENT A primitive issued by a service provider to acknowledge or complete some procedure previously invoked by a request by the service userCONFIRM A primitive issued by a service user to acknowledge or complete some procedure previously invoked by an indication to that userRESPONSE A primitive issued by a service provider either to: indicate that a procedure has been invoked by the peer service user on the connection and to provide the associated parameters, or notify the service user of a provider-initiated action INDICATION A primitive issued by a service user to invoke some service and to pass the parameters needed to specify fully the requested serviceREQUEST Primitive Types

NETWORK MANAGEMENT Timing Sequence for Service Primitives

NETWORK MANAGEMENT TCP/IP Protocol Architecture Developed by the US Defense Advanced Research Project Agency (DARPA) for its packet switched network (ARPANET)‏ Used by the global Internet No official model but a working one. Application layer Host to host or transport layer Internet layer Network access layer Physical layer

NETWORK MANAGEMENT Physical interface between data transmission device (e.g. computer) and transmission medium or network Characteristics of transmission medium Signal levels Data rates etc. Physical Layer

NETWORK MANAGEMENT Exchange of data between end system and network Destination address provision Invoking services like priority Network Access Layer

NETWORK MANAGEMENT Systems may be attached to different networks Routing functions across multiple networks Implemented in end systems and routers Internet Layer (IP)‏

NETWORK MANAGEMENT Reliable delivery of data Ordering of delivery Transport Layer (TCP)‏

NETWORK MANAGEMENT Support for user applications e.g. http, SMPT Application Layer

NETWORK MANAGEMENT OSI v TCP/IP

NETWORK MANAGEMENT Usual transport layer is Transmission Control Protocol Reliable connection Connection Temporary logical association between entities in different systems TCP PDU Called TCP segment Includes source and destination port (c.f. SAP)‏ Identify respective users (applications)‏ Connection refers to pair of ports TCP tracks segments between entities on each connection TCP

NETWORK MANAGEMENT Alternative to TCP is User Datagram Protocol Not guaranteed delivery No preservation of sequence No protection against duplication Minimum overhead Adds port addressing to IP UDP

NETWORK MANAGEMENT TCP and UDP Headers

NETWORK MANAGEMENT IP (v4) header minimum 20 octets (160 bits)‏ 32-bit source and destination addresses Checksum applies to header to avoid incorrect delivery Protocol field shows if TCP, UDP etc. carried Flags and fragmentation offset used in fragmentation 1995 IPng became standard IPv6 in 1996 Enhancements for modern high speed networks Carry multimedia data streams Increase address space IP and IPv6

NETWORK MANAGEMENT IPv4 Header

NETWORK MANAGEMENT IPv6 Header

NETWORK MANAGEMENT TCP/IP Concepts

NETWORK MANAGEMENT Level in architecture at which entity is named Unique address for each end system (computer) and router Network level address IP or internet address (TCP/IP)‏ Network service access point or NSAP (OSI)‏ Process within the system Port number (TCP/IP)‏ Service access point or SAP (OSI)‏ Addressing level

NETWORK MANAGEMENT Process associated with port 1 in host A sends message to port 2 in host B Process at A hands down message to TCP to send to port 2 TCP hands down to IP to send to host B IP hands down to network layer (e.g. Ethernet) to send to router J Generates a set of encapsulated PDUs Trace of Simple Operation

NETWORK MANAGEMENT PDUs in TCP/IP

NETWORK MANAGEMENT Destination port Sequence number Checksum Example Header Information

NETWORK MANAGEMENT Most networks not isolated Different types of LAN Multiple similar LANs Multiple sites connected by WAN(s) May appear as large network Entire configuration referred to as an internet Note indefinite article and lower case “i” Each constituent network is a subnetwork Most important example of an internet is referred to simply as the Internet Note definite article and upper case “I” The Internet evolved from research-oriented packet-switching network Basis for development of internetworking technology Model for private internets Internetworking

NETWORK MANAGEMENT Each subnetwork supports communication among devices attached to that subnetwork End systems (ESs)‏ Subnetworks connected by intermediate systems (ISs)‏ Provide communications path and relay and routing functions Bridges and routers Different types of protocols used Bridge operates at layer 2 Relay between like networks Router operates at layer 3 Routes packets between potentially different networks Internetworking Devices

NETWORK MANAGEMENT Interconnect dissimilar subnetworks Provide a link between networks Provide for routing and delivery of data between processes on end systems attached to different networks Do not require modifications of architecture of subnetworks Must accommodate differences among networks Addressing schemes Maximum packet sizes Interfaces Reliability Satisfied by internetworking protocol implemented in all end systems and routers IP Routers

NETWORK MANAGEMENT Configuration for TCP/IP Example

NETWORK MANAGEMENT Action of Sender

NETWORK MANAGEMENT Action of Router

NETWORK MANAGEMENT Action of Receiver

NETWORK MANAGEMENT Internet Collection of communication networks interconnected by bridges and/or routers Intranet An internet used by single organization Provides key Internet applications (World Wide Web)‏ Operates within organization for internal purposes Can exist as isolated, self-contained internet May have links to the Internet Subnetwork Refers to a constituent network of an internet. This avoids ambiguity because the entire internet, from a user's point of view, is a single network Internetworking Terminology (1)‏

NETWORK MANAGEMENT End System (ES)‏ Device attached to one of the networks of an internet Supports end-user applications or services Intermediate System (IS)‏ Device used to connect two networks Permits communication between ES attached to different networks Bridge IS used to connect two LANs that use similar protocols Address filter Does not modify packets Layer 2 of the OSI model Router IS used to connect two networks that may or may not be similar Uses an internet protocol present in each router and each end system of the network Layer 3 of the OSI model Internetworking Terminology (2)

NETWORK MANAGEMENT Virtual Network A user thinks of an internet as a single virtual network that interconnects all hosts, and through which communication is possible; its underlying architecture is both hidden and irrelevant. UNIT II

NETWORK MANAGEMENT Internet Architecture and Philosophy Conceptually, a TCP/IP internet provides three sets of services as shown in the figure CONNECTIONLESS PACKET DELIVERY SERVICE RELIABLE TRANSPORT SERVICE APPLICATION SERVICES

NETWORK MANAGEMENT The Conceptual Service Organization Internet software is designed around three conceptual networking services arranged in a hierarchy; much of its success has resulted because this architecture is surprisingly robust and adaptable.

NETWORK MANAGEMENT Connectionless Delivery System This is the most fundamental internet service. This consists of a packet delivery system. Service is defined as an unreliable, best-effort, connectionless packet delivery system. The packet may be lost, duplicated, delayed, or delivered out of order, but the service will not detect such conditions, nor will it inform the sender or receiver.

NETWORK MANAGEMENT The service is called connectionless because each packet is treated independently from all others. Unreliability arises only when resources are exhausted or underlying networks fail.

NETWORK MANAGEMENT Purpose of the Internet Protocol The protocol that defines the unreliable, connectionless delivery mechanism is called internet protocol (IP). IP provides three important definitions. First, the IP protocol defines the basic unit of data transfer used throughout a TCP/IP internet. Second, IP software performs the forwarding function, choosing a path over which a packet will be sent. Third, in addition to the precise, formal specification of data formats and forwarding, IP includes a set of rules that embody the idea of unreliable delivery. The rules characterize how hosts and routers should process packets, how and when error messages should be generated, and the conditions under which packets can be discarded.

NETWORK MANAGEMENT The Ipv4 Datagram The analogy between a physical network and a TCP/IP internet is strong, the unit of transfer is a frame that contains a header and data. The header gives information such as the (physical ) source and destination addresses. The internet calls its basic transfer unit an Internet datagram.

NETWORK MANAGEMENT DATAGRAM DATA AREADATAGRAM HEADER The figure below shows a typical IP DATAGRAM

NETWORK MANAGEMENT DATAGRAM FORMAT

NETWORK MANAGEMENT VERS 4 bit in length contains the version of IP HLEN 4 bits in length, gives the datagram header length measured in 32-bit words. All fields in the header have fixed length except for the IP OPTIONS and corresponding PADDING filed. The most common header which contains no options and no padding, measures 20 octets and has a header length field equal to 5. TOTAL LENGTH field gives the length of the IP datagram measured in octets, including octets in the header and data. TOTAL LENGTH field is 16 bits long, the maximum possible size of an IP datagram is 65,535 octets.

NETWORK MANAGEMENT Datagram type of Service and Differentiated Services Informally called type of service TOS, the 8-bit Service Type filed specifies how the datagram should be handled. Figure in the next slide defines the filed.

NETWORK MANAGEMENT Datagram type of Service and Differentiated Services

NETWORK MANAGEMENT I t is possible to define 64 separate services. Designers tell that a router will need only a few services, and multiple codepoints will map to each service.