Lec4: TCP/IP, Network management model, Agent architectures Organized by: Nada Alhirabi NET 311 Lec4: TCP/IP, Network management model, Agent architectures Some of the slides from : COMP4690, by Dr Xiaowen Chu, HKBU

Protocol Architecture A protocol architecture is the layered structure of hardware and software that supports the exchange of data between systems and supports distributed applications, such as electronic mail and file transfer. At each layer of a protocol architecture, one or more common protocols are implemented in communicating systems. Each protocol provides a set of rules for the exchange of data between systems.

OSI Reference Model OSI: Open System Interconnection A 7-layer model Each layer performs a subset of the required communication functions Each layer relies on the next lower layer to perform more primitive functions Each layer provides services to the next higher layer Changes in one layer should not require changes in other layers

OSI Reference Model Application: supporting network applications - FTP, SMTP, HTTP, etc. Presentation: handle different data representations (e.g., encryption) Session: connections between apps Transport: host-host - TCP, UDP Network: routing of datagrams from source to dest - IP, routing protocols Link: data transfer between adjacent network elements - PPP, Ethernet Physical: bits “on the wire” Application (7) Presentation (6) Session (5) Transport (4) Network (3) Data link (2) Physical (1)

OSI Layers Physical Data Link Physical interface between devices Mechanical Electrical Functional Procedural Data Link Means of activating, maintaining and deactivating a reliable link Error detection and control Higher layers may assume error free transmission

OSI Layers Network Transport Transport of information Higher layers do not need to know about underlying technology Not needed on direct links Transport Exchange of data between end systems Error free In sequence No losses No duplicates Quality of service

OSI Layers Session Presentation Application Control of dialogues between applications Dialogue discipline Grouping Recovery Presentation Data formats and coding Data compression Encryption Application Means for applications to access OSI environment

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 Transport layer Internet layer (or Network Layer) Network access layer (or Link Layer) Physical layer

TCP/IP Protocol Architecture COMP4690, by Dr Xiaowen Chu, HKBU

TCP/IP Protocols COMP4690, by Dr Xiaowen Chu, HKBU

OSI vs. TCP/IP COMP4690, by Dr Xiaowen Chu, HKBU

TCP/IP An important protocol used widely on the Internet A routable protocol Supports communication with UNIX networks or any other network that work under the TCP/IP protocol The base protocol in UNIX networks is TCP/IP Can be used for configuring peer-to-peer as well as client-server networks of very large scale

A TCP/IP Application Scenario Lab The Internet Workstation Internet Router Local Router Workstation Configure the workstation for Internet access by Installing TCP/IP.

Basic TCP/IP Installation and Configuration Module Basic TCP/IP Installation and Configuration

TCP/IP Installation and Configuration A two-step process First, install the protocol With many modern OSs such as Windows XP, it is automatically installed Second, configure its properties When TCP/IP is automatically installed, the properties are set to be obtained from a DHCP server However, it is also possible to manually set the properties

TCP/IP Installation Steps Start Choose Network/ Properties From Network Neighborhood/ Properties. Install Protocol TCP/IP protocol installed. Add OK End Choose TCP/IP

Accessing the Window for TCP/IP Properties Under different Windows operating systems the TCP/IP properties are accessed in different ways The best and the most consistent way to access TCP/IP properties Windows is to go through the Control Panel and then select the Network Icon Another way to access the properties is to go through Network Neighborhood Thereafter, select the network properties (Based on the NIC) and then then continue to select the TCP/IP properties

Accessing TCP/IP Properties Tab Start Choose Network From Network Neighborhood/ Properties. TCP/IP/ Properties Proceed Define TCP/IP properties

Network Models

Architectural models for network management Network management architecture consists of three sections: Centralized: Consists of a key management station. Hierarchical : Consists of one main station at the center and various management stations distributed among the systems. Distributed: Consists of various stations for network management Distributed based on the geographic distance or function.

Centralized Management Model It is defined as a single network management system that runs network management applications and all the information are stored in a single centralized database. Examples: Open view (hp) net view (IBM) Sepctrum NM NM Network Management system Network Resource

Network Management Configuration Centralized vs distributed Centralized configuration COMP4690, by Dr Xiaowen Chu, HKBU

Network Management Configuration Centralized configuration One management station hosts NMS Remote monitors/probes on LAN segments Advantage: NMS has complete view Disadvantage: single point of failure COMP4690, by Dr Xiaowen Chu, HKBU

Advantages of the Centralized Management Model Facilitates decision making. Only single place is determined for network management. Easy access to the centralized database. Easy to expand and maintain the network. Highly secure.

Disadvantages of the Centralized Management Model In the case of failure in the network management, all the related network management systems will fail. Overloading the network management system due to the large amount of the exchanged information.

Network Management system Hierarchical model Hierarchical model is defined as a single network management system that manages various smaller network management systems that control network resources. Examples: Open view (hp) Cisco NM NM NM NM Network Management system Network Resource

B. Hierarchical Model (Cont.) Advantages: Distributing the load of the network. Distributing the load of managing the network. Bringing the network management systems closer to the managed network resources Disadvantages: High cost. Complicated and difficult in connection.

Distributed Management Model In this model network management systems are distributed on different indeterminate and in dependable places. Examples: CORBA(NCR) DCOM(Microsoft) NM NM NM NM NM Network Management system

Network Management Configuration Distributed configuration Each LAN has its own management station and a simple NMS One mgmt station/NMS manages the backbone and coordinates local NMSs Advantage: robust in case of failure Disadvantage: complexity, coordination

Network Management Configuration Distributed configuration COMP4690, by Dr Xiaowen Chu, HKBU

Distributed Management Model (Cont.) Advantages: Distributing the load on the entire network completely. Easy to expand the network. Reliable and consistent. Disadvantages: Very complicated. International standards are not yet defined. Low security.

Network Management Model Manager Management Stations Instructions Alerts Agent Managed Entity Resources MIB Management Information Base

Network Management Model (Cont.) Manager: A program that receives alerts from agents and sends instructions to them. Agents: A functional unit (Programs) located inside the managed devices (network resources) and provide management information to the devices and receives instructions to reconfigure the devices.

Network Management Model (Cont.) Managed Entity: The network devices (resources) that is managed and controlled. Management Information Base (MIB): A database of managed entities (resources) in the network and how they are accessed. Example: Remote Monitoring (Rmon) One of the most famous MIBs (management information bases) Used to monitor all the different components of LAN networks