NETWORK MANAGEMENT: A CAPSTONE DESIGN EXPERIENCE
Roger H. Brown
1
1
Roger H. Brown, Rensselaer At Hartford, Dept. of Engineering & Science, 275 Windsor St, Hartford, CT, 06120, [email protected] Abstract This paper describes a graduate course in
Network Management and its capstone project/design experience. First the paper introduces the objectives of Network Management and presents the characteristics and culminating features of the course assignments. We believe the network management project/design assignment is a valuable synthesizing opportunity and makes this a worthy capstone course in the Graduate Certificate program in Computer Network Communications. The Network Management course is offered by Rensselaer At Hartford and focuses on the essential aspects of monitoring, controlling and managing a significantly large enterprise network. The course encourages the computer science or engineering student to look at the bigger operational issues of network configuration, fault, performance, accounting and security management. The course and its design project span the disciplines of computer science, computer engineering, information technology and management. Second, the paper presents the project/design proposal requirements. Each student, working in groups of 2-4 students, is expected to prepare a proposal for network management systems and services for a hypothetical company that has medium-to-large size LANs and WAN networks. The requirements are open ended, and as a resulting benefit, the student teams explore contemporary management solutions as well as newer frontiers of object-oriented, web-based enterprise management. Th e paper concludes with an evaluation of the effectiveness of the project/design proposal assignment.
Index Terms capstone course, culminating experience, network management, project, proposal).
INTRODUCTION
Network Management in the context of real world telecommunications and digital networks is immense. In the telecommunications arena we have global or wide area network (WAN) infrastructures, made up of copper, fiber, satellite, and cellular or wireless communication channels, providing broadband data and voice services for many customers. WANs are international in scope and extent. Within the corporate or business environment we have local area networks (LANs) allowing each employee shared access to internal file servers, databases, application servers, email, etc. The LANs are connected to the WANs and everybody is connected to the “big I” Internet. It has been said that traditional companies known for voice and video communications are moving towards data communications. And at the same time, traditional data communication and computer companies are moving towards voice and video. It is a large, evolving, high technology field. The demands for network management systems and services are obvious.
Network Management in the context of a 3-credit, 15-week, graduate course must be more constrained. It is impossible to cover everything. The course and project work described herein applies to a course offered a Rensselaer At Hartford within the Computer Science and Computer Engineering graduate programs. The course has been offered for the past decade and has gone through several changes. We have changed because the protocols and the industry have changed and we have made changes to address the needs of the students. We have changed texts. In the past we have used Black [1], Feit [3], Hegering [4], Lieinwand and Fang [5], Miller [6], Rose [7], Stallings [8], Terplan [10], and most recently we have selected Subramanian [9]. Currently the course covers the operations management of the popular Internet or TCP/IP based networks more completely, while setting aside the management of the telecommunication (voice) networks.
The course is offered to computer science, computer engineering, and information technology graduate students. They have satisfied the prerequis ite courses - a minimum of the basic Computer Communication Networks course which is based on the 7 layer OSI model, and at least one additional follow-on advanced graduate course. Several advanced graduate courses are offered each year, giving the students the opportunity to have some background in local area networks (LANs), broadband or wide area networks (WANs), network analysis and design; or network security before embarking on a course in network management. While database is a critical part of managing information there is no expectation of background knowledge in relational or object oriented databases. Nor is there a prerequisite for software design or programming skills.
Define the Problem
Network management deals with the application of theories and principles of electrical engineering, computer engineering, computer science and information technology. Network management is not just limited to the data traffic of local and wide area networks, it also has roots in telecommunications, i.e. voice traffic. It is a broad subject. Many students are very new to concepts of managing a network and investigating the business or operational side of an enterprise network. The students will be challenged to broaden their knowledge of engineering and science, to include operations management.
To understand and to have some degree of comfort and confidence with the functions, tasks and operations of network management, it is essential that a student read as much as possible. So in essence, how can the course be structured that encourages reading without being dry and
unappealing. In addition, how can we structure assignments to allow each student to demonstrate their understanding of a newly acquired body of knowledge.
Possible Solutions
We could ask that students write a term paper on some aspect of network management, perhaps exploring a text chapter in more depth and integrating recent results found in ACM or IEEE journals or conference proceedings. While this would be a worthy assignment, perhaps traditional, it would not cause the student to study the topic of network management evenly or broadly. It would be an assignment with depth rather than breadth.
Idealy if we (students and faculty) could have a reasonably sized LAN coupled with a WAN, a network managment system console, many remote agents, with active traffic on the network, all at our finger tips, we could have quite the experience. However, such an “hands-on” opportunity is not the case on our campus. Our technical support staff do not want faculty or students managing, monitoring, controlling, adjusting, or fixing anything on the campus-wide network. Having a “crashable system” to experimentally manage is just not yet a realistic solution.
Give the students more quizes or exams in hopes that they will read and study more? Doubtful. If everybody is to take the same quiz or exam, then everybody must read the same set of articles, internet standards, and texts. Too much structure and not enough independent investigation.
Our choice is to assign a semes ter long project – a network management design experience We ask the students to work in groups of 2, 3, or 4 to investigate an “enterprise wide” networking infrastructure that is in need of network management systems and services (their problem) and propose a comprehensive solution. The project scope or specifications are constructed to encourage the following behaviors:
• reading beyond assigned text chapters;
• reading and application of internet standards documents;
• reading network vendor documentation; followed by
• writing and presenting a carefully thought out solution. In the sections that follow we present the content of the graduate level course in Network Management, the student design of a hypothetical enterprise network, followed by the scope and res ponsibilities of the Network Management Systems and Services Proposal that each project team will prepare and submit at the end of the semester.
NETWORK MANAGEMENT: C
OURSE CONTENT Terplan [10] provides an excellant definition of network management. He writes “Network management means deploying and coordinating resources in order to plan, operate, administer, analyze, evaluate, design, and expand communication networks to meet service level objectives at all times, at a reasonable cost, and with optimal capacity.” The definition sets the stage for the course and applies equally to an internet-based networking infrastructure as well as a “voice plus data” telecommunications network.Five Functional Areas
The Open Systems Interconnet (OSI) Reference model gave us a seven layer structure for organizing and defining a basic course in computer communication networks. Similarly, the International Organization for Standardization (ISO) for the OSI environment defines the following functional areas of network management.:
• Fault Management
• Configuration (and Name) Management
• Accounting Management
• Performance Management
• Security Management
The functional areas define the scope or topic areas of operational management that we wish to cover in our course in network management. As we explore each functional area we highlight the appropriate tools, applications, and supporting standards and protocols.
The Managed Object
As we begin, we define the concepts of a Managed Object (MO). A network may be managed by representing network resources as managed objects. Each MO is a data variable representing one aspect of the managed resource e.g. on/off status, number of packets sent, etc. A collection of MOs is called the MIB (Management Information Base), that is, a collection of access points at the agent(s) for the network management system (NMS). Monitoring equates to retrieving values from MIB objects in agents. Controlling equates to setting values within the MIB objects in agents.
MOs are standardized across systems. The Structure of Management Information (SMI) defines syntax (format) and semantics (meaning) of management information stored in the Management Information Base (MIB). Abstract Syntax One (ASN.1) is a formal language standardized by ITU-T (X.208 and X.680) and ISO 8824 that clarifies how data are arranged , what meaning they have and the expected data type. The transfer syntax is how data must be transformed before it is transferred over the network to/from agent and manager. The standard transfer syntax is Basic Encoding Rules (BER). Perhaps one of the more challenging tasks in the course is to give the student reading and writing experience in ASN.1 documentation.
Simple Network Management Protocol (SNMP) SNMP management, often called Internet management, is the mo st widely used network managment system [9]. The protocol(s) have matured and evolved into three revisions (SNMPv1, SNMPv2, SNMPv3) and is capable of managing more than just the Internet, as it is implemented in most network components in an enterprise network system. SNMP is the protocol to transfer messages to/from the agents and the managers. SNMPv1 and SNMPv2 is called “community based” with trivial security. It is used in many real networks as a read-only monitoring solution. We spend very little time on the international ISO and OSI standards in network management. Rather we spend more time on the study of the popular SNMP protocols and put more focus on
the security enhanced version 3 of SNMP. In version 3 we can truly authenticate and secure the exchange of messages to/from the manager and the agent. One inportant advantage is that the standard documentation for these standards, as shown in Table I, is readily availble, on the Internet, free of charge.
TABLE I
REQUEST FOR COMMENT (RFC): SNMPV3 STANDARDS
RFC Title Date
2571 An Architecture for Describing SNMP Management Frameworks
1999
2572 Message Processing and Dispatching for SNMP
1999
2573 SNMPv3 Applications 1999
2574 User-Based Security Model for SNMPv3
1999
2575 View-Based Access Control Model (VACM) for SNMP
1999
Remote Monitoring (RMON)
The RMON task or system is primarily a set of managed objects or MIBs and a methodology for monitoring the behavior of intranets, local area networks, traffic at the boundarie between LANs and WANs. RMON is a powerful tool for performance management where collected data can be presented in histograms and graphs to pictorial represent the network behavior. In addition, types of data traffic can monitored, answering the question: “which applications generate the most traffic?”
TABLE II
REQUEST FOR COMMENT (RFC): RMON 1 AND RMON 2 STANDARDS
RFC Title Date
1757 Remote Network Monitoring Management Information Base (RMON MIB)
Feb 1995
2021 Remote Network Monitoring
Management Information Base Version 2 (RMON2 MIB) using SMIv2
Jan 1997
Hardware / Software Management Tools
Management tools are necessary for troubleshooting a network. Engineers and operations personnel involved in fault management use tools on a daily basis. Some examples of tools discussed in class include:
• Bit Error Rate Testing
• UNIX Status monitoring (ifconfig, ping, nslookup, dig)
• Route Monitoring (netstat, traceroute)
• SNMP MIB browsers
• Protocol analyzers and network sniffers. Network Management Architecture
Starting with SNMPv1 protocol, the expected architecture of a Network Management System (NMS) is one manager and many agents. The manager is the centralized point of monitoring and control. The agents are
“software entites” that are installed in routers, switches, hosts, servers, interfa ces, and other network elements that are responsible for maintaining the local MIB, i.e. the many managed objects (MOs) and their current values. Simple architectures have the manager polling the agents (GetRequests) and agents providing (Get Responses) management data when asked. To reduce the burden of polling all network managment information, a policy of trap directed polling is implemented in the simple architecture. Traps are unsolicited messages from the agents to the manager when conditions warrant special notification. More complicated distributed architectures are possible using a hierarchy of agents, managers, and manager-of-managers. Independant systems of remote monitoring using the RMON MIB can be added to capture events, collect data, for fu rther off-line analysis.
Other Directions in Network Management
To explore all of the material discussed above requires a full semester. Many other topics exist within the realm of network management. We have tried to broaden the scope of the course and in clude the ISO standards of network management: Common Management Information Protocol (CMIP), Common Management Information Services (CMIS) and the corresponding object-oriented model of managed objects, Common Information Model (CIM).
In the last lecture, we introduce the concepts of desktop management and the Web-based Enterprise Management architecture. This leads to the introduction of Java Management Extensions. Regrettably more time is required to do justice to this new and expanding topic area.
ROLE
-PLAY
: STUDENTS DEFINE AND
DESIGN A NETWORK
Within the first two weeks of the semester each team is required to define an enterprise network for a large company. The company might have several divisions (each with an internal LAN) and at different locations (requiring wide area network connectivity). At one or more locations the company would have a connection to the Internet (global connectivity) and a web server to support their customer base. A simple “top-level” topology is shown in Figure 1. The more adventurous team might include wireless communications, satellite communications, dial-up remote access, “voice over IP, ” and/or virtual private networks (VPNs) with external vendors, clients, or partners.
They must select the technologies used for lo cal area networks (e.g. 10M 100M and/or 1000M Ethernet) and for a wide area network (e.g. ATM, Frame Relay). The network protocol stack of choice is TCP/IP since it is an open standard and supported by many vendors and computer platforms. TCP/IP is the practical choice when one looks ahead and sees that their managment solution will be SNMP-based.
The local sites must have several hundred users (clients) and/or servers (files, applications, database) such that the internal LAN design would require switches or internal
routers. Each local site would maintain connections with their external divisions (remote locations) via a wide area network service or dedicated leased lines and satellite connections. The students are encouraged to specify the flow of data (data, voice, multimedia, etc) within the divisions, division to division, and with external global customers, vendors, or partners. When students assert the flow and throughput of data on their hypothetical enterprise network then each team is more likely to design a more realistic network. In addition, each team must give some thought to scalability, we suggest that the company might “buy up” a small company and asked to integrate additional users and their subnets, file servers, applications, etc.
Division B Division A
Private WAN Internet
Division C Division D
FIGURE. 1
TOP-LEVEL TOPOLOGY OF AN ENTERPRISE NETWORK
Define the Extent and Size
Each team submits their network topology design for review and evaluation at the end of the second week of the semester. We look at each design and assess whether the proposed topology can be easily managed using the SNMP protocols, standard MIBs and RMON. That is, we wish to avoid proposing a relatively obscure technology, or a very new technology with a limited customer base. We want to be sure that the team will likely find management resource definitions in the text, in the Internet standards, at vendor
sites (e.g. Cisco) or by searching the web. The topology should not be trivial, rather it should be reasonably challenging and in need of a comprehensive network management solution. That is, the proposed network design must be extensive, both local and wide, and utilize at least three different physical layer technologies. Yet, not so complicated that it would require many different tools, extensive databases, and many MIBs.
Hypothetical Management Consulting Company Here is where the project group takes on the role of a consulting company. Project teams of 2 to 4 students assume that the network they have defined and designed needs to be effectively managed. Students are asked to prepare a comprehensive proposal for Network Management Systems and Services ( i.e. "managing") for a hypothetical company which has medium-to-large size LAN and WAN network.
What is expected is a total network management solution. Focusing on tasks to be performed from the five functional areas, hardware systems, tools and software applications rather than the cost of the proposed solution. That is, I do not believe that many project teams, certainly not every team, would be able to get enough costin g information to put a bottom line cost figure on the proposal. I have seen students try to contact vendors with hopes of getting pricing information, but once the “real-world” vendor realizes they are talking to a student and that there is no hope of a s ale – silence follows and the phone goes dead.
SCOPE OF THE PROPOSAL
The project teams are presented with a topical outline for their Network Management Systems and Services Proposal. The benefits are twofold. First, the students are given a clear idea, setting the expectations, of the basic structure of the proposal. Students are encouraged to add more subheadings and expand the Appendices as needed. Secondly, the outline structure provides a checklist for grading the ultimate project report.
As stated ealier, students are asked to form 2, 3, or 4 person teams. We strive for the ideal combination of talents and experience. That is, there is diversity in prerequisite knowledge, some students have taken the advanced graduate course on LANs while others have taken the course on Broadband Networks. Some have taken the course on Network Security and others have taken the Network Analysis and Design course.
Division of Responsibilities
If the project team is a 2-person team then the following division of labor or responsibilities are suggested:
• Students A and B hold joint responsibility for the network design, topology, technology selection, and Configuration Management
• Student A is the responsible lead for Fault and Security Management
• Student B is the responsible lead for Performance and Accounting Management
A 2-person team has the most obvious advantage that they cannot meet and leave another team member out of the conversation or decisions. If this course is offered by distance education, then a two person team is easily set up and if necessary, a single student working alone can complete a little more than half of the proposal, as Student A or B, and be graded accordingly.
If the project team is a 4-person team then the following division of labor or responsibilities are suggested:
• All team members hold joint responsibility for the network design, topology, technology selection, and Configuration Management and Appendices/Examples.
• Student A is responsible for Fault Management
• Student B is responsible for Security Management
• Student C is responsible for Performance Management
• Student D is responsible for Accounting Management Network Management System and Services Outline
• Introduction and Company Overview
• Configuration Management o Network Topology o System Architecture § Location of NM Managers § Location of Agents o Configuration Databases
o Standard vs. private MIBs
o Distributed and/or Centralized
o Data storage requirements. What is stored? Frequency of updates? Histories?
o NM Application Software and GUI Displays
o Staffing requirements and organizational structure
• Fault Management
o Monitoring Policy, e.g. Traps vs. Polling
o Required MIBs for Fault Management
o Use of RMON for Fault Prediction, Detection and/or Event Notification.
o Alarm filtering and correlation techniques.
o Trouble-ticket systems/software
o Staffing requirements and organizational structure
• Security Management
o Securing Network Access Points & Security Policies
o Client/server authentication
o Manager/agent authentication and confidentiality Using SNMPv3
§ Context and Access control.
§ MIB views: Read and/or Read/Write Access
o Required MIBs for Security Management
o Key and password management
o Staffing requirements and organizational structure
• Performance Management o RMON Stations and Probes
o MIBs implemented.for Performance Management
o Baseline monitoring and trend analysis
o Network Availability and Usage.
o Alarms and exception reporting
o Planning for growth: Capacity, utilization, trends, etc.
o Estimate percent bandwidth requirements just for network management traffic.
o Staffing requirements and organizational structure
• Accounting Management
o Traffic Monitoring and capacity analysis
o Hardware vs. software implementations
o RMON Stations
o MIBs implemented for Accounting
o Service level agreements and monitoring and Reporting
o Staffing requirements and organizational structure
• Appendices
o Standard MIBs installed at network management stations and at typical agents
o Vendor MIBs installed at various agents/stations
• Examples
o MIB Table management (e.g. Adding/deleting rows)
o Data collection of both scalars and tables using, GET, Get-Next, and the Get-Bulk commands.
o Typical PDU field assignemnts and transfer syntax BER
EVALUATION AND INTROSPECTION
When we examine the Network Management course, as offered at Rensselaer At Hartford, we truly see a capstone course. Clearly students who attempt the course without the prerequisite knowledge are ill-prepared to contribute to the project and we would expect that their fellow team members are dissapointed with that student’s ability to discuss wisely the design and management of a significant network infrastructure. The catalog description merely states that the basic course in computer network communications is a prerequisite. However, word of mouth (i.e the students agree) and faculty advisors know that at least one additional advanced graduate elective in the field of networking is strongly desired.
In addition, Network Management is listed as the last course to be taken in the Graduate Certificate in Computer Network Communications [2]. A Graduate Certificate is a 12-credit focused studies program.
Things Done Well
There are many things that are done well in this course on network management as indicated from course evaluations and dicussions with students who have completed the network certificate program. Included in the list of things done well are:
• An appreciation and respect for the SNMP protocols. Although simple, they are sold on the strength of the SNMPv3 archtitecture and protocols.
• ASN.1 language. Students have working knowledge of ASN.1 as it is used to define the many managed objects and MIB modules.
• A distributed network management system architecture. Students appreciate the inter-relationships of managers, agents, and RMON probes.
• A better appreciation of the business side of network management. Rather than just lust learning and evaluating the fastest or newest network technologies, the student is now more aware of the needs of the user (service oriented goals) and needs of the business to have efficient or effective netweork (utilization and availability goals).
• Newly found sources of information about their world of networking. Students, while researching and compiling information for their proposal, have come in contact with more of the scholarly literature, more of the trade and commercial literature, and sources of standards.
• Use of the standards within commercial network management products.
• Network management is put into a positive light. Students preparing a proposal must focus on the positive advantages of their network management solution. I think many students complete the course with a positive outlook on management.
• Opens new job opportunities. Several students have made use of their resulting project proposal as an “engineer or scientists” portfolio. They have carried a copy of their report with them to a job interview and have used it successfully as a topic of discussion with their potential new employer.
Things That Need More Attention
If the class is dominated by younger students without the real-world work experience, then most project teams struggle with the scope of a network management “proposal.” They ask, what do we put into a proposal? Although the propsal outline is given, putting the meat on the project remains a challenge.
To make the project experience more efficient, the course web page should grow to include links to newly discovered resources of network management information. For example, vendor specific MIBs, network management applications software, graphical user interface information, data presentation techniques should be added to the list of hot links.
If the course should make use of WebCT [11] then more guidance should be given to its navigation, use of chat rooms, and team interaction.
CONCLUSIONS AND FUTURE WORK
By asking the students to role -play as network management consultants and prepare a comprehensive management proposal for a sizeable enterprise network, their reading outside of class has become more focused and beneficial. Students now read with a goal in mind; the project gives purpose to their reading. Since the students are really in control of the content of the proposal they can selectively read to fill their assignments. Compare this to the general notion of “Here read all of this and I (the teacher) will ask exam questions based on those readings.”
The primary focus on an SNMP-based network with RMON has been successful. Students are able to get to the standards information since it is readily available on the Internet and integrate the standard protocols with the five functional area of operational management.
In previous years, the broader approach, covering both the Internet-centric networks and the telecommunication networks has proven to be difficult. Neither the students nor the instructor have been able to give both a balanced treatment. And there is natural leaning towards SNMP since more resources are available for their studies and for the project assignment.
As an area for further course development, the concepts of case-based learning should be explored. Case studies may not replace the successful project/proposal, rather we could consider more intereaction during class time to discuss real-world examples. We could gain experience through the lives of others in the field of network management.
REFERENCES
[1] Black, U., Network Management Standards: SNMP, CMIP, TMN, MIBs and Object Libraries, 2nd ed. New York: McGraw-Hill, (1995). [2] Brown, R.H., “A Graduate Certificate in Computer Network
Communications,” 30th ASEE/IEEE Frontiers in Education Conference, Kansas City, MO, October 2000.
[3] Feit, S., SNMP: A Guide to Network Management. New York: McGraw-Hill, (1995).
[4] Hegering, H.-G., S. Abeck, and B. Neumair, Integrated Management of Networked Systems. San Francisco, CA: Morgan Kaufmann, (1999).
[5] Leinwand, A. and K. Fang Conroy, Network Management: A Practical Perspective, 2nd ed. Reading, MA: Addison-Wesley, (1996).
[6] Miller, M. A., Managing Internetworks with SNMP, 2nd ed. New York: M&T Books, (1997).
[7] Rose, M. T., The Simple Book: An Introduction to Management of TCP/IP Based Internets, 2nd ed. Englewood Cliffs, NJ: Prentice-Hall, (1994).
[8] Stallings, W., SNMP, SNMPv2, SNMPv3 and RMON 1 and 2, 3rd ed. Reading, MA: Addison-Wesley, (1999).
[9] Subramanian, M., Network Management: Principles and Practice. Reading, MA: Addison-Wesley, (2000).
[10] Terplan, K., Communications Network Management, 2nd ed. Englewood Cliffs, NJ: Prentice-Hall, (1992).
