FYI VPNs and SNMP

1. FYIVPNs and SNMP Tahir Azim Courtesy: Umar Kalim, NIIT

2. Virtual Private Networks Courtesy: Umar Kalim, NIIT

3. Private Networks • To be used inside the organization • Intranet: A private network whose access is only limited to the users inside the organization • Extranet • Same as the intranet, but with one addition • Some users outside the organization can also access (some or all) resources • Limitations defined by the network administrator Courtesy: Umar Kalim, NIIT

4. Achieving Privacy • A small organization can remain isolated • Single site • A large organization with multiple sites can have its private “internet” Courtesy: Umar Kalim, NIIT

5. Achieving Privacy in Hybrid Networks • Require privacy, but also need to connect to the Internet • Solution: Hybrid network Courtesy: Umar Kalim, NIIT

6. Drawbacks of Hybrid and Private Networks • Private & Hybrid Networks are very costly • Duplication of equipment • Leased lines for inter-site connectivity • Difficult to administer if Internet connectivity is required (as well as privacy) Courtesy: Umar Kalim, NIIT

7. Overview: Virtual Private Networks • Use the global Internet for Internet access as well as inter-site access, i.e. both public & private communication • R1 & R2 use VPN-tech. to guarantee privacy Courtesy: Umar Kalim, NIIT

8. What is a VPN? • A technology based on two techniques which guarantee privacy • Tunneling • Simple • TLS/SSL • IPSec • Authentication Header (AH) • Encrypted Security Payload (ESP) Courtesy: Umar Kalim, NIIT

9. Tunneling • VPN specifies that each IP datagram destined for a private use in the organization must be encapsulated inside another datagram Actual source and destination Routers connecting the two sites Courtesy: Umar Kalim, NIIT

10. Addressing in VPN Courtesy: Umar Kalim, NIIT

11. Simple Network Management Protocol Courtesy: Umar Kalim, NIIT

12. SNMP • A framework for managing devices in an internet using the TCP/IP protocol suite • It provides the fundamental operations for monitoring and maintaining an internet • Application level protocol • So that it may monitor devices made by different manufacturers, installed on different networks • Limitations of the type of the network as well as the type of the device is removed Courtesy: Umar Kalim, NIIT

13. Concept of SNMP • Uses the concept of a manager and an agent • Manager is the host that controls/monitors a (set of) agent(s) • Agents are hosts that are being monitored • Mostly routers Courtesy: Umar Kalim, NIIT

14. Manager and Agents • Manager runs the SNMP client • Agent runs the SNMP server • Management is achieved by the simple interaction b/w the client and the server • Agents maintain information about parameters affecting performance • e.g. # of packets received, # of packets forwarded etc • The Manager has access to these parameters • Manager can also have the agent perform certain actions • e.g. Reboot the router Courtesy: Umar Kalim, NIIT

15. Manager and Agents • Agents can also contribute to the management process • The server program checks the parameters for certain defined thresholds • If a threshold is reached, or there is some unusual activity, the agent sends a warning message (called a trap) to the manager Courtesy: Umar Kalim, NIIT

16. Concept of SNMP • Manager checks an agent by requesting information that reflects the behaviour of the agent • A manager can force an agent to perform a task (by resetting certain values in the agents database) • An agent can help in the management by generating trap messages/warning in case of an unusual activity Courtesy: Umar Kalim, NIIT

17. Management Components • SNMP uses two other protocols to achieve its objectives • Structure of Management Information (SMI) • Management Information Base (MIB) Courtesy: Umar Kalim, NIIT

18. Role of SNMP • It defines the format of the packet to be sent from a manager to an agent and vice versa • Packets exchanged contain object names and their status • SNMP is responsible for reading and changing these values • It interprets the results and creates statistics (often using other s/w) Courtesy: Umar Kalim, NIIT

19. Role of SMI • To use SNMP we require rules • To name objects using a uniform convention for open access • To define what type of objects can be used (simple or structured, which simple types are available, their sizes etc), again for open access • SMI defines such rules • How to define objects • How to list their types Courtesy: Umar Kalim, NIIT

20. Role of MIB • For each entity to be managed, we must define • The number of objects • Name them • Associate a type with each • MIB creates a collection of named objects, their types, and their relationships to each other in an entity to be managed Courtesy: Umar Kalim, NIIT

21. An Analogy to understand the relationship • Before we write a computer program, the syntax must be defined. Also, the available data types must be defined etc [SMI] • Declaration of variables in the program [MIB] • Write code to read, change the variables, interpret their meaning etc [SNMP] Courtesy: Umar Kalim, NIIT

22. Operational Overview Courtesy: Umar Kalim, NIIT

23. THE END! Good Luck! Courtesy: Umar Kalim, NIIT