By Sachin Kumar Korenga & Rochita Thakkallapally Wireless Local Area Network Wireless LAN Management For Device Monitoring By Sachin Kumar Korenga & Rochita Thakkallapally

Introduction One of the fastest growing sectors in telecommunication and network industry is WLAN. According to a news the number of Americans using public WLANs in 2007 were 21,000,000+(millions). The advantages of WLAN over wired networks are (management of such wireless network are challenging.) Hierarchical topology of WLAN (Mobile Units associate with Access Point). MUs roaming from one AP to another. Many MUs don't have SNMP agent installed because of resource limitations. Security problems.

Wireless LAN Management : WLAN networks under IEEE 802.11a, b and g standards introduce new challenges in network management. Data quality maintenance, and signal strength assurance, authentication, network statistics data collection this are the challenges. 802.11: 802.11 works utilizing the Transmission Control Protocol/Internet Protocol (TCP/IP). 802.11 protocol is that it was intended to work in the 2.4 GHz Industrial-Scientific-Medical band. The 802.11 protocol characterizes a medium access control (MAC) layer, a MAC management and services layer, and 3 physical layers.

802.11b: 802.11b backings data transmission up to 11 Mbps, comparable to traditional Ethernet. 802.11b uses the same unregulated radio signalling frequency (2.4 GHz) as the first 802.11 standard. The 802.11b standard has more similitude's to the 802.11 standard by keeping up a similar MAC and interface utilizing a similar frequency band, 2.4 GHz ISM band. 802.11a: While 802.11b was in development, IEEE created a second extension to the original 802.11 standard called 802.11a. Because of its higher cost, 802.11a is generally found on business systems while 802.11b better serves the home market. 802.11a backings data transmission up to 54 Mbps and signals in a regulated frequency range around 5 GHz.

This higher frequency contrasted with 802. 11b shortens the range 802 This higher frequency contrasted with 802.11b shortens the range 802.11a systems. This standard was produced to offer higher data. 802.11g: The 802.11g standard was discharge in 2002 by the IEEE, characterizing new data rates up to 54 Mbps. Once more, there was no change to the MAC and interface layers of the 802.11 standard with the frequency band staying in the 2.4 GHz ISM band. 802.11g backings bandwidth up to 54 Mbps, and it utilizes the 2.4 GHz recurrence for more higher range.

Limitations : In today’s wireless networks, 802.11b and 802.11g are the two most common technologies used by enterprises and service providers for wireless user coverage. Radio interference is a serious issue that affects the performance of any wireless network. Radio interference can also cause transmission errors. In general WLAN management system will provide Configuration management. Performance management . Real-time monitoring. Fault management. Security management.

Simple Network Management Protocol All vendors of network-based components, computers, ridges, routers, switches. etc.. offer SNMP. There are three versions of SNMP current existing SNMP1, SNMP2 and SNMP3. Three key components of SNMP 1)Network management system (NMS) 2)Management agent 3)Management Information Base(MIB)

Existing NMSs Evaluation Some interesting management tools and software packages are introduced recently for WLAN applications i.e., Cisco Works by Cisco Systems, AMP by Airwave. The ideal candidate for the wireless NMS demands Open source Easy portable to multiple platforms especially linux Implemented in java and XML. OpenNMS Analysis Three main functional areas Determine the node and service availability provided by all the host of network Gather performance data from its monitored devices if these devices have a SNMP agent on it and store data in Round-Robin Database(RRD) Provide event management and notification system to monitor the changes happened in the network.

OpenNMS Architechture SNMP Data Collection System administrator configured XML files before the openNMS starts. Start OpenNMS and discover, daemon will retrieve IP information from configuration files. Discover checks node/interface table to see if the IP information already in it or not.

4. Discovery ping network to see if the non exiting IP address valid or not. 5. If the host exists generate a New Suspect event and send to both capsed and eventd. 6. Then capsd checks whether the device supports SNMP, and updates the information in database. 7. If the SNMP is supported, both eventd and collectd daemon will be notified. 8. If SNMP is supported, collector will retrieve MIBs information from host using SNMP get, set, etc. 9. Stores the event information in the event table. Lastly, user may review event information using web browser.

Association Data Storing: OpenNMS Limitations: It cant represent the tiered network structure of wireless local network such as how many mobile devices is associated with an access point and which device is associated with a specific access point. It cant monitor the performance of the devices because many mobile devices doesnt support SNMP. Association Data Storing: OpenNMS stores collected data into RRD repository. AP Information Collection: Collect data from monitored devices, calls SnmpCollector program to collect SNMP data from SNM supported devices.

Authentication: Authentication operation is achieved by set the AP's security MIB category.

Notification: Conclusion: If the performance of WLAN drops, an alert message will be sent to any devices which are aware of wireless devices performance. Conclusion: we have describe 802.11 protocol type, some wireless technology and there limitations, implementation of NMS based WLAN management technology which is based on openNMS framework.

Thank you.