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Saturday, May 5, 2007
Network technology has come a long way from the days of hubs and 10 BaseT Ethernet to complex multi-layered networks carrying voice, video and data. It is seen that with emergence of technologies such as VoIP, VPN, MPLS backbones and Wireless LANs, most organizations have adopted these technologies for the benefit they offer. It is also seen that organizations are looking for best-of-breed solutions leading to multi-vendor networks over a period of time. Add to that, a complex myriad of technologies and the network becomes a nightmare for the CIO to manage and maintain. Most CIOs are looking for panacea in network management solutions that will assist their teams in ensuring that the network is always available and performing optimally. Network management gurus typically use the acronym FCAPS (Fault/Configuration/Accounting/Performance/Security) which more or less sums up the challenges of network management and expectations from a network management tool.
FAULT MANAGEMENT
Almost all network devices today are manageable (ie they have an intelligent SNMP agent installed). This capability makes it very easy for a network management system to discover and classify the device. In addition, the SNMP agent provides additional information about the current status and connectivity with other devices.
Fault management systems (FMS) are able to discover and model the topology of complex network environments based on SNMP and other technologies (Routing tables, ARP caches etc). They are able to poll devices and receive traps to correctly depict the status on the topology map. In addition, these solutions allow capabilities to automate response to common events, the response typically being e-mail/SMS notifications, incident registration to a service desk or running custom scripts. Such detailed information helps administrators diagnose problems faster leading to reduced mean time to repair.
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To understand device connectivity (at Layer 2 and 3)
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To ensure the network is up and running
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Proactively locate faults in the network and rectify them before they impact end-users
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To reduce the number of symptomatic network
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Handling faults as 'Incidents' (as per ITIL best practice recommendations) and track the same till resolution
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Advanced fault management systems offer the most useful functionality of event correlation and root cause analysis. This system typically comprises in-built correlation logic and rule sets to correlate multiple incoming events and provide a possible single root-cause. This allows administrators to understand and diagnose network problems faster as compared to chasing events that are symptomatic. For example, when an upstream device goes down, all connected downstream device polls will generate failure messages.
Another common function that advanced fault management systems perform today is mapping discovered IT infrastructure to IT services. SLAs (based on availability and response times) can be attached to the IT services rather than individual elements. This allows administrators to understand the impact of a failing component on IT services and the relevant SLA that are affected.
CONFIGURATION MANAGEMENT
Configuration management is a process that covers a wider range of IT infrastructure and is not restricted only to network devices. Configuration changes on network devices are required for a wide variety of reasons including adding new boards to existing devices, firmware upgrades, manual addition/removal of routes on a router etc. Configuration management mandates that such changes be made only after relevant approvals from the CAB (Change Advisory Board) or similar approving authority. This is done so that the impact of the change on various IT and Business Services can be studied before actually performing the change. Rollback procedures are also defined to minimize disruption to services in case something goes wrong.
| Challenges Addressed |
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Being able to identify performance bottlenecks in complex networks
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Identification of baseline behavior of the network with alerts only if the performance is abnormal
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Catering to performance management for various subcomponents of the network including utilization, response time, error rates etc
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Being able to proactively fix performance related issues with impact analysis
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Configuration management solutions are also capable of reading device configuration at periodic intervals and comparing it to the deployed image to check for changes. Changes (if any) can be reported to the fault management system and automated actions such as redeploying the original image can be initiated. It is also important to ensure that unauthorized changes to device configurations do not take place (by deploying stricter access control on network devices).
ACCOUNTING MANAGEMENT
The primary challenges addressed by accounting management are-tracking network utilization by application/end-user/department for the purpose of chargeback; allocate appropriate network resources for business critical applications/departments
Accounting management involves tracking each individual user's utilization of network resources for the purposes of allocation of resources and billing for their use of the network. This type of information helps a network manager allocate the right kind of resources to users, as well as plan for network growth. With the same information, the cost of transmitting messages across the network can be computed and billed to the user if the traffic was revenue bearing.
 This type of management involves monitoring the login and logoff records, and checking the network usage to determine a user's use of the network. In addition, access privileges and usage quotas can be established and checked against actual for accounting information.
Technology used for accounting management typically involves probes/flow records to collect raw data related to traffic segregated by user/application. This data is collected, analyzed and appropriate reports are created to indicate the network resource usage. Accounting tools go a step further by analyzing the collected data and providing billing invoices to business units based on pre-defined chargeback information.
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