Using the Simple Network Management Protocol

Networks used to be fairly straight forward affairs, you’d have some basic hardware like switches and hubs, a few servers and the rest would be the PCs which needed to talk to each other.  Normally you could buy all these from the same provider so you’d have some uniformity in hardware.  In fact the first network I worked on would only allow certain network cards in their PCs, the ones they had written specific profiles for.

However as technology has developed, the diversity of devices has risen exponentially and all of these devices need to be managed, configured and of course fixed if they go wrong.  Troubleshooting a large , complex network filled with all sorts of different devices from a myriad of manufacturers would be almost impossible to achieve without some tools and protocols to help.  One of the oldest and arguably still the most important is SNMP (Simple Network Management Protocol) which is part of the TCP/IP network management protocol.

TCP/IP Network Management consists of three core factors

Management Information Base (MIB) which will specify which variables the network elements maintain, an updated version of this is specified in MIB-II (RFC 1213)

Common structures and an identification scheme which relate specifically to all the variables which are defined in the MIB.  The full name of this is the Structure of Management Information (SMI).

The protocol that connects the manager and the element is called the Simple Network Management Protocol (SNMP) which details the format of the packets exchanged.  It should be noted that although many protocols are supported – SNMP is normally used with UDP on most networks.

At it’s core SNMP is actually fairly simple, for example it only uses five types of message to be exchanged between the manager and the agent.  However this is more than enough to manage and control all number of devices across a standard network.   It is useful on many levels and now many organisations use it remotely to manage devices all across the world.  Of course, this goes for troubleshooting as well and if you combine with a VPN like the Italian one in this video – RAI streaming Estero  you have a powerful tool for controlling and managing even wide area networks across different countries.

SNMP began it’s life simply being used on internal networks but now powerful suites like HP Openview have expanded this functionality.

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