Step One: Survey Your Existing Data Transport

The top challenge in your SNMP implementation is making sure that you have enough bandwidth for SNMP traffic going to all your remote sites.

So the first step in your network assessment is to examine your present telemetry network map. You need to identify the existing transport that's currently in place and determine if any adjustments need to be made for SNMP monitoring.

Your goal here is to collect the information you need to create a new network drawing that represents the transport you'll need to deploy in order to support SNMP monitoring. This new map will be your guide to planning your transport upgrades.

The ideal transport for SNMP data is LAN - but in most cases, your LAN is not going to extend to all your remote sites.

If no LAN connection is available, you do have other options. You can also send SNMP data over an order wire, a radio overhead channel, a channel bank, or PPP over a dial-up or direct link.

The key question for all of these alternative transports is this: Do they provide sufficient bandwidth? UDP packets are small, and most SNMP traps are small, so you don't need a huge amount of bandwidth, but there has to be enough for your probable amount of network traffic.

Insufficient bandwidth is going to increase latency and reduce response time. Medium-bandwidth transport might be OK, but smaller bandwidths are going to be clearly inappropriate for mission-critical network alarm monitoring.

You should be very careful about using lower-bandwidth transports like 202 channels or serial links. These connections should be analyzed for their speed and capacity before being certified for SNMP traffic.

You should also watch out for communications links that involve multiple conversions from one type of transport to another. These will also increase the latency of your SNMP monitoring.

At any site where the currently available data transport is less than optimum, you're going to have to consider upgrading to a higher-bandwidth connection.

By the time you have completed your transport survey, you can divide your sites and their existing communication links into four categories:

  1. Sites that have transport that is already adequate for SNMP traffic.
  2. Sites whose data traffic can be re-routed from low-bandwidth transport to high-bandwidth transport.
  3. Sites that can be economically upgraded to bandwidth adequate for SNMP traffic.
  4. Sites that cannot be easily or cheaply upgraded to high-bandwidth or LAN traffic. (This is a serious potential pitfall; please see "High Costs of Migrating Remote Sites to LAN,")

Using this information, you can now redraw your telemetry network map to represent how your transport network needs to look for SNMP monitoring. This updated map will be your guide to systematically and efficiently upgrading your transport network.