1. Capacity

This is a basic question you should ask about all alarm collection equipment: can the device provide adequate coverage for your remote site?

Before you select equipment, develop a capacity profile for each of your remote sites. Think in terms of alarm inputs, not devices. How many contact closure inputs are at each site? How many analog inputs?

Your capacity profile will tell you whether you need a large, medium, or light-capacity proxy device. Proxy devices are available in different capacities, so don't feel like you're locked in with a one-size-fits-all solution.

Get the capacity you need, but don't overspend. Adequate coverage of your remote sites is a must-unmonitored equipment is a breeding ground for disasters-but there's no point in breaking your budget for capacity you won't use.

If you have sites that have a small number of alarms now, but are likely to grow in the future, be sure to ask equipment vendors if their proxy devices have expansion capabilities.

2. Dial-Up Backup

SNMP with Dial-up

LAN transport is highly reliable, but that doesn't mean it's 100% reliable. For mission-critical telemetry data, you always need a backup data path.

Look for a proxy device that includes dial-up modem capability, to give you continued visibility of your remote site even during a LAN failure.

A proxy device with dial-up capability is also the ideal way to integrate remote sites without LAN access into your SNMP monitoring. This eliminates the extra costs and inefficiencies of maintaining two separate monitoring systems, and you can add LAN to your sites later without replacing any monitoring equipment.


Redundant Power Supplies

3. Redundant Power Supplies

With all monitoring applications, redundant power is a must. Your monitoring devices have to be the most reliable elements in your network if they are to protect your revenue-generating equipment.

Look for a proxy device with dual power inputs. If one power supply fails, you'll have another on reserve-ensuring that you have continued visibility of mission-critical equipment.

Extra Features

4. Extra Features

The best quality proxy devices will support additional features for managing your remote sites. This saves money, because you don't need to buy extra equipment, and it gives you a simple, one-platform solution for managing every part of your remote site.

Some of the extra features you should look for in a top-quality proxy device include:

Terminal Server Functionality: Your proxy device can host remote Telnet sessions to interface with the craft ports of on-site telephony equipment like PBXs, switches, and routers. This gives you easy LAN access for configuring and rebooting equipment, saving a fortune in windshield time.

Ping Alarms: Your proxy device can also make sure that your IP network elements are operational, by regularly pinging their IP addresses. If a network device fails to respond to a ping, the proxy device will immediately send an SNMP trap to the SNMP manager.

Protocol Mediation: You may have additional remote site equipment that supports a classic telemetry protocol such as TBOS or TABS. Alarm output from these devices can be mediated to SNMP traps.


5. Vendor Support and Expertise

The most important features to look for in a proxy device is the vendor who stands behind the product. When you're evaluating vendors, be sure to look for two essential commitments.

Full Support for the Lifetime of the Unit: Monitoring equipment stays in the field a long time-an average of 7-8 years, or even longer in some industries. You want to make sure you have continued support during that time.

In the last decade, many monitoring equipment vendors, including some big companies and well-respected names, have dropped support for their older equipment-or in some cases gone out of business entirely.

When choosing your proxy agent, make sure the vendor is committed to you for the long haul.

Expert Consultation: Monitoring is a complex business. Network managers burdened with responsibilities can't make telemetry their full-time job.

As with any complex technology, you need to know telemetry thoroughly to design an optimal system-one that meets your network's needs, won't become obsolete tomorrow, and doesn't break your budget with unnecessary expense.

Select a vendor with a proven track record of expertise and client support, who is willing to take the time to listen to your needs, learn about your network-and give you free advice that's in your best interest.