Out of Band Access FAQ

What is Out of band access?

Out of band access is an important tool that allows you to gain access of equipment independent of the network connections. It essentially provides you with a backup path in case of network communication failure.

What is an example of out of band access?

An example of out of band access is a serial port connected to a modem that provides dial up access to the router.

Why is it important to have out of band access?

If you rely on any one data path to connect to your remote sites, you're running the risk that you'll lose communications and you'll have to send a tech to the site. This is why it is critical for your remote monitoring equipment to support out of band access. Two possible choices are LAN with dial-up backup or LAN with serial backup.

If I am using a serial connection as my primary alarm-reporting channel, do I still need a dial-up modem?

Even if you're using a serial connection as your primary alarm-reporting channel, a dial-up modem can still be a useful backup data path. If anything goes wrong with the serial connection, you can still receive alarms via dial-up reporting.

What is a downfall of using in band access as opposed to out of band access for SNMP management?

SNMP management information travels the same network path as your data. It uses the same WAN and LAN routers, hubs, and communications links. And there lies the problem. While the network is operating normally, SNMP packets flow between the managed devices and the management workstation with no problem. Its TRAPs, SETs, and GETs all flow with the same priority as regular traffic on the LAN/WAN and provide management information to the workstation or commands to the controlled devices. However, when the network goes down or is severely disrupted, SNMP traffic has no way to get between the managed device and the management workstation. Telnet is usually used in conjunction with an SNMP workstation. Telnet packets are also unable to move between the management workstation and managed devices during those network disruptions.

NetGuardian 832A's dial-up connection can be used as a primary or secondary path for reporting SNMP traps

How would out of band access provide a solution in communicating across an SNMP network?

With out of band access, a second path is available to the managed devices that do not depend on the LAN/WAN. It usually consists of an RS-232 access switch connected to the management port of each controlled device. Every network device that supports SNMP also contains a RS-232 management port. Although it doesn't provide the fancy GUI interface of most SNMP workstations, this method provides the native interface for each device being controlled.

Do the two methods (in-band SNMP and Out of Band access) compete with each other?

No, they compliment each other. System cost increases only slightly when adding out of band access management, while functionality increases quite dramatically. The SNMP GUI can be used for normal network monitoring and metrics, alarm reports, and data reduction. Then, when problems surface, you can connect to the remote access switch for direct control of your remote equipment. Since there is direct access to the management port, troubleshooting doesn't have the added complexity of a network coming between the device and the technician. And when the network is down, the same connectivity is still there. This provides a direct link between the technician and the device causing the problems.

Give Us a Call!

To find out more about this and other DPS applications, give us a call at our toll-free number and talk to one of our network specialists. They'll help you put together a perfect fit solution for your network!