On Tue, 21 November 2000, John Leong wrote:

Curious if any operator uses, or have interest in using, out of band network (e.g. modem, wireless etc.) for remote equipment (routers, switches, HVAC etc.) monitoring over and above doing it in band on the Internet.

I expect all providers, major and minor, will answer they do. However, this is one of those questions where everyone knows exactly what they mean, but they may not mean what you think. Some providers have a dedicated management network, independent of the IP network, connected to all of their equipment: building, network, security, servers, etc. Some providers have a dedicated management network connected just to their primary network boxes: routers, servers. Some use it for monitoring and maintenance, others only for repair and maintenance. Some providers have dialup (POTS) access connected to a management port for maintenance and repair of a few critical pieces of equipment, but not regularly used for monitoring. Some providers have distributed systems which monitors local equipment and send pages to local technicians. Other providers centralize this function in a single (and sometimes a backup) NOC. The most common system uses an in-band method (normally SNMP and PING) for monitoring and maintaining the network. An out-of-band method (normally POTS to console modems) is used for network repair activities. Building systems (HVAC, UPS, Fire, Security, etc) have some in-band monitoring, but alarms are generally sent by seperate out-of-band networks. A lot of times the decision is based on what types of systems a provider already had in place. But part of the difference may be due to the different accounting and revenue practices. In reality the distinction between "in-band" and "out-of-band" is artificial. The "in-band" network may be considered the revenue-generating or production network; while the "out-of-band" network is the network which doesn't generate revenue. They frequently aren't as seperate or independent as folks may think. The out-of-band network is often just a chunk of bandwidth you aren't using for revenue generating traffic.