Management interfaces allow network operators to manage network devices in their
networks. These interfaces generally provide the operator with a consistent operational
view of a device, including its configuration and operational status. A management
interface typically consists of two key elements: a protocol and a message format spec‐
ification. In the case of the protocol, this describes the syntax and semantics associated
with sending or receiving specific messages that either the manager or network element
generates. These messages often contain commands, queries, or responses to earlier
queries. In some cases, these messages can be emitted without a direct query—as is the
case with events (notifications) that are emitted asynchronously in response to some
event within the network element. The other key element of a management interface is
the message format and the meaning of those messages. Some management interfaces
define a data model that can be used as a directory of information available to the
network operator. In some cases, these can also be used to describe how a manager
might construct (or order) queries or commands between it and the device. The data
model also typically describes the relationship between manageable objects within the
system. For example, the system’s name might be kept in an object called sysName and
associated with another object called sysUpTime indicating the length of time the system
has been running. Both of these objects would be related in that they are contained
within the parent object called system, which represents the entire system.