Because it is easy to use and inexpensive, SNMP (the Simple Network Management Protocol) network management is the industry choice for managing wide area and local area networks. But this form of In Band Management via the network has one serious disadvantage.
SNMP management information travels the same network path as your data, using the same WAN and LAN routers, hubs, and communications links. This means that if your network is the issue, communication via SNMP will be subject to the same problems your network is experiencing. Compounding that, any secure information you may be loading into your remote device (like passwords, keys, or ID’s) are exposed to interception and cannot be considered absolutely secure.
When the network goes down or is severely disrupted, SNMP traffic cannot act as a bridge between the affected device and the management workstation. Any time the network connection is down, all forms of In-Band Management are useless.