Operations Manager can monitor physical network routers and switches, including the interfaces and ports on those devices, the virtual local area networks (VLANs) and Hot Standby Router Protocol (HSRP) groups that they participate in, and firewalls and load balancers. Operations Manager can monitor network devices that support a Simple Network Management Protocol (SNMP) and can provide port monitoring for devices that implement interface MIB (RFC 2863) and MIB-II (RFC 1213) standards.
Operations Manager provides the following monitoring for discovered network devices:
- Connection health - Based on looking at both
ends of a connection
- VLAN health - Based on health state of
switches in VLAN
- HSRP group health - Based on health state of
individual HSRP endpoints
- Port/Interface
- Up/down (operational and administrative
status)
- Volumes of inbound/outbound traffic (includes
abort, broadcast, carrier sense, collision, cyclic redundancy check
(CRC) rates, discard, error, Frame Check Sequence (FCS) error,
frame, giants, runts, ignored, MAC transmit/receive error, queue
rates)
- % Utilization
- Drop and broadcast rates
- Up/down (operational and administrative
status)
- Processor - % Utilization (for some certified
devices)
- Memory - including high utilization, high
buffer utilization, excessive fragmentation, and buffer allocation
failures (for some certified devices)
- In-depth memory counters (Cisco devices
only)
- Free memory
- In-depth memory counters (Cisco devices
only)
When you create a discovery rule, you designate a management server or gateway server to run the rule. Each management server or gateway server can run only one discovery rule. You might want to strategically place management servers on different network segments so that they can access the network devices that they are discovering.
Discovery rules run on a schedule that you can specify, and you can also run a rule on demand. Each time the discovery rule runs, it attempts to find new devices within its definition or changes to devices that were previously discovered. A discovery rule can perform explicit discovery or recursive discovery.
- Explicit discovery – An explicit
discovery rule only attempts to discover those devices that you
explicitly specify in the wizard by IP address or fully qualified
domain name (FQDN). It will only monitor those devices that it can
successfully access. The rule attempts to access the device by
using an Internet Control Message Protocol (ICMP), SNMP, or both
depending on the configuration of the rule.
- Recursive discovery – A recursive
discovery rule attempts to discover those devices that you
explicitly specify in the wizard by IP address, and other network
devices that are connected to the specified SNMP v1 or v2 device
and that the specified SNMP v1 or v2 device knows about through the
device’s Address Routing Protocol (ARP) table, its IP address
table, or the topology Management Information Block (MIB).
If you use recursive discovery, you can elect to discover all the other network devices that the specified SNMP v1 or v2 device knows about or only network devices that are connected to the specified SNMP v1 or v2 device and that are in a specified IP address range. You can also filter recursive discovery by using such properties as the device type, name, and object identifier (OID).
A discovery rule can perform only explicit or recursive discovery, but cannot perform a combination of discovery types. You can change the discovery type of a rule after the rule is created. If you know all the network devices that you want discovered, you should use explicit discovery. Recursive discovery can discover devices that you have no business requirement to monitor and as a result, can increase the administrative workload of monitoring your network.
A discovery rule can discover any combination of SNMP v1, v2, and v3 devices. SNMP v3 devices can only be discovered by explicit discovery or by being specified in a recursive discovery rule. If you specify an SNMP v3 device in a recursive discovery rule, the SNMP v3 device will be discovered but devices connected to it will not be discovered. If you specify an SNMP v1 or v2 device in a recursive discovery rule, only SNMP v1 and v2 devices connected to it will be included in the recursive discovery.