RMON 2
Remote Monitoring (RMON) is a management information base (MIB) or a group of management objects that you use to obtain or configure values using the Simple Network Management Protocol (SNMP).
Use CLI or EDM to globally enable RMON on the system.
After you globally enable RMON, you enable monitoring for individual devices on a port-by-port basis.
RMON1 is the original version of the protocol, which collects information for OSI Layer 1 and Layer 2 in Ethernet networks. RMON1 provides traffic statistics at the MAC layer, and provides statistics on Ethernet segments for packets and bytes received and transmitted.
RMON2 monitors and counts network layer and application layer protocol packets on configured network hosts, either VLAN or port interfaces, that you enable for monitoring. RMON2 monitors Segmented Management Instances at the mgmt configuration level for out-of-band (OOB), circuitless IP (CLIP), and VLAN interfaces.
Note
RMON2 counters on Segmented Management Instance interfaces are cleared only when a Segmented Management Instance interface is newly enabled, or when RMON2 is newly enabled on a previously enabled Segmented Management Instance interface.
The following figure shows which form of RMON monitors which layers in the OSI model:
The RMON2 feature is a management information base (MIB) or a group of management objects that you use to obtain or configure values using the Simple Network Management Protocol (SNMP). The switch supports a partial implementation of RMON2. The RMON2 feature adds the following MIBS: protocol directory, protocol distribution, address map, network-layer host and application layer host for the traffic passing through the (Control Processor) CP for these MIB tables.
The system only collects statistics for IP packets that pass through the CP. RMON2 does not monitor packets on other interfaces processed on the switch that do not pass through the CP. However, RMON2 monitors packets for applications listed in the RMON2 MIB, whether or not the application is enabled or supported on the switch.
After you globally enable RMON2, enable monitoring for individual devices. Identify the network hosts for the system to monitor with a manual configuration on the interfaces you want to monitor.
The RMON2 feature monitors a list of predefined protocols. The system begins to collect protocol statistics immediately after you enable RMON.
Protocols predefined by the system.
Address mapping between physical and network address on particular network hosts that you configure for monitoring.
Network host statistics for particular hosts on a network layer protocol (IP) that you configure for monitoring.
Application host statistics for a particular host on an application layer protocol that you configure for monitoring.
RMON2 MIBs
This section describes the following MIBs, on which RMON2 can collect statistics: protocol directory, protocol distribution, address map, network-layer host, and application layer host.
Protocol Directory MIB
The protocol directory lists all of the protocols RMON2 can monitor. The protocols include network layer, transport layer, and application layer protocols, under the OSI model. The system only monitors statistics for the predefined protocols. You cannot delete or add additional protocols to this table. The protocol directory MIB is enabled by default for the predefined protocols.
The predefined protocols include:
-
Internet Protocol (IP)
-
Secure Shell version 2 (SSHv2)
-
Transmission Control Protocol (TCP)
-
User Datagram Protocol (UDP)
-
File Transfer Protocol (FTP)
-
Hypertext Transfer Protocol (HTTP)
-
Telnet
-
Remote login (rlogin)
Note
RMON2 can count application packets received on a platform, even if the application is not enabled or supported, before dropping them.
-
Trivial File Transfer Protocol (TFTP)
-
Simple Network Management Protocol (SNMP)
Protocol distribution MIB
The protocol distribution MIB collects traffic statistics that each protocol generates by local area network (LAN) segment. The switch acts as the probe and the system collects protocol statistics for the entire switch as part of the group for all of the protocols predefined in the protocol directory table. The protocol distribution control table is part of this group. The protocol distribution control table is predefined with an entry for the management IP for the switch to represent the network segment where the system collects the statistics.
No CLI or EDM support exists to add or delete entries in this table.
Address map MIB
The address map MIB maps the network layer IP to the MAC layer address.
The system populates the address map control table MIB with an entry for each host interface that you enable for monitoring on the switch.
Network layer host MIB
The network layer host MIB monitors the Layer 3 traffic statistics for each host. The network layer host MIB monitors traffic packets in and out of hosts based on the network layer address. The network layer host controls the network and application layer host tables.
The system populates an entry for the management IP of the switch to represent the network segment where the system collects the statistics. You have to enable each host interface that you want to monitor on the switch.
The system only collects statistics for this group from packets that go to the CP.
Application layer host MIB
The application layer host MIB monitors traffic statistics by application protocol for each host.
The system populates an entry for the management IP of the switch to represent the network segment where the system collects the statistics. You have to enable each host interface that you want to monitor on the switch.
The system only collects statistics for this group from packets that go to the CP.
RMON2 Considerations
The following considerations apply to RMON2:
-
You must enable RMON globally before you enable RMON2 monitoring for a Segmented Management Instance interface.
-
You must configure an IPv4 address for the Segmented Management Instance management interface before you enable RMON2 monitoring.
-
You can enable RMON on a maximum of 30 IP interfaces on a host.
-
You cannot directly configure RMON for a routing VLAN that is an underlying management VLAN. In this case, RMON must be configured at the mgmt vlan configuration level.
-
RMON2 is not available if DHCP Client is configured on a Management Instance. DHCP Client is not available if RMON2 is configured on a Management Instance.
-
You cannot delete the IPv4 manual address from a Segmented Management Instance management interface that is RMON enabled. If the only IPv4 address is deleted outside of the normal configuration process, RMON is administratively disabled on the Segmented Management Instance management interface.