RMON or Remote MONitoring MIB was designed to manage the network itself. MIB I/II could be used to check each machines network performance, but would lead to large amounts of bandwidth for management traffic.
Using RMON you see the wire view of the network and not just a single host’s view. RMON has the capability to set performance thresholds and only report if the threshold is breached, again helping to reduce management traffic (effectively distributing the network management smarts!). RMON agents can reside in routers, switches, and dedicated boxes. The agents will gather up to 19 groups of statistics. The agents then forward this information upon request from a client.
Because RMON agents must look at every frame on the network, performance is a must. Early RMON agent’s performance could be classified based on processing power and memory.
Network Monitoring with RMON
Cisco Discovery Protocol (CDP)
Automatic Network Discovery. and the following are the activities of CDP:
- – CDP agent polls neighbor devices
- – Physical interface, IP address, chassis type exchanged
- – Each device maintains “CDP” cache table
- – Tables are read by management application
- – Applicable across frame networks
- – ILMI for ATM networks
Inter-Switch Link (ISL)
Maintains Switch-to-Switch Performance and the following are the activities of ISL:
- – Establishes membership through ASICs
- – Eliminates lookups and tables
- – Labels each packet as received (i.e., “packet tagging”)
- – Transports multiple VLANs across links
- – Maps effectively across mixed backbones
- – Protocol, end-station independent
Virtual Trunking Protocol (VTP)
Activities of VTP:
- – Assigns virtual interfaces across backbone
- – Maintains and manages global mapping table
- – Based on Layer 2 periodic advertisements
- – Reduces setup time and improves reliability
- – VTP pruning enhances VLAN efficiencies
