What are the pre-requisites for a good discovery topology?

Several prerequisites must be met for a successful discovery of the network topology.

• Switches and routers must be managed devices. This means that they must support SNMP and provide access to the required SNMP information.
• Switches and routers must support either CDP (Cisco Discovery Protocol) or LLDP (Link Layer Discovery Protocol). These protocols provide information about direct network connections between devices. Without CDP or LLDP information, the switch topology cannot be discovered reliably. The devices must expose this information through the corresponding MIBs.
• To assign end devices to switch ports, the switches must support the Bridge MIB. The Bridge MIB contains the forwarding table of the switch. This table lists the MAC addresses learned on each port. Without Bridge MIB support, end devices cannot be mapped to the switch ports.
• The assignment of end devices is based on MAC addresses detected within the network. It is therefore essential that the MAC addresses of all relevant devices can be identified during discovery.