Hi,

SNMP

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NetMap queries network devices via SNMP for:

• System information

• Interface information

• Bridge information

• 802.1X information (PAE MIB)

• Routing/IP information

• CDP MIB Information

This information is used to Build and maintain a model of the network topology and endpoint discovery.

NetMap uses SNMP Get, GetNext and GetBulk (when available) requests to  query the SNMP agents running on the network infrastructure devices to  gather specific Management Information Base (MIB) objects about their  status based on device type (Layer 2 or Layer 3).

In addition to polling each network device for all MIB data at a regular  interval, NetMap may also be commanded to poll port-specific  information when the NAC Profiler system is notified that an endpoint  has joined or left the network via SNMP traps sent by devices at the  network edge, switches typically.

Upon receipt and verification of a link state (link up, link down) or  MAC notification trap, NetTrap will notify the NAC Profiler Server that a  change has occurred on the network edge (endpoint joined or left a  network port). If the trapping device is in the NAC Profiler  configuration, the NetMap component module assigned to poll the device  that sent the trap will be commanded by the Server module to initiate a  poll of the device's port information to determine the change to the  endpoint topology that resulted in the trap being sent by the network  device.

The information gathered by NetMap is processed by the Server  accordingly to update the network topology, noting the endpoint joining  or leaving a port. Note that NetMap SNMP polling of network devices  resulting from a trap is localized to the port specified in the trap.  This is unlike the regular polling that occurs at the frequency  specified for each device type (L2 and L3) which gathers all SNMP  information from the device used by the NAC Profiler system.

DHCP:

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The NetWatch module listens for traffic including DHCP traffic.

The module will collect all the DHCP information on the traffic collected, like mac address, ip address,  DHCP Vendor Class Identifier in DHCP request, host name in DHCP request, requested specified options in DHCP request (option 55) and full list of DHCP options supported by the DHCP client as specified in the DHCP request.

All the endpointe data can then be used to map endpoints with profiles.

HTH,

Tiago