Configuring 802.1AB 802.1AB Overview
OmniSwitch AOS Release 8 Network Configuration Guide December 2017 page 13-7
LLDP Agent Security Mechanism
The OmniSwitch LLDP Agent Security mechanism provides a solution for secure access to the network
by detecting rogue devices and preventing them from accessing the internal network. LLDP agent secu-
rity can be achieved by allowing only one trusted LLDP remote agent on a network port.
User is provided an option to configure the Chassis ID subtype that can be used in validating the Chassis
ID type in the incoming LLDP PDU. If the Chassis ID is not configured, by default, the first LLDP remote
agent is learnt with the received Chassis ID. When more than one LLDP agent is learned on a port, the
port is moved to a violation state.
For example, when someone tries to take control over the network by connecting non-registered devices to
an NNI port, the LLDP Security mechanism is activated. One or both of the following actions are
performed according to the security configuration:
• When the rogue device is detected, a violation is reported on the port.
• The NNI port that is connected to the rogue device is blocked. Thus the rogue device is prevented from
accessing the internal network.
LLDP security mechanism can be enabled or disabled globally at chassis level, at slot level, or at
individual port level. When the LLDP agent security is enabled, the configured ports are monitored for
reception of any LLDPDU. When an LLDPDU is received, the remote agent ID is learned and the port is
considered as a trusted port if the port does not have any other LLDP remote agent assigned. If the remote
agent chassis ID and port IDs received are already present in the trusted remote agent database on the
same port, then the port remains in a trusted state.
However, a port is moved to violation state under the following conditions:
• When a link up is received on a LLDP security enabled port, if no LLDPDU is received even after
three times the LLDP timer interval period (30 seconds), the port is moved to a violation state.
• If a trusted remote agent exists, and if no LLDP remote agent is learned even after three times the
LLDP timer interval period (30 seconds), the port is moved to a violation state.
• If a new LLDP remote agent is learned after the link up and down, then the port is moved to a
violation state.
• If the same chassis ID and port ID exist in the trusted remote agent database but on a different port,
then the port remote agent is learned and the port is moved to a violation state.
• If a new LLDP remote agent is learned on a port that has a trusted LLDP remote agent, then the port is
moved to a violation state.
Three actions can be configured when an LLDP security violation occurs. The different violation actions
that can be configured are:
• trap - Generate a trap
• shutdown - Shutdown the port
• trap-and-shutdown - A trap is generated upon shutdown of the port due to violation.
When a shutdown occurs on a port, it can be cleared manually through the CLI interface using the clear
violations command.
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