RuggedCom RS400 manual Lldp Operation, Network Discovery

Network Discovery

10 Network Discovery

Network Discovery is based on LLDP (Link Layer Discovery Protocol) as defined by the IEEE 802.1AB standard. This feature provides the ability to:

•Enable LLDP per device and per port

•View LLDP statistics

•View neighbor information

•Report LLDP data via SNMP

10.1LLDP Operation

The IEEE standard, 802.1AB Link Layer Discovery Protocol (LLDP), promises to simplify troubleshooting of enterprise networks and enhance the ability of network management tools to discover and maintain accurate network topologies in multi-vendor environments. LLDP data are made available to NMS (Network Management Systems) via SNMP (LLDP-MIB is supported).

LLDP is a neighbor discovery protocol. It defines a standard method for Ethernet network devices such as switches and routers to advertise information about themselves to other nodes on the network and to store the information they discover. Details such as device configuration, device capabilities and device identification can be advertised using this protocol.

LLDP agent operation is typically implemented as two modules: the LLDP transmit module and LLDP receive module. The LLDP transmit module, when enabled, sends the local device's information at regular intervals, in 802.1AB standard format. Whenever the transmit module is disabled, it transmits an LLDPDU (LLDP data unit) with a time-to-live (TTL) TLV containing "0" in the information field. This enables remote devices to remove the information associated with the local device in their databases. The LLDP receive module, when enabled, receives remote devices’ information and updates its LLDP database of remote systems. When new or updated information is received, the receive module initiates a timer for the valid duration indicated by the TTL TLV in the received LLDPDU. A remote system's information is removed from the database when an LLDPDU is received from it with TTL TLV containing "0" in its information field.

LLDP is implemented to keep a record of only one device per Ethernet port. Therefore, if there are multiple devices sending LLDP information to a switch port on which LLDP is enabled, information about the neighbor on that port will change constantly.

RS400 213 ROS™ v3.5