Link Layer Discovery Protocol (LLDP) is a data link layer discovery protocol that has been designed by IEEE as part of 802.1AB specifications. This link layer discovery protocol has taken over the proprietary solutions that were available in Cisco, Juniper routers and Microsoft systems.
Discovery information includes device identifiers, port identifiers, versions, and other details. The protocol has been specifically designed in order to vehicle also vendor specific information that might complete the discovery for nodes capable of those extensions.
LLDP is running in an advertisement mode, LLDP node periodically sends advertisements to a constrained multicast address. Devices supporting LLDP can send information about themselves while they receive and record information about their neighbors. LLDP sends LLDPDUs periodically every 30sec and and upon change of the status or value of one object in the LLDP local MIB. It guaranties that all neighbors can store updated identifiers from all theirs adjacent nodes.
Marben has selected this protocol as part of its building blocks for the discovery of the optical control plane identifiers and roles. Such protocol enables the discovery of all identifiers that are used by the control plane in order to avoid any misconfiguration and reduce error-prone manual provisioning.
Marben has implemented a standard LLDP implementation that conforms with IEEE 802.1AB with support of optional tag-Length-Value object (TLV) . Marben offers a management API as a MIB like API to query the content of the local and remote port, port statistics, system management addresses and Organizationally Unique Identifier (OUI)
For the purpose of discovery in GMPLS networks, two possible options are commonly used:
Identifiers are exchanged using 802.1AB port identifiers, i.e. using sub-type 7 as "locally assigned" or using the reserved sub-type, or are exchanged using an OUI-TLV per vendors.
MARBEN LLDP software architecture
The benefits for an optical equipment vendors is that this discovery mechanism is based on IEEE 802.1AB standard and would enables interoperability among multivendor devices with only few adaptation on the extended. It facilitates troubleshooting as LLDP is now used as standard network management tools.