Link Layer Discovery Protocol (LLDP) enables systems in the network to exchange connectivity and management information for the purpose of topology discovery. The information can include system capabilities, management addresses, and other information relevant to network operations. The network diagnostics service uses LLDP to detect problems that might lead to limited or degraded network connectivity.
On any LAN, individual components such as systems and switches are not configured in isolation. To host network traffic efficiently, the configuration of systems on the network must be coordinated with each other.
When you manually configure each system, switch, and other components, ensuring compatibility among the components is a challenge. The manual configuration of systems is risky and can easily cause misconfigurations, particularly if different administrators work independently on different systems. A better alternative is to use LLDP, which enables systems to transmit their individual configuration information to peer systems and helps to detect any misconfigurations.
Oracle Solaris supports the use of LLDP to promote the exchange of system and network connectivity information between systems on the network, which reduces the risk of misconfigured network resources.
In this release, LLDP is used by the network diagnostics service to automatically detect problems that could lead to limited or degraded network connectivity, or both. Enabling the LLDP service enhances the ability to perform network diagnostics on your Oracle Solaris system. For more information about network diagnostics, see Chapter 4, Performing Network Diagnostics With the network-monitor Transport Module Utility in Troubleshooting Network Administration Issues in Oracle Solaris 11.4.
In Oracle Solaris, LLDP is also used to exchange data center bridging exchange protocol (DCBX) Type-Length-Value (TLV) units. DCBX provides configuration information about DCB features such as priority-based flow control (PFC) and enhanced transmission selection (ETS). For more information about DCB, see Managing Converged Networks by Using Data Center Bridging.
With LLDP, the system administrator can easily detect faulty system configurations, particularly in complex networks such as virtual local area networks (VLANs) and link aggregations. Information about the network topology can be obtained readily without having to trace physical connections between servers, switches, and other devices that comprise the network.
LLDP is implemented with the following components:
LLDP package – You install this package to enable the LLDP. This package includes the LLDP daemon, command-line utilities, the service manifest and scripts, and other components that are required for LLDP to operate.
LLDP service – You can enable the LLDP service by using the svcadm command. This service uses the fault management resource identifier (FMRI) of the service management facility (SMF) service instance, svc:/network/lldp:default, to manage the LLDP daemon, lldpd. This LLDP service is responsible for starting, stopping, restarting, or refreshing the lldpd daemon. This service is automatically enabled after you install the LLDP package.
lldpadm command – You can use this command to administer LLDP on individual links and to configure the operating mode of LLDP, to specify TLV units that are transmitted, and to configure DCBX TLV units. For information about TLV units, see Information the LLDP Agent Advertises.
You must use this command to set the per-agent LLDP properties and global LLDP properties and to get LLDP information for a specific agent or its peer.
The lldpadm subcommands are described in the following sections. For more information about the lldpadm command, see the lldpadm(8) man page.
LLDP daemon – The LLDP services manage LLDP agents on the system. They also interact with snmpd, the daemon for the Simple Network Management Protocol (SNMP), to retrieve LLDP information that is received on the system through SNMP.
LLDP agents – LLDP agents are the LLDP instances that are associated with a physical datalink on which LLDP is enabled. LLDP agents transmit information about the datalink to its peer and also receive information from the peer. You can configure an LLDP agent to advertise specific information about the associated physical datalink. You can enable LLDP only on physical datalinks.
The LLDP agent transmits and receives LLDP data units (LLDPDUs). The agent manages and stores information that is contained in these LLDPDUs in the following types of data stores:
Local management information base (MIB) – This data store contains network information that pertains to a system's specific link on which the LLDP agent is enabled. A local MIB contains both common and unique information. For example, the chassis ID is common information that is shared among all the LLDP agents on the system. However, port IDs for the system's datalinks are different. Therefore, each agent manages its own local MIB.
The LLDP agent operates in the following modes:
Transmit only (txonly) – The LLDP agent does not process incoming LLDPDUs. Therefore, the remote MIB is empty.
Receive only (rxonly) – The agent processes only incoming LLDPDUs and stores the information in remote MIBs. However, no information from the local MIB is transmitted.
Transmit and receive (both) – The agent transmits local information and processes incoming LLDPDUs and therefore maintains both local and remote MIBs.
Disabled (disable) – The agent does not exist.
For information about setting agent modes, see How to Enable LLDP for Specific Ports.