1. Introduction to LLDP Network Management
Network engineers frequently encounter the task of managing complex network environments. In LLDP network management, monitoring and measuring the status and performance of network operations are essential. When issues arise, such as network component failures, overutilization of resources, or complete system collapses, they need to be swiftly addressed. The effective use of LLDP plays a crucial role in diagnosing and resolving these problems, ensuring smooth network operations.
Therefore, a large part of network management is actually the management of resources in the network, including the hardware, software and services provided in the network.
To elaborate, you will feel that network management is complicated and trivial, not that simple, right?
But whether you are a network engineer or a network administrator, you must handle this content. Therefore, in many cases, the more basic the work, the more it tests your ability.
Many workers will choose some management software to free their hands, such as Wireshark, which can intercept various network data packets and is also commonly used to locate various problems.
However, you will find that the scale of enterprise networks is getting larger and larger, the types of network equipment are increasing, and their respective configurations are intricate… The requirements for the network management capabilities of each network engineer are also getting higher and higher.
Traditional network management can only analyze the three-layer network topology structure, and cannot determine the detailed topology information of network devices, whether there are configuration conflicts, etc.
At this time, a standard Layer 2 information exchange protocol is needed. LLDP provides a standard link layer discovery method:
- The device layer 2 information obtained through LLDP can quickly obtain the topology status of the connected devices
- Shows the paths between clients, switches, routers, application servers, and network servers
- Detect configuration conflicts between devices and query reasons for network failures
At this time, you can use the network management system to monitor the link status of devices that support the LLDP protocol, and quickly locate the fault when a network failure occurs.
This article will help you understand all the contents of LLDP. If you find it useful, please forward it to your friends and share it with more network workers in need.
01 LLDP Working Principle
LLDP can organize the information of local devices and publish it to its remote devices. The local device saves the received remote device information in the form of standard MIB. The working principle is shown in the figure:
The basic implementation principle of LLDP is as follows:
(1) The LLDP module updates its own LLDP local system MIB and the local device’s customized LLDP extended MIB through the interaction of the LLDP agent with the physical topology MIB, entity MIB, interface MIB, and other types of MIBs on the device.
(2) Encapsulate local device information into LLDP frames and send them to the remote device.
(3) Receive LLDP frames sent by remote devices and update its own LLDP remote system MIB and the remote device’s customized LLDP extended MIB.
(4) By sending and receiving LLDP frames through the LLDP agent, the device can clearly know the information of the remote device, including which interface of the remote device is connected, the MAC address of the remote device, and other information.
The LLDP local system MIB is used to store local device information, including device ID, interface ID, system name, system description, interface description, network management address, and other information.
The LLDP remote system MIB is used to store remote device information, including device ID, interface ID, system name, system description, interface description, network management address, and other information.
The LLDP agent performs the following tasks:
- Maintains the LLDP local system MIB and LLDP remote system MIB.
- When the local state changes, the LLDP local system MIB information is extracted and sent to the remote device. When the local device state information does not change, the LLDP local system MIB information is extracted and sent to the remote device according to a certain period.
- Identify and process received LLDP frames.
- When the status of the LLDP local system MIB or the LLDP remote system MIB changes, an LLDP alarm is sent to the network management system.
02 Why LLDP Network Management is Essential for Modern Networks
(1) Single neighbor networking mode
The single-neighbor networking mode means that the interfaces of router devices or the interfaces of router and media terminal ME (MediaEndpoint) are directly connected without any devices in between, and the interfaces have only one neighbor device.
As shown in the figure, RouterA and RouterB, as well as RouterA and ME, are directly connected. Each interface of RouterA and RouterB has only one neighbor.
(2) Link aggregation networking mode
Link aggregation networking mode means that link aggregation exists between interfaces of router devices. The interfaces are directly connected, and each interface between the link aggregation has only one neighbor device.
As shown in Figure 2, link aggregation exists between RouterA and RouterB, and each interface of RouterA and RouterB has only one neighbor.
(3) Example for configuring the LLDP function – single-neighbor network
Network Requirements
RouterA and RouterB, and RouterA and ME are directly connected. The network management system NMS has reachable routes to RouterA and RouterB, and SNMP configuration has been completed.
The network administrator wants to obtain the communication status of the links between RouterA and ME devices, and between RouterA and RouterB, and alarm information about device function changes on the NMS to understand the detailed network topology and determine whether there are configuration conflicts in the network.
Configuration Roadmap
The network administrator wants to obtain the communication status of the links between RouterA and ME devices, and between RouterA and RouterB, and alarm information about device function changes on the NMS. This can be achieved by configuring the LLDP function. The configuration roadmap is as follows:
(1) Enable LLDP globally on RouterA and RouterB.
(2) Configure the management IP addresses of RouterA and RouterB to facilitate management by the network management system.
(3) Enable the alarm function of RouterA and RouterB to transmit alarm information to the NMS in a timely manner.
Procedure
(1) Enable LLDP globally on RouterA and RouterB.
# Configure RouterA.
<Huawei>system-view
[Huawei] sysnameRouterA
[RouterA] lldpenable
# Configure RouterB.
<Huawei>system-view
[Huawei] sysnameRouterB
[RouterB] lldpenable
(2) Configure the management IP addresses of RouterA and RouterB
# Configure RouterA.
[RouterA] lldpmanagement-address 10.10.10.1
# Configure RouterB.
[RouterB] lldpmanagement-address 10.10.10.2
(3) Enable LLDP alarms on RouterA and RouterB
# Configure RouterA.
[RouterA] snmp-agenttrap enable feature-name lldptrap
# Configure RouterB.
[RouterB] snmp-agenttrap enable feature-name lldptrap