LLDP configuration· 1

Overview·· 1

Background· 1

Basic concepts 1

How LLDP works 6

Protocols and standards 6

LLDP configuration task list 6

Performing basic LLDP configuration· 7

Enabling LLDP· 7

Setting the LLDP operating mode· 7

Setting the LLDP re-initialization delay· 8

Enabling LLDP polling· 8

Configuring the advertisable TLVs 8

Configuring the management address and its encoding format 9

Setting other LLDP parameters 10

Setting an encapsulation format for LLDPDUs 10

Configuring CDP compatibility· 11

Configuration prerequisites 11

Configuring CDP compatibility· 11

Configuring LLDP trapping· 12

Displaying and maintaining LLDP· 13

LLDP configuration examples 13

Basic LLDP configuration example· 13

CDP-compatible LLDP configuration example· 16

 

This chapter includes these sections:

·          Overview

·          LLDP configuration task list

·          Displaying and maintaining LLDP

·          LLDP configuration examples

 

NOTE: ·      The term "switch" or "device" in this chapter refers to the switching engine on a WX3000E wireless switch. ·      The WX3000E series comprises WX3024E and WX3010E wireless switches. ·      The port numbers in this chapter are for illustration only.

 

Overview

Background

In a heterogeneous network, it is important that different types of network devices from different vendors can discover one another and exchange configuration for interoperability and management sake. A standard configuration exchange platform was created.

The IETF drafted the Link Layer Discovery Protocol (LLDP) in IEEE 802.1AB. The protocol operates on the data link layer to exchange device information between directly connected devices. With LLDP, a device sends local device information (including its major functions, management IP address, device ID, and port ID) as TLV (type, length, and value) triplets in LLDP Data Units (LLDPDUs) to the directly connected devices, and at the same time, stores the device information received in LLDPDUs sent from the LLDP neighbors in a standard management information base (MIB). It allows a network management system to quickly detect and identify Layer 2 network topology changes.

 

NOTE: For more information about MIBs, see the Network Management and Monitoring Configuration Guide.

 

Basic concepts

LLDPDUs

LLDP sends device information in LLDPDUs. LLDPDUs are encapsulated in Ethernet II or Subnetwork Access Protocol (SNAP) frames.

1.        Ethernet II-encapsulated LLDPDU format

Figure 1 Ethernet II-encapsulated LLDPDU format

 

The fields in the Ethernet II-encapsulated LLDPDU are described in Table 1.

Table 1 Fields in an Ethernet II-encapsulated LLDPDU

Field	Description
Destination MAC address	The MAC address to which the LLDPDU is advertised. It is fixed to 0x0180-C200-000E, a multicast MAC address.
Source MAC address	The MAC address of the sending port. If the port does not have a MAC address, the MAC address of the sending bridge is used.
Type	The Ethernet type for the upper layer protocol. It is 0x88CC for LLDP.
Data	LLDPDU
FCS	Frame check sequence, a 32-bit CRC value used to determine the validity of the received Ethernet frame

 

2.        SNAP-encapsulated LLDPDU format

Figure 2 SNAP-encapsulated LLDPDU format

 

The fields in the SNAP-encapsulated LLDPDU are described in Table 2.

Table 2 Fields in a SNAP-encapsulated LLDPDU

Field	Description
Destination MAC address	The MAC address to which the LLDPDU is advertised. It is fixed at 0x0180-C200-000E, a multicast MAC address.
Source MAC address	The MAC address of the sending port.
Type	The SNAP type for the upper layer protocol. It is 0xAAAA-0300-0000-88CC for LLDP.
Data	LLDPDU
FCS	Frame check sequence, a 32-bit CRC value used to determine the validity of the received Ethernet frame.

 

LLDPDUs

LLDP uses LLDPDUs to exchange information. An LLDPDU comprises multiple TLV sequences. Each carries a specific type of device information, as shown in Figure 3.

Figure 3 LLDPDU encapsulation format

 

An LLDPDU can carry up to 28 types of TLVs. Mandatory TLVs include Chassis ID TLV, Port ID TLV, Time To Live TLV, and End of LLDPDU TLV. Other TLVs are optional.

TLVs

TLVs are type, length, and value sequences that carry information elements. The type field identifies the type of information, the length field measures the length of the information field in octets, and the value field contains the information itself.

LLDPDU TLVs fall into the following categories:

·          Basic management TLVs

·          Organizationally (IEEE 802.1 and IEEE 802.3) specific TLVs

·          LLDP-MED (media endpoint discovery) TLVs

Basic management TLVs are essential to device management. Organizationally specific TLVs and LLDP-MED TLVs are used for enhanced device management; they are defined by standardization or other organizations and are optional to LLDPDUs.

1.        Basic management TLVs

Table 3 lists the basic management TLV types. Some of them must be included in every LLDPDU.

Table 3 Basic LLDP TLVs

Type	Description	Remarks
Chassis ID	Bridge MAC address of the sending device	Mandatory
Port ID	ID of the sending port If the LLDPDU carries LLDP-MED TLVs, the port ID TLV carries the MAC address of the sending port or the bridge MAC in case the port does not have a MAC address. If the LLDPDU carries no LLDP-MED TLVs, the port ID TLV carries the port name.
Time To Live	Life of the transmitted information on the receiving device
End of LLDPDU	Marks the end of the TLV sequence in the LLDPDU
Port Description	Port description of the sending port	Optional
System Name	Assigned name of the sending device
System Description	Description of the sending device
System Capabilities	Identifies the primary functions of the sending device and the enabled primary functions
Management Address	Management address, and the interface number and object identifier (OID) associated with the address

 

2.        IEEE 802.1 organizationally specific TLVs

Table 4 IEEE 802.1 organizationally specific TLVs

Type	Description
Port VLAN ID	Port’s VLAN identifier (PVID). An LLDPDU carries only one TLV of this type.
Port And Protocol VLAN ID	Indicates whether the device supports protocol VLANs and, if so, what VLAN IDs these protocols will be associated with. An LLDPDU can carry multiple different TLVs of this type.
VLAN Name	Textual name of any VLAN to which the port belongs. An LLDPDU can carry multiple different TLVs of this type.
Protocol Identity	Indicates protocols supported on the port. An LLDPDU can carry multiple different TLVs of this type.
DCBX	Data center bridging exchange protocol

 

NOTE: The switching engine on a WX3000E wireless switch only supports receiving protocol identity TLVs.

 

3.        IEEE 802.3 organizationally specific TLVs

Table 5 IEEE 802.3 organizationally specific TLVs

Type	Description
MAC/PHY Configuration/Status	Contains the bit-rate and duplex capabilities of the sending port, support for auto negotiation, enabling status of auto negotiation, and the current rate and duplex mode.
Power Via MDI	Contains the power supply capability of the port, including the Power over Ethernet (PoE) type, which can be Power Sourcing Equipment (PSE) or Powered Device (PD), PoE mode, whether PSE power supply is supported, whether PSE power supply is enabled, and whether the PoE mode is controllable.
Link Aggregation	Indicates the aggregation capability of the port (whether the link is capable of being aggregated), and the aggregation status (whether the link is in an aggregation).
Maximum Frame Size	Indicates the supported maximum frame size. It is now the MTU of the port.
Power Stateful Control	Power state control configured on the sending port, including the power type of the PSE/PD, PoE sourcing/receiving priority, and PoE sourcing/receiving power.

 

NOTE: The Power Stateful Control TLV is defined in IEEE P802.3at D1.0. The later versions no longer support this TLV. H3C devices send this type of TLVs only after receiving them.

 

LLDP-MED TLVs

LLDP-MED TLVs provide multiple advanced applications for voice over IP (VoIP), such as basic configuration, network policy configuration, and address and directory management. LLDP-MED TLVs provide a cost-effective and easy-to-use solution for deploying voice devices in Ethernet. LLDP-MED TLVs are shown in Table 6.

Table 6 LLDP-MED TLVs

Type	Description
LLDP-MED Capabilities	Allows a network device to advertise the LLDP-MED TLVs it supports.
Network Policy	Allows a network device or terminal device to advertise VLAN ID of the specific port, VLAN type, and the Layer 2 and Layer 3 priorities for specific applications.
Extended Power-via-MDI	Allows a network device or terminal device to advertise power supply capability. This TLV is an extension of the Power Via MDI TLV.
Hardware Revision	Allows a terminal device to advertise its hardware version.
Firmware Revision	Allows a terminal device to advertise its firmware version.
Software Revision	Allows a terminal device to advertise its software version.
Serial Number	Allows a terminal device to advertise its serial number.
Manufacturer Name	Allows a terminal device to advertise its vendor name.
Model Name	Allows a terminal device to advertise its model name.
Asset ID	Allows a terminal device to advertise its asset ID. The typical case is that the user specifies the asset ID for the endpoint to facilitate directory management and asset tracking.
Location Identification	Allows a network device to advertise the appropriate location identifier information for a terminal device to use in the context of location-based applications.

 

Management address

The management address of a device is used by the network management system to identify and manage the device for topology maintenance and network management. The management address is encapsulated in the management address TLV.

How LLDP works

Operating Modes of LLDP

LLDP can operate in one of the following modes:

·          TxRx mode. A port in this mode sends and receives LLDPDUs.

·          Tx mode. A port in this mode only sends LLDPDUs.

·          Rx mode. A port in this mode only receives LLDPDUs.

·          Disable mode. A port in this mode does not send or receive LLDPDUs.

When the LLDP operating mode of a port changes, its LLDP protocol state machine re-initializes. A re-initialization delay, which is user configurable, prevents LLDP from being initialized too frequently during times of frequent operating mode change. With this delay configured, before a port can initialize LLDP, it must wait for the specified interval after the LLDP operating mode changes.

Transmitting LLDPDUs

An LLDP-enabled port operating in TxRx mode or Tx mode sends LLDPDUs to its directly connected devices both periodically and when the local configuration changes. A frame transmit interval between two successive LLDP frames prevents the network from being overwhelmed by LLDPDUs during times of frequent local device information change.

This interval is shortened to 1 second in either of the following cases:

·          A new neighbor is discovered. A new LLDPDU is received carrying device information new to the local device.

·          The LLDP operating mode of the port changes from Disable/Rx to TxRx or Tx.

This is the fast sending mechanism of LLDP. This feature sends a specific number of LLDPDUs at 1-second intervals to help LLDP neighbors discover the local device as soon as possible. Then, the normal LLDPDU transmit interval resumes.

Receiving LLDPDUs

An LLDP-enabled port operating in TxRx mode or Rx mode checks the validity of TLVs carried in every received LLDPDU. If valid, the information is saved and an aging timer is set for it based on the time to live (TTL) value in the Time to Live TLV carried in the LLDPDU. If the TTL value is zero, the information is aged out immediately.

Protocols and standards

·          IEEE 802.1AB-2005, Station and Media Access Control Connectivity Discovery

·          ANSI/TIA-1057, Link Layer Discovery Protocol for Media Endpoint Devices

LLDP configuration task list

Complete these tasks to configure LLDP:

Task		Remarks
Performing basic LLDP configuration	Enabling LLDP	Required
	Setting the LLDP operating mode	Optional
	Setting the LLDP re-initialization delay	Optional
	Enabling LLDP polling	Optional
	Configuring the advertisable TLVs	Optional
	Configuring the management address and its encoding format	Optional
	Setting other LLDP parameters	Optional
	Setting an encapsulation format for LLDPDUs	Optional
Configuring CDP compatibility		Optional
Configuring LLDP trapping		Optional

 

NOTE: LLDP-related configurations made in Ethernet interface view take effect only on the current port, and those made in port group view take effect on all ports in the current port group.

 

Performing basic LLDP configuration

Enabling LLDP

To make LLDP take effect on specific ports, you must enable LLDP both globally and on these ports.

Follow these steps to enable LLDP:

To do…		Use the command…	Remarks
Enter system view		system-view	—
Enable LLDP globally		lldp enable	Required Enabled by default.
Enter Ethernet interface view or port group view	Enter Layer 2 Ethernet interface view	interface interface-type interface-number	Required Use either command.
	Enter port group view	port-group manual port-group-name
Enable LLDP		lldp enable	Optional By default, LLDP is enabled on a port.

 

Setting the LLDP operating mode

LLDP can operate in one of the following modes.

·          TxRx mode. A port in this mode sends and receives LLDPDUs.

·          Tx mode. A port in this mode only sends LLDPDUs.

·          Rx mode. A port in this mode only receives LLDPDUs.

·          Disable mode. A port in this mode does not send or receive LLDPDUs.

Follow these steps to set the LLDP operating mode:

To do…		Use the command…	Remarks
Enter system view		system-view	—
Enter Ethernet interface view or port group view	Enter Layer 2 Ethernet interface view	interface interface-type interface-number	Required Use either command.
	Enter port group view	port-group manual port-group-name
Set the LLDP operating mode		lldp admin-status { disable | rx | tx | txrx }	Optional TxRx by default.

 

Setting the LLDP re-initialization delay

When LLDP operating mode changes on a port, the port initializes the protocol state machines after a certain delay. By adjusting the LLDP re-initialization delay, you can avoid frequent initializations caused by frequent LLDP operating mode changes on a port.

Follow these steps to set the LLDP re-initialization delay for ports:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Set the LLDP re-initialization delay	lldp timer reinit-delay delay	Optional 2 seconds by default.

 

Enabling LLDP polling

With LLDP polling enabled, a device periodically checks for local configuration changes. On detecting a configuration change, the device sends LLDPDUs to inform neighboring devices of the change.

Follow these steps to enable LLDP polling:

To do…		Use the command…	Remarks
Enter system view		system-view	—
Enter Ethernet interface view or port group view	Enter Layer 2 Ethernet interface view	interface interface-type interface-number	Required Use either command.
	Enter port group view	port-group manual port-group-name
Enable LLDP polling and set the polling interval		lldp check-change-interval interval	Required Disabled by default.

 

Configuring the advertisable TLVs

Follow these steps to configure the advertisable LLDPDU TLVs on the specified port or ports:

To do…		Use the command…	Remarks
Enter system view		system-view	—
Enter Ethernet interface view or port group view	Enter Layer 2 Ethernet interface view	interface interface-type interface-number	Required Use either command.
	Enter port group view	port-group manual port-group-name
Configure the advertisable TLVs (Layer 2 Ethernet interface view or port group view)		lldp tlv-enable { basic-tlv { all | port-description | system-capability | system-description | system-name } | dot1-tlv { all | port-vlan-id | protocol-vlan-id [ vlan-id ] | vlan-name [ vlan-id ] } | dot3-tlv { all | link-aggregation | mac-physic | max-frame-size | power } | med-tlv { all | capability | inventory | location-id { civic-address device-type country-code { ca-type ca-value }&<1–10> | elin-address tel-number } | network-policy | power-over-ethernet } }	Optional By default, all types of LLDP TLVs except location identification TLVs are advertisable on a Layer 2 Ethernet port.

 

Configuring the management address and its encoding format

LLDP encodes management addresses in numeric or character string format in management address TLVs.

By default, management addresses are encoded in numeric format. If a neighbor encoded its management address in character string format, you must configure the encoding format of the management address as string on the connecting port to guarantee normal communication with the neighbor.

Follow these steps to configure a management address to be advertised and its encoding format on a port or group of ports:

To do…		Use the command…	Remarks
Enter system view		system-view	—
Enter Ethernet interface view or port group view	Enter Layer 2 Ethernet interface view	interface interface-type interface-number	Required Use either command.
	Enter port group view	port-group manual port-group-name
Allow LLDP to advertise the management address in LLDPDUs and configure the advertised management address		lldp management-address-tlv [ ip-address ]	Optional By default, the management address is sent through LLDPDUs. For a Layer 2 Ethernet port, the management address is the main IP address of the lowest-ID VLAN carried on the port. If none of the carried VLANs is assigned an IP address, no management address will be advertised.
Configure the encoding format of the management address as character string		lldp management-address-format string	Optional By default, the management address is encapsulated in the numeric format.

 

Setting other LLDP parameters

The Time to Live TLV carried in an LLDPDU determines how long the device information carried in the LLDPDU can be saved on a recipient device.

By setting the TTL multiplier, you can configure the TTL of locally sent LLDPDUs, which determines how long information about the local device can be saved on a neighboring device. The TTL is expressed by using the following formula:

TTL = Min (65535, (TTL multiplier × LLDPDU transmit interval))

As the expression shows, the TTL can be up to 65535 seconds. TTLs greater than 65535 will be rounded down to 65535 seconds.

Follow these steps to change the TTL multiplier:

To do…	Use the command…	Remarks
Enter system view	system-view	—
Set the TTL multiplier	lldp hold-multiplier value	Optional 4 by default.
Set the LLDPDU transmit interval	lldp timer tx-interval interval	Optional 30 seconds by default.
Set the LLDPDU transmit delay	lldp timer tx-delay delay	Optional 2 seconds by default.
Set the number of LLDPDUs sent each time fast LLDPDU transmission is triggered	lldp fast-count count	Optional 3 by default.

 

NOTE: To ensure that LLDP neighbors can receive LLDPDUs to update information about the current device before it is aged out, configure both the LLDPDU transmit interval and delay to be less than the TTL.

 

Setting an encapsulation format for LLDPDUs

LLDPDUs can be encapsulated in the following formats: Ethernet II or SNAP frames.

·          With Ethernet II encapsulation configured, an LLDP port sends LLDPDUs in Ethernet II frames and only processes incoming, Ethernet II encapsulated LLDPDUs.

·          With SNAP encapsulation configured, an LLDP port sends LLDPDUs in SNAP frames and only processes incoming, SNAP encapsulated LLDPDUs.

By default, LLDPDUs are encapsulated in Ethernet II frames. If the neighbor devices encapsulate LLDPDUs in SNAP frames, configure the encapsulation format for LLDPDUs as SNAP to guarantee normal communication with the neighbors.

Follow these steps to set the encapsulation format for LLDPDUs to SNAP:

To do…		Use the command…	Remarks
Enter system view		system-view	—
Enter Ethernet interface view or port group view	Enter Layer 2 Ethernet interface view	interface interface-type interface-number	Required Use either command.
	Enter port group view	port-group manual port-group-name
Set the encapsulation format for LLDPDUs to SNAP		lldp encapsulation snap	Required Ethernet II encapsulation format applies by default.

 

NOTE: LLDP-CDP (Cisco Discovery Protocol) packets use only SNAP encapsulation.

 

Configuring CDP compatibility

 

NOTE: For more information about voice VLANs, see the chapter “Voice VLAN configuration.”

 

To make your device work with Cisco IP phones, you must enable CDP compatibility.

If your LLDP-enabled device cannot recognize CDP packets, it does not respond to the requests of Cisco IP phones for the voice VLAN ID configured on the device. As a result, a requesting Cisco IP phone sends voice traffic without any tag to your device, disabling your device from differentiating the voice traffic from other types of traffic.

With CDP compatibility enabled, your device can receive and recognize CDP packets from a Cisco IP phone and respond with CDP packets, which carry the voice VLAN configuration TLVs. According to the voice VLAN configuration TLVs, the IP phone automatically configures the voice VLAN. The voice traffic is confined in the configured voice VLAN, and differentiated from other types of traffic.

Configuration prerequisites

Before you configure CDP compatibility, complete the following tasks:

·          Globally enable LLDP.

·          Enable LLDP on the port connecting to an IP phone and configure the port to operate in TxRx mode.

Configuring CDP compatibility

CDP-compatible LLDP operates in one of the follows modes:

·          TxRx: CDP packets can be transmitted and received.

·          Disable: CDP packets cannot be transmitted or received.

To make CDP-compatible LLDP take effect on specific ports, first enable CDP-compatible LLDP globally, and then configure CDP-compatible LLDP to operate in TxRx mode.

Follow these steps to enable LLDP to be compatible with CDP:

To do…		Use the command…	Remarks
Enter system view		system-view	—
Enable CDP compatibility globally		lldp compliance cdp	Required Disabled by default.
Enter Ethernet interface view or port group view	Enter Layer 2 Ethernet interface view	interface interface-type interface-number	Required Use either command.
	Enter port group view	port-group manual port-group-name
Configure CDP-compatible LLDP to operate in TxRx mode		lldp compliance admin-status cdp txrx	Required Disable mode by default.

 

CAUTION: The maximum TTL value allowed by CDP is 255 seconds. To make CDP-compatible LLDP work properly with Cisco IP phones, make sure that the product of the TTL multiplier and the LLDPDU transmit interval is less than 255 seconds.

 

Configuring LLDP trapping

LLDP trapping notifies the network management system (NMS) of events such as newly-detected neighboring devices and link malfunctions.

To prevent excessive LLDP traps from being sent when topology is unstable, set a trap transmit interval for LLDP.

Follow these steps to configure LLDP trapping:

To do…		Use the command…	Remarks
Enter system view		system-view	—
Enter Ethernet interface view or port group view	Enter Layer 2 Ethernet interface view	interface interface-type interface-number	Required Use either command.
	Enter port group view	port-group manual port-group-name
Enable LLDP trapping		lldp notification remote-change enable	Required Disabled by default.
Return to system view		quit	—
Set the LLDP trap transmit interval		lldp timer notification-interval interval	Optional 5 seconds by default.

 

Displaying and maintaining LLDP

To do…	Use the command…	Remarks
Display the global LLDP information or the information contained in the LLDP TLVs to be sent through a port	display lldp local-information [ global | interface interface-type interface-number ] [ | { begin | exclude | include } regular-expression ]	Available in any view
Display the information contained in the LLDP TLVs sent from neighboring devices	display lldp neighbor-information [ brief | interface interface-type interface-number [ brief ] | list [ system-name system-name ] ] [ | { begin | exclude | include } regular-expression ]	Available in any view
Display LLDP statistics	display lldp statistics [ global | interface interface-type interface-number ] [ | { begin | exclude | include } regular-expression ]	Available in any view
Display LLDP status of a port	display lldp status [ interface interface-type interface-number ] [ | { begin | exclude | include } regular-expression ]	Available in any view
Display types of advertisable optional LLDP TLVs	display lldp tlv-config [ interface interface-type interface-number ] [ | { begin | exclude | include } regular-expression ]	Available in any view

 

LLDP configuration examples

Basic LLDP configuration example

Network requirements

As shown in Figure 4, the NMS and Switch A are located in the same Ethernet. An MED device and Switch B are connected to GigabitEthernet 1/0/1 and GigabitEthernet 1/0/2 of Switch A.

Enable LLDP on the ports of Switch A and Switch B to monitor the link between Switch A and Switch B and the link between Switch A and the MED device on the NMS.

Figure 4 Network diagram for basic LLDP configuration

 

Configuration procedure

1.        Configure Switch A

# Enable LLDP globally.

<SwitchA> system-view

[SwitchA] lldp enable

# Enable LLDP on GigabitEthernet 1/0/1 and GigabitEthernet 1/0/2 (you can skip this step because LLDP is enabled on ports by default), and set the LLDP operating mode to Rx.

[SwitchA] interface gigabitethernet 1/0/1

[SwitchA-GigabitEthernet1/0/1] lldp enable

[SwitchA-GigabitEthernet1/0/1] lldp admin-status rx

[SwitchA-GigabitEthernet1/0/1] quit

[SwitchA] interface gigabitethernet 1/0/2

[SwitchA-GigabitEthernet1/0/2] lldp enable

[SwitchA-GigabitEthernet1/0/2] lldp admin-status rx

[SwitchA-GigabitEthernet1/0/2] quit

2.        Configure Switch B

# Enable LLDP globally.

<SwitchB> system-view

[SwitchB] lldp enable

# Enable LLDP on GigabitEthernet1/0/1 (you can skip this step because LLDP is enabled on ports by default), and set the LLDP operating mode to Tx.

[SwitchB] interface gigabitethernet 1/0/1

[SwitchB-GigabitEthernet1/0/1] lldp enable

[SwitchB-GigabitEthernet1/0/1] lldp admin-status tx

[SwitchB-GigabitEthernet1/0/1] quit

3.        Verify the configuration

# Display the global LLDP status and port LLDP status on Switch A.

[SwitchA] display lldp status

Global status of LLDP: Enable

The current number of LLDP neighbors: 2

The current number of CDP neighbors: 0

LLDP neighbor information last changed time: 0 days,0 hours,4 minutes,40 seconds

Transmit interval              : 30s

Hold multiplier                : 4

Reinit delay                   : 2s

Transmit delay                 : 2s

Trap interval                  : 5s

Fast start times               : 3

 

Port 1 [GigabitEthernet1/0/1]:

Port status of LLDP            : Enable

Admin status                   : Rx_Only

Trap flag                      : No

Polling interval               : 0s

 

Number of neighbors:             1

Number of MED neighbors        : 1

Number of CDP neighbors        : 0

Number of sent optional TLV    : 0

Number of received unknown TLV : 0

 

Port 2 [GigabitEthernet1/0/2]:

Port status of LLDP            : Enable

Admin status                   : Rx_Only

Trap flag                      : No

Polling interval               : 0s

 

Number of neighbors:             1

Number of MED neighbors        : 0

Number of CDP neighbors        : 0

Number of sent optional TLV    : 0

Number of received unknown TLV : 3

As the sample output shows, GigabitEthernet 1/0/1 of Switch A connects to a MED device, and GigabitEthernet 1/0/2 of Switch A connects to a non-MED device. Both ports operate in Rx mode, and they only receive LLDPDUs.

# Tear down the link between Switch A and Switch B and then display the global LLDP status and port LLDP status on Switch A.

[SwitchA] display lldp status

Global status of LLDP: Enable

The current number of LLDP neighbors: 1

The current number of CDP neighbors: 0

LLDP neighbor information last changed time: 0 days,0 hours,5 minutes,20 seconds

Transmit interval              : 30s

Hold multiplier                : 4

Reinit delay                   : 2s

Transmit delay                 : 2s

Trap interval                  : 5s

Fast start times               : 3

 

Port 1 [GigabitEthernet1/0/1]:

Port status of LLDP            : Enable

Admin status                   : Rx_Only

Trap flag                      : No

Polling interval               : 0s

 

Number of neighbors             : 1

Number of MED neighbors         : 1

Number of CDP neighbors         : 0

Number of sent optional TLV     : 0

Number of received unknown TLV  : 5

 

Port 2 [GigabitEthernet1/0/2]:

Port status of LLDP            : Enable

Admin status                   : Rx_Only

Trap flag                      : No

Polling interval               : 0s

 

Number of neighbors             : 0

Number of MED neighbors         : 0

Number of CDP neighbors         : 0

Number of sent optional TLV     : 0

Number of received unknown TLV  : 0

As the sample output shows, GigabitEthernet 1/0/2 of Switch A does not connect to any neighboring devices.

CDP-compatible LLDP configuration example

Network requirements

As shown in Figure 5:

·          GigabitEthernet 1/0/1 and GigabitEthernet 1/0/2 of Switch A are each connected to a Cisco IP phone.

·          Configure voice VLAN 2 on Switch A. Enable CDP compatibility of LLDP on Switch A to allow the Cisco IP phones to automatically configure the voice VLAN, confining their voice traffic within the voice VLAN to be isolated from other types of traffic.

Figure 5 Network diagram for CDP-compatible LLDP configuration

 

Configuration procedure

1.        Configure a voice VLAN on Switch A

# Create VLAN 2.

<SwitchA> system-view

[SwitchA] vlan 2

[SwitchA-vlan2] quit

# Set the link type of GigabitEthernet 1/0/1 and GigabitEthernet 1/0/2 to trunk and enable voice VLAN on them.

[SwitchA] interface gigabitethernet 1/0/1

[SwitchA-GigabitEthernet1/0/1] port link-type trunk

[SwitchA-GigabitEthernet1/0/1] voice vlan 2 enable

[SwitchA-GigabitEthernet1/0/1] quit

[SwitchA] interface gigabitethernet 1/0/2

[SwitchA-GigabitEthernet1/0/2] port link-type trunk

[SwitchA-GigabitEthernet1/0/2] voice vlan 2 enable

[SwitchA-GigabitEthernet1/0/2] quit

2.        Configure CDP-compatible LLDP on Switch A

# Enable LLDP globally and enable LLDP to be compatible with CDP globally.

[SwitchA] lldp enable

[SwitchA] lldp compliance cdp

# Enable LLDP (you can skip this step because LLDP is enabled on ports by default), configure LLDP to operate in TxRx mode, and configure CDP-compatible LLDP to operate in TxRx mode on GigabitEthernet 1/0/1 and GigabitEthernet 1/0/2.

[SwitchA] interface gigabitethernet 1/0/1

[SwitchA-GigabitEthernet1/0/1] lldp enable

[SwitchA-GigabitEthernet1/0/1] lldp admin-status txrx

[SwitchA-GigabitEthernet1/0/1] lldp compliance admin-status cdp txrx

[SwitchA-GigabitEthernet1/0/1] quit

[SwitchA] interface gigabitethernet 1/0/2

[SwitchA-GigabitEthernet1/0/2] lldp enable

[SwitchA-GigabitEthernet1/0/2] lldp admin-status txrx

[SwitchA-GigabitEthernet1/0/2] lldp compliance admin-status cdp txrx

[SwitchA-GigabitEthernet1/0/2] quit

3.        Verify the configuration

# Display the neighbor information on Switch A.

[SwitchA] display lldp neighbor-information

 

CDP neighbor-information of port 1[GigabitEthernet1/0/1]:

  CDP neighbor index : 1

  Chassis ID         : SEP00141CBCDBFE

  Port ID            : Port 1

  Sofrware version   : P0030301MFG2

  Platform           : Cisco IP Phone 7960

  Duplex             : Full

 

CDP neighbor-information of port 2[GigabitEthernet1/0/2]:

  CDP neighbor index : 2

  Chassis ID         : SEP00141CBCDBFF

  Port ID            : Port 1

  Sofrware version   : P0030301MFG2

  Platform           : Cisco IP Phone 7960

  Duplex             : Full

As the sample output shows, Switch A has discovered the IP phones connected to GigabitEthernet 1/0/1 and GigabitEthernet 1/0/2, and has obtained their LLDP device information.