Configuring LLDP· 1

Overview·· 1

Basic concepts 1

Working mechanism·· 5

Protocols and standards 6

LLDP configuration task list 6

Performing basic LLDP configuration· 6

Enabling LLDP· 6

Setting LLDP operating mode· 7

Setting the LLDP re-initialization delay· 7

Enabling LLDP polling· 8

Configuring the advertisable TLVs 8

Configuring the management address and its encoding format 9

Setting other LLDP parameters 10

Configuring the encapsulation format for LLDP frames 11

Configuring CDP compatibility· 11

Configuration prerequisites 12

Configuration procedure· 12

Configuring LLDP trapping· 12

Displaying and maintaining LLDP· 13

LLDP configuration examples 14

Basic LLDP configuration example· 14

CDP-compatible LLDP configuration example· 16

 

Overview

In a heterogeneous network, a standard configuration exchange platform makes sure different types of network devices from different vendors can discover one another and exchange configuration.

The Link Layer Discovery Protocol (LLDP) is specified 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 as TLV (type, length, and value) triplets in LLDP Data Units (LLDP frames) to the directly connected devices. Local device information includes its system capabilities, management IP address, device ID, port ID, and so on. The device stores the device information in LLDP frames from the LLDP neighbors in a standard MIB. For more information about MIBs, see Network Management and Monitoring Configuration Guide. LLDP enables a network management system to quickly detect and identify Layer 2 network topology changes.

Basic concepts

LLDP frame formats

LLDP sends device information in LLDP frames. LLDP frames are encapsulated in Ethernet II or SNAP frames.

1.     Ethernet II-encapsulated LLDP frame

Figure 1 Ethernet II-encapsulated LLDP frame

 

Table 1 Fields in an Ethernet II-encapsulated LLDP frame

Field	Description
Destination MAC address	MAC address to which the LLDP frame is advertised. It is fixed to 0x0180-C200-000E, a multicast MAC address.
Source MAC address	MAC address of the sending port.
Type	Ethernet type for the upper layer protocol. This field 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 LLDP frame

Figure 2 SNAP-encapsulated LLDP frame

 

Table 2 Fields in a SNAP-encapsulated LLDP frame

Field	Description
Destination MAC address	MAC address to which the LLDP frame is advertised. It is fixed at 0x0180-C200-000E, a multicast MAC address.
Source MAC address	MAC address of the sending port.
Type	SNAP type for the upper layer protocol. This field 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 TLVs. Each TLV carries a 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

A TLV is an information element that contains the type, length, and value fields.

LLDPDU TLVs include 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.

·     Basic management TLVs

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

Table 3 Basic management 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. ·     Otherwise, 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.

 

·     IEEE 802.1 organizationally specific TLVs

Table 4 IEEE 802.1 organizationally specific TLVs

Type	Description
Port VLAN ID	Port 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: ·     H3C devices support only receiving protocol identity TLVs. ·     Layer 3 Ethernet ports do not support IEEE 802.1 organizationally specific TLVs.

 

·     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 autonegotiation, enabling status of autonegotiation, and the current rate and duplex mode.
Power Via MDI	Contains the power supply capability of the port: ·     Port class (PSE or PD). ·     Power supply mode. ·     Whether PSE power supply is supported. ·     Whether PSE power supply is enabled. ·     Whether pair selection can be controlled.
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: ·     Power supply mode of the PSE/PD. ·     PSE/PD priority. ·     PSE/PD power.

 

NOTE: The Power Stateful Control TLV is defined in IEEE P802.3at D1.0 and is not supported in later versions. 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 network management system uses the management address of a device to identify and manage the device for topology maintenance and network management. The management address is encapsulated in the management address TLV.

Working mechanism

LLDP operating modes

LLDP can operate in one of the following modes:

·     TxRx mode—A port in this mode can send and receive LLDP frames.

·     Tx mode—A port in this mode can only send LLDP frames.

·     Rx mode—A port in this mode can only receive LLDP frames.

·     Disable mode—A port in this mode cannot send or receive LLDP frames.

Each time the LLDP operating mode of an LLDP agent changes, its LLDP protocol state machine re-initializes. A configurable reinitialization delay prevents frequent initializations caused by frequent changes to the operating mode. If you configure the reinitialization delay, an LLDP agent must wait the specified amount of time to initialize LLDP after the LLDP operating mode changes.

Transmitting LLDP frames

An LLDP-enabled port operating in TxRx mode or Tx mode sends LLDP frames to its directly connected devices both periodically and when the local configuration changes. To prevent LLDP frames from overwhelming the network during times of frequent changes to local device information, LLDP adds a frame transmission interval between two successive LLDP frames.

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

·     A new neighbor is discovered. A new LLDP frame 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.

The fast LLDP frame transmission mechanism successively sends the specified number of LLDP frames at a 1-second interval. The mechanism helps LLDP neighbors discover the local device as soon as possible. Then, the normal LLDP frame transmission interval resumes.

Receiving LLDP frames

An LLDP-enabled port operating in TxRx mode or Rx mode confirms the validity of TLVs carried in every received LLDP frame. If the TLVs are 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 LLDP frame. When the TTL value in the Time To Live TLV carried in the LLDP frame becomes zero, the information ages 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

·     DCB Capability Exchange Protocol Specification Rev 1.0

·     DCB Capability Exchange Protocol Base Specification Rev 1.01

LLDP configuration task list

Task		Remarks
Performing basic LLDP configuration	Enabling LLDP	Required.
	Setting 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.
	Configuring the encapsulation format for LLDP frames	Optional.
Configuring CDP compatibility		Optional.
Configuring LLDP trapping		Optional.

 

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

To enable LLDP:

 

Step	Command	Remarks
1.     Enter system view.	system-view	N/A
2.     Enable LLDP globally.	lldp enable	By default, LLDP is enabled on ports, but disabled globally.
3.     Enter Ethernet interface view or port group view.	·     Enter Layer 2 or Layer 3 Ethernet interface view: interface interface-type interface-number ·     Enter port group view: port-group manual port-group-name	Use either command.
4.     Enable LLDP.	lldp enable	Optional. By default, LLDP is enabled on a port.

 

Setting LLDP operating mode

Step	Command	Remarks
1.     Enter system view.	system-view	N/A
2.     Enter Ethernet interface view or port group view.	·     Enter Layer 2 or Layer 3 Ethernet interface view: interface interface-type interface-number ·     Enter port group view: port-group manual port-group-name	Use either command.
3.     Set the LLDP operating mode.	lldp admin-status { disable | rx | tx | txrx }	Optional. The default setting is TxRx.

 

Setting the LLDP re-initialization delay

When the LLDP operating mode changes on a port, the port initializes the protocol state machines after an LLDP reinitialization delay. By adjusting the delay, you can avoid frequent initializations caused by frequent changes to the LLDP operating mode on a port.

To set the LLDP reinitialization delay for ports:

 

Step	Command	Remarks
1.     Enter system view.	system-view	N/A
2.     Set the LLDP reinitialization delay.	lldp timer reinit-delay delay	Optional. The default setting is 2 seconds.

 

Enabling LLDP polling

With LLDP polling enabled, the switch periodically searches for local configuration changes. When the device detects a configuration change, it sends LLDP frames to inform neighboring switches of the change.

To enable LLDP polling on the specified port or ports:

 

Step	Command	Remarks
1.     Enter system view.	system-view	N/A
2.     Enter Ethernet interface view or port group view.	·     Enter Layer 2 or Layer 3 Ethernet interface view: interface interface-type interface-number ·     Enter port group view: port-group manual port-group-name	Use either command.
3.     Enable LLDP polling and set the polling interval.	lldp check-change-interval interval	By default, LLDP polling is disabled.

 

Configuring the advertisable TLVs

Step	Command	Remarks
1.     Enter system view.	system-view	N/A
2.     Enter Ethernet interface view or port group view.	·     Enter Layer 2 or Layer 3 Ethernet interface view: interface interface-type interface-number ·     Enter port group view: port-group manual port-group-name	Use either command.
3.     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.
4.     Configure the advertisable TLVs (Layer 3 Ethernet interface view).	lldp tlv-enable { basic-tlv { all | port-description | system-capability | system-description | system-name } | 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 } | power-over-ethernet } }	Optional. By default, all types of LLDP TLVs, except IEEE 802.1 organizationally specific TLVs, network policy TLVs, and location identification TLVs, are advertisable on a Layer 3 Ethernet port.

 

Configuring the management address and its encoding format

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

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

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

 

Step		Command	Remarks
1.     Enter system view.		system-view	N/A
2.     Enter Ethernet interface view or port group view.		·     Enter Layer 2 or Layer 3 Ethernet interface view: interface interface-type interface-number ·     Enter port group view: port-group manual port-group-name	Use either command.
3.     Allow LLDP to advertise the management address in LLDP frames and configure the advertised management address.	lldp management-address-tlv [ ip-address  ]		Optional. By default, the management address is sent through LLDP frames. ·     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. ·     For a Layer 3 Ethernet port, the management address is its own IP address. If no IP address is configured for the Layer 3 Ethernet port, no management address will be advertised.
4.     Configure the encoding format of the management address as string.	lldp management-address-format string		By default, the management address is encoded 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 × LLDP frame transmission interval))

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

Configuration restrictions and guidelines

·     Both the LLDP frame transmission interval and delay must be smaller than the TTL to make sure LLDP neighbors can receive LLDP frames to update information about the switch you are configuring before it is aged out.

·     H3C recommends that you set the LLDP frame transmission interval to be no smaller than four times the LLDP frame transmission delay.

·     If the LLDP frame transmission delay is greater than the LLDP frame transmission interval, the switch uses the LLDP frames transmission delay as the transmission interval.

Configuration procedure

To set related LLDP parameters:

 

Step	Command	Remarks
1.     Enter system view.	system-view	N/A
2.     Set the TTL multiplier.	lldp hold-multiplier value	Optional. The default setting is 4.
3.     Set the LLDP frame transmission interval.	lldp timer tx-interval interval	Optional. The default setting is 30 seconds.
4.     Set LLDP frame transmission delay.	lldp timer tx-delay delay	Optional. The default setting is 2 seconds.
5.     Set the number of LLDP frames sent each time fast LLDP frame transmission is triggered.	lldp fast-count count	Optional. The default setting is 3.

 

Configuring the encapsulation format for LLDP frames

LLDP frames can be encapsulated the following formats:

·     Ethernet II—With Ethernet II encapsulation configured, an LLDP port sends LLDP frames in Ethernet II frames and processes an incoming LLDP frame only when it is Ethernet II encapsulated.

·     SNAP—With SNAP encapsulation configured, an LLDP port sends LLDP frames in SNAP frames and processes an incoming LLDP frame only when it is SNAP encapsulated.

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

To configure the encapsulation format for LLDP frames as SNAP:

 

Step	Command	Remarks
1.     Enter system view.	system-view	N/A
2.     Enter Ethernet interface view or port group view.	·     Enter Layer 2 or Layer 3 Ethernet interface view: interface interface-type interface-number ·     Enter port group view: port-group manual port-group-name	Use either command.
3.     Configure the encapsulation format for LLDP frames as SNAP.	lldp encapsulation snap	Ethernet II encapsulation format applies by default.

 

Configuring CDP compatibility

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

CDP compatibility enables your switch to receive and recognize CDP packets from a Cisco IP phone and respond with CDP packets.

Configuration prerequisites

Before configuring CDP compatibility, complete the following tasks:

·     Enable LLDP globally.

·     Enable LLDP on the port connecting to an IP phone.

·     Configure LLDP to operate in TxRx mode on the port.

Configuration procedure

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 a port, follow these steps:

1.     Enable CDP-compatible LLDP globally.

2.     Configure CDP-compatible LLDP to operate in TxRx mode on the port.

The maximum TTL value that CDP allows is 255 seconds. To make CDP-compatible LLDP work correctly with Cisco IP phones, make sure the product of the TTL multiplier and the LLDP frame transmission interval is less than 255 seconds.

To enable LLDP to be compatible with CDP:

 

Step	Command			Remarks
1.     Enter system view.	system-view			N/A
2.     Enable CDP compatibility globally.	lldp compliance cdp			By default, CDP compatibility is disabled.
3.     Enter Ethernet interface view or port group view.		·     Enter Layer 2 or Layer 3 Ethernet interface view: interface interface-type interface-number ·     Enter port group view: port-group manual port-group-name		Use either command.
4.     Configure CDP-compatible LLDP to operate in TxRx mode.	lldp compliance admin-status cdp txrx		The default setting is disable mode.

 

Configuring LLDP trapping

LLDP trapping notifies the network management system of events such as newly detected neighboring devices and link failures.

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

To configure LLDP trapping:

 

Step	Command	Remarks
1.     Enter system view.	system-view	N/A
2.     Enter Ethernet interface view or port group view.	·     Enter Layer 2 or Layer 3 Ethernet interface view: interface interface-type interface-number ·     Enter port group view: port-group manual port-group-name	Use either command.
3.     Enable LLDP trapping.	lldp notification remote-change enable	By default, LLDP trapping is disabled.
4.     Return to system view.	quit	N/A
5.     Set the LLDP trap transmission interval.	lldp timer notification-interval interval	Optional. The default setting is 5 seconds.

 

Displaying and maintaining LLDP

Task	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 switches.	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

IMPORTANT: By default, Ethernet, VLAN, and aggregate interfaces are in DOWN state. Before configuring these interfaces, use the undo shutdown command to bring them up.

 

Basic LLDP configuration example

Network requirements

As shown in Figure 4, the NMS and Switch A are located in the same Ethernet.

Enable LLDP on the ports of Switch A and Switch B to perform the following tasks:

·     Monitor the link between Switch A and Switch B on the NMS.

·     Monitor the link between Switch A and the MED device on the NMS.

Figure 4 Network diagram

 

Configuration procedure

1.     Configure Switch A:

# Enable LLDP globally.

<SwitchA> system-view

[SwitchA] lldp enable

# Enable LLDP on GigabitEthernet 4/0/1. By default, LLDP is enabled on ports.

[SwitchA] interface gigabitethernet 4/0/1

[SwitchA-GigabitEthernet4/0/1] lldp enable

# Set the LLDP operating mode to Rx on GigabitEthernet 4/0/1.

[SwitchA-GigabitEthernet4/0/1] lldp admin-status rx

[SwitchA-GigabitEthernet4/0/1] quit

# Enable LLDP on GigabitEthernet 4/0/2. By default, LLDP is enabled on ports.

[SwitchA] interface gigabitethernet 4/0/2

[SwitchA-GigabitEthernet4/0/2] lldp enable

# Set the LLDP operating mode to Rx on GigabitEthernet 4/0/2.

[SwitchA-GigabitEthernet4/0/2] lldp admin-status rx

[SwitchA-GigabitEthernet4/0/2] quit

2.     Configure Switch B:

# Enable LLDP globally.

<SwitchB> system-view

[SwitchB] lldp enable

# Enable LLDP on GigabitEthernet 4/0/1. By default, LLDP is enabled on ports.

[SwitchB] interface gigabitethernet 4/0/1

[SwitchB-GigabitEthernet4/0/1] lldp enable

# Set the LLDP operating mode to Tx on GigabitEthernet 4/0/1.

[SwitchB-GigabitEthernet4/0/1] lldp admin-status tx

[SwitchB-GigabitEthernet4/0/1] quit

Verifying the configuration

# Verify the following items:

·     GigabitEthernet 4/0/1 of Switch A connects a MED device.

·     GigabitEthernet 4/0/2 of Switch A connects a non-MED device.

·     Both ports operate in Rx mode, in other words, they only receive LLDP frames.

[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 [GigabitEthernet4/0/1]:

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 [GigabitEthernet4/0/2]:

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

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

# Verify that GigabitEthernet 4/0/2 of Switch A does not connect to any neighboring switches.

[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 [GigabitEthernet4/0/1]:

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 [GigabitEthernet4/0/2]:

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

CDP-compatible LLDP configuration example

Network requirements

As shown in Figure 5, enable CDP compatibility of LLDP on Switch A.

Figure 5 Network diagram

 

Configuration procedure

1.     Configure CDP-compatible LLDP on Switch A:

# Enable LLDP globally, and enable CDP compatibility globally.

[SwitchA] lldp enable

[SwitchA] lldp compliance cdp

# Enable LLDP on GigabitEthernet 4/0/1. By default, LLDP is enabled on ports.

[SwitchA] interface gigabitethernet 4/0/1

[SwitchA-GigabitEthernet4/0/1] lldp enable

# Configure LLDP to operate in TxRx mode on GigabitEthernet 4/0/1.

[SwitchA-GigabitEthernet4/0/1] lldp admin-status txrx

[SwitchA-GigabitEthernet4/0/1] lldp compliance admin-status cdp txrx

[SwitchA-GigabitEthernet4/0/1] quit

# Enable LLDP on GigabitEthernet 4/0/2. By default, LLDP is enabled on ports.

[SwitchA] interface gigabitethernet 4/0/2

[SwitchA-GigabitEthernet4/0/2] lldp enable

# Configure LLDP to operate in TxRx mode on GigabitEthernet 4/0/2.

[SwitchA-GigabitEthernet4/0/2] lldp admin-status txrx

[SwitchA-GigabitEthernet4/0/2] lldp compliance admin-status cdp txrx

[SwitchA-GigabitEthernet4/0/2] quit

2.     Verify the configuration:

# Verify that Switch A has completed the following tasks:

¡     Discovering the IP phones connected to GigabitEthernet 4/0/1 and GigabitEthernet 4/0/2.

¡     Obtaining IP phone information.

[SwitchA] display lldp neighbor-information

 

CDP neighbor-information of port 1[GigabitEthernet4/0/1]:

  CDP neighbor index : 1

  Chassis ID         : SEP00141CBCDBFE

  Port ID            : Port 1

  Software version   : P0030301MFG2

  Platform           : Cisco IP Phone 7960

  Duplex             : Full

 

CDP neighbor-information of port 2[GigabitEthernet4/0/2]:

  CDP neighbor index : 2

  Chassis ID         : SEP00141CBCDBFF

  Port ID            : Port 1

  Sofrware version   : P0030301MFG2

  Platform           : Cisco IP Phone 7960

  Duplex             : Full