Configuring LLDP

This section describes points to note regarding LLDP and CDP (Cisco Discovery Protocol) data received by the switch from other devices. LLDP operation includes both transmitting LLDP packets to neighbor devices and reading LLDP packets received from neighbor devices. CDP operation is limited to reading incoming CDP packets from neighbor devices. (HP switches do not generate CDP packets.)

Incoming CDP and LLDP packets tagged for VLAN 1 are processed even if VLAN 1 does not contain any ports. VLAN 1 must be present, but it is typically present as the default VLAN for the switch.

	NOTE: The switch may pick up CDP and LLDP multicast packets from VLAN 1 even when CDP- and /or LLDP-enabled ports are not members of VLAN 1.

LLDP and CDP neighbor data

With both LLDP and (read-only) CDP enabled on a switch port, the port can read both LLDP and CDP advertisements, and stores the data from both types of advertisements in its neighbor database. (The switch stores only CDP data that has a corresponding field in the LLDP neighbor database.) The neighbor database itself can be read by either LLDP or CDP methods or by using the show lldp commands. Take note of the following rules and conditions:

• If the switch receives both LLDP and CDP advertisements on the same port from the same neighbor, the switch stores this information as two separate entries if the advertisements have different chassis ID and port ID information.

• If the chassis and port ID information are the same, the switch stores this information as a single entry. That is, LLDP data overwrites the corresponding CDP data in the neighbor database if the chassis and port ID information in the LLDP and CDP advertisements received from the same device is the same.

• Data read from a CDP packet does not support some LLDP fields, such as "System Descr," "SystemCapSupported," and "ChassisType." For such fields, LLDP assigns relevant default values. Also:

  • The LLDP "System Descr" field maps to CDP's "Version" and "Platform" fields.

  • The switch assigns "ChassisType" and "PortType" fields as "local" for both the LLDP and the CDP advertisements it receives.

  • Both LLDP and CDP support the "System Capability" TLV. However, LLDP differentiates between what a device is capable of supporting and what it is actually supporting, and separates the two types of information into subelements of the System Capability TLV. CDP has only a single field for this data. Thus, when CDP System Capability data is mapped to LLDP, the same value appears in both LLDP System Capability fields.

  • System Name and Port Descr are not communicated by CDP, and thus are not included in the switch's Neighbors database.

	NOTE: Because HP switches do not generate CDP packets, they are not represented in the CDP data collected by any neighbor devices running CDP. A switch with CDP disabled forwards the CDP packets it receives from other devices, but does not store the CDP information from these packets in its own MIB.

LLDP data transmission/collection and CDP data collection are both enabled in the switch's default configuration. In this state, an SNMP network management application designed to discover devices running either CDP or LLDP can retrieve neighbor information from the switch regardless of whether LLDP or CDP is used to collect the device-specific information.

Protocol state	Packet generation	Inbound data management	Inbound packet forwarding
CDP Enabled[1]	N/A	Store inbound CDP data.	No forwarding of inbound CDP packets.
CDP Disabled	N/A	No storage of CDP data from neighbor devices.	Floods inbound CDP packets from connected devices to outbound ports.
LLDP Enabled1	Generates and transmits LLDP packets out all ports on the switch.	Store inbound LLDP data.	No forwarding of inbound LLDP packets.
LLDP Disabled	No packet generation.	No storage of LLDP data from neighbor devices.	No forwarding of inbound LLDP packets.
[1] Both CDP data collection and LLDP transmit/receive are enabled in the default configuration. If a switch receives CDP packets and LLDP packets from the same neighbor device on the same port, it stores and displays the two types of information separately if the chassis and port ID information in the two types of advertisements is different. In this case, if you want to use only one type of data from a neighbor sending both types, disable the unwanted protocol on either the neighbor device or on the switch. However, if the chassis and port ID information in the two types of advertisements is the same, the LLDP information overwrites the CDP data for the same neighbor device on the same port.

CDP operations

By default the switches have CDP enabled on each port. This is a read-only capability, meaning that the switch can receive and store information about adjacent CDP devices but does not generate CDP packets.

When a CDP-enabled switch receives a CDP packet from another CDP device, it enters that device's data in the CDP Neighbors table, along with the port number where the data was received—and does not forward the packet. The switch also periodically purges the table of any entries that have expired. (The hold time for any data entry in the switch's CDP Neighbors table is configured in the device transmitting the CDP packet and cannot be controlled in the switch receiving the packet.) A switch reviews the list of CDP neighbor entries every three seconds and purges any expired entries.

	NOTE: For details on how to use an SNMP utility to retrieve information from the switch's CDP Neighbors table maintained in the switch's MIB, see the documentation provided with the particular SNMP utility.

To standardize device discovery on all HP switches, LLDP will be implemented while offering limited read-only support for CDP, as documented in this manual. For the latest information on your switch model, consult the Release Notes (available on the HP Networking website.) If LLDP has not yet been implemented (or if you are running an older version of software), consult a previous version of the Management and Configuration Guide for device discovery details.

	NOTE: LLDP-MED is an extension for LLDP, and the switch requires that LLDP be enabled as a prerequisite to LLDP-MED operation.

An SNMP utility can progressively discover LLDP devices in a network by:

Also, by using show commands to access the switch's neighbor database for information collected by an individual switch, system administrators can learn about other devices connected to the switch, including device type (capability) and some configuration information. In VoIP deployments using LLDP-MED on the switches, additional support unique to VoIP applications is also available. See LLDP-MED.

xxx.xxx.xxx.xxx: This IP address is not configured or is a DHCP address.

LLDP-MED (ANSI/TIA-1057/D6) extends the LLDP (IEEE 802.1AB) industry standard to support advanced features on the network edge for Voice Over IP (VoIP) endpoint devices with specialized capabilities and LLDP-MED standards-based functionality. LLDP-MED in the switches uses the standard LLDP commands described earlier in this section, with some extensions, and also introduces new commands unique to LLDP-MED operation. The show commands described elsewhere in this section are applicable to both LLDP and LLDP-MED operation. LLDP-MED benefits include:

This section describes how to configure and use LLDP-MED features in the switches to support VoIP network edge devices (media endpoint devices) such as:

LLDP-MED interoperates with directly connected IP telephony (endpoint) clients having these features and services:

	NOTE: LLDP-MED is intended for use with VoIP endpoints and is not designed to support links between network infrastructure devices, such as switch-to-switch or switch-to-router links.

Example of LLDP-MED network elements

LLDP-MED operational support

The switches offer two configurable TLVs supporting MED-specific capabilities:

• medTlvEnable (for per-port enabling or disabling of LLDP-MED operation)

• medPortLocation (for configuring per-port location or emergency call data)

	NOTE: LLDP-MED operation also requires the port speed and duplex TLV (dot3TlvEnable; page 14-41), which is enabled in the default configuration. Topology change notifications provide one method for monitoring system activity. However, because SNMP normally employs UDP, which does not guarantee datagram delivery, topology change notification should not be relied upon as the sole method for monitoring critical endpoint device connectivity.

Syntax

With LLDP enabled on the switch in the default configuration, each port is configured to transmit and receive LLDP packets. These options enable you to control which ports participate in LLDP traffic and whether the participating ports allow LLDP traffic in only one direction or in both directions.

This is an optional command you can use to include a specific IP address in the outbound LLDP advertisements for specific ports.

Syntax

Replaces the default IP address for the port with an IP address you specify. This can be any IP address configured in a static VLAN on the switch, even if the port does not belong to the VLAN configured with the selected IP address.

The no form of the command deletes the specified IP address.

If there are no IP addresses configured as management addresses, the IP address selection method returns to the default operation.

Default: The port advertises the IP address of the lowest-numbered VLAN (VID) to which it belongs. If there is no IP address configured on the VLANs to which the port belongs, and if the port is not configured to advertise an IP address from any other (static) VLAN on the switch, the port advertises an address of 127.0.0.1.)

	NOTE: This command does not accept either IP addresses acquired through DHCP or Bootp, or IP addresses that are not configured in a static VLAN on the switch.

Example

If port 3 belongs to a subnetted VLAN that includes an IP address of 10.10.10.100 and you want port 3 to use this secondary address in LLDP advertisements, you need to execute the following command:

(HP_Switch_name#) lldp config 3 ipAddrEnable 10.10.10.100

Syntax

Example

If you want to exclude the system name TLV from the outbound LLDP advertisements for all ports on a switch, use this command:

(HP_Switch_name#) no lldp config 1-24 basicTlvEnable system_name

If you later decide to reinstate the system name TLV on ports 1-5, use this command:

(HP_Switch_name#) lldp config 1-5 basicTlvEnable system_name

Syntax

For outbound advertisements, this TLV includes the (local) switch port's current speed and duplex settings, the range of speed and duplex settings the port supports, and the method required for reconfiguring the speed and duplex settings on the device (autonegotiation during link initialization, or manual configuration.)

Using SNMP to compare local and remote information can help in locating configuration mismatches.

(Default: Enabled)

	NOTE: For LLDP operation, this TLV is optional. For LLDP-MED operation, this TLV is mandatory.

Syntax

Configures location of emergency call data the switch advertises per port in the location_id TLV. This TLV is for use by LLDP-MED endpoints employing location-based applications.

	NOTE: The switch allows one medPortLocation entry per port (without regard to type.) Configuring a new medPortLocation entry of any type on a port replaces any previously configured entry on that port.

Enables configuration of a physical address on a switch port and allows up to 75 characters of address information.

COUNTRY-STR	A two-character country code, as defined by ISO 3166. Some examples include FR (France), DE (Germany), and IN (India.) This field is required in a civic-addr command. (For a complete list of country codes, visit www.iso.org.)
WHAT	A single-digit number specifying the type of device to which the location data applies: 0: Location of DHCP server 1: Location of switch 2: Location of LLDP-MED endpoint (recommended application) This field is required in a civic-addr command.
Type/Value Pairs [CA-TYPE|CA-VALUE]	A series of data pairs, each composed of a location data "type" specifier and the corresponding location data for that type. That is, the first value in a pair is expected to be the civic address "type" number (CA-TYPE), and the second value in a pair is expected to be the corresponding civic address data (CA-VALUE.) For example, if the CA-TYPE for "city name" is "3," the type/value pair to define the city of Paris is "3 Paris." Multiple type/value pairs can be entered in any order, although HP recommends that multiple pairs be entered in ascending order of the CA-TYPE. When an emergency call is placed from a properly configured class 3 endpoint device to an appropriate PSAP, the country code, device type, and type/value pairs configured on the switch port are included in the transmission. The "type" specifiers are used by the PSAP to identify and organize the location data components in an understandable format for response personnel to interpret. A civic-addr command requires a minimum of one type/value pair, but typically includes multiple type/value pairs as needed to configure a complete set of data describing a given location. CA-TYPE: This is the first entry in a type/value pair and is a number defining the type of data contained in the second entry in the type/value pair (CA-VALUE.) Some examples of CA-TYPE specifiers include: 3=city 6=street (name) 25=building name (Range: 0 - 255) CA-VALUE: This is the second entry in a type/value pair and is an alphanumeric string containing the location information corresponding to the immediately preceding CA-TYPE entry. Strings are delimited by either blank spaces, single quotes (' … '), or double quotes ("… ".) Each string should represent a specific data type in a set of unique type/value pairs comprising the description of a location, and each string must be preceded by a CA-TYPE number identifying the type of data in the string. NOTE: A switch port allows one instance of any given CA-TYPE. For example, if a type/value pair of 6 Atlantic (to specify "Atlantic" as a street name) is configured on port A5 and later another type/value pair of 6 Pacific is configured on the same port, Pacific replaces Atlantic in the civic address location configured for port A5.
elin-addr emergency-number	This feature is intended for use in ECS applications to support class 3 LLDP-MED VoIP telephones connected to a switch in an MLTS infrastructure. An ELIN is a valid NANP format telephone number assigned to MLTS operators in North America by the appropriate authority. The ELIN is used to route emergency (E911) calls to a PSAP. (Range: 1-15 numeric characters)

Syntax

Enables or disables each port in <PORT-LIST> for sending notification to configured SNMP trap receivers if an LLDP data change is detected in an advertisement received on the port from an LLDP neighbor.

(Default: Disabled)

Example

This command enables SNMP notification on ports 1 - 5:

(HP_Switch_name#) lldp enable-notification 1-5

Syntax

Enables or disables LLDP operation on the switch.

The no form of the command, regardless of individual LLDP port configurations, prevents the switch from transmitting outbound LLDP advertisements and causes the switch to drop all LLDP advertisements received from other devices.

The switch preserves the current LLDP configuration when LLDP is disabled. After LLDP is disabled, the information in the LLDP neighbors database remains until it times-out.

(Default: Enabled)

Example

To disable LLDP on the switch:

(HP_Switch_name#) no lldp run

Syntax

An LLDP-MED device connecting to a switch port may use the data contained in the MED TLVs from the switch to configure itself. However, the lldp refresh-interval setting (default: 30 seconds) for transmitting advertisements can cause an unacceptable delay in MED device configuration.

To support rapid LLDP-MED device configuration, the lldp fast-start-count command temporarily overrides the refresh-interval setting for the fast-start-count advertisement interval. This results in the port initially advertising LLDP-MED at a faster rate for a limited time. Thus, when the switch detects a new LLDP-MED device on a port, it transmits one LLDP-MED advertisement per second out the port for the duration of the fast-start-count interval. In most cases, the default setting should provide an adequate fast-start-count interval.

(Default: 5 seconds)

	NOTE: This global command applies only to ports on which a new LLDP-MED device is detected. It does not override the refresh-interval setting on ports where non-MED devices are detected.

This interval controls how often active ports retransmit advertisements to their neighbors.

Syntax

Changes the interval between consecutive transmissions of LLDP advertisements on any given port.

(Default: 30 seconds)

	NOTE: The refresh-interval must be greater than or equal to (4 x delay-interval.) (The default delay-interval is 2.) For example, with the default delay-interval, the lowest refresh-intervalyou can use is 8 seconds (4 x 2=8.) Thus, if you want a refresh-interval of 5 seconds, you must first change the delay interval to 1 (that is, 4 x 1 5.) If you want to change the delay-interval, use the setmib command.

Syntax

Changes the multiplier an LLDP switch uses to calculate the Time-to-Live for the LLDP advertisements it generates and transmits to LLDP neighbors. When the Time-to-Live for a given advertisement expires, the advertised data is deleted from the neighbor switch's MIB.

(Default: 4; Range 2–10)

Example

If the refresh-interval on the switch is 15 seconds and the holdtime-multiplier is at the default, the Time-to-Live for advertisements transmitted from the switch is 60 seconds (4 x 15.)

To reduce the Time-to-Live, you could lower the holdtime-interval to 2, which would result in a Time-to-Live of 30 seconds.

(HP_Switch_name#) lldp holdtime-multiplier 2

To change the delay interval between advertisements generated by value or status changes to the LLDP MIB, use the following command.

Syntax

Uses setmib to change the minimum time (delay-interval) any LLDP port will delay advertising successive LLDP advertisements because of a change in LLDP MIB content.

(Default: 2; Range 1–8192)

	NOTE: The LLDP refresh-interval (transmit interval) must be greater than or equal to (4 x delay-interval.) The switch does not allow increasing the delay interval to a value that conflicts with this relationship. That is, the switch displays Inconsistent value if (4 x delay-interval) exceeds the current transmit interval, and the command fails. Depending on the current refresh-interval setting, it may be necessary to increase the refresh-interval before using this command to increase the delay-interval.

	NOTE: For the 5400zl, 3800, and 8200zl switches, when the switch is in enhanced secure mode, the following prompt appears before the sensitive information for the setmib command is displayed: The setmib command should not be used in enhanced secure mode. For more information, see the Access Security Guide.

Example

To change the delay-interval from 2 seconds to 8 seconds when the refresh-interval is at the default 30 seconds, you must first set the refresh-interval to a minimum of 32 seconds (32 = 4 x 8.) (See Changing the transmit-delay interval.)

Changing the transmit-delay interval

Syntax

Uses setmib to change the minimum time (reinitialization delay interval) an LLDP port will wait before reinitializing after receiving an LLDP disable command followed closely by a txonly or tx_rx command. The delay interval commences with execution of the lldp admin-status <PORT-LIST> disable command.

(Default: 2 seconds; Range 1–10 seconds)

Example

The following command changes the reinitialization delay interval to five seconds:

(HP_Switch_name#) setmib lldpreinitdelay.0 -i 5

This enhancement filters out PVID mismatch log messages on a per-port basis. PVID mismatches are logged when there is a difference in the PVID advertised by a neighboring switch and the PVID of the switch port which receives the LLDP advertisement. Logging is an LLDP feature that allows detection of possible vlan leakage between adjacent switches. However, if these events are logged too frequently, they can overwhelm the log buffer and push relevant logging data out of log memory, making it difficult to troubleshoot another issue.

Logging is disabled and enabled with the support of CLI commands.

This enhancement also includes displaying the Mac-Address in the PVID mismatch log message when the port ID is Mac-Address instead of displaying garbage characters in the peer device port ID field.

Use the following command to disable the logging of the PVID mismatch log messages:

Syntax

Syntax

Syntax

Displays the LLDP port-specific configuration for all ports in <PORT-LIST> , including which optional TLVs and any non-default IP address that are included in the port's outbound advertisements.

Per-port configuration display

Syntax

Without the <PORT-LIST> option, displays the global switch information and the per-port information currently available for populating outbound LLDP advertisements.

With the <PORT-LIST> option, displays only the following port-specific information that is currently available for outbound LLDP advertisements on the specified ports:

	NOTE: This command displays the information available on the switch. Use the lldp config <PORT-LIST> command to change the selection of information that is included in actual outbound advertisements. In the default LLDP configuration, all information displayed by this command is transmitted in outbound advertisements.

Example

In the default configuration, the switch information currently available for outbound LLDP advertisements appears similar to the display in Displaying the global and per-port information available for outbound advertisements.

Displaying the global and per-port information available for outbound advertisements

(HP_Switch_name#) show lldp info local 1-2

  LLDP Local Port Information Detail

   Port     : 1
   PortType : local
   PortId   : 1
   PortDesc : 1

---------------------------------------- 
   Port     : 2
   PortType : local
   PortId   : 2
   PortDesc : 2

Syntax

The global LLDP statistics command displays an overview of neighbor detection activity on the switch, plus data on the number of frames sent, received, and discarded per-port.

The per-port LLDP statistics command enhances the list of per-port statistics provided by the global statistics command with some additional per-port LLDP statistics.

Global LLDP Counters:

Per-Port LLDP Counters:

Examples

(HP_Switch_name#) show lldp stats

 LLDP Device Statistics

  Neighbor Entries List Last Updated : 2 hours
  New Neighbor Entries Count : 20
  Neighbor Entries Deleted Count : 20
  Neighbor Entries Dropped Count : 0
  Neighbor Entries AgeOut Count : 20

 LLDP Port Statistics
 
  Port   | NumFramesRecvd NumFramesSent NumFramesDiscarded
  ------ + -------------- ------------- ------------------ 
  A1     | 97317          97843         0
  A2     | 21             12            0
  A3     | 0              0             0
  A4     | 446            252           0
  A5     | 0              0             0
  A6     | 0              0             0
  A7     | 0              0             0
  A8     | 0              0             0

(HP_Switch_name#) show lldp stats 1

 LLDP Port Statistics Detail

  PortName : 1
  Frames Discarded  : 0
  Frames Invalid    : 0
  Frames Received   : 7309
  Frames Sent       : 7231
  TLVs Unrecognized : 0
  TLVs Discarded    : 0
  Neighbor Ageouts  : 0

In the default configuration, LLDP is enabled and in both transmit and receive mode on all active ports. The LLDP configuration includes global settings that apply to all active ports on the switch, and per-port settings that affect only the operation of the specified ports.

The commands in this section affect both LLDP and LLDP-MED operation.

Syntax

Displays the LLDP global configuration, LLDP port status, and SNMP notification status.

Example of viewing the general LLDP configuration

show lldp config produces the following display when the switch is in the default LLDP configuration:

(HP_Switch_name#) show lldp config

LLDP Global Configuration

LLDP Enabled [Yes] :             Yes
LLDP Transmit Interval [30] :    30
LLDP Hold time Multiplier [4] :  4
LLDP Delay Interval [2] :        2
LLDP Reinit Interval [2] :       2
LLDP Notification Interval [5] : 5
LLDP Fast Start Count [5] :      5

LLDP Port Configuration
Port | AdminStatus NotificationEnabled  Med Topology Trap Enabled
---- + ----------- -------------------  -------------------------
A1 |    Tx_Rx          False            False
A2 |    Tx_Rx          False            False
A3 |    Tx_Rx          False            False
A4 |    Tx_Rx          False            False
A5 |    Tx_Rx          False            False
A6 |    Tx_Rx          False            False
A7 |    Tx_Rx          False            False
A8 |    Tx_Rx          False            False

	NOTE: The values displayed in the LLDP column correspond to the lldp refresh-interval command

This optional feature provides information an SNMP application can use to track LLDP-MED connects and disconnects.

Syntax

Topology change notification, when enabled on an LLDP port, causes the switch to send an SNMP trap if it detects LLDP-MED endpoint connection or disconnection activity on the port, or an age-out of the LLDP-MED neighbor on the port. The trap includes the following information:

The show running command shows whether the topology change notification feature is enabled or disabled. For example, if ports A1 to A10 have topology change notification enabled, the following entry appears in the show running output:

lldp top-change-notify A1-A10

(Default: Disabled)

	NOTE: To send traps, this feature requires access to at least one SNMP server. If a detected LLDP-MED neighbor begins sending advertisements without LLDP-MED TLVs, the switch sends a top-change-notify trap.

The medTlvEnable option on the switch is enabled in the default configuration and supports the following LLDP-MED TLVs:

	NOTE: LLDP-MED operation requires the macphy_config TLV subelement (enabled by default) that is optional for IEEE 802.1AB LLDP operation. For more information, see the dot3TlvEnable macphy_config command.

Policy elements

These policy elements may be statically configured on the switch or dynamically imposed during an authenticated session on the switch using a RADIUS server and 802.1X or MAC authentication. (Web authentication does not apply to VoIP telephones and other telecommunications devices that are not capable of accessing the switch through a Web browser.) The QoS and voice VLAN policy elements can be statically configured with the following CLI commands:

vlan vid voice

vlan vid tagged | untagged <PORT-LIST>

int <PORT-LIST> qos priority 0 - 7

vlan vid qos dscp codepoint

	NOTE: A codepoint must have an 802.1p priority before you can configure it for use in prioritizing packets by VLAN-ID. If a codepoint you want to use shows No Override in the Priority column of the DSCP policy table (display with show qos-dscp map, then use qos-dscp map codepoint priority 0 - 7 to configure a priority before proceeding. For more information on this topic, see the Advanced Traffic Management Guide.

Location data for LLDP-MED devices

You can configure a switch port to advertise location data for the switch itself, the physical wall-jack location of the endpoint (recommended), or the location of a DHCP server supporting the switch, endpoint, or both. You also have the option of configuring these different address types:

Civic address	Physical address data such as city, street number, and building information.
ELIN (Emergency Location Identification Number)	An emergency number typically assigned to MLTS (Multiline Telephone System) Operators in North America.
Coordinate-based location	Attitude, longitude, and altitude information (Requires configuration via an SNMP application.)

Configuring coordinate-based locations

Latitude, longitude, and altitude data can be configured per switch port using an SNMP management application. For more information, see the documentation provided with the application. A further source of information on this topic is the RFC 3825: Dynamic Host Configuration Protocol Option for Coordinate-based Location Configuration Information.

	NOTE: Endpoint use of data from a medPortLocation TLV sent by the switch is device-dependent. See the documentation provided with the endpoint device.

The code assignments in the following table are examples from a work-in-progress (the internet draft titled "Dynamic Host Configuration Protocol (DHCPv4 and DHCPv6) Option for Civic Addresses Configuration Information draft-ietf-geopriv-dhcp-civil-06" dated May 30, 2005.) For the actual codes to use, contact the PSAP or other authority responsible for specifying the civic addressing data standard for your network.

Some location codes used in CA-TYPE fields

Location element	Code	Location element	Code
national subdivision	1	street number	19
regional subdivision	2	additional location data	22
city or township	3	unit or apartment	26
city subdivision	4	floor	27
street	6	room number	28
street suffix	18

Example

Suppose a system operator wants to configure the following information as the civic address for a telephone connected to her company's network through port A2 of a switch at the following location:

Description	CA-type	CA-VALUE
national subdivision	1	CA
city	3	Widgitville
street	6	Main
street number	19	1433
unit	26	Suite 4-N
floor	27	4
room number	28	N4-3

Example of a civic address configuration shows the commands for configuring and displaying the above data.

Example of a civic address configuration

(HP_Switch_name#) lldp config 2 medportlocation civic-addr US 2 1 CA 3
Widgitville 6 Main 19 1433 26 Suite_4—N 27 4 28 N4—3

(HP_Switch_name#) show lldp config 2
 LLDP Port Configuration Detail
  Port : A2
  AdminStatus [Tx_Rx] : Tx_Rx
  NotificationEnabled [False] : False
  Med Topology Trap Enabled [False] : False
  Country Name          : US 
  What                  : 2
  Ca-Type               : 1
  Ca-Length             : 2
  Ca-Value              : CA 
  Ca-Type               : 3
  Ca-Length             : 11
  Ca-Value              : Widgitville
  Ca-Type               : 6
  Ca-Length             : 4
  Ca-Value              : Main
  Ca-Type               : 19
  Ca-Length             : 4
  Ca-Value              : 1433
  Ca-Type               : 26
  Ca-Length             : 9
  Ca-Value              : Suite_4-N 
  Ca-Type               : 27
  Ca-Length             : 1
  Ca-Value              : 4
  Ca-Type               : 28
  Ca-Length             : 4
  Ca-Value              : N4-3

LLDP operating notes

Neighbor maximum

The neighbors table in the switch supports as many neighbors as there are ports on the switch. The switch can support multiple neighbors connected through a hub on a given port, but if the switch neighbor maximum is reached, advertisements from additional neighbors on the same or other ports will not be stored in the neighbors table unless some existing neighbors time-out or are removed.

LLDP packet forwarding

An 802.1D-compliant switch does not forward LLDP packets, regardless of whether LLDP is globally enabled or disabled on the switch.

One IP address advertisement per port

LLDP advertises only one IP address per port, even if multiple IP addresses are configured by lldp config <PORT-LIST> ipAddrEnable (see syntax) on a given port.

802.1Q VLAN information

LLDP packets do not include 802.1Q header information and are always handled as untagged packets.

Effect of 802.1X operation

If 802.1X port security is enabled on a port, and a connected device is not authorized, LLDP packets are not transmitted or received on that port. Any neighbor data stored in the neighbor MIB for that port prior to the unauthorized device connection remains in the MIB until it ages out. If an unauthorized device later becomes authorized, LLDP transmit and receive operation resumes.

Disconnecting a neighbor LLDP device

After disconnecting a neighbor LLDP device from the switch, the neighbor can continue to appear in the switch's neighbor database for an extended period if the neighbor's holdtime-multiplier is high; especially if the refresh-interval is large. See Changing the time-to-live for transmitted advertisements.

Mandatory TLVs

All mandatory TLVs required for LLDP operation are also mandatory for LLDP-MED operation.

Enabling topology change notification

Enabling topology change notification on a switch port and then connecting or disconnecting an LLDP-MED endpoint on that port causes the switch to send an SNMP trap to notify the designated management stations. The port number included in the trap corresponds to the internal number the switch maintains for the designated port, and not the port's external (slot/number) identity. To match the port's external slot/number to the internal port number appearing in an SNMP trap, use the walkmib ifDescr command, as shown in Matching internal port numbers to external slot/port numbers.

Matching internal port numbers to external slot/port numbers

Syntax

Without the <PORT-LIST> option, provides a global list of the individual devices it has detected by reading LLDP advertisements. Discovered devices are listed by the inbound port on which they were discovered.

Multiple devices listed for a single port indicates that such devices are connected to the switch through a hub.

Discovering the same device on multiple ports indicates that the remote device may be connected to the switch in one of the following ways:

With the <PORT-LIST> option, provides a listing of the LLDP data that the switch has detected in advertisements received on the specified ports.

For descriptions of the various types of information displayed by these commands, see Table 6-4.

Examples

(HP_Switch_name#) show lldp info remote

 LLDP Remote Devices Information

  LocalPort | ChassisId                 PortId PortDescr SysName
  --------- + ------------------------- ------ --------- -------------
  1         | 00 11 85 35 3b 80         6      6         HP Switch 3500yl
  2         | 00 11 85 cf 66 60         8      8         HP Switch 3500yl

An LLLDP-MED listing of an advertisement received from an LLDP-MED (VoIP telephone) source

To display the current power data for an LLDP-MED device connected to a port, use the following command:

show lldp info remote-device <PORT-LIST>

To display the current PoE configuration on the switch, use the following commands: