Introduction
This article describes the Link Layer Discovery Protocol (LLDP), LLDP for Media Endpoint Devices (LLDP-MED) and Voice VLAN, and general configuration information. LLDP is a Layer 2 protocol defined by the IEEE Standard 802.1AB-2005. LLDP allows network devices to share device-related information to or from directly connected devices on the network. LLDP is designed to be managed with the Simple Network Management Protocol (SNMP), and SNMP-based Network Management Systems (NMS). LLDP can be configured, and the information it provides can be accessed, using either the command line interface or SNMP.
Link Layer Discovery Protocol (LLDP)
LLDP enables Ethernet network devices, such as switches and routers, to transmit and/or receive descriptive information, and to store such information learned about other devices. The data sent and received by LLDP is useful for many reasons:
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Devices can discover neighbors — other devices directly connected to it.
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Devices can use LLDP to advertise some parts of their Layer 2 configuration to their neighbors.
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Some kinds of misconfiguration can be more easily detected and corrected.
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The LLDP-MED extension provides a level of plug & play configuration of peripheral devices.
LLDP is a link level (“one hop”) protocol; LLDP information can only be sent to and received from devices that are directly connected to each other, or connected via a hub or repeater. LLDP packets are not forwarded on to other devices on the network.
The information transmitted in LLDP advertisements flows in one direction only, from one device to its neighbors, and the communication ends there. Transmitted advertisements do not solicit responses, and received advertisements do not trigger acknowledgment. LLDP operates over physical ports only. For example, it can be configured on switch ports that belong to static or dynamic aggregated links (channel groups), but not on the aggregated links themselves; and on switch ports that belong to VLANs, but not on the VLANs themselves.
LLDP provides a way for the switch to:
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Transmit information about itself to neighbors
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Receive device information from neighbors
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Store and manage information in an LLDP MIB
Each port can be configured to transmit local information, receive neighbor information, or both.
Interactions with other features
LLDP has the following interactions with other switch features:
Spanning tree:
Ports blocked by a spanning tree protocol can still transmit and receive LLDP advertisements.
802.1x:
Ports blocked by 802.1x port authorization cannot transmit or receive LLDP advertisements. If LLDP has stored information for a neighbor on the port before it was blocked, this information will eventually time out and be discarded.
VLAN tagging:
LLDP packets are untagged; they do not contain 802.1Q header information with VLAN identifier and priority tagging.
Virtual Chassis Stacking (VCStack) resiliency link:
When a port is configured as a VCStack resiliency link port, LLDP does not operate on the port; LLDP neither transmits nor receives advertisements, and any LLDP configuration and data stored for the port, including counters, is discarded.
Mirror ports:
LLDP does not operate on mirror analyzer ports.
LLDP-MED
LLDP for Media Endpoint Devices (LLDP-MED), is an extension of LLDP used between LAN network connectivity devices, such as a switch, and the media endpoint devices connected to it, such as IP phones. LLDP-MED is specified in ANSI/TIA-1057-2006. The AT device supports Application Type 1: Voice. LLDP-MED uses the LLDP advertisement, transmission, and storage mechanisms, but transmits, receives, and stores data specifically related to managing the voice endpoint devices. This includes information about network policy, location, hardware configuration, and, for Power over Ethernet (PoE) capable devices, power management.
Voice VLAN
Many IP phones (or other IP voice devices) have two interfaces: one to connect to the network and another that allows a computer or similar device to connect to the network via the IP phone. It is often desirable to treat the voice and data traffic separately so that appropriate Quality of Service (QoS) policies can be applied to each. The Voice VLAN feature uses LLDP-MED to convey to the IP phone a set of configuration information (such as VLAN ID and User Priority tagging, and DiffServ Code Point (DSCP)), that the phone can apply to voice traffic. In response, the IP phone sends voice traffic according to this configuration. The data traffic coming through the IP phone from the PC is sent with the default configuration, typically untagged with normal priority.
LLDP Advertisements
LLDP transmits advertisements as packets called LLDP Data Units (LLDPDUs). An LLDPDU consists of a set of Type-Length-Value elements (TLV), each of which contains a particular type of information about the device or port transmitting it. A single LLDPDU contains multiple TLVs. TLVs are short information elements that communicate data, such as variable length strings, in a standardized format. Each TLV advertises a single type of information, such as its device ID, type, or management addresses.
LLDP sends mandatory TLVs in each advertisement; it can also be configured to send one or more optional TLVs, from the following groups:
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Mandatory Base TLVs, included in all LLDP advertisements. See IEEE 802.1AB-2005.
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Optional Base TLVs, which may be included in any LLDP advertisements. See IEEE 802.1AB-2005.
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IEEE 802.1 Organizationally Specific TLVs (802.1 TLVs). See IEEE 802.1AB-2005 Annex F.
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IEEE 802.3 Organizationally Specific TLVs (802.3 TLVs). See IEEE 802.1AB-2005 Annex G.
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LLDP-MED Organizationally Specific TLVs (LLDP-MED TLVs), included in LLDP-MED advertisements. See ANSI/TIA-1057- 2006.
Configuring LLDP
You can configure LLDP on the device using either:
This article will cover configuring through CLI.
For additional information reference: Link Layer Discovery Protocol Overview and Configuration Guide
Enable LLDP
awplus> enable
awplus# configure terminal
awplus(config)# lldp run
Configure ports for LLDP
awplus(config)# interface <port-list>
awplus(config-if)# lldp tlv-select <all, tlv>
awplus(config-if)# exit
awplus(config)# exit
awplus(config)# interface <port-list>
awplus(config-if)# no lldp {[transmit] [receive]}
Review LLDP configuration
awplus# show lldp
awplus# show lldp interface <port-list>
awplus# show lldp local-info
awplus# show run lldp
Example:
To display the Global configuration for LLDP in the device:
awplus# show lldp
LLDP Global Configuration: [Default Values]
LLDP Status ............... Enabled [Disabled]
Notification Interval ..... 5 secs [5]
Tx Timer Interval ......... 30 secs [30]
Hold-time Multiplier ...... 4 [4]
(Computed TTL value ....... 120 secs)
Reinitialization Delay .... 2 secs [2]
Tx Delay .................. 2 secs [2]
Port Number Type .......... Port-Number [Port-Number]
Fast Start Count .......... 3 [3]
LLDP Global Status:
Total Neighbor Count ...... 2
Neighbors table last updated 77 hrs 41 mins 5 secs ago
To review information for port1.0.50:
awplus# show lldp interface port1.0.50
LLDP Port Status and Configuration:
* = LLDP is inactive on this port because it is a mirror analyser port
Notification Abbreviations:
RC = LLDP Remote Tables Change TC = LLDP-MED Topology Change
TLV Abbreviations:
Base: Pd = Port Description Sn = System Name
Sd = System Description Sc = System Capabilities
Ma = Management Address
802.1: Pv = Port VLAN ID Pp = Port And Protocol VLAN ID
Vn = VLAN Name Pi = Protocol Identity
802.3: Mp = MAC/PHY Config/Status Po = Power Via MDI (PoE)
La = Link Aggregation Mf = Maximum Frame Size
MED: Mc = LLDP-MED Capabilities Np = Network Policy
Lo = Location Identification Pe = Extended PoE In = Inventory
Optional TLVs Enabled for Tx
Port Rx/Tx Notif Management Addr Base 802.1 802.3 MED
--------------------------------------------------------------------------------
1.0.50 Rx Tx -- -- 10.52.253.2 ---------- -------- -------- McNpLoPe--
To display the device own information:
awplus# show lldp local-info
LLDP Local Information:
Local port1.0.1:
Chassis ID Type .................. MAC address
Chassis ID ....................... eccd.6d73.1a3e
Port ID Type ..................... Interface name
Port ID .......................... port1.0.1
TTL .............................. 120
Port Description ................. port1.0.1
System Name ...................... awplus
System Description ............... Allied Telesis router/switch, AW+
v5.4.3-0.2
System Capabilities - Supported .. Bridge, Router
- Enabled .... Bridge, Router
Management Address ............... 10.52.68.1
Port VLAN ID (PVID) .............. 403
Port & Protocol VLAN - Supported . Yes
- Enabled ... No
- VIDs ...... 0
VLAN Names ....................... mgmt
Protocol IDs ..................... 9000, 0026424203000000, 0027424203000002,
0069424203000003, 888e01, aaaa0300e02b00bb,
88090101, 00540000e302, 000a424203000101,
0800, 0806, 86dd
MAC/PHY Auto-negotiation ......... Supported, Enabled
Advertised Capability ....... 1000BaseTFD, 100BaseTXFD, 100BaseTX,
10BaseTFD, 10BaseT
Operational MAU Type ........ 1000BaseTFD (30)
Power Via MDI (PoE) .............. [not supported]
Link Aggregation ................. Supported, Disabled
Maximum Frame Size ............... 1500
LLDP-MED Device Type ............. Network Connectivity
LLDP-MED Capabilities ............ LLDP-MED Capabilities, Network Policy,
Location Identification, Inventory
Network Policy ................... [not configured]
Location Identification .......... [not configured]
Extended Power Via MDI (PoE) ..... [not supported]
Inventory Management:
Hardware Revision ........... E-0
Firmware Revision ........... 2.0.4
Software Revision ........... 5.4.3-0.2
Serial Number ............... A1ZPC800F
Manufacturer Name ........... Allied Telesis Inc.
Model Name .................. x610-48Ts/X
Asset ID .................... [zero length]
Configure LLDP-MED
In most cases, configuring LLDP-MED using SNMP or using the CLI has the same effect. However, the effect of configuring location information using SNMP differs from the CLI. When location information is assigned to a port by SNMP and a matching location is not found on the device, then a new location is automatically created and assigned to the specified port.
If the location is unset by SNMP later, then the location is removed to prevent accumulating SNMPset location information. However, if the location is being used for other ports, the automatically created location is not removed until no ports use it. Once it is modified or assigned to other ports by CLI commands, the location remains even after no ports use the location.
Configure a Voice VLAN
awplus> enable
awplus# configure terminal
awplus(config)# vlan database
awplus(config-vlan)# vlan <vid> [name]
awplus(config-vlan)# exit
awplus(config)# interface <port-list>
awplus(config-if)# switchport voice vlan <vid>
awplus(config-if)# switchport voice vlan priority <0-7>
awplus(config-if)# switchport voice dscp <0-63>
awplus(config-if)# exit
awplus(config)#
Enable LLDP-MED
awplus(config)# interface <port-list>
awplus(config-if)# lldp tlv-select <all, tlv>
awplus(config-if)# exit
awplus(config)# exit
awplus(config)# interface <port-list>
awplus(config-if)# no lldp {[transmit] [receive]}
Configure LLDP-MED
awplus(config)# location civic-location identifier <civic-loc-id>
awplus(config-civic)# country <country>
awplus(config-civic)# city <city>
awplus(config-civic)# primary-road-name <primary-road-name>
awplus(config-civic)# street-suffix <street-suffix>
awplus(config-civic)# house-number <house-number>
awplus(config-civic)# exit
awplus(config)#
Review LLDP-MED configuration
awplus# show lldp
awplus# show lldp interface <port-list>
awplus# show lldp local-info
awplus# show location
Monitor LLDP-MED
awplus# show lldp neighbors
awplus# show lldp neighbors detail
awplus# show lldp statistics
awplus# show lldp statistics interface <port-list>
Example: LLDP-MED
To displays a summary of information received from neighbors via specified ports:
awplus# show lldp neighbors
LLDP Neighbor Information:
Total number of neighbors on these ports .... 2
System Capability Codes:
O = Other P = Repeater B = Bridge W = WLAN Access Point
R = Router T = Telephone C = DOCSIS Cable Device S = Station Only
LLDP-MED Device Type and Power Source Codes:
1 = Class I 3 = Class III PSE = PoE Both = PoE&Local Prim = Primary
2 = Class II N = Network Con. Locl = Local Unkn = Unknown Back = Backup
Local Neighbor Neighbor Neighbor System MED
Port Chassis ID Port ID Sys Name Cap. Ty Pwr
--------------------------------------------------------------------------------
1.0.1 eccd.6d48.e4f1 port1.0.2
1.0.50 eccd.6d42.7195 port1.3.1 awplus --B-R---
To displays in detail the information received from neighbors
awplus# show lldp neighbors detail
LLDP Detailed Neighbor Information:
Local port1.0.1:
Neighbors table last updated 77 hrs 34 mins 51 secs ago
Chassis ID Type .................. MAC address
Chassis ID ....................... eccd.6d48.e4f1
Port ID Type ..................... Interface name
Port ID .......................... port1.0.2
TTL .............................. 120 (secs)
Port Description ................. [not advertised]
System Name ...................... [not advertised]
System Description ............... [not advertised]
System Capabilities .............. [not advertised]
Management Addresses ............. [not advertised]
Port VLAN ID (PVID) .............. [not advertised]
Port & Protocol VLAN ............. [not advertised]
VLAN Names ....................... [not advertised]
Protocol IDs ..................... [not advertised]
MAC/PHY Auto-negotiation ......... [not advertised]
Power Via MDI (PoE) .............. [not advertised]
Link Aggregation ................. [not advertised]
Maximum Frame Size ............... [not advertised]
LLDP-MED Capabilities ............ [not advertised]
Network Policy ................... [not advertised]
Location Identification .......... [not advertised]
Extended Power Via MDI (PoE) ..... [not advertised]
Inventory Management:
Hardware Revision ........... [not advertised]
Firmware Revision ........... [not advertised]
Software Revision ........... [not advertised]
Serial Number ............... [not advertised]
Manufacturer Name ........... [not advertised]
Model Name .................. [not advertised]
Asset ID .................... [not advertised]
Local port1.0.50:
Neighbors table last updated 77 hrs 34 mins 52 secs ago
Chassis ID Type .................. MAC address
Chassis ID ....................... eccd.6d42.7195
Port ID Type ..................... Interface name
Port ID .......................... port1.3.1
TTL .............................. 120 (secs)
Port Description ................. "LINK TO AR4050S"
System Name ...................... awplus
System Description ............... Allied Telesis router/switch, AW+
v5.4.6-0.4
System Capabilities - Supported .. Bridge, Router
- Enabled .... Bridge, Router
Management Addresses ............. 10.52.253.1
Port VLAN ID (PVID) .............. 0
Port & Protocol VLAN - Supported . Yes
- Enabled ... No
- VIDs ...... 0
VLAN Names ....................... VLAN2000
Protocol IDs ..................... 9000, 0026424203000000, 0027424203000002,
0069424203000003, 888e01, aaaa0300e02b00bb,
88090101, 00540000e302, 000a424203000101,
0800, 0806, 86dd
MAC/PHY Auto-negotiation ......... Supported, Enabled
Advertised Capability ....... Other Type 8000
Operational MAU Type ........ 10GigBaseSR (36)
Power Via MDI (PoE) .............. Not Supported
Port Class .................. PSE
Pair Control Ability ........ Disabled
Power Class ................. Unknown
Link Aggregation ................. Supported, Disabled
Maximum Frame Size ............... 1522 (Octets)
LLDP-MED Capabilities ............ [not advertised]
Network Policy ................... [not advertised]
Location Identification .......... [not advertised]
Extended Power Via MDI (PoE) ..... [not advertised]
Inventory Management:
Hardware Revision ........... [not advertised]
Firmware Revision ........... [not advertised]
Software Revision ........... [not advertised]
Serial Number ............... [not advertised]
Manufacturer Name ........... [not advertised]
Model Name .................. [not advertised]
Asset ID .................... [not advertised]
To displays the global LLDP statistics (packet and event counters):
awplus# show lldp statistics
Global LLDP Packet and Event Counters:
Frames: Out ................... 27906
In .................... 18606
In Errored ............ 0
In Dropped ............ 0
TLVs: Unrecognized .......... 0
Discarded ............. 0
Neighbors: New Entries ........... 2
Deleted Entries ....... 0
Dropped Entries ....... 0
Entry Age-outs ........ 0
To displays the LLDP statistics for specified ports:
awplus#show lldp statistics interface port1.0.50
LLDP Packet and Event Counters:
port1.0.50
Frames: Out ................... 9306
In .................... 9306
In Errored ............ 0
In Dropped ............ 0
TLVs: Unrecognized .......... 0
Discarded ............. 0
Neighbors: New Entries ........... 1
Deleted Entries ....... 0
Dropped Entries ....... 0
Entry Age-outs ........ 0