LLDP support on management interface feature requires a system to form LLDP neighborship over the system management interface,
through which it advertises and learns LLDP neighbor information. This information about neighbors can be used to learn about
the neighbors and in turn the topology of the devices for Operations, Administration, and Maintenance (OAM) purposes.
Advantages of LLDP
Cisco Discovery Protocol (CDP) versus LLDP
The CDP is a device discovery protocol that runs over Layer 2. Layer 2 is also known as the data link layer that runs on all
Cisco devices, such as routers, bridges, access servers, and switches. This protocol allows the network management applications
to automatically discover and learn about other Cisco devices that connect to the network.
The LLDP is also a device discovery protocol that runs over Layer 2. This protocol allows the network management applications
to automatically discover and learn about other non-Cisco devices that connect to the network.
Interoperability between non-Cisco devices using LLDP
LLDP is also a neighbor discovery protocol that is used by network devices to advertise information about themselves to other
devices on the network. This protocol runs over the data link layer, which allows two systems running different network layer
protocols to learn about each other.
With LLDP, the user can also access the information about a particular physical network connection. If the user uses a non-Cisco
monitoring tool (via SNMP) LLDP helps you identify the Object Identifiers (OIDs) that the system supports. The following OIDs
are supported:
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1.0.8802.1.1.2.1.4.1.1.4
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1.0.8802.1.1.2.1.4.1.1.5
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1.0.8802.1.1.2.1.4.1.1.6
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1.0.8802.1.1.2.1.4.1.1.7
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1.0.8802.1.1.2.1.4.1.1.8
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1.0.8802.1.1.2.1.4.1.1.9
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1.0.8802.1.1.2.1.4.1.1.10
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1.0.8802.1.1.2.1.4.1.1.11
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1.0.8802.1.1.2.1.4.1.1.12
Neighbor Discovery
System advertises the LLDP TLV (Type Length Value) details over the management network using which other devices in the management
network can learn about this device.
Prerequisites to Configure LLDP
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LLDP full stack functionality is supported on all the three management interfaces supported in NCS 1002 system.
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Users can selectively enable or disable LLDP on any of the management interfaces on demand.
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Users can selectively enable or disable LLDP transmit or receive functionality at the management interface level.
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Information gathered using LLDP can be stored in the device Management Information Database (MIB) and queried with the Simple
Network Management protocol (SNMP).
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LLDP operational data are available in both Command Line Interface and netconf-yang interface.
Enabling LLDP Globally
When the user enables LLDP globally, all interfaces that support LLDP are automatically enabled for both transmit and receive
operations.
Note
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The user can override this default operation at the interface to disable receive or transmit operations.
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The following table describes the global LLDP attributes that the user can configure:
Table 1.
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Attribute
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Default
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Range
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Description
|
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Holdtime
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120
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0-65535
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Specifies the hold time (in sec). Hold time refers to the time or duration that an LLDP device maintains the neighbor information
before discarding.
|
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Reinit
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2
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2-5
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Delay (in sec) for LLDP initialization on any interface
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Timer
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30
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5-65534
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Specifies the rate at which LLDP packets are sent (in sec)
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The following example shows the commands to configure LLDP globally. The global LLDP configuration enables LLDP on all the
three management interfaces.
RP/0/RP0/CPU0:regen#configure terminal
RP/0/RP0/CPU0:regen(config)#lldp management enable
RP/0/RP0/CPU0:regen(config)#lldp holdtime 30
RP/0/RP0/CPU0:regen(config)#lldp reinit 2
RP/0/RP0/CPU0:regen(config)#commit
Verification
The user can verify the LLDP configuration using the show running-config lldp command.
The output of show running-config lldp command is as follows:RP/0/RP0/CPU0:regen#show running-config lldp
Tue Dec 10 10:36:11.567 UTC
lldp
timer 30
reinit 2
holdtime 120
management enable
!
The user can verify the LLDP data using the show lldp interface and show lldp neighbors commands.
The output of Show lldp interface command is as follows:
RP/0/RP0/CPU0:regen#show lldp interface
Thu Nov 7 08:45:22.934 UTC
MgmtEth0/RP0/CPU0/0:
Tx: enabled
Rx: enabled
Tx state: IDLE
Rx state: WAIT FOR FRAME
MgmtEth0/RP0/CPU0/1:
Tx: enabled
Rx: enabled
Tx state: IDLE
Rx state: WAIT FOR FRAME
The output of show lldp neighbors command is as follows:
RP/0/RP0/CPU0:M-131#show lldp neighbors
Mon Dec 2 11:01:20.143 CET
Capability codes:
(R) Router, (B) Bridge, (T) Telephone, (C) DOCSIS Cable Device
(W) WLAN Access Point, (P) Repeater, (S) Station, (O) Other
Device ID Local Intf Hold-time Capability Port ID
[DISABLED] MgmtEth0/RP0/CPU0/0 120 B gi19
MYS-130 MgmtEth0/RP0/CPU0/1 120 R MgmtEth0/RP0/CPU0/1
Where [ DISABLED] shows that the LLDP is disabled on the interface MgmtEth0/RP0/CPU0/0.
Enabling LLDP on Each Management Interface
The following example shows the commands to configure LLDP at the management interface level.
RP/0/RP0/CPU0:ios(config)#interface mgmtEth 0/RP0/CPU0/X
RP/0/RP0/CPU0:ios(config-if)#lldp enable
RP/0/RP0/CPU0:ios(config-if)#commit
Disabling LLDP Transmit and Receive Operations
The following example shows the commands to disable the LLDP transmit operations at the specified management interface.
RP/0/RP0/CPU0:ios(config)#interface mgmtEth 0/RP0/CPU0/X
RP/0/RP0/CPU0:ios(config-if)#lldp transmit disable
RP/0/RP0/CPU0:ios(config-if)#commit
The following example shows the commands to disable the LLDP receive operations at the specified management interface.
RP/0/RP0/CPU0:ios(config)#interface mgmtEth 0/RP0/CPU0/X
RP/0/RP0/CPU0:ios(config-if)#lldp receive disable
RP/0/RP0/CPU0:ios(config-if)#commit
Debugging LLDP Issues
The following commands are used for debugging issues in the LLDP functionality.
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show lldp traffic
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debug lldp all
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debug lldp errors
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debug lldp events
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debug lldp packets
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debug lldp tlvs
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debug lldp trace
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debug lldp verbose
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