Reset Search
 

 

Article

forward-lldp on Tagged vs Untagged ports

« Go Back

Information

 
Titleforward-lldp on Tagged vs Untagged ports
Symptoms
Topology:

CE1 1/1 --- 1/1 MLX 1/2 --- 2/2 CE2

User is attempting to configure MLX to forward all LLDP PDUs between CE1 and CE2 so that they can establish LLDP Neighboring.
Environment
Software Release: NI 6.0.0
Fixed in Version: N/A
Cause
On Brocade Devices, LLDP isalways sent out as Untagged traffic.

If the LLDP interface is marked as untagged in a VLAN, LLDP is sent out that on that VLAN. This can be seen using the "show lldp local-info" command:

CE1 where VLAN 1 (Default) is set as Untagged:
!
vlan 1 name DEFAULT-VLAN
!
## No entry for "no untagged" therefore the port is untagged in the default vlan
NetIron MLX-4 Router# sh lldp local
Local port: 1/1
+ Chassis ID (MAC address): 0024.3880.c400
+ Port ID (MAC address): 0024.3880.c400
+ Time to live: 120 seconds
+ System name : "NetIron MLX-4 Router"
+ Port description : "10GigabitEthernet1/1"
+ System capabilities : bridge, router
Enabled capabilities: router
+ 802.3 MAC/PHY : auto-negotiation not supported
Operational MAU type : 1000BaseCX-FD
+ Link aggregation: not capable
+ Maximum frame size: 1548 octets
+ Port VLAN ID: 1
+ Management address (IPv4): 10.18.26.43

If there is no Untagged VLAN assigned to the LLDP interface, the MLX will automatically assign VLAN 4095 as untagged and LLDP will send out on that vlan. LLDPLocal-info will also show as "none".
!
vlan1 name DEFAULT-VLAN
no untagged ethe 1/1
!


NetIron MLX-4 Router# sh lldp local
Local port: 1/1
+ Chassis ID (MAC address): 0024.3880.c400
+ Port ID (MAC address): 0024.3880.c400
+ Time to live: 120 seconds
+ System name : "NetIron MLX-4 Router"
+ Port description : "10GigabitEthernet1/1"
+ System capabilities : bridge, router
Enabled capabilities: router
+ 802.3 MAC/PHY : auto-negotiation not supported
Operational MAU type : 1000BaseCX-FD
+ Link aggregation: not capable
+ Maximum frame size: 1548 octets
+ Port VLAN ID:none
+ Management address (IPv4): 10.18.26.43

NetIron MLX-4 Router(config-vlan-17)# sh vlan 4095

PORT-VLAN 4095, Name CONTROL-VLAN, Priority Level 0, Priority Force 0, Creation Type STATIC
Topo HW idx : 65535 Topo SW idx: 257 Topo next vlan: 0
L2 protocols : NONE
Untagged Ports : ethe 1/1
Associated Virtual Interface Id: NONE
----------------------------------------------------------
Port Type Tag-Mode Protocol State
1/1 PHYSICAL UNTAGGED NONE FORWARDING

Verified by debug packet capture:

[xpp10ge_cpu_transmit]: Transmit MP CPU packet
Time stamp : 00 day(s) 01h 11m 22s:,
**********************************************************************
00: 0000 c44f 0010 0fff-ffc0 0138 ffff fc00 FID = 0x0000
10: 0180 c200 000e 0024-3880 c400 88cc 0207 Offset = 0x10
20: 0400 2438 80c4 0004-0703 0024 3880 c400 VLAN = 4095(0x0fff)
30: 0602 0078 0a14 4e65-7449 726f 6e20 4d4c CAM = 0x00009c
40: 582d 3420 526f 7574-6572 0814 3130 4769 SFLOW = 0
50: 6761 6269 7445 7468-6572 6e65 7431 2f31 DBL TAG = 0
60: 0e04 0014 0010 fe09-0012 0f01 0000 0100
70: 00fe 0900 120f 0300-0000 0000 fe06 0012
Pri CPU MON SRC PType US BRD DAV SAV DPV SV ER TXA SAS Tag MVID
7 0 0 CPU f 0 0 0 0 0 0 0 0 0 0 0

0024.3880.c400 -> 0180.c200.000e [Type:0x88cc]
**********************************************************************


On the Intermediary device (MLX with forward-lldp configured) there must be an untagged VLAN assigned. If not the traffic will drop at the NP:

SR1629128-MLX2# sh np stat all e 1/1

Port 1/1 RX
NP Rx Raw Good Packet = (7)
NP Rx Forward Packet = (0)
NP Rx Discard Packet = (7)
NP Rx Misc Packet = (7)
NP Rx Unicast Packet = (0)
NP Rx Broadcast Packet = (0)
NP Rx Multicast Packet = (7)


This will show as a VLAN Tag Error in the LP:

LP-1# dm xpp reason-log show
Device Id : 0
---------------

Reason Log#1 = 0x00000001
Reason Log#2 = 0x00000000
Reason Log#3 = 0x00000000
Reason Log#4 = 0x00000000

Log# Processing Block Category Description
0 Rx Processing Discard packet VLAN tag error


This traffic is dropped as the MLX has no ports associated with this VLAN:

MLX2(config)# sh vlan 4095

PORT-VLAN 4095, Name CONTROL-VLAN, Priority Level 0, Priority Force 0, Creation Type STATIC
Topo HW idx : 65535 Topo SW idx: 257 Topo next vlan: 0
L2 protocols : NONE
Associated Virtual Interface Id: NONE
----------------------------------------------------------
No ports associated with VLAN
Arp Inspection: 0
DHCP Snooping: 0
IPv4 Multicast Snooping: Disabled
IPv6 Multicast Snooping: Disabled


No Virtual Interfaces configured for this vlan

We are not able to manually configure VLAN 4095, and the only way to add an interface to this control VLAN is to enable LLDP which breaks the functionality of "forward-lldp"
Resolution
The LLDP-Bridge (MLX configured with forward-lldp) must have the interfaces connecting to the devices wishing to peer via LLDP untagged in a VLAN.
Additional notes

Feedback

 

Was this article helpful?


   

Feedback

Please tell us how we can make this article more useful.

Characters Remaining: 255