How to determine the type of label allocated on the penultimate hop

12

By default, the egress node assigns implicit-null labels to the penultimate hop. When an implicit-null label is assigned to an LSR, the LSR directly pops the labels without having to replace the label at the top of the stack with this implicit-null label. If the penultimate hop adds a label to the label stack, the label distribution mode has been changed.

Typical failure: In the MPLS view, the label assigned to the penultimate hop is explicit-null or non-null. The penultimate hop is assigned a label other than 3. You can check the label distribution mode according to the configuration in the MPLS view.

Solution: Configure the PHP feature in the MPLS view and set the label distribution mode to implicit-null. Or you can delete the configuration of the label distribution mode.

Other related questions:
How to configure the egress node to assign explicit-null labels to the penultimate hop
If the label of the penultimate hop is implicit-null, the value of the label that the egress node assigns to the penultimate hop is 3. If the label of the penultimate hop is non-null, the PHP feature is not used and the egress node properly assigns labels to the penultimate hop. The value of the label is equal to or larger than 16. Typical failure: The label distribution mode is not modified, or the label distribution mode is set to non-null. Solution: In the MPLS view, set the label distribution mode to explicit-null.

What types of LDP labels are there
LDP labels include: Explicit-null label Implicit-null label Non-null label

How do I determine the optical modules and cables supported by a card or switch
For CE series switches: - To determine the optical modules and cables supported by a card of the CE12800 series switches, see the "Indicators and Ports" section of the card model under "Cards" in the CloudEngine 12800 Series Switches Hardware Description. - To determine the optical modules and cables supported by CE8800&CE7800&CE6800&CE5800 series switches, see the "Appearance and Structure" section of the specific chassis model under Chassis > Chassis Models in the CloudEngine 8800&7800&6800&5800 Series Switches Hardware Description.

How to view the electronic labels
You can use commands to view the electronic labels. To view the part number and production date, run the display elabel command. [Board Properties] BoardType=CX22EMFF BarCode=21023514201091000095 Item=02351420 Description=S3752P-EI-48S, S3752P-EI-48S Mainframe(48 100 BASE-X ports and 2 100/1000 BASE-X ports and 2 SFP GE (1000 BASE-X) ports (SFP Req.) and DC -48V) Manufactured=2009-01-24 VendorName=Huawei IssueNumber=00 CLEICode= BOM=02351420 BarCode: electronic label Manufactured: production date BOM: part number

If you have more questions, you can seek help from following ways:
To iKnow To Live Chat
Scroll to top