Description

Transit traffic impact on a PFE which was earlier restarted with " request chassis fpc slot <X> pfe-instance <Y> restart"

 

 

Symptoms

This is a rare issue seen on specific platforms (PTX10001-36MR and PTX10004/PTX10008/PTX10016 with LC1201/LC1202) acting as a provider edge or core device in MPLS (Multiprotocol Label Switching), after PFE (Packet Forwarding Engine) restart, MPLS traffic flow might not be as expected after the restart.


- MPLS packets arrive via interface hosted on a PFE that was restarted
- Label SWAP performed on the packet
- Outgoing packet has unexpected top label "0":

user@PTX10008> show route label 19

mpls.0: 20 destinations, 20 routes (20 active, 0 holddown, 0 hidden)
+ = Active Route, - = Last Active, * = Both

19                 *[LDP/9] 00:56:27, metric 1
                    >  to 10.250.50.2 via ae50.0, Swap 118        <<<< swap to 118, but downstream device sees label "0"
                       to 10.250.122.2 via ae122.0, Swap 158

Solution

This issue is fixed in the Junos Releases listed in PR1770859

Modification History

2024-09-05 : modifying symptoms field and making KB public
2023-11-28 : Article Created