Description

It is seen that after a system or a FPC reload that PPPoE subscribers will fail to log back in.

Symptoms

This issue is very specific to the following.

 

1) PWHT PPPoE clients

2) LT anchor interface resides on a MPC2NG flex Q card

3) LT interface configuration is missing the "hierarchical-scheduler maximum-hierarchy-levels 2"

4) Chassis config missing "flexible-queuing-mode"

 

Specifics:

FPC 2      REV 11  750-054904  CAEN0675     MPC2E NG PQ & Flex Q

 

labroot@medford-re0# run show configuration chassis | display set        

set chassis pseudowire-service device-count 8000

set chassis fpc 2 pic 0 tunnel-services bandwidth 10g

set chassis fpc 2 pic 0 inline-services bandwidth 10g

set chassis fpc 2 pic 1 tunnel-services

set chassis fpc 2 pic 1 inline-services bandwidth 10g

set chassis fpc 2 flexible-queuing-mode ******This is required. If missing issue will be seen if FPC2 reloads.

set chassis network-services enhanced-ip

 

Lt- Interface config

labroot@medford-re0# run show configuration interfaces lt-2/0/0 

hierarchical-scheduler maximum-hierarchy-levels 2; *****This is required. If missing from configuration issue will be seen.

 

PSX interface configuration

set interfaces ps1122 anchor-point lt-2/0/0

set interfaces ps1122 flexible-vlan-tagging

set interfaces ps1122 auto-configure stacked-vlan-ranges dynamic-profile SVLAN_PROFILE accept pppoe

set interfaces ps1122 auto-configure stacked-vlan-ranges dynamic-profile SVLAN_PROFILE ranges any,any

set interfaces ps1122 auto-configure remove-when-no-subscribers

set interfaces ps1122 esi 00:11:11:11:11:11:11:11:11:22

set interfaces ps1122 esi single-active

set interfaces ps1122 unit 0 encapsulation ethernet-ccc

 

The MX will show RX PADI and TX PADO but the PADO is not seen at the CPE resulting in retries:

Example:  System show's that the PADO is generatated but never seen on the wire.  Also, lt interface is show no TX/RX
labroot@medford-re0> show pppoe statistics     
Active PPPoE sessions: 0
  PacketType                       Sent         Received
    PADI                              0                1
    PADO                              1                0
    PADR                              0                0
    PADS                              0                0
    PADT                              0                0
    Service name error                0                0
    AC system error                   0                0
    Generic error                     0                0
    Malformed packets                 0                0
    Unknown packets                   0                0

labroot@medford-re0> show pppoe statistics    
Active PPPoE sessions: 0
  PacketType                       Sent         Received
    PADI                              0                2
    PADO                              2                0
    PADR                              0                0
    PADS                              0                0
    PADT                              0                0
    Service name error                0                0
    AC system error                   0                0
    Generic error                     0                0
    Malformed packets                 0                0
    Unknown packets                   0                0

Lt interface stats show all "0"

Logical interface lt-2/0/0.32767 (Index 341) (SNMP ifIndex 21484) (Generation 157)
  Egress queues: 8 supported, 4 in use
  Queue counters:       Queued packets  Transmitted packets      Dropped packets
    0                                0                    0                    0
    1                                0                    0                    0
    2                                0                    0                    0
    3                                0                    0                    0
    Flags: Up SNMP-Traps 0x4000 VLAN-Tag [ 0x0000.0 ]  Encapsulation: ENET2
    Traffic statistics:
     Input  bytes  :                    0
     Output bytes  :                    0
     Input  packets:                    0
     Output packets:                    0
   Local statistics:
    Input  bytes  :                    0
    Output bytes  :                    0
    Input  packets:                    0
    Output packets:                    0
   Transit statistics:
    Input  bytes  :                    0                    0 bps
    Output bytes  :                    0                    0 bps
    Input  packets:                    0                    0 pps
    Output packets:                    0                    0 pps

 

 

 

Solution

Having a MPC2E NG PQ & Flex Q the following configuration statements are required even when COS is NOT used for these clients.

 

set chassis fpc<x> flexible-queuing-mode

 

set interfaces lt-x/x/x hierarchical-scheduler maximum-hierarchy-levels 2

 

Modification History

2024-09-13 : Article Created