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Cisco Bug: CSCvu63556 - 7.1.2 - pm-mpls T flag should not be set and DS field should be left empty when no TOS is configured

Last Modified

Sep 02, 2020

Products (1)

  • Cisco ASR 9000 Series Aggregation Services Routers

Known Affected Releases

7.1.2.ROUT 7.2.1.ROUT 7.3.1.CE

Description (partial)

Symptom:
When no TOS is configured in PM. PM probe packet sets T flag and use DS field for DSCP  = 0.
this will prevent the node from inter-op with older releases as they may not support T flag and will result in intro-op issue.
        0                   1                   2                   3
        0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |Version| Flags |  Control Code |        Message Length         |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |  QTF  |  RTF  | RPTF  |              Reserved                 |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
       |                       Session Identifier          |    DS     |
       +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Conditions:
Querier use 7.1.1 or later release, responder use older releases.

enable interface delay measurement with pm-mpls without tos config.

performance-measurement
 interface Bundle-Ether1
  delay-measurement
 delay-profile interfaces
  probe
   protocol pm-mpls
   no tos
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