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Cisco Bug: CSCvv87440 - clockClass 6 advertised immediately on T-GM connection restore (still in HOLDOVER)

Last Modified

Oct 08, 2020

Products (1)

  • Cisco ASR 920 Series Aggregation Services Router

Known Affected Releases

17.3.1

Description (partial)

Symptom:
topology:

GM ----------- gig 0/0/8 ---- R6 ---- Ten0/0/14 ------------ Ten 0/0/13 -- R14


T-BC router using G.8275.1 FTP profile, in HOLDOVER mode (both FREQ source and PTP lost)

on T-GM connectivity restore T-BC incorrectly advertises clockClass 6 immediately, without getting phase aligned to T-GM first


##### R6 #####
r6-asr920-12sz#sh clock
16:22:53.273 CEST Fri Sep 25 2020

r6-asr920-12sz#show plat soft pt fo dom 24
PTPd Foreign Master Information:

Current Master: TP-2-UP

Port: TP-2-UP
  GM Clock Identity: 0x00:B0:AE:FF:FE:01:1C:A3
  Clock Stream Id: 4
  Priority1: 128
  Priority2: 10
  Local Priority: 1
  Clock Quality:
    Class: 6
    Accuracy: Within 100ns
    Offset (Log Variance): 0x4E5D
  Source Port Identity:
    Clock Identity: 0x00:B0:AE:FF:FE:01:1C:A3
    Port Number: 1
  Steps Removed: 1
  masterOnly: FALSE
  Qualified: TRUE


r6-asr920-12sz#!
r6-asr920-12sz#show ptp clock run 



                      PTP Boundary Clock [Domain 24] [Hybrid]

         State          Ports          Pkts sent      Pkts rcvd      Redundancy Mode

         HOLDOVER       5              245694         122707         Hot standby

                               PORT SUMMARY
                                                                          PTP Master
Name     Tx Mode      Role         Transport    State        Sessions     Port Addr

R3-INTRA mcast        negotiated   Ethernet     Master       1            UNKNOWN
R10-DOWN mcast        master       Ethernet     Master       1            -
R14-DOWN mcast        master       Ethernet     Master       1            -
GM2-UP   mcast        negotiated   Ethernet     Master       1            UNKNOWN
TP-2-UP  mcast        negotiated   Ethernet     Slave        1            UNKNOWN




##### R14 #####
r14-asr-920-12-sz-im#sh clock
16:22:59.450 CEST Fri Sep 25 2020

r14-asr-920-12-sz-im#show plat soft pt fo dom 24
PTPd Foreign Master Information:

Current Master: R6-UP          <<<< R6 selected

Port: R6-UP
  GM Clock Identity: 0x00:B0:AE:FF:FE:01:1C:A3
  Clock Stream Id: 0
  Priority1: 128
  Priority2: 10
  Local Priority: 9
  Clock Quality:
    Class: 6                            <<<<< already receiving CC 6
    Accuracy: Within 100ns
    Offset (Log Variance): 0x4E5D
  Source Port Identity:
    Clock Identity: 0xA4:53:0E:FF:FE:1B:71:3F
    Port Number: 3
  Steps Removed: 2
  masterOnly: FALSE
  Qualified: TRUE

Port: R10-INTRA
  GM Clock Identity: 0x00:B0:AE:FF:FE:01:1C:A3
  Clock Stream Id: 2
  Priority1: 128
  Priority2: 10
  Local Priority: 20
  Clock Quality:
    Class: 248
    Accuracy: Unknown
    Offset (Log Variance): 0xFFFF
  Source Port Identity:
    Clock Identity: 0x18:80:90:FF:FE:55:28:3F
    Port Number: 4
  Steps Removed: 1
          
r14-asr-920-12-sz-im#
r14-asr-920-12-sz-im#show ptp clock run 



                      PTP Boundary Clock [Domain 24] [Hybrid]

         State          Ports          Pkts sent      Pkts rcvd      Redundancy Mode

         PHASE_ALIGNED  6              126607945      79572176       Hot standby

                               PORT SUMMARY
                                                                           PTP Master
Name      Tx Mode      Role         Transport    State        Sessions     Port Addr

R6-UP     mcast        negotiated   Ethernet     Slave        1            UNKNOWN            <<<< aligned to R6
R18-DOWN  mcast        master       Ethernet     Master       1            -
R10-INTRA mcast        negotiated   Ethernet     Master       1            UNKNOWN
R15-DOWN  mcast        master       Ethernet     Master       1            -
R3-UP     mcast        negotiated   Ethernet     Master       1            UNKNOWN
SLAVE     mcast        master       Ethernet     Master       1            -

Conditions:
G.8275.1 FTP profile
ASR-920-12SZ-IM

R6 has no other FREQ/PTP source but T-GM via gig 0/0/8
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