Guest

Preview Tool

Cisco Bug: CSCvh69968 - 2 consecutive ptp delay_requests are ignoring by the Nexus switch

Last Modified

Aug 13, 2019

Products (1)

  • Cisco Nexus 5000 Series Switches

Known Affected Releases

7.3(2)N1(1)

Description (partial)

Symptom:
*   PTP implementation has an internal sync mechanism between the PD (Platform Dependent) and PI (Platform Independent) components of PTP.
  *   During this time the ACL for PTP (packets on port 319/320) are disabled for a sub second.
  *   Now if switch receives PTP Delay requests when the ACL is disabled, then we land up in this scenario of a missing Delay Response
  *   In this particular case also we have hit the same case, as confirmed by the logs. B40C is missing as shown below around the same time mentioned before.
     *   Note in this particular case I would have expected the counters to be intact, as the message did not even reach PTP on the SUP side to be processed.

24) Event:E_PTP_MST_PKT_EV, length:72, at 279884 usecs after Thu Jan 11 16:00:33 2018 If_index 0x1a023000 :Pkt M:01 V:02 LEN:002c D:00 S:00:0f:53:ff:fe:25:54:80 P:0100 SEQ:b40d Int:7f tstamp 0 sec 0 nsec;
25) Event:E_PTP_MST_PKT_EV, length:72, at 465683 usecs after Thu Jan 11 16:00:28 2018 If_index 0x1a023000 :Pkt M:01 V:02 LEN:002c D:00 S:00:0f:53:ff:fe:25:54:80 P:0100 SEQ:b40b Int:7f tstamp 0 sec 0 nsec;


dnyod1-cs1b# show ptp counters all
----------------------------------------------------------------
PTP Packet Counters of Interface Eth1/36:
----------------------------------------------------------------
Packet Type                  TX                      RX
----------------    --------------------    --------------------
Announce                     7912171                       0
Sync                         7912168                       0
FollowUp                     7885632                       0
Delay Request                      0                      76
Delay Response                    74                       0
PDelay Request                     0                       0
PDelay Response                    0                       0
PDelay Followup                    0                       0
Management                         0                       0
----------------------------------------------------------------
PTP Packet Counters of Interface Eth1/46:
----------------------------------------------------------------
Packet Type                  TX                      RX
----------------    --------------------    --------------------
Announce                     4630508                       0
Sync                         4630508                       0
FollowUp                     4614885                       0
Delay Request                      0                 4614648
Delay Response               4614645                       0
PDelay Request                     0                       0
PDelay Response                    0                       0
PDelay Followup                    0                       0
Management                         0                       0


dnyod1-cs1b# show ptp counters all

PTP Packet Counters of Interface Eth1/36:
----------------------------------------------------------------
Packet Type                  TX                      RX
----------------    --------------------    --------------------
Announce                     5486450                       0
Sync                         5486448                       0
FollowUp                     5468030                       0
Delay Request                      0                 5545936
Delay Response               5545916                       0
PDelay Request                     0                       0
PDelay Response                    0                       0
PDelay Followup                    0                       0
Management                         0                       0
----------------------------------------------------------------

Conditions:
if 2 consecutive ptp delay_requests come from client in short time interval switches are ignoring these packets
Bug details contain sensitive information and therefore require a Cisco.com account to be viewed.

Bug Details Include

  • Full Description (including symptoms, conditions and workarounds)
  • Status
  • Severity
  • Known Fixed Releases
  • Related Community Discussions
  • Number of Related Support Cases
Bug information is viewable for customers and partners who have a service contract. Registered users can view up to 200 bugs per month without a service contract.