PR1358019 - On MX Series platforms with MS-MPC or MS-MIC, if a large sum of similar packets (for example, thousands of packets) are received, because of the flaw in the method to process these packets, data/management path was completely blocked and deadlocked. Eventually, traffic might be blocked.

When the MS-MPC/MS-PIC is in this state, you will see similar syslog messages:

May  1 12:05:04  MSRouter-RE0 fpc1 Transient flow-control asserted by MAC on ms-1/0 for 4 seconds
... <multiple times once per second> ...
May  1 12:05:07  MSRouter-RE0 fpc1 Transient flow-control asserted by MAC on ms-1/0 for 4 seconds
May  1 12:05:08  MSRouter-RE0 fpc1 Prolonged flow-control asserted by MAC on ms-1/0, bringing interface down 
May  1 12:05:08  MSRouter-RE0 fpc1 ms-1/0: MAC stuck, trigger coredump via nmi

The cause is a software defect appears in Junos software version 15.1. The software defect has been corrected and integrated in the following Junos software versions:

• junos:16.1R7-S5
• junos:16.2R3
• junos:17.2R2-S7
• junos:17.3R3-S5
• junos:17.4R2-S4
• junos:17.4R3
• junos:18.2R2-S3
• junos:18.2R3
• junos:18.3R3
• junos:18.4R1-S5
• junos:18.4R2
• junos:19.1R1-S2
• junos:19.1R2
• junos:19.2R1
• junos:19.3R1 or later

The software defect has been corrected. Juniper Networks recommended customers using MS-MPC and MS-MIC to upgrade to Junos software with the fix.
Please contact JTAC if you have any questions about this issue - PR1358019

First publication 2019-12-26

• PR1358019 - Traffic might be blocked on MX with MS-MPC/MS-MIC