Description

On Junos platform that have redundant routing engine including virtual-chassis for EX and QFX series, protocol flap might be seen when master RE is rebooted by CLI command even though enabling GRES. This issue was resolved by PR1703044. This KB describes the details of this behavior.

Symptoms

On GRES enabled platforms, protocol flaps might be seen when rebooting master FPC by CLI command. Here is the sample output when the BGP flap is seen. 
{master:1}
user@Switch> request system reboot member 1
Reboot the system ? [yes,no] (no) yes

~snip~

*** FINAL System shutdown message from root@Switch ***

System going down IMMEDIATELY
Then peer device detects BGP down due to BGP_IO_ERROR_CLOSE_SESSION. 
May 16 13:39:47.188 2024  peer rpd[2060]: %DAEMON-4-BGP_IO_ERROR_CLOSE_SESSION: BGP peer 10.10.10.5 (External AS 11111): Error event Broken pipe(32) for I/O session - closing it

Solution

The issue might be seen when FIN packets go out before rebooting master RE and it will cause TCP session terminate. As a software fix, eliminating FIN packets to go out in the same scenario.
The issue has been fixed through PR1703044.
https://prsearch.juniper.net/problemreport/PR1703044

Modification History

2024-06-26 : Article Created