Our customer needs the LMIC runtime hot-swap feature, which is only available from 24.4R1 onwards
(https://www.juniper.net/documentation/us/en/software/junos/release-notes/24.4/junos-release-notes-24.4r1/topics/new-features/feature-descriptions/chassis-3.html).
They upgraded to 24.X . LMIC hot swap feature works in this version.
But once they upgraded to 25.2R1-S2, LMIC hot swapping doesn't work anymore.
Offlining: labroot@jtac-mx304-r2012-re0> request chassis mic offline fpc-slot 0 mic-slot 0 fpc 0 mic 0 offline initiated,use "show chassis fpc mic-status " to verify | labroot@jtac-mx304-r2012-re0> show chassis fpc mic-status Slot 0 Online FPC-BUILTIN MIC 0 Announce offline MRATE LMIC 16x100G/4x400G MIC 1 Online MRATE LMIC 16x100G/4x400G PIC 1 Online MRATE LMIC 16x100G/4x400G | labroot@jtac-mx304-r2012-re0> show chassis fpc mic-status Slot 0 Online FPC-BUILTIN MIC 0 Offline MRATE LMIC 16x100G/4x400G MIC 1 Online MRATE LMIC 16x100G/4x400G PIC 1 Online MRATE LMIC 16x100G/4x400G | labroot@jtac-mx304-r2012-re0> show chassis hardware Hardware inventory: Item Version Part number Serial number Description <snip> MIC 0 REV 30 750-122718 BCFL0841 MRATE LMIC 16x100G/4x400G MIC 1 REV 30 750-122718 BCFJ0039 MRATE LMIC 16x100G/4x400G PIC 1 BUILTIN BUILTIN MRATE LMIC 16x100G/4x400G After reseat: labroot@jtac-mx304-r2012-re0> show chassis fpc mic-status Slot 0 Online FPC-BUILTIN MIC 1 Online MRATE LMIC 16x100G/4x400G PIC 1 Online MRATE LMIC 16x100G/4x400G | labroot@jtac-mx304-r2012-re0> request chassis mic online fpc-slot 0 mic-slot 0 FPC 0, MIC 0 is empty | labroot@jtac-mx304-r2012-re0> show chassis hardware Hardware inventory: Item Version Part number Serial number Description <snip> MIC 1 REV 30 750-122718 BCFJ0039 MRATE LMIC 16x100G/4x400G PIC 1 BUILTIN BUILTIN MRATE LMIC 16x100G/4x400G After FPC restart: labroot@jtac-mx304-r2012-re0> show chassis fpc mic-status Slot 0 Online FPC-BUILTIN MIC 0 Online MRATE LMIC 16x100G/4x400G PIC 0 Online MRATE LMIC 16x100G/4x400G MIC 1 Online MRATE LMIC 16x100G/4x400G PIC 1 Online MRATE LMIC 16x100G/4x400G | labroot@jtac-mx304-r2012-re0> show chassis hardware Hardware inventory: Item Version Part number Serial number Description <snip> MIC 0 REV 30 750-122718 BCFL0841 MRATE LMIC 16x100G/4x400G PIC 0 BUILTIN BUILTIN MRATE LMIC 16x100G/4x400G Xcvr 1 REV 01 740-061409 1G3CQAA9360DU QSFP-100GBASE-LR4 MIC 1 REV 30 750-122718 BCFJ0039 MRATE LMIC 16x100G/4x400G PIC 1 BUILTIN BUILTIN MRATE LMIC 16x100G/4x400G
The issue is because the LMIC is not detecting assembly ID after re-insertion.
root@jtac-mx304-r2012-re0-fpc0:/# dmesg | grep pic0 [ 39.190016] 0x000000010000-0x000000490000 : "pic0-fpga-primary" [ 39.195121] 0x000000800000-0x000000c80000 : "pic0-fpga-golden" [ 39.217984] jnx-connector pic0: empty:insert_ev <snip> [ 844.748686] jnx-connector pic0: insert_wait:timeout_ev [ 844.748690] jnx-connector pic0: Failed to get assembly ID <<<<<<<<<<<<<<<<<<<<< [ 844.754112] jnx-connector pic0: insert_wait:timeout_ev -> failed:timeout_ev
By increasing the debounce-interval value from 2000 ms to 3000 ms, the assembly ID can now be correctly read after JACK OUT and JACK IN operations.
This is getting fixed via internal PR1928177.
This is currently planned to be fixed in below releases.
26.X, 25.4R2 (& above), 25.4R1-S2 (& above)