Understanding Fabric Fault Handling on Enhanced Switch Fabric Board (SFB2)
The MX2000 line of routers support Switch Fabric Boards (SFBs) and enhanced SFBs (SFB2s) but not both at the same time. The SFB and SFB2 host three fabric planes each. So, the chassis supports a total of 24 planes. Junos OS Release 15.1F6 and 16.1R1 support fabric fault handling for each plane in both SFB and SFB2. In earlier releases, fabric fault handling is supported for each SFB, not for each plane.
Table 1 lists the differences between fabric fault handling per plane and per SFB.
SFB Level (SFB) |
Plane Level (SFB and SFB2) |
|---|---|
Cyclic redundancy check(CRC) errors on any link on the SFB are indicated on the SFB. |
CRC errors on any link on the SFB or SFB2 are indicated on the plane. |
On encountering destination errors, the line card isolates the SFB (all 3 planes). |
On encountering destination errors, the line card isolates the corresponding plane. Other planes continue to operate. |
Fabric fault handling per-plane provides the following benefits:
Increased granularity, which helps identify, isolate, and repair faults.
Alarms and log messages provide fault information per plane instead of per SFB, which makes debugging easier.
If an SFB has a single faulty plane, the other two planes can continue to operate. There is no need to take the entire SFB offline.
In case of transient errors, while repairing you can isolate a single plane instead of isolating the bouncing the SFB.
To view fabric fault handling information for all 24 planes,
use the extended option with the existing fabric commands.