Pic Considerations; Sonet/Sdh Pics - Juniper EX9200 Features Manual

High Availability Feature Guide for EX9200 Switches
168

PIC Considerations

Take the following PIC restrictions into consideration before performing a unified ISSU:
Unsupported PICs—If a PIC is not supported by unified ISSU, at the beginning of the
upgrade, the software issues a warning that the PIC will be taken offline. After the PIC
is brought offline and the unified ISSU is complete, the PIC is brought back online with
the new firmware.
PIC combinations—For some PICs, newer Junos OS services can require significant
Internet Processor ASIC memory, and some configuration rules might limit certain
combinations of PICs on particular platforms. With a unified ISSU:
If a PIC combination is not supported by the software version that the device is being
upgraded from, the validation check displays a message and aborts the upgrade.
If a PIC combination is not supported by the software version to which the device is
being upgraded, the validation check displays a message and aborts the upgrade,
even if the PIC combination is supported by the software version from which the
device is being upgraded.
Interface statistics—Interface statistics might be incorrect because:
During bootup of the new microkernel on the Packet Forwarding Engine, host-bound
traffic is not handled and might be dropped, causing packet loss.
During the hardware update of the Packet Forwarding Engine and its interfaces,
traffic is halted and discarded. (The duration of the hardware update depends on
the number and type of interfaces and on the device configuration.)
During a unified ISSU, periodic statistics collection is halted. If hardware counters
saturate or wrap around, the software does not display accurate interface statistics.
CIR oversubscription—If oversubscription of the committed information rate (CIR) is
configured on logical interfaces:
And the sum of the CIR exceeds the physical interface's bandwidth, after a unified
ISSU is performed, each logical interface might not be given its original CIR.
And the sum of the delay buffer rate configured on logical interfaces exceeds the
physical interface's bandwidth, after a unified ISSU is performed, each logical
interface might not receive its original delay-buffer-rate calculation.

SONET/SDH PICs

Table 11 on page 169 lists the SONET/SDH PICs that are supported during a unified ISSU.
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