Extreme Networks ExtremeWare Version 7.8, Troubleshooting Manual

Page: 70 / 122

70 Advanced System Diagnostics and Troubleshooting Guide
Diagnostics
System (CPU and Backplane) Health Check
The purpose of the system health check feature is to ensure that communication between the CPU on
the management switch module (MSM) and all I/O cards within the chassis is functioning properly.
NOTE
The system health check feature is supported only on “i” series Summit, Alpine, and BlackDiamond
switches.
The system health checking cycle consists of two parts:
• CPU health check
• Backplane health check (BlackDiamond platform only)
These health checks detect data-path packet errors by automatically checking the end-to-end data path
through the switch by periodically sending packets and then checking the integrity of those packets.
They take automatic action when errors are found. All error messages are logged in the system log and
can also be reviewed using the displayed output of CLI
show
commands. These health checks are
enabled by default, run in the background, and are non-invasive.
Health Check Packet Types
The CPU health check has five types of diagnostic packets, each consisting of 1024 bytes. The CPU
health check packets are generated by the CPU on the I/O slots and sent back to the CPU through the
CPU packet path.
The backplane health check packet is a 384-byte packet generated by the CPU on the MSM and sent
across the chassis backplane to each backplane link.
Backplane Health Check States
The system health check performs its diagnostic tasks according to the following states:
• INITIALIZATION—Health check functionality is initialized after the boot cycle is completed.
• SEND—The CPU sends 10 successive 384-byte packets to each backplane link on an I/O module in
the chassis.
• WAIT—The CPU waits 5 seconds for each backplane diagnostic test and 3 seconds for each CPU
diagnostic test before performing a check on the packets that were sent.
•
CHECK—A packet integrity test is performed on all of the health check packets for an I/O module
to determine whether each packet was successfully sent across the backplane without error or loss. If
five health check packets are lost or errored, the sequence cycles back to the SEND state and begins
again.
The health check feature is run three times on an I/O module. If the health check fails three times,
the CPU generates a failure message.
•
SNC—If all health check packets on an I/O module are received and pass the integrity check, the
test sequence cycles back to the SEND state and begins on the next I/O module.