Installation guide

Overview
1-10
The log message format is similar to the format used by syslog messages (RFC 3164). Log messages include
message severity, source (facility), the time the message was generated and a textual message describing the
situation triggering the event. For more information on using the switch logging functionality, see
Configuring System Logging on page 8-9.
1.2.1.7 Process Monitor
The switch process monitor constantly checks to ensure processes under its control are up and running. Each
monitored process sends the process monitor periodic heartbeat messages. A process that is down (due to a
software crash or stuck in an endless loop) is detected when its heartbeat is not received. Such a process is
terminated (if still running) and restarted (if configured) by the process monitor.
1.2.1.8 Hardware Abstraction Layer and Drivers
The Hardware Abstraction Layer (HAL) provides an abstraction library with an interface hiding hardware/
platform specific data. Drivers include platform specific components such as Ethernet, flash memory storage
and thermal sensors.
1.2.1.9 Redundancy
Using the switch redundancy functionality, up to 12 switches can be configured in a redundancy group (and
thereby provide group monitoring). In the event of a switch failure, a switch within the cluster takes control.
Therefore, the switch supported network is always up and running even if a switch fails or is removed for
maintenance or software upgrade. Switch redundancy provides minimal traffic disruption in the event of a
switch failure or intermediate network failure.
The following redundancy features are supported:
• Up to 12 switch redundancy members supported per group. Each member is capable of tracking
statistics for the entire group in addition to their own.
• Each redundancy group is capable of supporting an Active/Active configuration. Each redundancy
group can support two or more primary members, each responsible for group load sharing.
• Members within the same redundancy group can be deployed across different subnets and maintain
their interdependence as redundancy group members.
• Each member of the redundancy group supports AP load balancing by default.
• Members of the redundancy group support license aggregation. When a new member joins the group,
the new member can leverage the access port adoption license(s) of existing members.
• Each member of the redundancy group (including the reporting switch) capable of displaying cluster
performance statistics for all members in addition to their own.
• Centralized redundancy group management using the switch CLI.
For information in configuring the switch for redundancy group support, see
Configuring Switch Redundancy on page 5-35.
1.2.1.10 Secure Network Time Protocol (SNTP)
Secure Network Time Protocol (SNTP) manages time and/or network clock synchronization within the switch
managed network environment. SNTP is a client/server implementation. The switch (a SNTP client)
periodically synchronizes its clock with a master clock (an NTP server). For example, the switch resets its clock
to 07:04:59 upon reading a time of 07:04:59 from its designated NTP server. Time synchronization is
recommended for switch network operations. The following holds true: