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Graceful Restart
Graceful restart (also known as non-stop forwarding) is a protocol-based mechanism that preserves the
forwarding table of the restarting router and its neighbors for a specified period to minimize the loss of
packets.
A graceful-restart router does not immediately assume that a neighbor is permanently down and so does not
trigger a topology change.
Dell Networking OS supports graceful restart for the following protocols:
•
Border gateway protocol
•
Open shortest path first
•
Protocol independent multicast — sparse mode
•
Intermediate system to intermediate system
Software Resiliency
During normal operations, the Dell Networking OS monitors the health of both hardware and software
components in the background to identify potential failures, even before these failures manifest.
System Health Monitoring
The Dell Networking OS also monitors the overall health of the system.
Key parameters such as CPU utilization, free memory, and error counters (for example, CRC failures and
packet loss) are measured, and after exceeding a threshold are used to initiate recovery mechanism.
Failure and Event Logging
Dell Networking systems provide multiple options for logging failures and events.
Trace Log
To track the execution of a program, developers interlace messages with software code.
These messages are called trace messages and are primarily used for debugging and to provide lower-level
information than event messages, which system administrators use. Dell Networking OS retains trace
messages for hardware and software and stores them in files (logs) on the internal flash.
•
Trace Log — contains trace messages that relate to software and hardware events, state, and errors.
Trace Logs are stored in internal flash under the directory TRACE_LOG_DIR.
High Availability (HA)
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Table of Contents
Troubleshooting
