Tracing IS-IS Protocol Traffic

You can trace various types of IS-IS protocol traffic to help debug IS-IS protocol issues. To trace IS-IS protocol traffic include the traceoptions statement at the [edit protocols isis] hierarchy level:

You can specify the following IS-IS protocol-specific trace options using the flag statement:

• csn—Complete sequence number PDU (CSNP) packets
• error—Errored packets
• graceful-restart—Graceful restart operations
• hello—Hello packets
• ldp-synchronization—Synchronization between IS-IS and LDP
• lsp—Link-state PDU packets
• lsp-generation—Link-state PDU generation packets
• nsr-synchronization—NSR synchronization events
• packets—All IS-IS protocol packets
• psn—Partial sequence number PDU (PSNP) packets
• spf—Shortest-path-first (SPF) calculations

You can optionally specify one or more of the following flag modifiers:

• detail—Detailed trace information
• receive—Packets being received
• send—Packets being transmitted

  Note: Use the flag modifier detail with caution as this may cause the CPU to become very busy.

Global tracing options are inherited from the configuration set by the traceoptions statement at the [edit routing-options] hierarchy level. You can override the following global trace options for the IS-IS protocol using the traceoptions flag statement included at the [edit protocols isis] hierarchy level:

• all—All tracing operations
• general—All normal operations and routing table changes (a combination of the normal and route trace operations)
• normal—Normal events
• policy—Policy processing
• route—Routing information
• state—State transitions
• task—Routing protocol task processing
• timer—Routing protocol timer processing

Note: Use the trace flag all with caution as this may cause the CPU to become very busy.

Examples: Tracing IS-IS Protocol Traffic

A common configuration traces SPF calculations, LSP calculations, normal protocol operations, and errors in protocol operation:

Trace only unusual or abnormal operations to the file routing-log, and trace detailed information about all IS-IS packets to the file isis-log:

Perform detailed tracing of mesh-group flooding:

IS-IS LSP packets that contain errors are discarded by default. To log these errors, specify the error tracing operation:

Related Topics

• traceoptions statement
• For more information about tracing and global tracing options, see Tracing Global Routing Protocol Operations.