Displays IS-IS link-state packet (LSP) logging information.
Privileged EXEC mode
IS-IS is supported only on devices based on the DNX chipset family. For a list of such devices, see "Supported Hardware".
The show isis spf-log command displays the following information:
| Output field | Description | 
|---|---|
| When | When (in hours: minutes : seconds) a full SPF calculation occurred. The last 20 occurrences are logged. | 
| Duration | The time required to complete this SPF run, Elapsed time is normal clock time (not CPU time). Other options for this field are: 
 | 
| Nodes | The number of routers and pseudonodes (LANs) that make up the topology calculated in this SPF run. | 
| Count | The number of events that triggered this SPF run. When a topology change has occurred, multiple link-state packets (LSPs) are received in a short time. Since a router waits about 5 seconds before running a full SPF run, it can include all new information. This count includes the number of events (such as receiving new LSPs) that occurred while the router was waiting the 5 second interval before running full SPF. | 
| Last Trigger LSP | When a full SPF calculation is triggered by the arrival of a new LSP, the router stores the LSP ID. The LSP ID can provide a clue about the source of routing instability in an area. If multiple LSPs in a single level are causing SPF runs, only the LSP ID of the last received LSP is recorded. | 
| Triggers | The reason that a full SPF calculations was triggered. | 
| Alternate Route Check | PSPF deleted an IPv4 or IPv6 route. Full SPF must run to find the alternate route. | 
| Route Change in L1 SPF Run | The L1 SPF run added or deleted an IPv4 or IPv6 route. The L2 SPF must run to accommodate this change. | 
| LSP Purged | An LSP was purged. A full SPF calculation must process this change. | 
| LSP Added | A new LSP has appeared in the database. A full SPF calculation is needed to process this new LSP. | 
| Summary Address Change | A summary address configuration change has occurred. | 
| Adjacency State Change | An adjacency was added or deleted. | 
| Admin Distance Change | The administrative distance configuration has changed. | 
| LSP Header Change | The LSP header (attached or overload bits) is changed. | 
| IS Neighbor TLV Change | An IS neighbor TLV was added or deleted in an LSP. | 
| Area Address TLV Change | The area address TLV changed. | 
| Interface IP Address Change | The IP address configuration changed. | 
| IP Address TLV Change | An IP address TLV changed in the LSP. | 
| IPv6 Address TLV Change | An IPv6 address TLV changed in the LSP. | 
| IS-IS Level Change | The IS-IS level configuration changed. | 
| Interface Metric Change | The IS-IS interface metric configuration changed. | 
| LSP Changed - PSPF Disabled | The LSP changed and PSPF is disabled. | 
| LSP Overload Bit Change | The overload bit in the LSP header changed. | 
| Interface State Change | The interface state changed to up or down. | 
| Redist Prefix-List Change | The redistribution list configuration changed. | 
| Redist Policy Change | The redistribution policy configuration changed. | 
| Maximum Path Change | The IS-IS maximum path configuration changed. | 
| IP Load Sharing Change | The IP load sharing configuration changed. | 
| User Cleared IS-IS Route | The user cleared a specific IS-IS route. | 
| User Cleared IS-IS Routes | The user cleared all IS-IS routes. | 
| Neighbor NLPID Change | NLPID set is changed in received hellos. | 
| ISIS Enable | IS-IS was enabled. | 
| ISTCT_SPF Computation | The user issued the disable-incremental-stct-spf-opt command. | 
| User Cleared IS-IS All | The user issued the clear isis all command. | 
| Interface Config Change | ISIS was enabled or disabled on a port. | 
| User Trigger | The user issued the clear isis spf-trigger command. | 
| Recompute InterLeve Routes | The neighbor IS-type is changed either from L1 to L12 or L12 to L1 | 
| Exited Overload State | IS-IS exited from an overload condition. | 
The following is sample output for the show isis spf-log command.
device# show isis spf-log ISIS Level-1 SPF Log When Duration Nodes Count Last-Trigger-LSP Trigger 10h34m13s 0ms 1 10 R1.00-00 Interface State Change 10h34m38s 0ms 1 2 R1.00-00 Interface Config Change 10h34m43s 0ms 1 18 R1.00-00 Interface Config Change 10h34m48s 0ms 1 5 R1.00-00 Interface State Change ISIS Level-2 SPF Log When Duration Nodes Count Last-Trigger-LSP Trigger 10h34m13s 0ms 1 10 R1.00-00 Interface State Change 10h34m38s 0ms 1 2 R1.00-00 Interface Config Change 10h34m43s 0ms 1 18 R1.00-00 Interface Config Change 10h34m48s 0ms 1 5 R1.00-00 Interface State Change
The following is sample output for the show isis spf-log command when the detail keyword is used.
device# show isis spf-log detail
ISIS Level-1 SPF Log
 When      Duration Nodes Count Last-Trigger-LSP         Trigger
  12h18m45s 0ms      1     10    R1.00-00             Interface State Change    
  Ipv4 Route updates: 0 Ipv6 Route updates: 0
        First Trigger: 12h18m50s Ve 305 State Changed to Up
  12h19m10s 0ms      1     2     R1.00-00             Interface Config Change   
  Ipv4 Route updates: 0 Ipv6 Route updates: 0
        First Trigger: 12h19m15s Ve 310 State Changed to Down
  12h19m15s 0ms      1     18    R1.00-00             Interface Config Change   
  Ipv4 Route updates: 0 Ipv6 Route updates: 0
        First Trigger: 12h19m18s Ve 301 State Changed to Down
  12h19m20s 0ms      1     5     R1.00-00             Interface State Change    
  Ipv4 Route updates: 0 Ipv6 Route updates: 0
        First Trigger: 12h19m25s LSP R1.00-00 Area Address TLV Changed
ISIS Level-2 SPF Log
 When      Duration Nodes Count Last-Trigger-LSP         Trigger
  12h18m45s 0ms      1     10    R1.00-00             Interface State Change    
  Ipv4 Route updates: 0 Ipv6 Route updates: 0
        First Trigger: 12h18m50s Ve 305 State Changed to Up
  12h19m10s 0ms      1     2     R1.00-00             Interface Config Change   
  Ipv4 Route updates: 0 Ipv6 Route updates: 0
        First Trigger: 12h19m15s Ve 310 State Changed to Down
  12h19m15s 0ms      1     18    R1.00-00             Interface Config Change   
  Ipv4 Route updates: 0 Ipv6 Route updates: 0
        First Trigger: 12h19m18s Ve 301 State Changed to Down
  12h19m20s 0ms      1     5     R1.00-00             Interface State Change  
…
 
	  
	  
		The following is sample output for the show isis spf-log command when the level-1 keyword is used.
device# show isis spf-log level-1 ISIS Level-1 SPF Log When Duration Nodes Count Last-Trigger-LSP Trigger 12h19m40s 0ms 1 10 R1.00-00 Interface State Change 12h20m5s 0ms 1 2 R1.00-00 Interface Config Change 12h20m10s 0ms 1 18 R1.00-00 Interface Config Change 12h20m15s 0ms 1 5 R1.00-00 Interface State Change