The fast convergence default optimize feature modifies the default settings of all the protocols to recommended defaults for fast convergence. To revert the defaults to pre-fast-convergence settings for both IS-IS and OSPF, no routing-default-optimize command is used. This command sends signals to IS-IS and OSPF and modifies the default configuration for these protocols.

By default, the fast convergence settings is enabled which means when you upgrade the software, you can automatically see the new behavior. This makes easier integration of the devices in a multi-vendor deployment and reduces support cases for poor convergence.

When default optimize is disabled, existing protocol default configuration is used. When default optimize is enabled, new protocol defaults are used. The show running configurations does not display configuration lines for default settings even when default settings are being used.

A configuration of a protocol overrides the default, but a change to default optimize does not override any configuration.

The following is the sample output of spf-interval command in IS-IS:

Device(config-if)# router isis
Device(config-router)# spf-interval 10 5500 5500

If a non-default value is configured, it will be displayed in show running configuration output:

Device(config-router)# spf-interval 5 50 200
Device(config-router)# do show run | inc spf-interval
 spf-interval 5 50 200

You can revert to the default values by configuring the default values or by removing the non-default configuration.

The following table summarizes the configuration impacted by default optimize:

The following table summarizes the configuration impacted by default optimize for OSPFv2/v3:

The following is the sample output of show ip ospf command for OSPFv2 with the default-optimize values.

Device# show ip ospf                                                         
 Routing Process "ospf 10" with ID 1.1.1.1                               
 Start time: 00:00:01.471, Time elapsed: 03:00:34.706                    
 Supports only single TOS(TOS0) routes                                   
 Supports opaque LSA                                                     
 Supports Link-local Signaling (LLS)                                     
 Supports area transit capability                                        
 Supports NSSA (compatible with RFC 3101)                                
 Supports Database Exchange Summary List Optimization (RFC 5243)         
 Event-log enabled, Maximum number of events: 1000, Mode: cyclic         
 Router is not originating router-LSAs with maximum metric               
 Initial SPF schedule delay 50 msecs                                     
 Minimum hold time between two consecutive SPFs 200 msecs                
 Maximum wait time between two consecutive SPFs 5000 msecs               
 Incremental-SPF disabled                                                
 Initial LSA throttle delay 50 msecs                                     
 Minimum hold time for LSA throttle 200 msecs                            
 Maximum wait time for LSA throttle 5000 msecs
Minimum LSA arrival 100 msecs
LSA group pacing timer 240 secs
Interface flood pacing timer 33 msecs
Retransmission pacing timer 66 msecs
EXCHANGE/LOADING adjacency limit: initial 300, process maximum 300
Number of external LSA 18. Checksum Sum 0x075EB2
Number of opaque AS LSA 0. Checksum Sum 0x000000
Number of DCbitless external and opaque AS LSA 0
Number of DoNotAge external and opaque AS LSA 0
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Number of areas transit capable is 0
External flood list length 0
IETF NSF helper support enabled
Cisco NSF helper support enabled
Reference bandwidth unit is 100 mbps
    Area BACKBONE(0)
        Number of interfaces in this area is 4 (2 loopback)
        Area has RRR enabled
        Area has no authentication
        SPF algorithm last executed 02:27:23.736 ago
        SPF algorithm executed 20 times
        Area ranges are
        Number of LSA 94. Checksum Sum 0x321DCF
        Number of opaque link LSA 0. Checksum Sum 0x000000
        Number of DCbitless LSA 0
        Number of indication LSA 0
        Number of DoNotAge LSA 0
        Flood list length 0

The following is the sample output of show ospf command for OSPFv3 with the default-optimize values.

Device# show ospfv3                                                           
 OSPFv3 10 address-family ipv6                                           
 Router ID 11.11.11.11                                                   
 Supports NSSA (compatible with RFC 3101)
Supports Database Exchange Summary List Optimization (RFC 5243)
Event-log enabled, Maximum number of events: 1000, Mode: cyclic
Router is not originating router-LSAs with maximum metric
Initial SPF schedule delay 50 msecs
Minimum hold time between two consecutive SPFs 200 msecs
Maximum wait time between two consecutive SPFs 5000 msecs
Initial LSA throttle delay 50 msecs
Minimum hold time for LSA throttle 200 msecs
Maximum wait time for LSA throttle 5000 msecs
Minimum LSA arrival 100 msecs
LSA group pacing timer 240 secs
Interface flood pacing timer 33 msecs
Retransmission pacing timer 66 msecs
Retransmission limit dc 24 non-dc 24
EXCHANGE/LOADING adjacency limit: initial 300, process maximum 300
Number of external LSA 0. Checksum Sum 0x000000
Number of areas in this router is 1. 1 normal 0 stub 0 nssa
Graceful restart helper support enabled
Reference bandwidth unit is 100 mbps
RFC1583 compatibility enabled
    Area BACKBONE(0)
        Number of interfaces in this area is 2
        SPF algorithm executed 7 times
        Number of LSA 3. Checksum Sum 0x012426
        Number of DCbitless LSA 0
        Number of indication LSA 0
        Number of DoNotAge LSA 0
        Flood list length 0