P Commands

This chapter describes the Cisco NX-OS Hot Standby Router Protocol (HSRP) commands that begin with P.

preempt (HSRP)

To configure a preemption delay, use the preempt command. To disable this feature, use the no form of this command.

preempt [delay {minimum min-delay | reload rel-delay | sync sync-delay}]

no preempt [delay {minimum min-delay | reload rel-delay | sync sync-delay}]

Syntax Description

delay minimum min-delay

(Optional) Specifies the minimum number of seconds that preemption is delayed to allow routing tables to be updated before a router becomes active. The default value is 0.

reload rel-delay

(Optional) Specifies the time delay after the router has reloaded. This period applies only to the first interface-up event after the router has reloaded. The default value is 0.

sync sync-delay

(Optional) Specifies the maximum number of seconds to allow IP redundancy clients to prevent preemption. When this period expires, preemption occurs regardless of the state of the IP redundancy clients. The default value is 0.


Command Default

The default delay time for all options is 0 seconds.

Command Modes

Interface configuration or HSRP template mode

Command History

Release
Modification

6.0(2)N1(1)

This command was introduced.


Usage Guidelines

Specifying a minimum delay allows routing tables to be updated before a router becomes active. When a router first comes up, it does not have a complete routing table. A high-priority router will only delay preemption if it first receives a hello packet from a low-priority active router. If the high-priority router does not receive a hello packet from the low-priority active router when it is starting up, it assumes there is no active router for the group and becomes active as soon as possible.

Examples

This example shows how to configure a delay when a router becomes active when its priority is 110: 

switch# configure terminal

switch(config)# interface ethernet 0/1

switch(config-if)# no switchport

switch(config-if)# ip address 10.0.0.1 255.255.255.0

switch(config-if)# hsrp 4

switch(config-if-hsrp)# priority 110

switch(config-if-hsrp)# preempt

switch(config-if-hsrp)# authentication text sanjose

switch(config-if-hsrp)# ip 10.0.0.3

switch(config-if-hsrp)# end

 
   
 
    
   
 Related Commands
 
   
 
    
 
      
      
      
 
        
        

          Command 
        
 		 
        
        

          Description 
        
 		 
      
 
      
 
       
 feature hsrp 
 		 
       
 Enables the HSRP configuration. 
 		 
      
 
      
 
       
 show hsrp 
 		 
       
 Displays HSRP information. 
 		 
      
 
      
    
 
   
 
   
 
   
 
 
     
    
    
   
 priority (HSRP) 
 
    
   
 To set the priority level within a Hot Standby Router Protocol (HSRP) group, use the priority command. To remove the priority level, use the no form of this command. 
 
    
   
priority level [forwarding-threshold lower lower-value upper upper-value] 
 
    
   
no priority level [forwarding-threshold lower lower-value upper upper-value] 
 
    
   
 Syntax Description
 
   
 
    
 
      
      
      
 
       
 level 
 		 
       
 Interface priority for a virtual router. The range of values is from 1 to 255. If this router is the owner of the IP addresses, then the value is automatically set to 255. The default is 100. 
 		 
      
 
      
 
       
 forwarding-threshold 
 		 
       
 (Optional) Sets the threshold used by a virtual port channel (vPC) to determine when to fail over to the vPC trunk. 
 		 
      
 
      
 
       
 lower lower-value 
 		 
       
 (Optional) Sets the low threshold value. The range is from 1 to 255. The default is 1. 
 		 
      
 
      
 
       
 upper upper-value 
 		 
       
 (Optional) Sets the upper threshold value. The range is from 1 to 255. The default is 255. 
 		 
      
 
      
    
 
   
 
   
 
   
 
 
    
   
 Command Default 
 
    
   
 level: 100
lower-value: 1
upper-value: 255 
 
    
   
 Command Modes 
 
    
   
 HSRP configuration or HSRP template mode 
 
    
   
 Command History
 
   
 
    
 
      
      
      
 
        
        

          Release 
        
 		 
        
        

          Modification 
        
 		 
      
 
      
 
       
 6.0(2)N1(1) 
 		 
       
 This command was introduced. 
 		 
      
 
      
    
 
   
 
   
 
   
 
 
    
   
 Usage Guidelines 
 
    
   
 Use the priority command to control which virtual router becomes the active router. HSRP compares the priorities of all virtual routers in the HSRP group and selects the router with the numerically highest priority. If two virtual routers have equal priority, HSRP selects the router with the highest IP address. 
 
    
   
 Examples 
 
    
   
 This example shows how to configure a virtual router with a priority of 254: 
 
    
   
 
    
switch# configure terminal

 
   
 
    
   
 
    
switch(config)# interface ethernet 0/1

 
   
 
    
   
 
    
switch(config-if)# no switchport

 
   
 
    
   
 
    
switch(config-if)# ip address 10.0.0.1 255.255.255.0

 
   
 
    
   
 
    
switch(config-if)# hsrp 4

 
   
 
    
   
 
    
switch(config-if-hsrp)# priority 254

 
   
 
    
   
 
    
 
   
 
    
   
 Related Commands
 
   
 
    
 
      
      
      
 
        
        

          Command 
        
 		 
        
        

          Description 
        
 		 
      
 
      
 
       
 feature hsrp 
 		 
       
 Enables the HSRP configuration. 
 		 
      
 
      
 
       
 show hsrp 
 		 
       
 Displays HSRP information.