threshold metric through weight (real server)
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Table Of Contents
weight (firewall farm real server)
threshold metric
To set a threshold metric other than the default value, use the threshold metric command in tracking configuration mode. To disable the threshold metric, use the no form of this command.
threshold metric {up number [down number] | down number [up number]}
no threshold metric
Syntax Description
Command Default
No threshold is configured.
Command Modes
Tracking configuration (config-track)
Command History
Usage Guidelines
This command is available only to IP-route threshold metric objects tracked by the track ip route metric threshold global configuration command.
The default up and down threshold values are 254 and 255, respectively. With these values, IP-route threshold tracking gives the same result as IP-route reachability tracking.
Examples
In the following example, the tracking process is tracking the IP-route threshold metric. The metric default value is changed to 16 for the up threshold and to 20 for the down threshold.
track 1 ip route 10.22.0.0/16 metric thresholdthreshold metric up 16 down 20delay down 20Related Commands
track ip route
Tracks the state of IP routing and enters tracking configuration mode.
threshold percentage
To set a threshold percentage for a tracked object in a list of objects, use the threshold percentage command in tracking configuration mode. To disable the threshold percentage, use the no form of this command.
threshold percentage {up number [down number] | down number [up number]}
no threshold percentage
Syntax Description
up
Specifies the up threshold.
down
Specifies the down threshold.
number
Threshold value. The range is from 0 to 100.
Command Default
No threshold percentage is configured.
Command Modes
Tracking configuration (config-track)
Command History
Usage Guidelines
When you configure a tracked list using the track object-number list command, there are two keywords available: boolean and threshold. If you specify the threshold keyword, you can specify either the percentage or weight keywords. If you specify the percentage keyword, then the weight keyword is unavailable. If you specify the weight keyword, then the percentage keyword is unavailable.
You should configure the up percentage first. The valid range is from 1 to 100. The down percentage depends on what you have configured for up. For example, if you configure 50 percent for up, you will see a range from 0 to 49 percent for down.
Examples
In the following example, the tracked list 11 is configured to measure the threshold using an up percentage of 50 and a down percentage of 32:
track 11 list threshold percentageobject 1object 2threshold percentage up 50 down 32Related Commands
threshold weight
To set a threshold weight for a tracked object in a list of objects, use the threshold weight command in tracking configuration mode. To disable the threshold weight, use the no form of this command.
threshold weight {up number [down number] | down number [up number]}
no threshold weight [{up number [down number] | down number [up number]}]
Syntax Description
up
Specifies the up threshold.
down
Specifies the down threshold.
number
Threshold value. The range is from 1 to 255.
Command Default
No threshold weight is configured.
Command Modes
Tracking configuration (config-track)
Command History
Usage Guidelines
When you configure a tracked list of objects using the track object-number list command, there are two keywords available: boolean and threshold. If you specify the threshold keyword, you can specify either the percentage or weight keywords. If you specify the weight keyword, then the percentage keyword is unavailable. If you specify the percentage keyword, then the weight keyword is unavailable.
You should configure the up weight first. The valid range is from 1 to 255. The available down weight depends on what you have configured for the up weight. For example, if you configure 25 for up, you will see a range from 0 to 24 for down.
Examples
In the following example, the tracked list 12 is configured to measure a threshold using a specified weight:
track 12 list threshold weightobject 1object 2threshold weight up 35 down 22Related Commands
timeout (custom UDP probe)
To set a timeout for custom User Datagram Protocol (UDP) probes, use the timeout command in custom UDP probe configuration mode. To restore the default timeout, use the no form of this command.
timeout seconds
no timeout
Syntax Description
seconds
Time, in seconds, that IOS SLB waits for a response packet from the server after sending a custom UDP probe request packet. Valid range is 1 to 255. The default value is 30 seconds.
Defaults
The default custom UDP probe timeout is 30 seconds.
Command Modes
Custom UDP probe configuration
Command History
Examples
In the following example the custom UDP probe timeout is set to 20 seconds:
Router(config)# ip slb probe PROBE6 custom udpRouter(config-slb-probe)# timeout 20Related Commands
track
To configure an interface to be tracked where the Gateway Load Balancing Protocol (GLBP) weighting changes based on the state of the interface, use the track command in global configuration mode. To remove the tracking, use the no form of this command.
track object-number interface type number {line-protocol | ip routing}
no track object-number interface type number {line-protocol | ip routing}
Syntax Description
Command Default
The state of the interfaces is not tracked.
Command Modes
Global configuration (config)
Command History
Usage Guidelines
Use the track command in conjunction with the glbp weighting and glbp weighting track commands to configure parameters for an interface to be tracked. If a tracked interface on a GLBP router goes down, the weighting for that router is reduced. If the weighting falls below a specified minimum, the router will lose its ability to act as an active GLBP virtual forwarder.
As of Cisco IOS Release 15.1(3)T, a maximum of 1000 objects can be tracked. Although 1000 tracked objects can be configured, each tracked object uses CPU resources. The amount of available CPU resources on a router is dependent upon variables such as traffic load and how other protocols are configured and run. The ability to use 1000 tracked objects is dependent upon the available CPU. Testing should be conducted on site to ensure that the service works under the specific site traffic conditions.
Examples
In the following example, Fast Ethernet interface 0/0 tracks whether serial interfaces 2/0 and 3/0 are up. If either serial interface goes down, the GLBP weighting is reduced by the default value of 10. If both serial interfaces go down, the GLBP weighting will fall below the lower threshold and the router will no longer be an active forwarder. To resume its role as an active forwarder, the router must have both tracked interfaces back up, and the weighting must rise above the upper threshold.
Router(config)# track 1 interface serial 2/0 line-protocolRouter(config-track)# exitRouter(config)# track 2 interface serial 3/0 line-protocolRouter(config-track)# exitRouter(config)# interface FastEthernet 0/0Router(config-if)# ip address 10.21.8.32 255.255.255.0Router(config-if)# glbp 10 weighting 110 lower 95 upper 105Router(config-if)# glbp 10 weighting track 1Router(config-if)# glbp 10 weighting track 2In the following example, Fast Ethernet interface 0/0 tracks whether serial interface 2/0 is enabled for IP routing, whether it is configured with an IP address, and whether the state of the interface is up. If serial interface 2/0 goes down, the GLBP weighting is reduced by a value of 20.
Router(config)# track 2 interface serial 2/0 ip routingRouter(config-track)# exitRouter(config)# interface FastEthernet 0/0Router(config-if)# ip address 10.21.8.32 255.255.255.0Router(config-if)# glbp 10 weighting 110 lower 95 upper 105Router(config-if)# glbp 10 weighting track 2 decrement 20Related Commands
glbp weighting
Specifies the initial weighting value of a GLBP gateway.
glbp weighting track
Specifies an object to be tracked that affects the weighting of a GLBP gateway.
track application
To track the presence of Home Agent (HA), Gateway GPRS Support Node (GGSN), or Packet Data Serving Node (PDSN), traffic on a router and to enter tracking configuration mode, use the track application command in global configuration mode. To disable tracking of HA, GGSN, or PDSN traffic, use the no form of this command.
track object-number application {home-agent | ggsn | pdsn}
no track object-number application {home-agent | ggsn | pdsn}
Syntax Description
Command Default
Home Agent, GGSN, and PDSN traffic is not tracked.
Command Modes
Global configuration (config)
Command History
Usage Guidelines
Use this command to monitor the presence of Home Agent, PDSN, and GGSN traffic on a router for mobile wireless applications.
When a redundant pair of Home Agents running HSRP between them loses connectivity, both HSRP nodes become active. Once the connectivity is restored between the two nodes, a graceful way is needed to restore proper HSRP states without losing Home Agent bindings. During the time of no connectivity, one of the nodes will continue to process Home Agent, GGSN, or PDSN traffic while the other will not. The node that continues to process traffic needs to remain active once connectivity is restored. To ensure that the active node remains in the active state, the priority of the HSRP group member that does not process Home Agent traffic is reduced. Reducing the priority of the node that is not processing Home Agent traffic ensures that this node will become the standby after connectivity is restored. When connectivity is restored, the normal Home Agent state synchronization will get all bindings back into the inactive node and, depending on the preempt configuration, it may switch over again. This state synchronization ensures that no Mobile IP, GGSN or PDSN bindings are lost.
Note
The home-agent, ggsn, or pdsn keywords do not appear in the CLI if the corresponding application is not present in the Cisco IOS image.
As of Cisco IOS Release 15.1(3)T, a maximum of 1000 objects can be tracked. Although 1000 tracked objects can be configured, each tracked object uses CPU resources. The amount of available CPU resources on a router is dependent upon variables such as traffic load and how other protocols are configured and run. The ability to use 1000 tracked objects is dependent upon the available CPU. Testing should be conducted on site to ensure that the service works under the specific site traffic conditions.
Examples
The following example shows how to configure a router to track home agent traffic:
Router(config)# track 4 application home-agentRouter(config-track)#Related Commands
track interface
To configure an interface to be tracked and to enter tracking configuration mode, use the track interface command in global configuration mode. To remove the tracking, use the no form of this command.
track object-number interface type number {line-protocol | ip routing}
no track object-number interface type number {line-protocol | ip routing}
Syntax Description
Command Default
No interface is tracked.
Command Modes
Global configuration (config)
Command History
Usage Guidelines
This command reports a state value to clients. A tracked IP-routing object is considered up when the following criteria exist:
•
•
•
Interface IP routing will go down when one of the following criteria exist:
•
•
•
No space is required between the type number values.
Tracking the IP-routing state of an interface using the track interface ip routing command can be more useful in some situations than just tracking the line-protocol state using the track interface line-protocol command, especially on interfaces for which IP addresses are negotiated. For example, on a serial interface that uses the Point-to-Point Protocol (PPP), the line protocol could be up (link control protocol [LCP] negotiated successfully), but IP could be down (IPCP negotiation failed).
The track interface ip routing command supports the tracking of an interface with an IP address acquired through any of the following methods:
•
•
•
•
As of Cisco IOS Release 15.1(3)T, a maximum of 1000 objects can be tracked. Although 1000 tracked objects can be configured, each tracked object uses CPU resources. The amount of available CPU resources on a router is dependent upon variables such as traffic load and how other protocols are configured and run. The ability to use 1000 tracked objects is dependent upon the available CPU. Testing should be conducted on site to ensure that the service works under the specific site traffic conditions.
Examples
In the following example, the tracking process is configured to track the IP-routing capability of serial interface 1/0:
Router(config)# track 1 interface serial1/0 ip routingRouter(config-track)#Related Commands
track ip route
To track the state of an IP route and to enter tracking configuration mode, use the track ip route command in global configuration mode. To remove the tracking, use the no form of this command.
track object-number ip route ip-address/prefix-length {reachability | metric threshold}
no track object-number ip route ip-address/prefix-length {reachability | metric threshold}
Syntax Description
Command Default
The route to the subnet address is not tracked.
Command Modes
Global configuration (config)
Command History
Usage Guidelines
A tracked IP-route object is considered up and reachable when a routing-table entry exists for the route and the route is not inaccessible.
To provide a common interface to tracking clients, route metric values are normalized to the range of 0 to 255, where 0 is connected and 255 is inaccessible. The resulting value is compared against threshold values to determine the tracking state as follows:
•
•
The tracking process uses a per-protocol configurable resolution value to convert the real metric to the scaled metric. The metric value communicated to clients is always such that a lower metric value is better than a higher metric value.
Use the threshold metric tracking configuration command to specify a threshold metric other than the default threshold metric.
As of Cisco IOS Release 15.1(3)T, a maximum of 1000 objects can be tracked. Although 1000 tracked objects can be configured, each tracked object uses CPU resources. The amount of available CPU resources on a router is dependent upon variables such as traffic load and how other protocols are configured and run. The ability to use 1000 tracked objects is dependent upon the available CPU. Testing should be conducted on site to ensure that the service works under the specific site traffic conditions.
Examples
In the following example, the tracking process is configured to track the reachability of 10.22.0.0/16:
Router(config)# track 1 ip route 10.22.0.0/16 reachabilityIn the following example, the tracking process is configured to track the threshold metric using the default threshold metric values:
Router(config)# track 1 ip route 10.22.0.0/16 metric thresholdRelated Commands
show track
Displays HSRP tracking information.
threshold metric
Sets a threshold metric other than the default value.
track ip sla
To track the state of a Cisco IOS IP Service Level Agreements (SLAs) operation and to enter tracking configuration mode, use the track ip sla command in global configuration mode. To remove the tracking, use the no form of this command.
track object-number ip sla operation-number [state | reachability]
no track object-number ip sla operation-number [state | reachability]
Syntax Description
Command Default
IP SLAs tracking is disabled.
Command Modes
Global configuration (config)
Command History
Usage Guidelines
Every IP SLAs operation maintains an operation return-code value. This return code is interpreted by the tracking process. The return code may return OK, OverThreshold, and several other return codes. Different operations may have different return-code values, so only values common to all operation types are used.
Two aspects of an IP SLAs operation can be tracked: state and reachability. The difference between these aspects relates to the acceptance of the OverThreshold return code. Table 102 shows the state and reachability aspects of IP SLAs operations that can be tracked.
Table 102 Comparison of State and Reachability Operations
State
OK
(all other return codes)
Up
Down
Reachability
OK or over threshold
(all other return codes)
Up
Down
As of Cisco IOS Release 15.1(3)T, a maximum of 1000 objects can be tracked. Although 1000 tracked objects can be configured, each tracked object uses CPU resources. The amount of available CPU resources on a router is dependent upon variables such as traffic load and how other protocols are configured and run. The ability to use 1000 tracked objects is dependent upon the available CPU. Testing should be conducted on site to ensure that the service works under the specific site traffic conditions.
Examples
The following example shows how to configure the tracking process to track the state of IP SLAs operation 2:
Router(config)#track 1 ip sla 2 stateThe following example shows how to configure the tracking process to track the reachability of IP SLAs operation 3:
Router(config)#track 2 ip sla 3 reachabilityRelated Commands
track ip route
Tracks the state of an IP route and enters tracking configuration mode.
track list
To specify a list of objects to be tracked and the thresholds to be used for comparison, use the track list command in global configuration mode. To disable the tracked list, use the no form of this command.
track object-number list {boolean {and | or} | threshold {weight | percentage}}
no track object-number list {boolean {and | or} | threshold {weight | percentage}}
Syntax Description
Command Default
The object list is not tracked.
Command Modes
Global configuration (config)
Command History
Usage Guidelines
As of Cisco IOS Release 15.1(3)T, a maximum of 1000 objects can be tracked. Although 1000 tracked objects can be configured, each tracked object uses CPU resources. The amount of available CPU resources on a router is dependent upon variables such as traffic load and how other protocols are configured and run. The ability to use 1000 tracked objects is dependent upon the available CPU. Testing should be conducted on site to ensure that the service works under the specific site traffic conditions.
Examples
A track list object may be configured to track two serial interfaces when both serial interfaces are "up" and when either serial interface is "down," for example:
Router(config)# track 1 interface serial2/0 line-protocolRouter(config-track)# exitRouter(config)# track 2 interface serial2/1 line-protocolRouter(config-track)# exitRouter(config)# track 100 list boolean andRouter(config-track)# object 1Router(config-track)# object 2A track list object may be configured to track two serial interfaces when either serial interface is "up" and when both serial interfaces are "down," for example:
Router(config)# track 1 interface serial2/0 line-protocolRouter(config-track)# exitRouter(config)# track 2 interface serial2/1 line-protocolRouter(config-track)# exitRouter(config)# track 101 list boolean orRouter(config-track)# object 1Router(config-track)# object 2A track list object may be configured to track two serial interfaces when both serial interfaces are "up" and when both serial interface is "down," for example:
Router(config)# track 1 interface serial2/0 line-protocolRouter(config-track)# exitRouter(config)# track 2 interface serial2/1 line-protocolRouter(config-track)# exitRouter(config)# track 102 threshold weightRouter(config-track)# object 1 weight 10Router(config-track)# object 2 weight 10Router(config-track)# threshold weight up 20 down 0The configuration shown above provides some hysteresis in case one of the serial interfaces is flapping.
Related Commands
track resolution
To specify resolution parameters for a tracked object, use the track resolution command in global configuration mode. To disable this functionality, use the no form of this command.
track resolution ip route {eigrp resolution-value | isis resolution-value | ospf resolution-value | static resolution-value}
no track resolution ip route {eigrp resolution-value | isis resolution-value | ospf resolution-value | static resolution-value}
Syntax Description
Command Default
The track ip route metric resolution default values are used.
Command Modes
Global configuration (config)
Command History
Usage Guidelines
The track ip route command causes tracking of a route in the routing table. If a route exists in the table, the metric value is converted into a number in the range from 0 to 255. The metric resolution for the specified routing protocol is used to do the conversion. There are default values for the metric resolution but the track resolution command can be used to change the metric resolution default values.
Examples
In the following example, the EIGRP routing protocol has a resolution value of 280.
track resolution ip route eigrp 280Related Commands
track rtr
Note
To track the state of a Cisco IOS IP Service Level Agreements (SLAs) operation and to enter tracking configuration mode, use the track rtr command in global configuration mode. To remove the tracking, use the no form of this command.
track object-number rtr operation-number {state | reachability}
no track object-number rtr operation-number {state | reachability}
Syntax Description
Command Default
IP SLAs tracking is disabled.
Command Modes
Global configuration (config)
Command History
Usage Guidelines
Every IP SLAs operation maintains an operation return-code value. This return code is interpreted by the tracking process. The return code may return OK, OverThreshold, and several other return codes. Different operations may have different return-code values, so only values common to all operation types are used.
Two aspects of an IP SLAs operation can be tracked: state and reachability. The difference between these aspects relates to the acceptance of the OverThreshold return code. Table 102 shows the state and reachability aspects of IP SLAs operations that can be tracked.
Table 103 Comparison of State and Reachability Operations
State
OK
(all other return codes)
Up
Down
Reachability
OK or over threshold
(all other return codes)
Up
Down
Examples
The following example shows how to configure the tracking process to track the state of IP SLAs operation 2:
track 1 rtr 2 stateThe following example shows how to configure the tracking process to track the reachability of IP SLAs operation 3:
track 2 rtr 3 reachabilitytrack stub-object
To create a stub object that can be tracked by Embedded Event Manager (EEM) and to enter tracking configuration mode, use the track stub-object command in global configuration mode. To remove the stub object, use the no form of this command.
track object-number stub-object
no track object-number stub-object
Syntax Description
Command Default
No stub objects are created.
Command Modes
Global configuration (config)
Command History
Usage Guidelines
Use the track stub-object command to create a stub object, which is an object that can be tracked and manipulated by an external process, EEM. After the stub object is created, the default-state command can be used to set the default state of the stub object.
EEM is a distributed, scalable, and customized approach to event detection and recovery offered directly in a Cisco IOS device. EEM offers the ability to monitor events and take informational or corrective action when the monitored events occur or when a threshold is reached. An EEM policy is an entity that defines an event and the actions to be taken when that event occurs.
As of Cisco IOS Release 15.1(3)T, a maximum of 1000 objects can be tracked. Although 1000 tracked objects can be configured, each tracked object uses CPU resources. The amount of available CPU resources on a router is dependent upon variables such as traffic load and how other protocols are configured and run. The ability to use 1000 tracked objects is dependent upon the available CPU. Testing should be conducted on site to ensure that the service works under the specific site traffic conditions.
Examples
The following example shows how to create and configure stub object 1 with a default state of up:
Router(config)#track 1 stub-objectRouter(config-track)#default-state upRelated Commands
default-state
Sets the default state for a stub object.
show track
Displays tracking information.
track timer
To specify the interval during which the tracking process polls the tracked object, use the track timer command in global configuration mode. To disable this functionality, use the no form of this command.
track timer {interface | ip route | sla } | list | stub}{ seconds | msec milliseconds}
no track timer {interface | ip route | sla } | list | stub}{ seconds | msec milliseconds}
Syntax Description
Command Default
If you do not use the track timer command to specify a polling interval, a tracked object will be tracked at the default polling interval.
Command Modes
Global configuration (config)
Command History
Examples
In the following example, the tracking process is configured to poll the tracked interface every 3 seconds:
Router# configure terminalRouter(config)# track timer interface 3url (WSP probe)
To specify the URL path that a Wireless Session Protocol (WSP) probe is to request from the server, use the url command in WSP probe configuration mode. To restore the default settings, use the no form of this command.
url [path]
no url [path]
Syntax Description
Defaults
If no URL path is specified, the default is /.
Command Modes
WSP probe configuration (config-slb-probe)
Command History
Examples
The following example configures a ping probe named PROBE3, enters WSP probe configuration mode, and configures the probe to request URL path http://localhost/test.txt:
Router(config)# ip slb probe PROBE3 wspRouter(config-slb-probe)# url http://localhost/test.txtRelated Commands
username (IOS SLB)
To configure an ASCII regular expression string to be matched against the username attribute for RADIUS load balancing, use the username (IOS SLB) command in SLB RADIUS map configuration mode. To delete the username match string, use the no form of this command.
username string
no username string
Syntax Description
string
ASCII regular expression string to be matched against the username attribute in the RADIUS payload.
For information about regular expressions and how to use them in Cisco IOS software configurations, refer to the "Understanding Regular Expressions" section of the "Using the Cisco IOS Command-Line Interface" chapter of the Cisco IOS Configuration Fundamentals Configuration Guide:
http://www.cisco.com/en/US/docs/ios/fundamentals/configuration/guide/cf_cli-basics.html
Defaults
None
Command Modes
SLB RADIUS map configuration (config-slb-radius-map)
Command History
Usage Guidelines
For a given IOS SLB RADIUS map, you can configure a single calling-station-id command or a single username (IOS SLB) command, but not both.
Examples
The following example specifies that, for IOS SLB RADIUS map 1, string ...?525* is to be matched against the username attribute in the RADIUS payload:
Router(config)# ip slb map 1 radiusRouter(config-slb-radius-map)# username ...?525*Related Commands
virtual
To configure virtual server attributes, use the virtual command in SLB virtual server configuration mode. To remove the attributes, use the no form of this command.
Encapsulation Security Payload (ESP) and Generic Routing Encapsulation (GRE) Protocols
virtual ipv4-address [ipv4-netmask [group]] {esp | gre | protocol}
no virtual ipv4-address [ipv4-netmask [group]] {esp | gre | protocol}
TCP and User Datagram Protocol (UDP)
virtual ipv4-address [ipv4-netmask [group]] [ipv6 ipv6-address [prefix ipv6-prefix]] {tcp | udp} [port | any] [service service]
no virtual ipv4-address [ipv4-netmask [group]] [ipv6 ipv6-address [prefix ipv6-prefix]] {tcp | udp} [port | any] [service service]
Syntax Description
Command Default
No default behavior or values.
Command Modes
SLB virtual server configuration (config-slb-vserver)
Command History
Usage Guidelines
The no virtual command is allowed only if the virtual server was removed from service by the no inservice command.
For some applications, it is not feasible to configure all the virtual server TCP or UDP port numbers for IOS SLB. To support such applications, you can configure IOS SLB virtual servers to accept flows destined for all ports. To configure an all-port virtual server, specify a port number of 0 or any.
Note
Specifying port 9201 for connection-oriented WSP mode also activates the Wireless Application Protocol (WAP) finite state machine (FSM), which monitors WSP and drives the session FSM accordingly.
In RADIUS load balancing, IOS SLB maintains session objects in a database to ensure that re-sent RADIUS requests are load-balanced to the same real server.
IOS SLB supports general packet radio service (GPRS) Tunneling Protocol (GTP) v0, v1, and v2 real servers. A GTP v0 or v1 real server cannot manage GTP v2 requests. Therefore, you must configure separate virtual servers for GTPv2 real servers and for GTP v0 or v1 real servers.
IOS SLB supports dual-stack addresses for GTP load balancing only. To support dual-stack addresses:
•
•
Examples
The following example specifies that the virtual server with the IPv4 address 10.0.0.1 performs load balancing for TCP connections for the port named www. The virtual server processes HTTP requests.
Router(config)# ip slb vserver PUBLIC_HTTPRouter(config-slb-vserver)# virtual 10.0.0.1 tcp wwwThe following example specifies that the virtual server with the IPv4 address 10.0.0.13 performs load balancing for UDP connections for all ports. The virtual server processes HTTP requests.
Router(config)# ip slb vserver PUBLIC_HTTPRouter(config-slb-vserver)# virtual 10.0.0.13 udp 0Related Commands
ip slb vserver
Identifies a virtual server.
show ip slb vservers
Displays information about the virtual servers defined to IOS Server Load Balancing (IOS SLB).
vrrp authentication
To authenticate Virtual Router Redundancy Protocol (VRRP) packets received from other routers in the group, use the vrrp authentication command in interface configuration mode. To disable VRRP authentication, use the no form of this command.
vrrp group authentication {text-string | text text-string | md5 {key-chain key-chain | key-string [0 | 7] key-string [timeout seconds]}}
no vrrp group authentication {text-string | text text-string | md5 {key-chain key-chain | key-string [0 | 7] key-string [timeout seconds]}}
Syntax Description
Command Default
VRRP authentication is disabled.
Command Modes
Interface configuration (config-if)
Command History
Usage Guidelines
VRRP does not accept a virtual router group number 0 and never has an empty group. The valid range for the VRRP group is 1 to 255.
When a VRRP packet arrives from another router in the VRRP group, its authentication string is compared to the string configured on the local system. If the strings match, the message is accepted. If they do not match, the packet is discarded. The authentication string is sent unencrypted in all VRRP messages when using the vrrp authentication text text-string option.
All routers within the VRRP group must be configured with the same authentication string. If the same authentication string is not configured, the routers in the VRRP group will not communicate with each other and any misconfigured router in the group will change its state to master.
If password encryption is configured with the service password-encryption command, the software saves the key-string as encrypted text.
Note
The timeout seconds keyword and argument specify the duration that the VRRP group will accept message digests based on both the old and new keys. This option allows time for configuration of all routers in a group with the new key. VRRP route flapping can be minimized by changing the keys on all the routers, provided that the master router is changed last. The master router should have its key string changed no later than one holdtime period, specified by the vrrp timers advertise interface configuration command, after the backup routers. This procedure ensures that the backup routers do not time out the master router.
Examples
The following example shows how to configure an authentication text string of x30dn78k:
vrrp 1 authentication x30dn78kThe following example shows how to configure an MD5 key string:
interface Ethernet0/1description ed1-cat5a-7/10vrrp 1 ip 10.21.0.10vrrp 1 priority 110vrrp 1 authentication md5 key-string f00c4sThe key ID for key-string authentication is always zero. If a key chain is configured with a key ID of zero, then the following configuration will work:
Router 1
key chain vrrp1key 0key-string 54321098452103ab!interface Ethernet0/1vrrp 1 ip 10.21.0.10vrrp 1 authentication md5 key-chain vrrp1Router 2
interface Ethernet0/1vrrp 1 ip 10.21.0.10vrrp 1 authentication md5 key-string 54321098452103abRelated Commands
vrrp delay
To configure the delay period before the initialization of all Virtual Router Redundancy Protocol (VRRP) groups on an interface, use the vrrp delay command in interface configuration mode. To remove all configured delays, use the no form of this command.
vrrp delay {minimum seconds [reload seconds] | reload seconds}
no vrrp delay {minimum seconds [reload seconds] | reload seconds}
Syntax Description
Command Default
No delay value is used.
Command Modes
Interface configuration (config-if)
Command History
Usage Guidelines
Use the vrrp delay command to configure the delay period before the initialization of VRRP groups. This command applies to all VRRP groups on an interface. This command cannot be configured per-VRRP group.
The minimum seconds value is the minimum time (in seconds) to delay VRRP group initialization after an interface comes up. This minimum delay period applies to all subsequent interface events.
The reload seconds value is the time period to delay after the router has reloaded. This delay period applies only to the first interface-up event after the router has reloaded.
The recommended minimum seconds value is 30 seconds and the recommended reload seconds value is 60 seconds.
The no vrrp delay command removes all delays, and is equivalent to configuring 0 for each argument. When the no vrrp delay command is configure, there is no appreciable delay between the interface coming up and the VRRP groups on that interface becoming operational.
Examples
The following example shows how to configure a minimum delay of 30 seconds and a reload delay of 60 seconds:
Router(config)# interface gigabitethernet0/0/0Router(config-if)# vrrp delay minimum 30 reload 60Related Commands
vrrp description
To assign a description to the Virtual Router Redundancy Protocol (VRRP) group, use the vrrp description command in interface configuration mode. To remove the description, use the no form of this command.
vrrp group description text
no vrrp group description
Syntax Description
group
Virtual router group number. The group number range is from 1 to 255.
text
Text (up to 80 characters) that describes the purpose or use of the group.
Command Default
There is no description of the VRRP group.
Command Modes
Interface configuration (config-if)
Command History
Examples
The following example enables VRRP on Ethernet interface 0. VRRP group 1 is described as Building A — Marketing and Administration.
interface ethernet 0ip address 10.0.1.1 255.255.255.0!vrrp 1 ip 10.0.1.20vrrp 1 description Building A - Marketing and AdministrationRelated Commands
vrrp ip
To enable the Virtual Router Redundancy Protocol (VRRP) on an interface and identify the IP address of the virtual router, use the vrrp ip command in interface configuration mode. To disable VRRP on the interface and remove the IP address of the virtual router, use the no form of this command.
vrrp group ip ip-address [secondary]
no vrrp group ip ip-address [secondary]
Syntax Description
Command Default
VRRP is not configured on the interface.
Command Modes
Interface configuration (config-if)
Command History
Usage Guidelines
The vrrp ip command activates VRRP on the configured interface. The first IP address specified in the VRRP configuration is used as the primary address for the virtual router. For VRRP to elect a designated router, at least one router on the cable must have been configured with the primary address of the virtual router. Configuration of the primary address on the master router always overrides a primary address that is currently in use.
VRRP does not support address learning. All addresses must be configured.
All routers in the VRRP group must be configured with the same primary address for the virtual router. If different primary addresses are configured, the routers in the VRRP group will not communicate with each other and any misconfigured routers in the group will change their state to master.
Configure this command once without the secondary keyword to indicate the virtual router IP address. If you want to indicate additional IP addresses supported by this group, then do so and include the secondary keyword.
Note
VRRP must be in the master state for proxy Address Resolution Protocol (ARP) to use the VRRP virtual MAC address.
Examples
The following example shows how to enable VRRP on Ethernet interface 0. The VRRP group is 1. IP address 10.0.1.20 is the address of the virtual router.
interface ethernet 0ip address 10.0.1.1 255.255.255.0ip address 10.0.2.1 255.255.255.0 secondary!vrrp 1 ip 10.0.1.20vrrp 1 ip 10.0.2.20 secondaryRelated Commands
show vrrp
Displays a summary or detailed status of one or all configured VRRP groups.
vrrp name
To link a Virtual Router Redundancy Service (VRRS) client to a Virtual Router Redundancy Protocol (VRRP) group, use the vrrp name command in interface configuration mode. To disassociate a VRRS group from VRRS, use the no form of this command.
vrrp group-number name [vrrp-group-name]
no vrrp group-number name [vrrp-group-name]
Syntax Description
group-number
Virtual router group number. The group number range is from 1 to 255.
vrrp-group-name
(Optional) VRRP group name.
Command Default
VRRS clients are not linked to VRRP groups.
Command Modes
Interface configuration (config-if)
Command History
Usage Guidelines
Use the vrrp name command to link VRRS clients to VRRP groups. VRRP provides stateless redundancy for IP routing. VRRP by itself is limited to maintaining its own state. Linking a VRRS client to a VRRP group allows client applications to implement stateful failover. IP redundancy clients are other Cisco IOS processes or applications that use VRRP to provide or withhold a service or resource dependent upon the state of the group.
Use the no vrrp name command to dissociates a VRRP group from VRRS. After this, the same VRRP group can be attached to a different VRRP name; or the VRRS name can be applied to a different VRRP group.
Examples
The following example shows how to link VRRS clients to a VRRP group named VRRP-Partition-1:
Router(config)# interface gigabitethernet0/0/0Router(config-if)# vrrp 1 name VRRP-Partition-1Related Commands
vrrs follow
Configures a name association between VRRS plug-ins and the VRRS server.
vrrp name
Links a VRRS client to a VRRP group.
vrrp preempt
To configure the router to take over as master virtual router for a Virtual Router Redundancy Protocol (VRRP) group if it has higher priority than the current master virtual router, use the vrrp preempt command in interface configuration mode. To disable this function, use the no form of this command.
vrrp group preempt [delay minimum seconds]
no vrrp group preempt
Syntax Description
Defaults
This command is enabled.
Command Modes
Interface configuration (config-if)
Command History
Usage Guidelines
By default, the router being configured with this command will take over as master virtual router for the group if it has a higher priority than the current master virtual router. You can configure a delay, which will cause the VRRP router to wait the specified number of seconds before issuing an advertisement claiming master ownership.
Note
Examples
The following example configures the router to preempt the current master virtual router when its priority of 200 is higher than that of the current master virtual router. If the router preempts the current master virtual router, it waits 15 seconds before issuing an advertisement claiming it is the master virtual router.
vrrp 1 preempt delay minimum 15vrrp 1 priority 200Related Commands
vrrp ip
Enables VRRP and identifies the IP address of the virtual router.
vrrp priority
Sets the priority level of the router within a VRRP group.
vrrp priority
To set the priority level of the router within a Virtual Router Redundancy Protocol (VRRP) group, use the vrrp priority command in interface configuration mode. To remove the priority level of the router, use the no form of this command.
vrrp group priority level
no vrrp group priority level
Syntax Description
group
Virtual router group number. The group number range is from 1 to 255.
level
Priority of the router within the VRRP group. The range is from 1 to 254. The default is 100.
Defaults
level: 100
Command Modes
Interface configuration (config-if)
Command History
Usage Guidelines
Use this command to control which router becomes the master virtual router.
Examples
The following example configures the router with a priority of 254:
vrrp 1 priority 254Related Commands
vrrp shutdown
To disable the Virtual Router Redundancy Protocol (VRRP) group on an interface, use the vrrp shutdown command in interface configuration mode.
vrrp group-number shutdown
Syntax Description
Defaults
VRRP groups configured by the vrrp group-number ip command are enabled by default.
Command Modes
Interface configuration (config-if)
Command History
12.3(11)T
This command was introduced.
Cisco IOS XE Release 2.6
This command was integrated into Cisco IOS XE Release 2.6.
Usage Guidelines
When a VRRP group has been configured using the vrrp group-number ip command, the protocol is fully operational. The vrrp shutdown command is not displayed on the router, and to disable the protocol for one group, you must explicitly specify the group using the vrrp shutdown command.
Examples
The following example shows how to disable one VRRP group on Ethernet interface 0/1 (group 1) while retaining the VRRP group on Ethernet interface 0/2 (group 2):
interface ethernet0/1ip address 10.0.1.1 255.255.255.0vrrp 1 ip 10.0.1.254vrrp 1 shutdown!interface ethernet0/2ip address 10.0.42.1 255.255.255.0vrrp 2 ip 10.0.42.254Related Commands
show vrrp
Displays a summary or detailed status of one or all configured VRRP groups.
vrrp ip
Enables the VRRP on an interface and identify the IP address of the virtual router.
vrrp sso
To enable Virtual Router Redundancy Protocol (VRRP) support of Stateful Switchover (SSO) if it has been disabled, use the vrrp sso command in global configuration mode. To disable VRRP support of SSO, use the no form of this command.
vrrp sso
no vrrp sso
Syntax Description
This command has no arguments or keywords.
Command Default
VRRP support of SSO is enabled by default.
Command Modes
Global configuration (config)
Command History
Usage Guidelines
Use this command to enable VRRP support of SSO if it has been manually disabled by the no vrrp sso command.
Examples
The following example shows how to disable VRRP support of SSO:
Router(config)# no vrrp ssoRelated Commands
vrrp timers advertise
To configure the interval between successive advertisements by the master virtual router in a Virtual Router Redundancy Protocol (VRRP) group, use the vrrp timers advertise command in interface configuration mode. To restore the default value, use the no form of this command.
vrrp group timers advertise [msec] interval
no vrrp group timers advertise [msec] interval
Syntax Description
Defaults
interval: 1 second
Command Modes
Interface configuration (config-if)
Command History
Usage Guidelines
The advertisements being sent by the master virtual router communicate the state and priority of the current master virtual router.
The vrrp timers advertise command configures the time between successive advertisement packets and the time before other routers declare the master router to be down. Routers or access servers on which timer values are not configured can learn timer values from the master router. The timers configured on the master router always override any other timer settings. All routers in a VRRP group must use the same timer values. If the same timer values are not set, the routers in the VRRP group will not communicate with each other and any misconfigured router will change its state to master.
Examples
The following example shows how to configure the master virtual router to send advertisements every 4 seconds:
vrrp 1 timers advertise 4Related Commands
vrrp timers learn
To configure the router, when it is acting as backup virtual router for a Virtual Router Redundancy Protocol (VRRP) group, to learn the advertisement interval used by the master virtual router, use the vrrp timers learn command in interface configuration mode. To prevent the local router from learning the advertisement interval of the master virtual router, use the no form of this command.
vrrp group timers learn
no vrrp group timers learn
Syntax Description
group
Virtual router group number to which the command applies. The group number range is from 1 to 255.
Defaults
Disabled; the local router calculates the downtime of the master virtual router based on the advertisement interval of the local router as configured by the vrrp timers advertise command.
Command Modes
Interface configuration (config-if)
Command History
Usage Guidelines
If this command is configured, when the local router is acting as a backup virtual router for the group, it will learn the advertisement interval of the current master virtual router from its master advertisements. The local router will use that value to calculate how long it should wait before deciding that the master virtual router has gone down. This command synchronizes timers with the current master virtual router.
Examples
The following example configures the router, when it is acting as backup virtual router, to learn the advertisement interval from the advertisements of the current master virtual router:
vrrp 1 timers learnRelated Commands
vrrp track
To configure the Virtual Router Redundancy Protocol (VRRP) to track an object, use the vrrp track command in interface configuration mode. To disable the tracking, use the no form of this command.
vrrp group track object-number [decrement priority]
no vrrp group track object-number [decrement priority]
Syntax Description
Defaults
The default decrement value is 10. The range is from 1 and 255.
Command Modes
Interface configuration (config-if)
Command History
Usage Guidelines
You can configure VRRP to track specific objects, such as an interface or IP route, that can alter the priority level of a virtual router for a VRRP group. The tracked objects are first defined using the track interface or track ip route global configuration command. The client process, in this case VRRP, registers interest in tracking these objects and can then be notified when the tracked object changes state.
Examples
In the following example, the tracking process is configured to track the IP routing capability of serial interface 1/0. VRRP on Ethernet interface 0/0 then registers with the tracking process to be informed of any changes to the IP routing state of serial interface 1/0. If the IP state on serial interface 1/0 goes down, then the priority of the VRRP group is reduced by 10.
If both serial interfaces are operational, then Router A will be the master virtual router because it has the higher priority.
However, if IP routing on serial interface 1/0 in Router A fails, then the HSRP group priority will be reduced and Router B will take over as the master virtual router, thus maintaining a default virtual gateway service to hosts on the 10.1.0.0 subnet.
Router A Configuration
!track 100 interface serial1/0 ip routing!interface Ethernet0/0ip address 10.1.0.21 255.255.0.0vrrp 1 ip 10.1.0.1vrrp 1 priority 105vrrp 1 track 100 decrement 10Router B Configuration
!track 100 interface serial1/0 ip routing!interface Ethernet0/0ip address 10.1.0.22 255.255.0.0vrrp 1 ip 10.1.0.1vrrp 1 priority 100vrrp 1 track 100 decrement 10Related Commands
track interface
Configures an interface to be tracked.
track ip route
Tracks the state of an IP route.
vrrs
To specify a distinct AAA accounting method list to use, a non-zero delay time for accounting-off messages, and additional attributes other than the default for a Virtual Router Redundancy Protocol (VRRP) group, enter the vrrs command in the global configuration mode. To return to the default values, use the no form of this command.
vrrs vrrs-group-name
no vrrs name
Syntax Description
Command Default
Accounting-on and accounting-off messages for a VRRP group are set with default accounting attributes, without any delay for accounting-off messages, and using the VRRS default accounting method list.
Command Modes
Global configuration (config)
Command History
Usage Guidelines
The VRRS group name specified by the vrrs-group-name argument should match a VRRP group as configured by the vrrp name command in interface configuration mode.
Note
.The following RADIUS attributes are included in accounting messages by default:
•
•
•
•
•
Examples
The following example shows how to configure a VRRS group named vrrp-group-1:
Router(config)# vrrs vrrp-group-1Router(config-vrrs)# exitRouter(config)# interface gigabitethernet 1/0/0Router(config-if)# ip address 10.1.0.2 255.0.0.0Router(config-if)# vrrp 1 ip 10.1.0.10Router(config-if)# vrrp 1 name vrrp-group-1Related Commands
vrrp ip
Enables the VRRP on an interface and identifies the IP address of the virtual router.
vrrp name
Links a VRRS client to a VRRP group.
vrrs follow
To configure a name association between Virtual Router Redundancy Service (VRRS) plug-ins and the VRRS server, use the vrrs follow command in subinterface configuration mode. To disassociate the VRRS plug-ins from a server, use the no form of this command.
vrrs follow name
no vrrs follow name
Syntax Description
name
A name that associates the VRRS plug-ins with a First Hop Redundancy Protocol (FHRP) server, via VRRS, that shares the same name.
Command Default
VRRS plug-ins remain detached and in the DOWN state.
Command Modes
Subinterface configuration (config-subif)
Command History
Usage Guidelines
This command can be applied only to subinterfaces.
The no vrrs follow command disassociate the VRRS plug-ins from a server. The VRRS plug-ins are disabled after this, and are forced to the DOWN state until they are reattached to a new name.
Examples
The following example configures a name association between the VRRS interface-state and mac-address plug-ins and the VRRS server:
Router(config)# interface gigabitethernet0/0/0.1Router(config-subif)# ip address 172.24.1.1 255.255.255.0Router(config-subif)# vrrs follow name1Router(config-subif)# vrrs interface-stateRouter(config-subif)# vrrs mac-addressRelated Commands
vrrs interface-state
Configures the VRRP shutdown plug-in on an interface.
vrrs mac-address
Configures the VRRS mac-address plug-in on an interface.
vrrs interface-state
To configure the Virtual Router Redundancy Protocol (VRRP) shutdown plug-in on an interface, use the vrrs interface-state command in subinterface configuration mode. To disable the shutdown plug-in, use the no form of this command.
vrrs interface-state
no vrrs interface-state
Syntax Description
This command has no arguments or keywords.
Command Default
The VRRS shutdown plug-in remains detached and in the DOWN state.
Command Modes
Subinterface configuration (config-subif)
Command History
Usage Guidelines
Use the vrrs interface-state command to configure the VRRP shutdown plug-in on an interface. When the line protocol is configured, and the Virtual Router Redundancy Service (VRRS) is in a nonactive state, the line protocol state of the interface is transitioned to down.
The vrrs follow command associates the interface-state plug-in with a First Hop Redundancy Protocol (FHRP) that is using the same name with VRRS. Removal of the vrrs interface-state command, or a change in the VRRS state to an active state, causes the line protocol state of the interface to transition to UP.
Examples
The following example shows how to configure the VRRP shutdown plug-in on an interface:
Router(config)# interface gigabitethernet0/0/1.1Router(config-subif)# ip address 10.0.0.0 255.255.255.0Router(config-subif)# vrrs follow vrrp-partition-1Router(config-subif)# vrrs interface-stateRouter(config-subif)# vrrs mac-address arp interval 5 duration 60Related Commands
vrrs follow
Configures a name association between VRRS plug-ins and the VRRS server.
vrrs mac-address
Configures the VRRS mac-address plug-in on an interface.
vrrs mac-address
To configure the Virtual Router Redundancy Service (VRRS) mac-address plug-in on an interface, use the vrrs mac-address command in subinterface configuration mode. To disable the mac-address plug-in, use the no form of this command.
vrrs mac-address [arp [interval seconds ] [duration seconds]]
no vrrs mac-address [arp [interval seconds] [duration seconds]]
Syntax Description
Command Default
The VRRS mac-address plug-in remains detached and in the DOWN state.
Command Modes
Subinterface configuration (config-subif)
Command History
Usage Guidelines
Use the vrrs mac-address command to configure the VRRS mac-address plug-in on an interface. When a virtual-MAC is configured, and VRRS is in an ACTIVE state, a virtual-MAC is added to the interface that is to be associated with the Primary IP address configured on that interface. Use the vrrs follow command to associate the mac-address plug-in with a First Hop Redundancy Protocol (FHRP) that is using the same name as VRRS. The mac-address plug-in can be enabled with all defaults by configuring the vrrs mac-address command with no optional keywords or arguments.
Examples
The following example shows how to configure the VRRS mac-address plug-in on an interface:
Router(config)# interface gigabitethernet0/0/1.1Router(config-subif)# ip address 10.0.0.0 255.255.255.0Router(config-subif)# vrrs follow vrrp-partition-1Router(config-subif)# vrrs interface-stateRouter(config-subif)# vrrs mac-address arp interval 5 duration 60Related Commands
vrrs follow
Configures a name association between VRRS plug-ins and the VRRS server.
vrrs interface-state
Configures the VRRP shutdown plug-in on an interface.
weight (firewall farm real server)
To specify a real server's capacity, relative to other real servers in the firewall farm, use the weight command in firewall farm real server configuration mode. To restore the default weight value, use the no form of this command.
weight setting
no weight
Syntax Description
setting
Weight setting to use for the real server predictor algorithm. Valid settings range from 1 to 255. The default weight setting is 8.
Defaults
The default setting to use for the real server predictor algorithm is 8.
Command Modes
Firewall farm real server configuration (config-slb-fw-real)
Command History
Examples
The following example specifies the relative weights of three real servers as 16, 8 (by default), and 24, respectively:
Router(config)# ip slb firewallfarm FIRE1Router(config-slb-fw)# real 10.10.1.1Router(config-slb-fw-real)# weight 16Router(config-slb-fw-real)# inserviceRouter(config-slb-fw-real)# exitRouter(config-slb-fw)# real 10.10.1.2Router(config-slb-fw-real)# inserviceRouter(config-slb-fw-real)# exitRouter(config-slb-fw)# real 10.10.1.3Router(config-slb-fw-real)# weight 24Related Commands
weight (real server)
To specify a real server's capacity, relative to other real servers in the server farm, use the weight command in SLB real server configuration mode. To restore the default weight value, use the no form of this command.
weight setting
no weight
Syntax Description
setting
Weight setting to use for the real server predictor algorithm. Valid settings range from 1 to 255. The default weight setting is 8.
Defaults
The default setting to use for the real server predictor algorithm is 8.
Command Modes
SLB real server configuration (config-slb-sfarm)
Command History
Usage Guidelines
The static weights you define using this command are overridden by the weights calculated by Dynamic Feedback Protocol (DFP). If DFP is removed from the network, IOS Server Load Balancing (IOS SLB) reverts to these static weights.
Examples
The following example specifies the relative weights of three real servers as 16, 8 (by default), and 24, respectively:
Router(config)# ip slb serverfarm PUBLIC!-----First real serverRouter(config-slb-sfarm)# real 10.10.1.1!-----Assigned weight of 16Router(config-slb-real)# weight 16!-----EnabledRouter(config-slb-real)# inserviceRouter(config-slb-real)# exit!-----Second real serverRouter(config-slb-sfarm)# real 10.10.1.2!-----Enabled with default weightRouter(config-slb-real)# inserviceRouter(config-slb-real)# exit!-----Third real serverRouter(config-slb-sfarm)# real 10.10.1.3!-----Assigned weight of 24, not enabledRouter(config-slb-real)# weight 24Related Commands
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