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Table Of Contents
Multiple Virtual Router Support
VRRP Router Priority and Preemption
How Object Tracking Affects the Priority of a VRRP Router
Disabling VRRP on an Interface
Configuring VRRP Object Tracking
Configuring VRRP Authentication
How VRRP MD5 Authentication Works
Configuring VRRP MD5 Authentication Using a Key String
Configuring VRRP MD5 Authentication Using a Key Chain
Verifying the VRRP MD5 Authentication Configuration
Configuring VRRP Text Authentication
Enabling the Router to Send SNMP VRRP Notifications
Configuration Examples for VRRP
VRRP Object Tracking Verification: Example
VRRP MD5 Authentication Configuration Using a Key String: Example
VRRP MD5 Authentication Configuration Using a Key Chain: Example
VRRP Text Authentication: Example
Disabling a VRRP Group on an Interface: Example
Configuring VRRP
First Published: May 2, 2005Last Updated: February 27, 2009The Virtual Router Redundancy Protocol (VRRP) is an election protocol that dynamically assigns responsibility for one or more virtual routers to the VRRP routers on a LAN, allowing several routers on a multiaccess link to utilize the same virtual IP address. A VRRP router is configured to run the VRRP protocol in conjunction with one or more other routers attached to a LAN. In a VRRP configuration, one router is elected as the virtual router master, with the other routers acting as backups in case the virtual router master fails.
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest feature information and caveats, see the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the "Feature Information for VRRP" section.
Use Cisco Feature Navigator to find information about platform support and Cisco IOS and Catalyst OS software image support. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Contents
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Configuration Examples for VRRP
Restrictions for VRRP
VRRP is designed for use over multi-access, multicast, or broadcast capable Ethernet LANs. VRRP is not intended as a replacement for existing dynamic protocols.
VRRP is supported on Ethernet, Fast Ethernet, Bridge Group Virtual Interface (BVI), and Gigabit Ethernet interfaces, Multiprotocol Label Switching (MPLS) Virtual Private Networks (VPNs), VRF-aware MPLS VPNs and VLANs.
Because of the forwarding delay that is associated with the initialization of a BVI interface, it is necessary to set the VRRP advertise timer to a value equal to or greater than the forwarding delay on the BVI interface. This setting prevents a VRRP router on a recently initialized BVI interface from unconditionally taking over the master role. Use the bridge forward-time command to set the forwarding delay on the BVI interface. Use the vrrp timers advertise command to set the VRRP advertisement timer.
Information About VRRP
Before you configure VRRP, you should understand the following concepts:
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VRRP Operation
There are several ways a LAN client can determine which router should be the first hop to a particular remote destination. The client can use a dynamic process or static configuration. Examples of dynamic router discovery are as follows:
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The drawback to dynamic discovery protocols is that they incur some configuration and processing overhead on the LAN client. Also, in the event of a router failure, the process of switching to another router can be slow.
An alternative to dynamic discovery protocols is to statically configure a default router on the client. This approach simplifies client configuration and processing, but creates a single point of failure. If the default gateway fails, the LAN client is limited to communicating only on the local IP network segment and is cut off from the rest of the network.
VRRP can solve the static configuration problem. VRRP enables a group of routers to form a single virtual router. The LAN clients can then be configured with the virtual router as their default gateway. The virtual router, representing a group of routers, is also known as a VRRP group.
VRRP is supported on Ethernet, Fast Ethernet, BVI, and Gigabit Ethernet interfaces, on MPLS VPNs, VRF-aware MPLS VPNs and VLANs.
Figure 1 shows a LAN topology in which VRRP is configured. In this example, Routers A, B, and C are VRRP routers (routers running VRRP) that comprise a virtual router. The IP address of the virtual router is the same as that configured for the Ethernet interface of Router A (10.0.0.1).
Figure 1 Basic VRRP Topology
Because the virtual router uses the IP address of the physical Ethernet interface of Router A, Router A assumes the role of the virtual router master and is also known as the IP address owner. As the virtual router master, Router A controls the IP address of the virtual router and is responsible for forwarding packets sent to this IP address. Clients 1 through 3 are configured with the default gateway IP address of 10.0.0.1.
Routers B and C function as virtual router backups. If the virtual router master fails, the router configured with the higher priority will become the virtual router master and provide uninterrupted service for the LAN hosts. When Router A recovers, it becomes the virtual router master again. For more detail on the roles that VRRP routers play and what happens if the virtual router master fails, see the "VRRP Router Priority and Preemption" section later in this document.
Figure 2 shows a LAN topology in which VRRP is configured so that Routers A and B share the traffic to and from clients 1 through 4 and that Routers A and B act as virtual router backups to each other if either router fails.
Figure 2 Load Sharing and Redundancy VRRP Topology
In this topology, two virtual routers are configured. (For more information, see the "Multiple Virtual Router Support" section later in this document.) For virtual router 1, Router A is the owner of IP address 10.0.0.1 and virtual router master, and Router B is the virtual router backup to Router A. Clients 1 and 2 are configured with the default gateway IP address of 10.0.0.1.
For virtual router 2, Router B is the owner of IP address 10.0.0.2 and virtual router master, and Router A is the virtual router backup to Router B. Clients 3 and 4 are configured with the default gateway IP address of 10.0.0.2.
VRRP Benefits
Redundancy
VRRP enables you to configure multiple routers as the default gateway router, which reduces the possibility of a single point of failure in a network.
Load Sharing
You can configure VRRP in such a way that traffic to and from LAN clients can be shared by multiple routers, thereby sharing the traffic load more equitably among available routers.
Multiple Virtual Routers
VRRP supports up to 255 virtual routers (VRRP groups) on a router physical interface, subject to the platform supporting multiple MAC addresses. Multiple virtual router support enables you to implement redundancy and load sharing in your LAN topology.
Multiple IP Addresses
The virtual router can manage multiple IP addresses, including secondary IP addresses. Therefore, if you have multiple subnets configured on an Ethernet interface, you can configure VRRP on each subnet.
Preemption
The redundancy scheme of VRRP enables you to preempt a virtual router backup that has taken over for a failing virtual router master with a higher priority virtual router backup that has become available.
Authentication
VRRP message digest 5 (MD5) algorithm authentication protects against VRRP-spoofing software and uses the industry-standard MD5 algorithm for improved reliability and security.
Advertisement Protocol
VRRP uses a dedicated Internet Assigned Numbers Authority (IANA) standard multicast address (224.0.0.18) for VRRP advertisements. This addressing scheme minimizes the number of routers that must service the multicasts and allows test equipment to accurately identify VRRP packets on a segment. The IANA assigned VRRP the IP protocol number 112.
VRRP Object Tracking
VRRP object tracking provides a way to ensure the best VRRP router is virtual router master for the group by altering VRRP priorities to the status of tracked objects such as interface or IP route states.
Multiple Virtual Router Support
You can configure up to 255 virtual routers on a router physical interface. The actual number of virtual routers that a router interface can support depends on the following factors:
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In a topology where multiple virtual routers are configured on a router interface, the interface can act as a master for one virtual router and as a backup for one or more virtual routers.
VRRP Router Priority and Preemption
An important aspect of the VRRP redundancy scheme is VRRP router priority. Priority determines the role that each VRRP router plays and what happens if the virtual router master fails.
If a VRRP router owns the IP address of the virtual router and the IP address of the physical interface, this router will function as a virtual router master.
Priority also determines if a VRRP router functions as a virtual router backup and the order of ascendancy to becoming a virtual router master if the virtual router master fails. You can configure the priority of each virtual router backup with a value of 1 through 254 using the vrrp priority command.
For example, if Router A, the virtual router master in a LAN topology, fails, an election process takes place to determine if virtual router backups B or C should take over. If Routers B and C are configured with the priorities of 101 and 100, respectively, Router B is elected to become virtual router master because it has the higher priority. If Routers B and C are both configured with the priority of 100, the virtual router backup with the higher IP address is elected to become the virtual router master.
By default, a preemptive scheme is enabled whereby a higher priority virtual router backup that becomes available takes over for the virtual router backup that was elected to become virtual router master. You can disable this preemptive scheme using the no vrrp preempt command. If preemption is disabled, the virtual router backup that is elected to become virtual router master remains the master until the original virtual router master recovers and becomes master again.
VRRP Advertisements
The virtual router master sends VRRP advertisements to other VRRP routers in the same group. The advertisements communicate the priority and state of the virtual router master. The VRRP advertisements are encapsulated in IP packets and sent to the IP Version 4 multicast address assigned to the VRRP group. The advertisements are sent every second by default; the interval is configurable.
VRRP Object Tracking
Object tracking is an independent process that manages creating, monitoring, and removing tracked objects such as the state of the line-protocol of an interface. Clients such as the Hot Standby Router Protocol (HSRP), Gateway Load Balancing Protocol (GLBP), and now VRRP register their interest with specific tracked objects and act when the state of an object changes.
Each tracked object is identified by a unique number that is specified on the tracking command-line interface (CLI). Client processes such as VRRP use this number to track a specific object.
The tracking process periodically polls the tracked objects and notes any change of value. The changes in the tracked object are communicated to interested client processes, either immediately or after a specified delay. The object values are reported as either up or down.
VRRP object tracking gives VRRP access to all the objects available through the tracking process. The tracking process provides the ability to track individual objects such as a the state of an interface line protocol, state of an IP route, or the reachability of a route.
VRRP provides an interface to the tracking process. Each VRRP group can track multiple objects that may affect the priority of the VRRP router. You specify the object number to be tracked and VRRP will be notified of any change to the object. VRRP increments (or decrements) the priority of the virtual router based on the state of the object being tracked.
ISSU—VRRP
VRRP supports In Service Software Upgrade (ISSU). In Service Software Upgrade (ISSU) allows a high-availability (HA) system to run in Stateful Switchover (SSO) mode even when different versions of Cisco IOS software are running on the active and standby Route Processors (RPs) or line cards.
ISSU provides the ability to upgrade or downgrade from one supported Cisco IOS release to another while continuing to forward packets and maintain sessions, thereby reducing planned outage time. The ability to upgrade or downgrade is achieved by running different software versions on the active RP and standby RP for a short period of time to maintain state information between RPs. This feature allows the system to switch over to a secondary RP running upgraded (or downgraded) software and continue forwarding packets without session loss and with minimal or no packet loss. This feature is enabled by default.
For detailed information about ISSU, see the Cisco IOS In Service Software Upgrade Process document at the following URL:
http://www.cisco.com/en/US/docs/ios/ha/configuration/guide/ha-inserv_updg.html
For detailed information about ISSU on the 7600 series routers, see the ISSU and eFSU on Cisco 7600 Series Routers document at the following URL:
SSO—VRRP
With the introduction of the SSO—VRRP feature, VRRP is Stateful Switchover (SSO) aware. VRRP can detect when a router is failing over to the secondary RP and continue in its current group state.
SSO functions in networking devices (usually edge devices) that support dual Route Processors (RPs). SSO provides RP redundancy by establishing one of the RPs as the active processor and the other RP as the standby processor. SSO also synchronizes critical state information between the RPs so that network state information is dynamically maintained between RPs.
Prior to being SSO aware, if VRRP was deployed on a router with redundant RPs, a switchover of roles between the active RP and the standby RP would result in the router relinquishing its activity as a VRRP group member and then rejoining the group as if it had been reloaded. The SSO—VRRP feature enables VRRP to continue its activities as a group member during a switchover. VRRP state information between redundant RPs is maintained so that the standby RP can continue the router's activities within the VRRP during and after a switchover.
This feature is enabled by default. To disable this feature, use the no vrrp sso command in global configuration mode.
For more information, see the Stateful Switchover document at the following URL:
http://www.cisco.com/en/US/docs/ios/ha/configuration/guide/ha-stfl_swovr.html
How to Configure VRRP
This section contains the following procedures:
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Customizing VRRP
Perform this task to customize VRRP.
Customizing the behavior of VRRP is optional. Be aware that as soon as you enable a VRRP group, that group is operating. It is possible that if you first enable a VRRP group before customizing VRRP, the router could take over control of the group and become the virtual router master before you have finished customizing the feature. Therefore, if you plan to customize VRRP, it is a good idea to do so before enabling VRRP.
How Object Tracking Affects the Priority of a VRRP Router
The priority of a device can change dynamically if it has been configured for object tracking and the object that is being tracked goes down. The tracking process periodically polls the tracked objects and notes any change of value. The changes in the tracked object are communicated to VRRP, either immediately or after a specified delay. The object values are reported as either up or down. Examples of objects that can be tracked are the line protocol state of an interface or the reachability of an IP route. If the specified object goes down, the VRRP priority is reduced. The VRRP router with the higher priority can now become the virtual router master if it has the vrrp preempt command configured. See the "VRRP Object Tracking" section for more information on object tracking.
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Enabling VRRP
Perform this task to enable VRRP.
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Disabling VRRP on an Interface
Disabling VRRP on an interface allows the protocol to be disabled, but the configuration retained. This ability was added with the introduction of the VRRP MIB, RFC 2787, Definitions of Managed Objects for the Virtual Router Redundancy Protocol.
You can use a Simple Network Management Protocol (SNMP) management tool to enable or disable VRRP on an interface. Because of the SNMP management capability, the vrrp shutdown command was introduced to represent a method via the CLI for VRRP to show the state that had been configured using SNMP.
When the show running-config command is entered, you can see immediately if the VRRP group has been configured and set to enabled or disabled. This is the same functionality that is enabled within the MIB.
The no form of the command enables the same operation that is performed within the MIB. If the vrrp shutdown command is specified using the SNMP interface, then entering the no vrrp shutdown command using the Cisco IOS CLI will reenable the VRRP group.
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Configuring VRRP Object Tracking
Perform the following task to configure VRRP object tracking.
Restrictions
If a VRRP group is the IP address owner, its priority is fixed at 255 and cannot be reduced through object tracking.
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Configuring VRRP Authentication
VRRP ignores unauthenticated VRRP protocol messages. The default authentication type is text authentication.
The following sections describe configuration tasks for VRRP authentication. The task you perform depends on whether you want to use text authentication, a simple MD5 key string, or MD5 key chains for authentication.
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How VRRP MD5 Authentication Works
MD5 authentication provides greater security than the alternative plain text authentication scheme. MD5 authentication allows each VRRP group member to use a secret key to generate a keyed MD5 hash of the packet that is part of the outgoing packet. A keyed hash of an incoming packet is generated and if the generated hash does not match the hash within the incoming packet, the packet is ignored.
The key for the MD5 hash can either be given directly in the configuration using a key string or supplied indirectly through a key chain.
A router will ignore incoming VRRP packets from routers that do not have the same authentication configuration for a VRRP group. VRRP has three authentication schemes:
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VRRP packets will be rejected in any of the following cases:
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Restrictions
Interoperability with vendors that may have implemented the RFC 2338 method is not enabled.
Text authentication cannot be combined with MD5 authentication for a VRRP group at any one time. When MD5 authentication is configured, the text authentication field in VRRP hello messages is set to all zeroes on transmit and ignored on receipt, provided the receiving router also has MD5 authentication enabled.
Configuring VRRP MD5 Authentication Using a Key String
Perform this task to configure VRRP MD5 authentication using a key string.
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Configuring VRRP MD5 Authentication Using a Key Chain
Perform this task to configure VRRP MD5 authentication using a key chain. Key chains allow a different key string to be used at different times according to the key chain configuration. VRRP will query the appropriate key chain to obtain the current live key and key ID for the specified key chain.
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Verifying the VRRP MD5 Authentication Configuration
To verify the MD5 authentication configuration, perform the following steps.
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Step 1
Use this command to verify that the authentication is configured correctly:
Router# show vrrpEthernet0/1 - Group 1State is MasterVirtual IP address is 10.21.0.10Virtual MAC address is 0000.5e00.0101Advertisement interval is 1.000 secPreemption is enabledmin delay is 0.000 secPriority is 100Authentication MD5, key-string, timeout 30 secsMaster Router is 10.21.0.1 (local), priority is 100Master Advertisement interval is 1.000 secMaster Down interval is 3.609 secThis output shows that MD5 authentication is configured and the f00d4s key string is used. The timeout value is set at 30 seconds.
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Use this command to verify that both routers have authentication configured, that the MD5 key ID is the same on each router, and that the MD5 key strings are the same on each router:
Router1#: debug vrrp authenticationVRRP: Sent: 21016401FE050000AC1801FE0000000000000000VRRP: HshC: B861CBF1B9026130DD34AED849BEC8A1VRRP: Rcvd: 21016401FE050000AC1801FE0000000000000000VRRP: HshC: B861CBF1B9026130DD34AED849BEC8A1VRRP: HshR: C5E193C6D84533FDC750F85FCFB051E1VRRP: Grp 1 Adv from 172.24.1.2 has failed MD5 authRouter2#: debug vrrp authenticationVRRP: Sent: 21016401FE050000AC1801FE0000000000000000VRRP: HshC: C5E193C6D84533FDC750F85FCFB051E1VRRP: Rcvd: 21016401FE050000AC1801FE0000000000000000VRRP: HshC: C5E193C6D84533FDC750F85FCFB051E1VRRP: HshR: B861CBF1B9026130DD34AED849BEC8A1VRRP: Grp 1 Adv from 172.24.1.1 has failed MD5 auth
Configuring VRRP Text Authentication
Perform this task to configure VRRP text authentication.
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Enabling the Router to Send SNMP VRRP Notifications
The VRRP MIB supports SNMP Get operations, which allow network devices to get reports about VRRP groups in a network from the network management station.
Enabling VRRP MIB trap support is performed through the CLI, and the MIB is used for getting the reports. A trap notifies the network management station when a router becomes a Master or backup router. When an entry is configured from the CLI, the RowStatus for that group in the MIB immediately goes to the active state.
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Configuration Examples for VRRP
This section provides the following configuration examples:
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Configuring VRRP: Example
In the following example, Router A and Router B each belong to three VRRP groups.
In the configuration, each group has the following properties:
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Router A
interface ethernet 1/0ip address 10.1.0.2 255.0.0.0vrrp 1 priority 120vrrp 1 authentication ciscovrrp 1 timers advertise 3vrrp 1 timers learnvrrp 1 ip 10.1.0.10vrrp 5 priority 100vrrp 5 timers advertise 30vrrp 5 timers learnvrrp 5 ip 10.1.0.50vrrp 100 timers learnno vrrp 100 preemptvrrp 100 ip 10.1.0.100no shutdownRouter B
interface ethernet 1/0ip address 10.1.0.1 255.0.0.0vrrp 1 priority 100vrrp 1 authentication ciscovrrp 1 timers advertise 3vrrp 1 timers learnvrrp 1 ip 10.1.0.10vrrp 5 priority 200vrrp 5 timers advertise 30vrrp 5 timers learnvrrp 5 ip 10.1.0.50vrrp 100 timers learnno vrrp 100 preemptvrrp 100 ip 10.1.0.100no shutdownVRRP Object Tracking: Example
In the following example, the tracking process is configured to track the state of the line protocol on serial interface 0/1. VRRP on Ethernet interface 1/0 then registers with the tracking process to be informed of any changes to the line protocol state of serial interface 0/1. If the line protocol state on serial interface 0/1 goes down, then the priority of the VRRP group is reduced by 15.
track 1 interface Serial0/1 line-protocol!interface Ethernet1/0ip address 10.0.0.2 255.0.0.0vrrp 1 ip 10.0.0.3vrrp 1 priority 120vrrp 1 track 1 decrement 15VRRP Object Tracking Verification: Example
The following examples verify the configuration shown in the "VRRP Object Tracking: Example" section:
Router# show vrrpEthernet1/0 - Group 1State is MasterVirtual IP address is 10.0.0.3Virtual MAC address is 0000.5e00.0101Advertisement interval is 1.000 secPreemption is enabledmin delay is 0.000 secPriority is 105Track object 1 state Down decrement 15Master Router is 10.0.0.2 (local), priority is 105Master Advertisement interval is 1.000 secMaster Down interval is 3.531 secRouter# show trackTrack 1Interface Serial0/1 line-protocolLine protocol is Down (hw down)1 change, last change 00:06:53Tracked by:VRRP Ethernet1/0 1VRRP MD5 Authentication Configuration Using a Key String: Example
The following example shows how to configure MD5 authentication using a key string and timeout of 30 seconds:
interface Ethernet0/1description ed1-cat5a-7/10vrrp 1 ip 10.21.0.10vrrp 1 priority 110vrrp 1 authentication md5 key-string f00c4s timeout 30exitVRRP MD5 Authentication Configuration Using a Key Chain: Example
The following example shows how to configure MD5 authentication using a key chain:
key chain vrrp1key 1key-string f00c4sexit!interface ethernet0/1description ed1-cat5a-7/10vrrp 1 priority 110vrrp 1 authentication md5 key-chain vrrp1vrrp 1 ip 10.21.0.10In this example, VRRP queries the key chain to obtain the current live key and key ID for the specified key chain.
VRRP Text Authentication: Example
The following example shows how to configure VRRP text authentication using a text string:
interface fastethernet 0/0ip address 10.21.8.32 255.255.255.0vrrp 10 authentication text stringxyzvrrp 10 ip 10.21.8.10Disabling a VRRP Group on an Interface: Example
The following example shows how to disable one VRRP group on Ethernet interface 0/1 while retaining VRRP for group 2 on Ethernet interface 0/2:
interface ethernet0/1ip address 10.24.1.1 255.255.255.0vrrp 1 ip 10.24.1.254vrrp 1 shutdowninterface ethernet0/2ip address 10.168.42.1 255.255.255.0vrrp 2 ip 10.168.42.254VRRP MIB Trap: Example
The following example shows how to enable the VRRP MIB trap support functionality:
snmp-server enable traps vrrpsnmp-server host 10.1.1.0 community abc vrrpAdditional References
The following sections provide references related to VRRP.
Related Documents
VRRP commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples
Key chains and key management commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples
Object tracking
HSRP
"Configuring HSRP" module
GLBP
"Configuring GLBP" module
Standards
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.
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MIBs
RFCs
Technical Assistance
Feature Information for VRRP
Table 1 lists the features in this module and provides links to specific configuration information.
Not all commands may be available in your Cisco IOS software release. For details on when support for a specific command was introduced, see the command reference documentation.
Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which Cisco IOS and Catalyst OS software images support a specific software release, feature set, or platform. To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.
Table 1 Feature Information for VRRP
FHRP—VRF-Aware VRRP
12.2(15)T
12.0(18)ST
12.2(31)SG
12.2(17d)SXBThe FHRP—VRF-Aware VRRP feature adds VRRP support for VRF-Aware MPLS VPNs.
FHRP—VRRP Enhancements
12.3(14)T
The FHRP—VRRP Enhancements feature adds support for the following capabilities:
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The following sections provide information about this feature:
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The following command was introduced by this feature: debug vrrp authentication.
The following commands were modified by this feature: vrrp authentication and show vrrp.
ISSU—VRRP
12.2(33)SRC
VRRP supports In Service Software Upgrade (ISSU). ISSU allows a high-availability (HA) system to run in Stateful Switchover (SSO) mode even when different versions of Cisco IOS software are running on the active and standby Route Processors (RPs) or line cards.
This feature provides customers with the same level of HA functionality for planned outages due to software upgrades as is available with SSO for unplanned outages. That is, the system can switch over to a secondary RP and continue forwarding packets without session loss and with minimal or no packet loss.
This feature is enabled by default.
The following sections provide information about this feature:
There are no new or modified commands for this feature.
SSO—VRRP
12.2(33)SRC
12.2(33)SXIVRRP is now SSO aware. VRRP can detect when a router is failing over to the secondary RP and continue in its current VRRP group state.
This feature is enabled by default.
The following sections provide information about this feature:
The following commands were introduced or modified by this feature: debug vrrp ha, vrrp sso, show vrrp.
Virtual Router Redundancy Protocol
12.2(13)T
12.2(14)SVRRP enables a group of routers to form a single virtual router to provide redundancy. The LAN clients can then be configured with the virtual router as their default gateway. The virtual router, representing a group of routers, is also known as a VRRP group.
All sections provide information about this feature.
The following commands were introduced by this feature: debug vrrp all, debug vrrp error, debug vrrp events, debug vrrp packets, debug vrrp state, show vrrp, show vrrp interface, vrrp authentication, vrrp description, vrrp ip, vrrp preempt, vrrp priority, vrrp timers advertise, vrrp timers learn.
VRRP Object Tracking
12.3(2)T 12.2(25)S
The VRRP Object Tracking feature extends the capabilities of the VRRP to allow tracking of specific objects within the router that can alter the priority level of a virtual router for a VRRP group.
The following sections provide information about this feature:
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The following command was introduced by this feature: vrrp track.
The following command was modified by this feature: show track.
VRRP MIB—RFC 2787
12.3(11)T
The VRRP MIB—RFC 2787 feature enables an enhancement to the MIB for use with SNMP-based network management. The feature adds support for configuring, monitoring, and controlling routers that use VRRP.
The following sections provide information about this feature:
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The following command was introduced by this feature: vrrp shutdown.
The following commands were modified by this feature: snmp-server enable traps and snmp-server host.
Glossary
virtual router—One or more VRRP routers that form a group. The virtual router acts as the default gateway router for LAN clients. Also known as a VRRP group.
virtual router backup—One or more VRRP routers that are available to assume the role of forwarding packets if the virtual router master fails.
virtual router master—The VRRP router that is currently responsible for forwarding packets sent to the IP addresses of the virtual router. Usually the virtual router master also functions as the IP address owner.
virtual IP address owner—The VRRP router that owns the IP address of the virtual router. The owner is the router that has the virtual router address as its physical interface address.
VRRP router—A router that is running VRRP.
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