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Table Of Contents
Virtual Router Redundancy Service
Configuring the Clients That Use VRRS
Monitoring and Maintaining VRRS
Configuration Examples for VRRS
Example: Configuring a VRRS Server
Example: Configuring the Clients that use VRRS
Example: Configuring VRRS Accounting
Example: Confirming Operation of the VRRS Interface-State Plug-in
Example: Confirming Operation of the VRRS MAC-Address plug-in
Virtual Router Redundancy Service
First Published: February 26, 2010Last Updated: February 26, 2010Virtual Router Redundancy Service (VRRS) provides a multiclient information abstraction and management service between a First Hop Redundancy Protocol (FHRP) and a registered client. The VRRS multiclient service provides a consistent interface with FHRP protocols by abstracting over several FHRPs and providing an idealized view of their state. VRRS manages data updates, allowing interested clients to register in one place and receive updates for named FHRP groups or all registered FHRP groups.
Virtual Router Redundancy Protocol (VRRP) is an FHRP that acts as a server that pushes FHRP status information out to all registered VRRS clients. Clients obtain status on essential information provided by the FHRP, including current and previous redundancy states, active and inactive L3 and L2 addresses, and, in some cases, information about other redundant gateways in the network. Clients can use this information to provide stateless and stateful redundancy information to clients and protocols.
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 VRRS" section.
Use Cisco Feature Navigator to find information about platform support and Cisco 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 VRRS
Restrictions for VRRS
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Information About VRRS
VRRS Overview
VRRS improves the scalability of FHRP. VRRS provides a stateless redundancy service to applications (VRRS clients) by monitoring VRRP. VRRS provides a database of the current VRRP state and operates without maintaining sessions or keeping track of previous states of the clients and servers with which it communicates. VRRP acts as a VRRS server. VRRS 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.
VRRS by itself is limited to maintaining its own state. Linking a VRRS client to a VRRP group provides a mechanism that allows VRRS to provide a service to client applications so they can implement stateless or stateful failover. Stateless failover is failover without syncing of state. Stateful failover requires communication with a nominated backup before failure so that operational data is not lost when failover occurs.
Using VRRS with VRRP
VRRP provides server support for VRRS. The VRRP server pushes state and status information to VRRS when an internal update occurs. VRRS updates its internal database upon receiving a server update, and then sends push notifications to each of the VRRS clients associated with the shared name. Clients are interested in the protocol state, virtual MAC address, and virtual IP address information associated with a group. The association name between a client and a VRRP group is a character name string. The information provided by VRRS allows clients to perform various activities that are dependent on the state of the associated VRRP group.
VRRP notifies VRRS of its current state (master, backup, or nonoperational INIT). The VRRP state is then passed on to clients or acted on by a plug-in. A VRRP group should be configured with a name to activate VRRS. Clients should be configured with the same name to bind them with VRRS.
The VRRP group name associates the VRRP group with any clients that are configured as part of VRRS with the same name.
VRRS Servers and Clients
VRRP acts as the VRRS server. Clients act on the VRRP server state. When a VRRP group changes state, VRRS clients act by altering their behavior (perfoming tasks such as shutting down interfaces or appending accounting logs) depending on the state received from VRRS.
The following can be VRRS clients:
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VRRS plug-ins extend the failover of VRRP without the need for configuring VRRP groups on all subinterfaces. Configuring a VRRS plug-in on subinterfaces is a substitute for having to configure multiple VRRP groups on many subinterfaces. Plug-ins provide a light-weight version of VRRP and scale better than a fully configured VRRP group. The state of the plug-ins follows the VRRP server state. Client plug-ins are configured on other subinterfaces that share the same physical interface as VRRP.
VRRS MAC-Address Plug-in
The VRRS MAC-Address plug-in provides a mechanism for controlling a virtual MAC address associated with the primary interface IP address. If the VRRS MAC-Address plug-in is configured on an interface, and a VRRP group shares a name association with the plug-in, then a VRRS active state associates a v irtual MAC address with the configured primary IP address.
The VRRS MAC-Address plug-in is only interested in the VRRS active state, which is interpreted as up. All other states are interpreted as down. When the state is up and the additional interface criteria listed below have been met, then the VRRS MAC-Address plug-in provides the following services:
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When VRRS is in a nonactive state, the virtual MAC address is unassociated from the primary IP address.
When you use the VRRS MAC-Address plug-in, the VRRS Interface-State plug-in must also be used in order to prevent address conflicts with other redundant members.
Additional interface criteria:
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The VRRS MAC-Address plug-in is associated with a VRRS group name by configuring the vrrs follow name command.
VRRS Interface-State Plug-in
The VRRS Interface-State plug-in provides a mechanism for controlling the line-protocol state of a subinterface based on the state of VRRP. The VRRS Interface-State plug-in is an extension of the VRRS, and is directly controlled by the push events associated with the VRRS. If the plug-in is configured on an interface, and a VRRP group shares a name association with the VRRS plug-in, then a VRRS active state allows the lin- protocol state of the interface to be up. A VRRS nonactive state will cause the line protocol of the interface to be down.
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The VRRS Interface-State plug-in is associated with a VRRS group name by configuring the vrrs follow name command.
The Interface-State plug-in restricts the operation of the no shutdown command. When an interface is line-protocol down, the interface state will not go up.
VRRS Accounting Plug-in
The VRRS Accounting plug-in provides a configurable AAA method list mechanism that provides updates to a RADIUS server when a VRRS group transitions its state.
The VRRS accounting plug-in is an extension of existing AAA system accounting messages. The VRRS Accounting plug-in provides accounting-on and accounting-off messages and an additional Vendor-Specific Attribute (VSA) that sends the configured VRRS name in RADIUS accounting messages. The VRRS name is configured using the vrrp name command in interface configuration mode.
The VRRS Accounting plug-in sends an accounting-on message to RADIUS when a VRRS group transitions to the master state, and it sends an accounting-off message when a VRRS group transitions from the master state.
The following RADIUS attributes are included in VRRS accounting messages by default:
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Accounting messages for a VRRS transitioning out of master state are sent after all PPPoE accounting stop messages for sessions that are part of that VRRS.
The VRRS accounting type is implemented by AAA to support VRRS accounting.
How to Configure VRRS
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Configuring a VRRS Server
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DETAILED STEPS
Configuring the Clients That Use VRRS
Perform this task to configure the clients, including VRRS plug-ins, that use VRRS. This task is configured on multiple subinterfaces.
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DETAILED STEPS
Configuring VRRS Accounting
Perform this task to configure VRRS to send AAA accounting messages to the AAA server when there is a state-change in VRRS from active to standby or from standby to active.
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Monitoring and Maintaining VRRS
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DETAILED STEPS
Step 1
This command enables VRRP debugging statements for VRRS interactions.
Router# debug vrrp vrrsVRRP VRRS debugging is on*Feb 5 09:29:47.005: VRRP: Registered VRRS group "name1"*Feb 5 09:29:53.237: VRRP: Updated info for VRRS group name1*Feb 5 09:30:14.153: VRRP: Unregistered VRRS group "name1"*Feb 5 09:30:14.153: VRRP: Registered VRRS group "name2"*Feb 5 09:30:22.689: VRRP: Unregistered VRRS group "name2"Step 2
This command enables debug messages for VRRS accounting.
Router# debug vrrs accounting00:16:13: VRRS/ACCT/EV: entry create for abc(0x4E8C1F0)00:16:13: VRRS/ACCT/EV: abc(0x4E8C1F0 12000006) client add ok2(No group)Step 3
This command enables VRRS infrastructure debug messages.
Router# debug vrrs infra*Sep 9 16:09:53.848: VRRS: Client 21 is not registered*Sep 9 16:09:53.848: VRRS: Client 21 unregister failed*Sep 9 16:09:53.848: VRRS: Client VRRS TEST CLIENT registered, id 21*Sep 9 16:09:53.848: VRRS: Client 21 add, group VRRP-TEST-1 does not exist, allocating...*Sep 9 16:09:53.848: VRRS: Client 21 add to VRRP-TEST-1. Vrrs handle F7000001, client handle FE720*Sep 9 16:09:53.848: VRRS: Server VRRP add, group VRRP-TEST-1, state INIT, vrrs handle F7000001Step 4
This command enables VRRS plug-in debug messages.
Router# debug vrrs pluginFeb 17 19:15:38.052: VRRS-P(mac): GigEth0/0/0.1 Add 0000.12ad.0001 to MAC filter, using (afilter_add)Feb 17 19:15:38.053: VRRS-P(mac): Active count increase to (2) for MAC : 0000.12ad.0001Step 5
This command displays a list of VRRS clients.
Router# show vrrs clientsID Priority All-groups Name------------------------------1 High No VRRS-Plugins2 Low Yes VRRS-Accounting3 Normal No PPPOE-VRRS-CLIENTStep 6
This command displays information about VRRS groups.
Router# show vrrs group DT-CLUSTER-3DT-CLUSTER-3Server Not configured, state INIT, old state INIT, reason ProtocolAddress family IPv4, Virtual address 0.0.0.0, Virtual mac 0000.0000.0000Active interface address 0.0.0.0, standby interface address 0.0.0.0Client 5 VRRS TEST CLIENT, priority LowStep 7
This command displays details about the internal VRRS plug-in database.
Router# show vrrs plugin databaseVRRS Plugin Database------------------------------------------------Name = VRRS_NAME_1Server connection = LiveState = DisabledMAC addr = 0000.5e00.0101Test Control = FalseClient Handle = 3741319170Interface list =gige0/0/0.2gige0/0/0.3Step 8
This command displays a summary of all VRRS groups.
Router# show vrrs summaryGroup Server State Virtual-address ------------------------------------------------------------------------------ DT-CLUSTER-3 UNKNOW INIT 0.0.0.0DT-CLUSTER-2 VRRP BACKUP 11.1.1.1DT-CLUSTER-1 VRRP ACTIVE 1.1.1.1Configuration Examples for VRRS
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Example: Configuring a VRRS Server
Router# configure terminalRouter(config)# interface gigabitethernet0/0/0Router(config-if)# ip address 10.0.0.1 255.255.255.0Router(config-if)# vrrp 1 name name1Router(config-if)# vrrp 1 ip 10.0.1.20Router(config-if)# vrrp delay minimum 30 reload 60Example: Configuring the Clients that use VRRS
The following example shows how to configure the clients, including VRRS plug-ins, that use VRRS.
Router# configure terminalRouter(config)# interface gigabitethernet0/0/0.1Router(config-subif)# ip address 10.0.0.1 255.255.255.0Router(config-subif)# vrrs follow name1Router(config-subif)# vrrs interface-stateRouter(config-subif)# vrrs mac-addressExample: Configuring VRRS Accounting
The following example shows how to configure VRRS to send AAA accounting messages to the AAA server when there is a state change in VRRS from active to standby or from standby to active.
Router# configure terminalRouter(config)# aaa accounting vrrs vrrp-mlist-1 start-stop group radiusRouter(config)# aaa attribute list vrrp-1-attrRouter(config-attr-list)# attribute type account-delay "10"Router(config-attr-list)# exitRouter(config)# vrrs vrrp-name-1Router(config-vrrs)# accounting delay 10Router(config-vrrs)# accounting method METHOD1Router(config-vrrs)# attribute list vrrp-1-attrExample: Confirming Operation of the VRRS Interface-State Plug-in
Router(config)# interface GigabitEthernet0/0/0Router(config-if)# no ip addressRouter(config-if)# exitRouter(config)# interface GigabitEthernet0/0/0.1Router(config-if)# encapsulation dot1Q 1 nativeRouter(config-if)# ip address 172.16.1.1 255.255.255.0Router(config-if)# vrrp 1 name VRRS_NAME_1Router(config-if)# vrrp 1 ip 172.16.1.254Router(config-if)# exitRouter(config)# interface GigabitEthernet0/0/0.2Router(config-if)# encapsulation dot1Q 2Router(config-if)# ip address 192.168.42.1 255.255.255.0Router(config-if)# vrrs follow VRRS_NAME_1Router(config-if)# vrrs interface-stateRouter(config-if)# exitRouter(config)# interface GigabitEthernet0/0/0.3Router(config-if)# encapsulation dot1Q 3Router(config-if)# ip address 192.168.43.1 255.255.255.0Router(config-if)# vrrs follow VRRS_NAME_1Router(config-if)# vrrs interface-stateRouter(config-if)# exitRouter(config)# interface GigabitEthernet0/0/0.4Router(config-if)# encapsulation dot1Q 4Router(config-if)# ip address 192.168.44.1 255.255.255.0Router(config-if)# vrrs follow VRRS_NAME_2Router(config-if)# vrrs interface-stateRouter(config-if)# exitRouter# show ip interface briefInterface IP-Address OK? Method Status ProtocolGigabitEthernet0/0/0 unassigned YES NVRAM up upGigabitEthernet0/0/0.1 172.24.1.1 YES manual up upGigabitEthernet0/0/0.2 192.168.42.1 YES manual up upGigabitEthernet0/0/0.3 192.168.43.1 YES manual up upGigabitEthernet0/0/0.4 192.168.44.1 YES manual up down ! "interface-state" DOWN due to no VRRS serverRouter# show vrrs plugin databaseVRRS Plugin Database------------------------------------------------Name = VRRS_NAME_1Server connection = LiveState = ActiveMAC addr = 0000.5e00.0101Test Control = FalseClient Handle = 3741319170Interface list =GigE0/0/0.2GigE0/0/0.3------------------------------------------------Name = VRRS_NAME_2Server connection = DisconnectedState = DisabledMAC addr = 0000.0000.0000Test Control = FalseClient Handle = 603979779Interface list =GigE0/0/0.4Example: Confirming Operation of the VRRS MAC-Address plug-in
Router(config)# interface GigabitEthernet0/0/0Router(config-if)# no ip addressRouter(config-if)# exitRouter(config)# interface GigabitEthernet0/0/0.1Router(config-if)# encapsulation dot1Q 1 nativeRouter(config-if)# ip address 172.24.1.1 255.255.255.0Router(config-if)# vrrp 1 name VRRS_NAME_1Router(config-if)# vrrp 1 ip 172.24.1.254Router(config-if)# exitRouter(config)# interface GigabitEthernet0/0/0.2Router(config-if)# encapsulation dot1Q 2Router(config-if)# ip address 192.168.42.1 255.255.255.0Router(config-if)# vrrs follow VRRS_NAME_1Router(config-if)# vrrs mac-address arp interval 5 duration 360Router(config-if)# exitRouter(config)# interface GigabitEthernet0/0/0.3Router(config-if)# encapsulation dot1Q 3Router(config-if)# ip address 192.168.43.1 255.255.255.0Router(config-if)# vrrs follow VRRS_NAME_1Router(config-if)# vrrs mac-address arp interval 5 duration 360Router(config-if)# exitRouter(config)# interface GigabitEthernet0/0/0.4Router(config-if)# encapsulation dot1Q 4Router(config-if)# ip address 192.168.44.1 255.255.255.0Router(config-if)# vrrs follow VRRS_NAME_2Router(config-if)# vrrs mac-address arp interval 5 duration 360Router(config-if)# exitRouter# show ip arpProtocol Address Age (min) Hardware Addr Type InterfaceInternet 172.24.1.1 - aabb.cc00.fb00 ARPA GigabitEthernet0/0/0.1Internet 172.24.1.254 - 0000.5e00.0101 ARPA GigabitEthernet0/0/0.1Internet 192.168.42.1 - 0000.5e00.0101 ARPA GigabitEthernet0/0/0.2 ! "mac-address" enabled interfaces using VRRP MAC via VRRSInternet 192.168.43.1 - 0000.5e00.0101 ARPA GigabitEthernet0/0/0.3 ! "mac-address" enabled interfaces using VRRP MAC via VRRSInternet 192.168.44.1 - aabb.cc00.fb00 ARPA GigabitEthernet0/0/0.4 ! "mac-address" disabled interface using BIARouter# debug arpARP packet debugging is on*Sep 10 20:02:14.971: IP ARP: sent rep src 192.168.42.1 0000.5e00.0101,dst 192.168.42.1 ffff.ffff.ffff Ethernet0/0.2*Sep 10 20:02:14.971: IP ARP: sent rep src 192.168.43.1 0000.5e00.0101,dst 192.168.43.1 ffff.ffff.ffff Ethernet0/0.3*Sep 10 20:02:19.991: IP ARP: sent rep src 192.168.42.1 0000.5e00.0101,dst 192.168.42.1 ffff.ffff.ffff Ethernet0/0.2*Sep 10 20:02:19.991: IP ARP: sent rep src 192.168.43.1 0000.5e00.0101,dst 192.168.43.1 ffff.ffff.ffff Ethernet0/0.3Router# show controller gigabitethernet0/0/0Interface GigabitEthernet0/0/0Hardware is AMD UnknownADDR: 1EC55D8, FASTSEND: FC286088, MCI_INDEX: 0DIST ROUTE ENABLED: 0Route Cache Flag: 11amdp2_instance=0x1EC6798, registers=0x1EC5580, ib=0x1EC6D98rx ring entries=32, tx ring entries=64rxring=0x1EC6DE8, rxr shadow=0x1EC7020, rx_head=0, rx_tail=0txring=0x1EC70D8, txr shadow=0x1EC7510, tx_head=0, tx_tail=57, tx_count=57running=0, port id=0x5DCF8Software MAC address filter(hash:length/addr/mask/hits):0x00: 0 ffff.ffff.ffff 0000.0000.0000 00x4C: 0 0100.5e00.0012 0000.0000.0000 00x5F: 0 0000.5e00.0101 0000.0000.0000 0 ! Virtual MAC, note for this interface, it may be VRRP that added this MAC.0xC0: 0 0100.0ccc.cccc 0000.0000.0000 00xC0: 1 0180.c200.0002 0000.0000.0000 00xC5: 0 0180.c200.0007 0000.0000.0000 00xCC: 0 aabb.cc00.fb00 0000.0000.0000 0Router# show vrrs plugin databaseVRRS Plugin Database------------------------------------------------Name = VRRS_NAME_1Server connection = LiveState = ActiveMAC addr = 0000.5e00.0101Test Control = FalseClient Handle = 3741319170Interface list =GigE0/0/0.2GigE0/0/0.3------------------------------------------------Name = VRRS_NAME_2Server connection = DiconnectedState = DisabledMAC addr = 0000.0000.0000Test Control = FalseClient Handle = 603979779Interface list =GigE0/0/0.4Where to Go Next
If you want to configure additional VRRP features, see the "Configuring VRRP" document.
Additional References
Related Documents
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
VRRP MIB
To locate and download MIBs for selected platforms, Cisco software releases, and feature sets, use Cisco MIB Locator found at the following URL:
RFCs
RFC 2338
RFC 2787
Definitions of Managed Objects for the Virtual Router Redundancy Protocol
RFC 3768
Technical Assistance
Feature Information for VRRS
Table 1 lists the release history for this feature.
Use Cisco Feature Navigator to find information about platform support and software image support. Cisco Feature Navigator enables you to determine which 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.
Note
Glossary
AAA—authentication, authorization, and accounting.
RADIUS—Remote Authentication Dial-In User Service.
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.
VRRP—Virtual Router Redundancy Protocol. 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.
VSA—vendor-specific attribute. An attribute that has been implemented by a particular vendor.
Cisco and the Cisco Logo are trademarks of Cisco Systems, Inc. and/or its affiliates in the U.S. and other countries. A listing of Cisco's trademarks can be found at www.cisco.com/go/trademarks. Third party trademarks mentioned are the property of their respective owners. The use of the word partner does not imply a partnership relationship between Cisco and any other company. (1005R)
Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.
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