Implementing HSRP

The Hot Standby Router Protocol (HSRP) is an IP routing redundancy protocol designed to allow for transparent failover at the first-hop IP router. HSRP provides high network availability, because it routes IP traffic from hosts on networks without relying on the availability of any single router. HSRP is used in a group of routers for selecting an active router and a standby router. (An active router is the router of choice for routing packets; a standby router is a router that takes over the routing duties when an active router fails, or when preset conditions are met.)

Feature History for Implementing HSRP

Release 3.7.2

This feature was introduced.

Release 3.9.0

Support was added for the following features:

  • BFD for HSRP.

  • Hot restartability for HSRP.

Release 4.2.0

Multiple Group Optimization (MGO) for HSRP feature was added.

Release 4.2.1

Enhanced object tracking for HSRP and IP Static feature was added.


Note

GLBP is not supported on ASR9k.

Prerequisites for Implementing HSRP

  • You must be in a user group associated with a task group that includes the proper task IDs. The command reference guides include the task IDs required for each command. If you suspect user group assignment is preventing you from using a command, contact your AAA administrator for assistance.

Restrictions for Implementing HSRP

HSRP is supported on Ethernet interfaces, Ethernet sub-interfaces and Ethernet link bundles.

The following are restrictions for implementing HSRP:

  • Upto 4000 sessions are permitted on Ethernet sub-interfaces.

  • On bundle interfaces, the number of sessions per member vary depending on the number of bundle members and their location on network processor (NP) as listed here:

    • One member on one NP: 3999 HSRP sessions

    • Two members on same NP: 1999 HSRP sessions

    • Four members on same NP: 999 HSRP sessions

    • Two members, one on each NP: 3999 HSRP sessions

    • Four members, two on each NP: 1999 HSRP sessions


Note
HSRP version 2 authentication is not supported from release 4.3.x onwards.

Information About Implementing HSRP

To implement HSRP on Cisco IOS XR software software, you need to understand the following concepts:

HSRP Overview

HSRP is useful for hosts that do not support a router discovery protocol (such as Internet Control Message Protocol [ICMP] Router Discovery Protocol [IRDP]) and cannot switch to a new router when their selected router reloads or loses power. Because existing TCP sessions can survive the failover, this protocol also provides a more transparent recovery for hosts that dynamically choose a next hop for routing IP traffic.

When HSRP is configured on a network segment, it provides a virtual MAC address and an IP address that is shared among a group of routers running HSRP. The address of this HSRP group is referred to as the virtual IP address. One of these devices is selected by the protocol to be the active router. The active router receives and routes packets destined for the MAC address of the group. For n routers running HSRP, n + 1 IP and MAC addresses are assigned.

HSRP detects when the designated active router fails, at which point a selected standby router assumes control of the MAC and IP addresses of the HSRP group. A new standby router is also selected at that time.

Devices that are running HSRP send and receive multicast User Datagram Protocol (UDP) based hello packets to detect router failure and to designate active and standby routers.

HSRP Groups

An HSRP group consists of two or more routers running HSRP that are configured to provide hot standby services for one another. HSRP uses a priority scheme to determine which HSRP-configured router is to be the default active router. To configure a router as the active router, you assign it a priority that is higher than the priority of all the other HSRP-configured routers. The default priority is 100, so if you configure just one router to have a higher priority, that router will be the default active router.

HSRP works by the exchange of multicast messages that advertise priority among the HSRP group. When the active router fails to send a hello message within a configurable period of time, the standby router with the highest priority becomes the active router. The transition of packet-forwarding functions between routers is completely transparent to all hosts on the network.

Figure 1 shows routers configured as members of a single HSRP group.

Figure 1. Routers Configured as an HSRP Group

All hosts on the network are configured to use the IP address of the virtual router (in this case, 1.0.0.3) as the default gateway.

A single router interface can also be configured to belong to more than one HSRP group. Figure 2shows routers configured as members of multiple HSRP groups.

Figure 2. Routers Configured as Members of Multiple HSRP Groups

In Figure 2, the Ethernet interface 0 of Router A belongs to group 1. Ethernet interface 0 of Router B belongs to groups 1, 2, and 3. The Ethernet interface 0 of Router C belongs to group 2, and the Ethernet interface 0 of Router D belongs to group 3. When you establish groups, you might want to align them along departmental organizations. In this case, group 1 might support the Engineering Department, group 2 might support the Manufacturing Department, and group 3 might support the Finance Department.

Router B is configured as the active router for groups 1 and 2 and as the standby router for group 3. Router D is configured as the active router for group 3. If Router D fails for any reason, Router B assumes the packet-transfer functions of Router D and maintains the ability of users in the Finance Department to access data on other subnets.


Note

A different virtual MAC address (VMAC) is required for each sub interface. VMAC is determined from the group ID. Therefore, a unique group ID is required for each sub interface configured, unless the VMAC is configured explicitly.


Note

We recommend that you disable Spanning Tree Protocol (STP) on switch ports to which the virtual routers are connected. Enable RSTP or rapid-PVST on the switch interfaces if the switch supports these protocols.

HSRP and ARP

When a router in an HSRP group goes active, it sends a number of ARP responses containing its virtual IP address and the virtual MAC address. These ARP responses help switches and learning bridges update their port-to-MAC maps. These ARP responses also provide routers configured to use the burned-in address of the interface as its virtual MAC address (instead of the preassigned MAC address or the functional address) with a means to update the ARP entries for the virtual IP address. Unlike the gratuitous ARP responses sent to identify the interface IP address when an interface comes up, the HSRP router ARP response packet carries the virtual MAC address in the packet header. The ARP data fields for IP address and media address contain the virtual IP and virtual MAC addresses.

Preemption

The HSRP preemption feature enables the router with highest priority to immediately become the active router. Priority is determined first by the priority value that you configure, and then by the IP address. In each case, a higher value is of greater priority.

When a higher-priority router preempts a lower-priority router, it sends a coup message. When a lower-priority active router receives a coup message or hello message from a higher-priority active router, it changes to the speak state and sends a resign message.

ICMP Redirect Messages

Internet Control Message Protocol (ICMP) is a network layer Internet protocol that provides message packets to report errors and other information relevant to IP processing. ICMP provides many diagnostic functions and can send and redirect error packets to the host. When running HSRP, it is important to prevent hosts from discovering the interface (or real) MAC addresses of routers in the HSRP group. If a host is redirected by ICMP to the real MAC address of a router, and that router later fails, then packets from the host are lost.

ICMP redirect messages are automatically enabled on interfaces configured with HSRP. This functionality works by filtering outgoing ICMP redirect messages through HSRP, where the next-hop IP address may be changed to an HSRP virtual IP address.

To support ICMP redirects, redirect messages are filtered through HSRP, where the next-hop IP address is changed to an HSRP virtual address. When HSRP redirects are turned on, ICMP interfaces with HSRP do this filtering. HSRP keeps track of all HSRP routers by sending advertisements and maintaining a real IP address to virtual IP address mapping to perform the redirect filtering.

How to Implement HSRP

This section contains instructions for the following tasks:

Enabling HSRP

The hsrp ipv4 command activates HSRP on the configured interface. If an IP address is specified, that address is used as the designated address for the Hot Standby group. If no IP address is specified, the virtual address is learned from the active router. For HSRP to elect a designated router, at least one router in the Hot Standby group must have been configured with, or learned, the designated address. Configuring the designated address on the active router always overrides a designated address that is currently in use.

SUMMARY STEPS

    1.    configure

    2.    router hsrp

    3.    interface type interface-path-id

    4.    address-family ipv4

    5.    hsrp group-number version version-no

    6.    address { learn | address [secondary] }

    7.    commit


DETAILED STEPS
     Command or ActionPurpose
    Step 1 configure
          		 
    Step 2 router hsrp


    Example: 
    RP/0/RSP0/CPU0:router(config)# router hsrp
     

    Enables HSRP configuration mode.

     
    Step 3 interface type interface-path-id


    Example: 
    RP/0/RSP0/CPU0:router(config-hsrp)# interface GigabitEthernet 0/2/0/1
     

    Enables HSRP interface configuration mode on a specific interface.

     
    Step 4 address-family ipv4


    Example: 
    RP/0/RSP0/CPU0:router(config-hsrp-if)# address-family ipv4
     

    Enables HSRP address-family configuration mode on a specific interface.

     
    Step 5 hsrp group-number version version-no


    Example: 
    RP/0/RSP0/CPU0:router(config-hsrp-ipv4)# hsrp 1 version 1
     

    Enables HSRP group submode.

    Note   

    The version keyword is available only if IPv4 address-family is selected. By default, version is set to 2 for IPv6 address families.

     
    Step 6 address { learn | address [secondary] }


    Example: 
    RP/0/RSP0/CPU0:router(config-hsrp-gp)# address learn
     

    Activates HSRP on the configured interface.

    • If an IP address is specified, that address is used as the designated address for the Hot Standby group. If no IP address is specified, the virtual address is learned from the active router.

    Note   

    If you configure HSRP for IPv6, you must configure a link local IPv6 address or enable it using the autoconfig keyword. If you do not configure a linklocal IPv6 address, the router does not accept the configuration when you commit your changes using the commit keyword.

     
    Step 7 commit
          		 

    Enabling HSRP for IPv6

    Use the following steps to enable HSRP for IPv6.

    SUMMARY STEPS

      1.    configure

      2.    router hsrp

      3.    interface type interface-path-id

      4.    address-family ipv6

      5.    hsrp group-number

      6.    address linklocal {autoconfig | ipv6-address}

      7.    address global ipv6-address

      8.    commit


    DETAILED STEPS
       Command or ActionPurpose
      Step 1 configure
              		 
      Step 2 router hsrp


      Example: 
      RP/0/RSP0/CPU0:router(config)# router hsrp
       

      Enables HSRP configuration mode.

       
      Step 3 interface type interface-path-id


      Example: 
      RP/0/RSP0/CPU0:router(config-hsrp)# interface TenGigE 0/2/0/1
       

      Enables HSRP interface configuration mode on a specific interface.

       
      Step 4 address-family ipv6


      Example: 
      RP/0/RSP0/CPU0:router(config-hsrp-if)# address-family ipv6
       

      Enables HSRP address-family configuration mode on a specific interface.

       
      Step 5 hsrp group-number


      Example: 
      RP/0/RSP0/CPU0:router(config-hsrp-ipv4)# hsrp 1
       

      Enables HSRP group submode.

      Note   

      The version keyword is available only if IPv4 address-family is selected. By default, version is set to 2 for IPv6 address families.

       
      Step 6 address linklocal {autoconfig | ipv6-address}


      Example: 
      RP/0/RSP0/CPU0:router(config-hsrp-gp)# address linklocal autoconfig
       

      Activates HSRP on the configured interface and assigns a linklocal IPv6 address.

      • The virtual linklocal address must not match any other virtual linklocal address that is already configured for a different group.

        The virtual linklocal address must not match the interface linklocal IPv6 address.

        If you use the autoconfig keyword, the linklocal address is calculated using the EUI-64 format.

        Use the legacy-compatible keyword to be compatible with Cisco IOS and other legacy Cisco devices.

       
      Step 7 address global ipv6-address


      Example: 
      RP/0/RSP0/CPU0:router(config-hsrp-gp)# address global 2001:DB8:A:B::1
       

      Activates HSRP on the configured interface and assigns a global IPv6 address.

      Note   

      If you configure HSRP for IPv6, you must configure a link local IPv6 address or enable it using the autoconfig keyword. If you do not configure a linklocal IPv6 address, the router does not accept the configuration when you commit your changes using the commit keyword.

       
      Step 8 commit
              		 

      Configuring HSRP Group Attributes

      To configure other Hot Standby group attributes that affect how the local router participates in HSRP, use the following procedure in interface configuration mode as needed:

      SUMMARY STEPS

        1.    configure

        2.    router hsrp

        3.    interface type interface-path-id

        4.    hsrp use-bia

        5.    address-family ipv4

        6.    hsrp group-number version version-no

        7.    priority priority

        8.    track type instance [priority-decrement]

        9.    preempt [delay seconds]

        10.    authentication string

        11.    mac-address address

        12.    commit


      DETAILED STEPS
         Command or ActionPurpose
        Step 1 configure
                  		 
        Step 2 router hsrp


        Example: 
        RP/0/RSP0/CPU0:router(config)# router hsrp
         

        Enables HSRP configuration mode.

         
        Step 3 interface type interface-path-id


        Example: 
        RP/0/RSP0/CPU0:router(config-hsrp)# interface TenGigE  0/2/0/1
         

        Enables HSRP interface configuration mode on a specific interface.

         
        Step 4 hsrp use-bia


        Example: 
        RP/0/RSP0/CPU0:router(config-hsrp-if)# hsrp use-bia
         

        (Optional) Configures the HSRP to use the burned-in address of the interface as its virtual MAC address, instead of the preassigned MAC address or the functional address.

        • Enter the use-bia command on an interface when there are devices that reject Address Resolution Protocol (ARP) replies with source hardware addresses set to a functional address.

        • To restore the default virtual MAC address, use the no hsrp use-bia command.

         
        Step 5 address-family ipv4


        Example: 
        RP/0/RSP0/CPU0:router(config-hsrp-if)# address-family ipv4
         

        Enables HSRP address-family configuration mode on a specific interface.

         
        Step 6 hsrp group-number version version-no


        Example: 
        RP/0/RSP0/CPU0:router(config-hsrp-ipv4)# hsrp 1 version 1
         

        Enables HSRP group submode.

        Note   

        The version keyword is available only if IPv4 address-family is selected. By default, version is set to 2 for IPv6 address families.

         
        Step 7 priority priority


        Example: 
        RP/0/RSP0/CPU0:router(config-hsrp-gp)# priority 100
         

        (Optional) Configures HSRP priority.

        • The assigned priority is used to help select the active and standby routers. Assuming that preemption is enabled, the router with the highest priority becomes the designated active router. In case of ties, the primary IP addresses are compared, and the higher IP address has priority.

        • The priority of the device can change dynamically if an interface is configured with the track command and another interface on the device goes down.

        • If preemption is not enabled using the preempt command, the router may not become active even though it might have a higher priority than other HSRP routers.

        • To restore the default HSRP priority values, use the no priority command.

         
        Step 8 track type instance [priority-decrement]


        Example: 
        RP/0/RSP0/CPU0:router(config-hsrp-gp)# track TenGigE 0/3/0/1
         

        (Optional) Configures an interface so that the Hot Standby priority changes on the basis of the availability of other interfaces.

        • When a tracked interface goes down, the Hot Standby priority decreases by 10. If an interface is not tracked, its state changes do not affect the Hot Standby priority. For each interface configured for Hot Standby, you can configure a separate list of interfaces to be tracked.

        • The optional priority-decrement argument specifies by how much to decrement the Hot Standby priority when a tracked interface goes down. When the tracked interface comes back up, the priority is incrementally increased by the same amount.

        • When multiple tracked interfaces are down and the priority-decrement argument has been configured, these configured priority decrements are cumulative. If tracked interfaces are down, but none of them were configured with priority decrements, the default decrement is 10 and it is cumulative.

        • The preempt command must be used in conjunction with this command on all routers in the group whenever the best available router should be used to forward packets. If the preempt command is not used, the active router stays active, regardless of the current priorities of the other HSRP routers.

        • To remove the tracking, use the no preempt command.

         
        Step 9 preempt [delay seconds]


        Example: 
        RP/0/RSP0/CPU0:router(config-hsrp-gp)# preempt
         

        (Optional) Configures HSRP preemption and preemption delay.

        • When you configure preemption and preemption delay with the preempt command, the local router attempts to assume control as the active router when the local router has a Hot Standby priority higher than the current active router. If the preempt command is not configured, the local router assumes control as the active router only if it receives information indicating that no router is currently in the active state (acting as the designated router).

        • When a router first comes up, it does not have a complete routing table. If it is configured to preempt, it becomes the active router, yet it is unable to provide adequate routing services. This problem can be solved by configuring a delay before the preempting router actually preempts the currently active router.

        • The preempt delay seconds value does not apply if there is no router currently in the active state. In this case, the local router becomes active after the appropriate timeouts (see the timers command), regardless of the preempt delay seconds value.

        • To restore the default HSRP preemption and preemption delay values, use the no preempt command.

         
        Step 10 authentication string


        Example: 
        RP/0/RSP0/CPU0:router(config-hsrp-gp)# authentication company1
         

        (Optional) Configures an authentication string for the Hot Standby Router Protocol (HSRP).

        • The authentication string is sent unencrypted in all HSRP messages. The same authentication string must be configured on all routers and access servers on a LAN to ensure interoperation.

        • Authentication mismatch prevents a device from learning the designated Hot Standby IP address and the Hot Standby timer values from other routers configured with HSRP.

        • Authentication mismatch does not prevent protocol events such as one router taking over as the designated router.

        • To delete an authentication string, use the no authentication command.

         
        Step 11 mac-address address


        Example: 
        RP/0/RSP0/CPU0:router(config-hsrp-if)# mac-address 4000.1000.1060
         

        (Optional) Specifies a virtual MAC address for the HSRP.

        • We do not recommend this command, except for IBM networking environments in which first-hop redundancy is based on being able to use a virtual MAC address, and in which you cannot change the first-hop addresses in the PCs that are connected to an Ethernet switch.

        • HSRP is used to help end stations locate the first-hop gateway for IP routing. The end stations are configured with a default gateway. However, HSRP can provide first-hop redundancy for other protocols. Some protocols, such as Advanced Peer-to-Peer Networking (APPN), use the MAC address to identify the first-hop for routing purposes. In this case, it is often necessary to specify the virtual MAC address; the virtual IP address is unimportant for these protocols. Use the mac-address command to specify the virtual MAC address.

        • The MAC address specified is used as the virtual MAC address when the router is active.

        • The mac-address command is intended for certain APPN configurations.

        • In an APPN network, an end node is typically configured with the MAC address of the adjacent network node. Use the mac-address command in the routers to set the virtual MAC address to the value used in the end nodes.

        • Enter the no mac-address command to revert to the standard virtual MAC address (0000.0C07.ACn).

         
        Step 12 commit
                  		 

        Configuring the HSRP Activation Delay

        The activation delay for HSRP is designed to delay the startup of the state machine when an interface comes up. This give the network time to settle and avoids unnecessary state changes early after the link comes up.

        SUMMARY STEPS

          1.    configure

          2.    router hsrp

          3.    interface type interface-path-id

          4.    hsrp delay [minimum seconds ] [reload seconds]

          5.    address-family ipv4

          6.    hsrp group-number version version-no

          7.    address { learn | address [secondary] }

          8.    commit


        DETAILED STEPS
           Command or ActionPurpose
          Step 1 configure
                      		 
          Step 2 router hsrp


          Example: 
          RP/0/RSP0/CPU0:router(config)# router hsrp
           

          Enables HSRP configuration mode.

           
          Step 3 interface type interface-path-id


          Example: 
          RP/0/RSP0/CPU0:router(config-hsrp)# interface TenGigE 0/2/0/1
           

          Enables HSRP interface configuration mode on a specific interface.

           
          Step 4 hsrp delay [minimum seconds ] [reload seconds]


          Example: 
          RP/0/RSP0/CPU0:router(config-hsrp-if)#hsrp delay minimum 2 reload 10
           

          Delays the startup of the state machine when an interface comes up, so that the network has time to settle and there are no unnecessary state changes early after the link comes up. The reload delay is the delay applied after the first interface up event. The minimum delay is the delay that is applied after any subsequent interface up event (if the interface flaps).

           
          Step 5 address-family ipv4


          Example: 
          RP/0/RSP0/CPU0:router(config-hsrp-if)# address-family ipv4
           

          Enables HSRP address-family configuration mode on a specific interface.

           
          Step 6 hsrp group-number version version-no


          Example: 
          RP/0/RSP0/CPU0:router(config-hsrp-ipv4)# hsrp 1 version 1
           

          Enables HSRP group submode.

          Note   

          The version keyword is available only if IPv4 address-family is selected. By default, version is set to 2 for IPv6 address families.

           
          Step 7 address { learn | address [secondary] }


          Example: 
          RP/0/RSP0/CPU0:router(config-hsrp-gp)# address learn
           

          Activates HSRP on the configured interface.

          • If an IP address is specified, that address is used as the designated address for the Hot Standby group. If no IP address is specified, the virtual address is learned from the active router.

          Note   

          If you configure HSRP for IPv6, you must configure a link local IPv6 address or enable it using the autoconfig keyword. If you do not configure a linklocal IPv6 address, the router does not accept the configuration when you commit your changes using the commit keyword.

           
          Step 8 commit
                      		 

          Enabling HSRP Support for ICMP Redirect Messages

          By default, HSRP filtering of ICMP redirect messages is enabled on routers running HSRP.

          To configure the reenabling of this feature on your router if it is disabled, use the hsrp redirects command in interface configuration mode.

          SUMMARY STEPS

            1.    configure

            2.    router hsrp

            3.    interface type interface-path-id

            4.    hsrp redirects disable

            5.    address-family ipv4

            6.    hsrp group-number version version-no

            7.    address { learn | address [secondary] }

            8.    commit


          DETAILED STEPS
             Command or ActionPurpose
            Step 1 configure
                          		 
            Step 2 router hsrp


            Example: 
            RP/0/RSP0/CPU0:router(config)# router hsrp
             

            Enables HSRP configuration mode.

             
            Step 3 interface type interface-path-id


            Example: 
            RP/0/RSP0/CPU0:router(config-hsrp)# interface TenGigE 0/2/0/1
             

            Enables HSRP interface configuration mode on a specific interface.

             
            Step 4 hsrp redirects disable


            Example: 
            RP/0/RSP0/CPU0:router(config-hsrp-if)# hsrp redirects
             

            Configures Internet Control Message Protocol (ICMP) redirect messages to be sent when the Hot Standby Router Protocol (HSRP) is configured on an interface.

            • The hsrp redirects command can be configured on a per-interface basis. When HSRP is first configured on an interface, the setting for that interface inherits the global value. If ICMP redirects have been explicitly disabled on an interface, then the global command cannot reenable the functionality.

            • With the hsrp redirects command enabled, ICMP redirect messages are filtered by replacing the real IP address in the next-hop address of the redirect packet with a virtual IP address, if it is known to HSRP.

            • To revert to the default, which is that ICMP messages are enabled, use the no hsrp redirects command.

             
            Step 5 address-family ipv4


            Example: 
            RP/0/RSP0/CPU0:router(config-hsrp-if)# address-family ipv4
             

            Enables HSRP address-family configuration mode on a specific interface.

             
            Step 6 hsrp group-number version version-no


            Example: 
            RP/0/RSP0/CPU0:router(config-hsrp-ipv4)# hsrp 1 version 1
             

            Enables HSRP group submode.

            Note   

            The version keyword is available only if IPv4 address-family is selected. By default, version is set to 2 for IPv6 address families.

             
            Step 7 address { learn | address [secondary] }


            Example: 
            RP/0/RSP0/CPU0:router(config-hsrp-gp)# address learn
             

            Activates HSRP on the configured interface.

            • If an IP address is specified, that address is used as the designated address for the Hot Standby group. If no IP address is specified, the virtual address is learned from the active router.

            Note   

            If you configure HSRP for IPv6, you must configure a link local IPv6 address or enable it using the autoconfig keyword. If you do not configure a linklocal IPv6 address, the router does not accept the configuration when you commit your changes using the commit keyword.

             
            Step 8 commit
                          		 

            Multiple Group Optimization (MGO) for HSRP

            Multiple Group Optimization provides a solution for reducing control traffic in a deployment consisting of many subinterfaces. By running the HSRP control traffic for just one of the sessions, the control traffic is reduced for the subinterfaces with identical redundancy requirements. All other sessions are slaves of this primary session, and inherit their states from it.

            Customizing HSRP

            Customizing the behavior of HSRP is optional. Be aware that as soon as you enable a HSRP group, that group is in operation.

            SUMMARY STEPS

              1.    configure

              2.    router hsrp

              3.    interface type interface-path-id

              4.    address-family ipv4

              5.    hsrp group-no version version-no

              6.    name name

              7.    address { learn | address}

              8.    address address secondary

              9.    authentication string

              10.    bfd fast-detect

              11.    mac-address address

              12.    hsrp group-no slave

              13.    follow mgo-session-name

              14.    address ip-address

              15.    commit


            DETAILED STEPS
               Command or ActionPurpose
              Step 1 configure
                              		 
              Step 2 router hsrp


              Example: 
              RP/0/RSP0/CPU0:router(config)# router hsrp
               

              Enables HSRP configuration mode.

               
              Step 3 interface type interface-path-id


              Example: 
              RP/0/RSP0/CPU0:router(config-hsrp)# interface TenGigE 0/2/0/1
               

              Enables HSRP interface configuration mode on a specific interface.

               
              Step 4 address-family ipv4


              Example: 
              RP/0/RSP0/CPU0:router(config-hsrp-if)# address-family ipv4
               

              Enables HSRP address-family configuration mode on a specific interface.

               
              Step 5 hsrp group-no version version-no


              Example: 
              RP/0/RSP0/CPU0:router(config-hsrp-ipv4)# hsrp 1 version 2
               

              Enables HSRP group configuration mode on a specific interface.

              Note   

              The version keyword is available only if IPv4 address-family is selected. By default, version is set to 2 for IPv6 address families.

               
              Step 6 name name


              Example: 
              RP/0/RSP0/CPU0:router(config-hsrp-gp)# name s1
               

              Configures an HSRP session name.

               
              Step 7 address { learn | address}


              Example: 
              RP/0/RSP0/CPU0:router(config-hsrp-gp)# address learn
               

              Enables hot standby protocol for IP.

              • If an IP address is specified, that address is used as the designated address for the Hot Standby group. If no IP address is specified, the virtual address is learned from the active router.

               
              Step 8 address address secondary


              Example: 
              
RP/0/RSP0/CPU0:router(config-hsrp-gp)# address 10.20.30.1 secondary
               

              Configures the secondary virtual IPv4 address for a router.

               
              Step 9 authentication string


              Example: 
              
RP/0/RSP0/CPU0:router(config-hsrp-gp)# authentication company1
               

              Configures an authentication string for the Hot Standby Router Protocol (HSRP).

               
              Step 10 bfd fast-detect


              Example: 
              
RP/0/RSP0/CPU0:router(config-hsrp-gp)# bfd fast-detect
               

              Enables bidirectional forwarding(BFD) fast-detection on a HSRP interface.

               
              Step 11 mac-address address


              Example: 
              
RP/0/RSP0/CPU0:router(config-hsrp-gp)# mac-address 4000.1000.1060
               

              Specifies a virtual MAC address for the Hot Standby Router Protocol (HSRP).

               
              Step 12 hsrp group-no slave


              Example: 
              
RP/0/RSP0/CPU0:router(config-hsrp-gp)# hsrp 2 slave
               

              Enables HSRP slave configuration mode on a specific interface.

               
              Step 13 follow mgo-session-name


              Example: 
              
RP/0/RSP0/CPU0:router(config-hsrp-slave)# follow s1
               

              Instructs the slave group to inherit its state from a specified group.

               
              Step 14 address ip-address


              Example: 
              
RP/0/RSP0/CPU0:router(config-hsrp-slave)# address 10.3.2.2
               

              Configures the primary virtual IPv4 address for the slave group.

               
              Step 15 commit
                              		 

              Configuring a Primary Virtual IPv4 Address

              To enable hot standby protocol for IP, use the address (hsrp) command in the HSRP group submode.

              SUMMARY STEPS

                1.    configure

                2.    router hsrp

                3.    interface type interface-path-id

                4.    address-family ipv4

                5.    hsrp group-noversion version-no

                6.    address { learn | address}

                7.    commit


              DETAILED STEPS
                 Command or ActionPurpose
                Step 1 configure
                                  		 
                Step 2 router hsrp


                Example: 
                RP/0/RSP0/CPU0:router(config)# router hsrp
                 

                Enables HSRP configuration mode.

                 
                Step 3 interface type interface-path-id


                Example: 
                RP/0/RSP0/CPU0:router(config-hsrp)# interface TenGigE 0/2/0/1
                 

                Enables HSRP interface configuration mode on a specific interface.

                 
                Step 4 address-family ipv4


                Example: 
                RP/0/RSP0/CPU0:router(config-hsrp-if)# address-family ipv4
                 

                Enables HSRP address-family configuration mode on a specific interface.

                 
                Step 5 hsrp group-noversion version-no


                Example: 
                RP/0/RSP0/CPU0:router(config-hsrp-ipv4)# hsrp 1 version 2
                 

                Enables HSRP group configuration mode on a specific interface.

                Note   

                • The version keyword is available only if IPv4 address-family is selected. By default, version is set to 2 for IPv6 address families.

                • HSRP version 2 provides an extended group range of 0-4095.

                 
                Step 6 address { learn | address}


                Example: 
                RP/0/RSP0/CPU0:router(config-hsrp-ipv4)# address learn
                 

                Enables hot standby protocol for IP.

                 
                Step 7 commit
                                  		 

                Configuring a Secondary Virtual IPv4 Address

                To configure the secondary virtual IPv4 address for a router, use the address secondary command in the Hot Standby Router Protocol (HSRP) virtual router submode.

                SUMMARY STEPS

                  1.    configure

                  2.    router hsrp

                  3.    interface type interface-path-id

                  4.    address-family ipv4

                  5.    hsrp group-noversion version-no

                  6.    address address secondary

                  7.    commit


                DETAILED STEPS
                   Command or ActionPurpose
                  Step 1 configure
                                      		 
                  Step 2 router hsrp


                  Example: 
                  RP/0/RSP0/CPU0:router(config)# router hsrp
                   

                  Enables HSRP configuration mode.

                   
                  Step 3 interface type interface-path-id


                  Example: 
                  RP/0/RSP0/CPU0:router(config-hsrp)# interface TenGigE  0/2/0/1
                   

                  Enables HSRP interface configuration mode on a specific interface.

                   
                  Step 4 address-family ipv4


                  Example: 
                  RP/0/RSP0/CPU0:router(config-hsrp-if)# address-family ipv4
                   

                  Enables HSRP address-family configuration mode on a specific interface.

                   
                  Step 5 hsrp group-noversion version-no


                  Example: 
                  RP/0/RSP0/CPU0:router(config-hsrp-ipv4)# hsrp 1 version 2
                   

                  Enables HSRP group configuration mode on a specific interface.

                  Note   

                  • The version keyword is available only if IPv4 address-family is selected. By default, version is set to 2 for IPv6 address families.

                  • HSRP version 2 provides an extended group range of 0-4095.

                   
                  Step 6 address address secondary


                  Example: 
                  RP/0/RSP0/CPU0:router(config-hsrp-ipv4)# address 10.20.30.1 secondary
                   

                  Configures the secondary virtual IPv4 address for a router.

                   
                  Step 7 commit
                                      		 

                  Configuring a slave follow

                  To instruct the slave group to inherit its state from a specified group, use the slave follow command in HSRP slave submode mode.
                  SUMMARY STEPS

                    1.    configure

                    2.    router hsrp

                    3.    interface type interface-path-id

                    4.    address-family ipv4

                    5.    hsrp group-no slave

                    6.    follow mgo-session-name

                    7.    commit


                  DETAILED STEPS
                     Command or ActionPurpose
                    Step 1 configure
                                          		 
                    Step 2 router hsrp


                    Example: 
                    RP/0/RSP0/CPU0:router(config)# router hsrp
                     

                    Enables HSRP configuration mode.

                     
                    Step 3 interface type interface-path-id


                    Example: 
                    RP/0/RSP0/CPU0:router(config-hsrp)# interface TenGigE 0/2/0/1
                     

                    Enables HSRP interface configuration mode on a specific interface.

                     
                    Step 4 address-family ipv4


                    Example: 
                    RP/0/RSP0/CPU0:router(config-hsrp-if)# address-family ipv4
                     

                    Enables HSRP address-family configuration mode on a specific interface.

                     
                    Step 5 hsrp group-no slave


                    Example: 
                    RP/0/RSP0/CPU0:router(config-hsrp-ipv4)# hsrp 2 slave
                     

                    Enables HSRP slave configuration mode on a specific interface.

                     
                    Step 6 follow mgo-session-name


                    Example: 
                    RP/0/RSP0/CPU0:router(config-hsrp-slave)# follow m1
                     

                    Instructs the slave group to inherit its state from a specified group.

                     
                    Step 7 commit
                                          		 

                    Configuring a slave primary virtual IPv4 address

                    To configure the primary virtual IPv4 address for the slave group, use the slave primary virtual IPv4 address command in the HSRP slave submode.

                    SUMMARY STEPS

                      1.    configure

                      2.    router hsrp

                      3.    interface type interface-path-id

                      4.    address-family ipv4

                      5.    hsrp group-no slave

                      6.    address ip-address

                      7.    commit


                    DETAILED STEPS
                       Command or ActionPurpose
                      Step 1 configure
                                              		 
                      Step 2 router hsrp


                      Example: 
                      RP/0/RSP0/CPU0:router(config)# router hsrp
                       

                      Enables HSRP configuration mode.

                       
                      Step 3 interface type interface-path-id


                      Example: 
                      RP/0/RSP0/CPU0:router(config-hsrp)# interface TenGigE 0/2/0/1
                       

                      Enables HSRP interface configuration mode on a specific interface.

                       
                      Step 4 address-family ipv4


                      Example: 
                      RP/0/RSP0/CPU0:router(config-hsrp-if)# address-family ipv4
                       

                      Enables HSRP address-family configuration mode on a specific interface.

                       
                      Step 5 hsrp group-no slave


                      Example: 
                      RP/0/RSP0/CPU0:router(config-hsrp-ipv4)# hsrp 2 slave
                       

                      Enables HSRP slave configuration mode on a specific interface.

                       
                      Step 6 address ip-address


                      Example: 
                      RP/0/RSP0/CPU0:router(config-hsrp-slave)# address 10.2.3.2
                       

                      Configures the primary virtual IPv4 address for the slave group.

                       
                      Step 7 commit
                                              		 

                      Configuring a Secondary Virtual IPv4 address for the Slave Group

                      Perform this task to configure the secondary virtual IPv4 address for the slave group.

                      SUMMARY STEPS

                        1.    configure

                        2.    router hsrp

                        3.    interface type interface-path-id

                        4.    address-family ipv4

                        5.    hsrp group-no slave

                        6.    address address secondary

                        7.    commit


                      DETAILED STEPS
                         Command or ActionPurpose
                        Step 1 configure
                                                  		 
                        Step 2 router hsrp


                        Example: 
                        RP/0/RSP0/CPU0:router(config)# router hsrp
                         

                        Enables HSRP configuration mode.

                         
                        Step 3 interface type interface-path-id


                        Example: 
                        RP/0/RSP0/CPU0:router(config-hsrp)# interface TenGigE 0/2/0/1
                         

                        Enables HSRP interface configuration mode on a specific interface.

                         
                        Step 4 address-family ipv4


                        Example: 
                        RP/0/RSP0/CPU0:router(config-hsrp-if)# address-family ipv4
                         

                        Enables HSRP address-family configuration mode on a specific interface.

                         
                        Step 5 hsrp group-no slave


                        Example: 
                        RP/0/RSP0/CPU0:router(config-hsrp-address-family)# hsrp 2 slave
                         

                        Enables HSRP slave configuration mode on a specific interface.

                         
                        Step 6 address address secondary


                        Example: 
                        RP/0/RSP0/CPU0:router(config-hsrp-slave)# address 10.20.30.1 secondary
                         

                        Configures the secondary virtual IPv4 address for a router.

                         
                        Step 7 commit
                                                  		 

                        Configuring a slave virtual mac address

                        To configure the virtual MAC address for the slave group, use the slave virtual mac address command in the HSRP slave submode.

                        SUMMARY STEPS

                          1.    configure

                          2.    router hsrp

                          3.    interface type interface-path-id

                          4.    address-family ipv4

                          5.    hsrp group-no slave

                          6.    mac-address address

                          7.    commit


                        DETAILED STEPS
                           Command or ActionPurpose
                          Step 1 configure
                                                      		 
                          Step 2 router hsrp


                          Example: 
                          RP/0/RSP0/CPU0:router(config)# router hsrp
                           

                          Enables HSRP configuration mode.

                           
                          Step 3 interface type interface-path-id


                          Example: 
                          RP/0/RSP0/CPU0:router(config-hsrp)# interface TenGigE 0/2/0/1
                           

                          Enables HSRP interface configuration mode on a specific interface.

                           
                          Step 4 address-family ipv4


                          Example: 
                          RP/0/RSP0/CPU0:router(config-hsrp-if)# address-family ipv4
                           

                          Enables HSRP address-family configuration mode on a specific interface.

                           
                          Step 5 hsrp group-no slave


                          Example: 
                          RP/0/RSP0/CPU0:router(config-hsrp-ipv4)# hsrp 2 slave
                           

                          Enables HSRP slave configuration mode on a specific interface.

                           
                          Step 6 mac-address address


                          Example: 
                          RP/0/RSP0/CPU0:router(config-hsrp-slave)# mac-address 10.20.30
                           

                          Configures the virtual MAC address for the slave group.

                           
                          Step 7 commit
                                                      		 

                          Configuring an HSRP Session Name

                          To configure an HSRP session name, use the session name command in the HSRP group submode.

                          SUMMARY STEPS

                            1.    configure

                            2.    router hsrp

                            3.    interface type interface-path-id

                            4.    address-family ipv4

                            5.    hsrp group-noversion version-no

                            6.    name name

                            7.    commit


                          DETAILED STEPS
                             Command or ActionPurpose
                            Step 1 configure
                                                          		 
                            Step 2 router hsrp


                            Example: 
                            RP/0/RSP0/CPU0:router(config)# router hsrp
                             

                            Enables HSRP configuration mode.

                             
                            Step 3 interface type interface-path-id


                            Example: 
                            RP/0/RSP0/CPU0:router(config-hsrp)# interface TenGigE 0/2/0/1
                             

                            Enables HSRP interface configuration mode on a specific interface.

                             
                            Step 4 address-family ipv4


                            Example: 
                            RP/0/RSP0/CPU0:router(config-hsrp-if)# address-family ipv4
                             

                            Enables HSRP address-family configuration mode on a specific interface.

                             
                            Step 5 hsrp group-noversion version-no


                            Example: 
                            RP/0/RSP0/CPU0:router(config-hsrp-ipv4)# hsrp 1 version 2
                             

                            Enables HSRP group configuration mode on a specific interface.

                            Note   

                            • The version keyword is available only if IPv4 address-family is selected. By default, version is set to 2 for IPv6 address families.

                            • HSRP version 2 provides an extended group range of 0-4095.

                             
                            Step 6 name name


                            Example: 
                            RP/0/RSP0/CPU0:router(config-hsrp-ipv4)# name s1
                             

                            Configures an HSRP session name.

                             
                            Step 7 commit
                                                          		 

                            BFD for HSRP

                            Bidirectional Forwarding Detection (BFD) is a network protocol used to detect faults between two forwarding engines. BFD sessions can operate in one of the two modes, namely, asynchronous mode or demand mode. In asynchronous mode, both endpoints periodically send hello packets to each other. If a number of those packets are not received, the session is considered down. In demand mode, it is not mandatory to exchange hello packets; either of the hosts can send hello messages, if needed. Cisco supports the BFD asynchronous mode.

                            Advantages of BFD

                            • BFD provides failure detection in less than one second.

                            • BFD supports all types of encapsulation.

                            • BFD is not tied to any particular routing protocol, supports almost all routing protocols.

                            BFD Process

                            HSRP uses BFD to detect link failure and facilitate fast failover times without excessive control packet overhead.

                            The HSRP process creates BFD sessions as required. When a BFD session goes down, each Standby group monitoring the session transitions to Active state.

                            HSRP does not participate in any state elections for 10 seconds after a transition to Active state triggered by a BFD session going down.

                            Configuring BFD

                            For HSRP, configuration is applied under the existing HSRP-interface sub-mode, with BFD fast failure configurable per HSRP group and the timers (minimum-interface and multiplier) configurable per interface. BFD fast failure detection is disabled by default.

                            Enabling BFD

                            SUMMARY STEPS

                              1.    configure

                              2.    router hsrp

                              3.    interface type interface-path-id

                              4.    address-family ipv4

                              5.    hsrp [group number] version version-no bfd fast-detect [peer ipv4 ipv4-address interface-type interface-path-id]

                              6.    commit


                            DETAILED STEPS
                               Command or ActionPurpose
                              Step 1 configure
                                                              		 
                              Step 2 router hsrp


                              Example: 
                              RP/0/RSP0/CPU0:router(config)# router hsrp
                               

                              Enables HSRP configuration mode.

                               
                              Step 3 interface type interface-path-id


                              Example: 
                              RP/0/RSP0/CPU0:router(config-hsrp)# interface TenGigE 0/2/0/1
                               

                              Enables HSRP interface configuration mode on a specific interface.

                               
                              Step 4 address-family ipv4


                              Example: 
                              RP/0/RSP0/CPU0:router(config-hsrp-if)# address-family ipv4
                               

                              Enables HSRP address-family configuration mode on a specific interface.

                               
                              Step 5 hsrp [group number] version version-no bfd fast-detect [peer ipv4 ipv4-address interface-type interface-path-id]


                              Example: 
                              RP/0/RSP0/CPU0:router(config-hsrp-ipv4)# hsrp 1 version 2 bfd fast-detect peer ipv4 10.3.5.2 TenGigE 0/3/4/2
                               

                              Enables fast detection on a specific interface.

                              Note   

                              • The version keyword is available only if IPv4 address-family is selected. By default, version is set to 2 for IPv6 address families.

                              • HSRP version 2 provides an extended group range of 0-4095.

                               
                              Step 6 commit
                                                              		 

                              Modifying BFD timers (minimum interval)

                              Minimum interval determines the frequency of sending BFD packets to BFD peers (in milliseconds). The default minimum interval is 15ms.

                              SUMMARY STEPS

                                1.    configure

                                2.    router hsrp

                                3.    interface type interface-path-id

                                4.    hsrp bfd minimum-interval interval

                                5.    address-family ipv4

                                6.    commit


                              DETAILED STEPS
                                 Command or ActionPurpose
                                Step 1 configure
                                                                  		 
                                Step 2 router hsrp


                                Example: 
                                RP/0/RSP0/CPU0:router(config)# router hsrp
                                 

                                Enables HSRP configuration mode.

                                 
                                Step 3 interface type interface-path-id


                                Example: 
                                RP/0/RSP0/CPU0:router(config-hsrp)# interface TenGigE 0/2/0/1
                                 

                                Enables HSRP interface configuration mode on a specific interface.

                                 
                                Step 4 hsrp bfd minimum-interval interval


                                Example: 
                                RP/0/RSP0/CPU0:router(config-hsrp-if)# hsrp bfd minimum-interval 20
                                 

                                Sets the minimum interval to the specified period. The interval is in milliseconds; range is 15 to 30000 milliseconds.

                                 
                                Step 5 address-family ipv4


                                Example: 
                                RP/0/RSP0/CPU0:router(config-hsrp-if)# address-family ipv4
                                 

                                Enables HSRP address-family configuration mode on a specific interface.

                                 
                                Step 6 commit
                                                                  		 

                                Modifying BFD timers (multiplier)

                                Multiplier is the number of consecutive BFD packets which must be missed from a BFD peer before declaring that peer unavailable. The default multiplier is 3.

                                SUMMARY STEPS

                                  1.    configure

                                  2.    router hsrp

                                  3.    interface type interface-path-id

                                  4.    hsrp bfd multiplier multiplier

                                  5.    address-family ipv4

                                  6.    commit


                                DETAILED STEPS
                                   Command or ActionPurpose
                                  Step 1 configure
                                                                      		 
                                  Step 2 router hsrp


                                  Example: 
                                  RP/0/RSP0/CPU0:router(config)# router hsrp
                                   

                                  Enables HSRP configuration mode.

                                   
                                  Step 3 interface type interface-path-id


                                  Example: 
                                  RP/0/RSP0/CPU0:router(config-hsrp)# interface TenGigE 0/2/0/1
                                   

                                  Enables HSRP interface configuration mode on a specific interface.

                                   
                                  Step 4 hsrp bfd multiplier multiplier


                                  Example: 
                                  RP/0/RSP0/CPU0:router(config-hsrp-if)# hsrp bfd multiplier 30
                                   

                                  Sets the multiplier to the value. Range is 2 to 50.

                                   
                                  Step 5 address-family ipv4


                                  Example: 
                                  RP/0/RSP0/CPU0:router(config-hsrp-if)# address-family ipv4
                                   

                                  Enables HSRP address-family configuration mode on a specific interface.

                                   
                                  Step 6 commit
                                                                      		 

                                  Enhanced Object Tracking for HSRP and IP Static

                                  A failure between the active router and the core network cannot be detected using standard HSRP failure detection mechanisms. Object tracking is used to detect such failures. When such a failure occurs, the active router applies a priority decrement to its HSRP session. If this causes its priority to fall below that of the standby router, it will detect this from the HSRP control traffic, and then use this as a trigger to preempt and take over the active role.

                                  Cisco IOS XR software supports up to 512 tracked objects.

                                  The enhanced object tracking for HSRP and IP Static feature provides first-hop redundancy as well as default gateway selection based on IP Service Level Agreement (IPSLA).

                                  See the Cisco ASR 9000 Series Aggregation Services Router Routing Configuration Guide, for more information about enhanced object tracking for static routes.

                                  Configuring object tracking for HSRP

                                  To enable tracking of the named object with the specified decrement, use the following configuration in the HSRP group sub mode.

                                  SUMMARY STEPS

                                    1.    configure

                                    2.    router hsrp

                                    3.    interface type interface-path-id

                                    4.    address-family ipv4

                                    5.    hsrp group-number version version-no

                                    6.    track object name [priority-decrement]

                                    7.    commit


                                  DETAILED STEPS
                                     Command or ActionPurpose
                                    Step 1 configure
                                                                          		 
                                    Step 2 router hsrp


                                    Example: 
                                    RP/0/RSP0/CPU0:router(config)# router hsrp
                                     

                                    Enables HSRP configuration mode.

                                     
                                    Step 3 interface type interface-path-id


                                    Example: 
                                    RP/0/RSP0/CPU0:router(config-hsrp)# interface TenGigE 0/2/0/1
                                     

                                    Enables HSRP interface configuration mode on a specific interface.

                                     
                                    Step 4 address-family ipv4


                                    Example: 
                                    RP/0/RSP0/CPU0:router(config-hsrp-if)# address-family ipv4
                                     

                                    Enables HSRP address-family configuration mode on a specific interface.

                                     
                                    Step 5 hsrp group-number version version-no


                                    Example: 
                                    RP/0/RSP0/CPU0:router(config-hsrp-ipv4)# hsrp 1 version 1
                                     

                                    Enables HSRP group submode.

                                    Note   

                                    The version keyword is available only if IPv4 address-family is selected. By default, version is set to 2 for IPv6 address families.

                                     
                                    Step 6 track object name [priority-decrement]


                                    Example: 
                                    RP/0/RSP0/CPU0:router(config-hsrp-gp)# track object t1 2
                                     

                                    Enable tracking of the named object with the specified decrement.

                                     
                                    Step 7 commit
                                                                          		 

                                    Hot Restartability for HSRP

                                    In the event of failure of a HSRP process in one active group, forced failovers in peer HSRP active router groups should be prevented. Hot restartability supports warm RP failover without incurring forced failovers to peer HSRP routers for active groups.

                                    Configuration Examples for HSRP Implementation on Software

                                    This section provides the following HSRP configuration examples:

                                    Configuring an HSRP Group: Example

                                    The following is an example of enabling HSRP on an interface and configuring HSRP group attributes: 

                                    configure
router hsrp
interface TenGigE 0/2/0/1
address-family ipv4
hsrp 1 
name s1
address 10.0.0.5
timers 100 200
preempt delay 500
priority 20
track TenGigE 0/2/0/2
authentication company0
use-bia
commit
hsrp 2 slave
follow s1
address 10.3.2.2
commit

                                    Configuring a Router for Multiple HSRP Groups: Example

                                    The following is an example of configuring a router for multiple HSRP groups: 

                                    configure
router hsrp
interface TenGigE 0/2/0/3
address family ipv4
hsrp 1 
address 1.0.0.5
priority 20
preempt
authentication sclara
hsrp 2 
address 1.0.0.6 
priority 110
preempt
authentication mtview
hsrp 3 
address 1.0.0.7
preempt
authentication svale
commit

                                    Additional References

                                    Related Documents

                                    The following sections provide references related to HSRP

                                    Related Topic

                                    Document Title

                                    QoS commands: complete command syntax, command modes, command history, defaults, usage guidelines, and examples

                                    Quality of Service Commands on Cisco ASR 9000 Series Aggregation Services Router Modular Quality of Service Command Reference

                                    Class-based traffic shaping, traffic policing, low-latency queuing, and Modified Deficit Round Robin (MDRR)

                                    Configuring Modular Quality of Service Congestion Management on Cisco ASR 9000 Series Aggregation Services Router Modular Quality of Service Configuration Guide

                                    WRED, RED, and tail drop

                                    Configuring Modular QoS Congestion Avoidance on Cisco ASR 9000 Series Aggregation Services Router Modular Quality of Service Configuration Guide

                                    HSRP commands

                                    HSRP Commands on Cisco ASR 9000 Series Aggregation Services Router IP Addresses and Services Command Reference

                                    master command reference

                                    Cisco ASR 9000 Series Aggregation Services Router Commands Master List

                                    getting started material

                                    Cisco ASR 9000 Series Aggregation Services Router Getting Started Guide

                                    Information about user groups and task IDs

                                    Configuring AAA Services on Cisco ASR 9000 Series Aggregation Services Router System Security Configuration Guide

                                    Standards and RFCs

                                    Standard/RFC Title

                                    No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.

                                    		—

                                    MIBs

                                    MIB MIBs Link
                                     

                                    To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

                                    http:/​/​www.cisco.com/​go/​mibs

                                    Technical Assistance

                                    Description Link

                                    The Cisco Support website provides extensive online resources, including documentation and tools for troubleshooting and resolving technical issues with Cisco products and technologies.

                                    To receive security and technical information about your products, you can subscribe to various services, such as the Product Alert Tool (accessed from Field Notices), the Cisco Technical Services Newsletter, and Really Simple Syndication (RSS) Feeds.

                                    Access to most tools on the Cisco Support website requires a Cisco.com user ID and password.

                                    http:/​/​www.cisco.com/​support