- Implementing IPv6 Addressing and Basic Connectivity
- Implementing ADSL for IPv6
- Implementing Bidirectional Forwarding Detection for IPv6
- Implementing DHCP for IPv6
- Implementing EIGRP for IPv6
- Configuring First Hop Redundancy Protocols in IPv6
- Implementing IPsec in IPv6 Security
- Implementing IS-IS for IPv6
- Implementing IPv6 for Network Management
- Implementing IPv6 over MPLS
- Implementing IPv6 VPN over MPLS
- Implementing IPv6 Multicast
- PIMv6 Anycast RP Solution
- Implementing Multiprotocol BGP for IPv6
- Implementing NAT-PT for IPv6
- Implementing OSPFv3
- Implementing Policy-Based Routing for IPv6
- Implementing QoS for IPv6
- Implementing RIP for IPv6
- Implementing Selective Packet Discard in IPv6
- Implementing Static Routes for IPv6
- Implementing Traffic Filters for IPv6 Security
- IPv6 ACL Extensions for Hop by Hop Filtering
- Implementing Tunneling for IPv6
- IPv6 Virtual Fragmentation Reassembly
- IPv6 RFCs
- Finding Feature Information
- Prerequisites for First Hop Redundancy Protocols in IPv6
- Information About First Hop Redundancy Protocols in IPv6
Configuring First Hop Redundancy Protocols in IPv6
IPv6 routing protocols ensure router-to-router resilience and failover. However, in situations in which the path between a host and the first-hop router fails, or the first-hop router itself fails, first hop redundancy protocols (FHRPs) ensure host-to-router resilience and failover.
The Hot Standby Router Protocol (HSRP) protects data traffic in case of a gateway failure.
- Finding Feature Information
- Prerequisites for First Hop Redundancy Protocols in IPv6
- Information About First Hop Redundancy Protocols in IPv6
- How to Configure First Hop Redundancy Protocols in IPv6
- Configuration Examples for First Hop Redundancy Protocols in IPv6
- Additional References
- Feature Information for First Hop Redundancy Protocols in IPv6
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and 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 table at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Prerequisites for First Hop Redundancy Protocols in IPv6
HSRP version 2 must be enabled on an interface before HSRP IPv6 can be configured.
Information About First Hop Redundancy Protocols in IPv6
HSRP for IPv6
IPv6 routing protocols ensure router-to-router resilience and failover. However, in situations in which the path between a host and the first-hop router fails, or the first-hop router itself fails, first hop redundancy protocols (FHRPs) ensure host-to-router resilience and failover.
The Hot Standby Router Protocol (HSRP) protects data traffic in case of a gateway failure.
- HSRP for IPv6 Overview
- HSRP IPv6 Virtual MAC Address Range
- HSRP IPv6 UDP Port Number
- NSF and SSO-HSRP for IPv6 on VRF Interfaces
HSRP for IPv6 Overview
The HSRP is an FHRP designed to allow for transparent failover of the first-hop IP router. HSRP provides high network availability by providing first-hop routing redundancy for IP hosts on GigabitEthernet configured with a default gateway IP address. HSRP is used in a group of routers for selecting an active router and a standby router. In a group of router interfaces, the active router is the router of choice for routing packets; the standby router is the router that takes over when the active router fails or when preset conditions are met.
IPv6 hosts learn of available IPv6 routers through IPv6 neighbor discovery RA messages. These are multicast periodically, or may be solicited by hosts. HSRP is designed to provide only a virtual first hop for IPv6 hosts.
An HSRP IPv6 group has a virtual MAC address that is derived from the HSRP group number, and a virtual IPv6 link-local address that is, by default, derived from the HSRP virtual MAC address. Periodic RAs are sent for the HSRP virtual IPv6 link-local address when the HSRP group is active. These RAs stop after a final RA is sent when the group leaves the active state.
Periodic RAs for the interface link-local address stop after a final RA is sent while at least one virtual IPv6 link-local address is configured on the interface. No restrictions occur for the interface IPv6 link-local address other than that mentioned for the RAs. Other protocols continue to receive and send packets to this address.
HSRP uses a priority mechanism 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 IPv6 Virtual MAC Address Range
HSRP IPv6 uses a different virtual MAC address block than does HSRP for IP:
0005.73A0.0000 through 0005.73A0.0FFF (4096 addresses)
HSRP IPv6 UDP Port Number
Port number 2029 has been assigned to HSRP IPv6.
NSF and SSO-HSRP for IPv6 on VRF Interfaces
Cisco Nonstop Forwarding (NSF) and stateful switchover (SSO) are supported on HSRP for IPv6 on VRF interfaces, which makes HSRP for IPv6 VRF-aware.
For further information about SSO and NSF, see " Stateful Switchover " and " Cisco Nonstop Forwarding " in the Cisco IOS XE High Availability Configuration Guide .
How to Configure First Hop Redundancy Protocols in IPv6
Enabling an HSRP Group for IPv6 Operation
Prerequisites
HSRP version 2 must be enabled on an interface before HSRP IPv6 can be configured.
If an IPv6 address is entered, it must be link local. There are no HSRP IPv6 secondary addresses.
Enabling HSRP Version 2
DETAILED STEPS
Enabling and Verifying an HSRP Group for IPv6 Operation
In this task, when you enter the standby ipv6 command, a link-local address is generated from the link-local prefix, and a modified EUI-64 format interface identifier is generated in which the EUI-64 interface identifier is created from the relevant HSRP virtual MAC address.
A link-local address is an IPv6 unicast address that can be automatically configured on any interface using the link-local prefix FE80::/10 (1111 1110 10) and the interface identifier in the modified EUI-64 format. Link-local addresses are used in the stateless autoconfiguration process. Nodes on a local link can use link-local addresses to communicate; the nodes do not need site-local or globally unique addresses to communicate.
In IPv6, a router on the link advertises in RA messages any site-local and global prefixes, and its willingness to function as a default router for the link. RA messages are sent periodically and in response to router solicitation messages, which are sent by hosts at system startup.
A node on the link can automatically configure site-local and global IPv6 addresses by appending its interface identifier (64 bits) to the prefixes (64 bits) included in the RA messages. The resulting 128-bit IPv6 addresses configured by the node are then subjected to duplicate address detection to ensure their uniqueness on the link. If the prefixes advertised in the RA messages are globally unique, then the IPv6 addresses configured by the node are also guaranteed to be globally unique. Router solicitation messages, which have a value of 133 in the Type field of the ICMP packet header, are sent by hosts at system startup so that the host can immediately autoconfigure without needing to wait for the next scheduled RA message.
DETAILED STEPS
Configuration Examples for First Hop Redundancy Protocols in IPv6
Example: Enabling and Verifying an HSRP Group for IPv6 Operation
The following example shows configuration verification for an HSRP group for IPv6 that consists of Router1 and Router2. The show standby command is issued for each device to verify the device's configuration.
Router1 Configuration
interface GigabitEthernet0/0/0
description DATA VLAN for PCs
encapsulation dot1Q 100
ipv6 address 2001:DB8:CAFE:2100::BAD1:1010/64
standby version 2
standby 101 priority 120
standby 101 preempt delay minimum 30
standby 101 authentication ese
standby 101 track Serial0/1/0.17 90
standby 201 ipv6 autoconfig
standby 201 priority 120
standby 201 preempt delay minimum 30
standby 201 authentication ese
standby 201 track Serial0/1/0.17 90
Router1# show standby
GigabitFastEthernet0/0/0 - Group 101 (version 2)
State is Active
2 state changes, last state change 5w5d
Active virtual MAC address is 0000.0c9f.f065
Local virtual MAC address is 0000.0c9f.f065 (v2 default)
Hello time 3 sec, hold time 10 sec
Next hello sent in 2.296 secs
Authentication text "ese"
Preemption enabled, delay min 30 secs
Active router is local
Priority 120 (configured 120)
Track interface Serial0/1/0.17 state Up decrement 90
IP redundancy name is "hsrp-Fa0/0.100-101" (default)
GigabitEthernet0/0/0 - Group 201 (version 2)
State is Active
2 state changes, last state change 5w5d
Virtual IP address is FE80::5:73FF:FEA0:C9
Active virtual MAC address is 0005.73a0.00c9
Local virtual MAC address is 0005.73a0.00c9 (v2 IPv6 default)
Hello time 3 sec, hold time 10 sec
Next hello sent in 2.428 secs
Authentication text "ese"
Preemption enabled, delay min 30 secs
Active router is local
Standby router is FE80::20F:8FFF:FE37:3B70, priority 100 (expires in 7.856 sec)
Priority 120 (configured 120)
Track interface Serial0/1/0.17 state Up decrement 90
IP redundancy name is "hsrp-Fa0/0.100-201" (default)
Router2 Configuration
interface GigabitEthernet0/0/0
description DATA VLAN for Computers
encapsulation dot1Q 100
ipv6 address 2001:DB8:CAFE:2100::BAD1:1020/64
standby version 2
standby 101 preempt
standby 101 authentication ese
standby 201 ipv6 autoconfig
standby 201 preempt
standby 201 authentication ese
Router2# show standby
GigabitEthernet0/0/0 - Group 101 (version 2)
State is Standby
7 state changes, last state change 5w5d
Active virtual MAC address is 0000.0c9f.f065
Local virtual MAC address is 0000.0c9f.f065 (v2 default)
Hello time 3 sec, hold time 10 sec
Next hello sent in 0.936 secs
Authentication text "ese"
Preemption enabled
MAC address is 0012.7fc6.8f0c
Standby router is local
Priority 100 (default 100)
IP redundancy name is "hsrp-Fa0/0.100-101" (default)
GigabitEthernet0/0/0 - Group 201 (version 2)
State is Standby
7 state changes, last state change 5w5d
Virtual IP address is FE80::5:73FF:FEA0:C9
Active virtual MAC address is 0005.73a0.00c9
Local virtual MAC address is 0005.73a0.00c9 (v2 IPv6 default)
Hello time 3 sec, hold time 10 sec
Next hello sent in 0.936 secs
Authentication text "ese"
Preemption enabled
Active router is FE80::212:7FFF:FEC6:8F0C, priority 120 (expires in 7.548 sec)
MAC address is 0012.7fc6.8f0c
Standby router is local
Priority 100 (default 100)
IP redundancy name is "hsrp-Fa0/0.100-201" (default)
Additional References
Related Documents
| Related Topic |
Document Title |
|---|---|
| IPv6 link-local addresses and stateless autoconfiguration |
" Implementing IPv6 Addressing and Basic Connectivity ," Cisco IOS XE IPv6 Configuration Guide |
| SSO and NSF |
" Stateful Switchover " and " Cisco Nonstop Forwarding, " Cisco IOS XE High Availability Configuration Guide . |
| IPv6 supported feature list |
" Start Here: Cisco IOS XE Software Release Specifics for IPv6 Features ," Cisco IOS XE IPv6 Configuration Guide |
| IPv6 commands: complete command syntax, command mode, command history, defaults, usage guidelines, and examples |
Cisco IOS IPv6 Command Reference |
| Cisco IOS master command list, all releases |
Standards
| Standard |
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 |
|---|---|
| None |
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 |
Title |
|---|---|
| RFC 2281 |
Cisco Hot Standby Router Protocol (HSRP) |
Technical Assistance
| Description |
Link |
|---|---|
| The Cisco Support and Documentation website provides online resources to download documentation, software, and tools. Use these resources to install and configure the software and to troubleshoot and resolve technical issues with Cisco products and technologies. Access to most tools on the Cisco Support and Documentation website requires a Cisco.com user ID and password. |
http://www.cisco.com/cisco/web/support/index.html |
Feature Information for First Hop Redundancy Protocols in IPv6
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
| Table 1 | Feature Information for First Hop Redundancy Protocols for IPv6 |
| Feature Name |
Releases |
Feature Configuration Information |
|---|---|---|
| IPv6 services: HSRP for IPv6 |
Cisco IOS XE Release 3.1S Cisco IOS XE Release 3.3SG |
The HSRP is an FHRP designed to allow for transparent failover of the first-hop IPv6 router. The following commands were modified for this release: show ipv6 interface, show standby, standby ipv6, standby preempt, standby priority, standby version. |
| NSF/SSO - HSRPv6 on VRF interfaces |
Cisco IOS XE Release 3.1S |
The NSF/SSO - HSRPv6 on VRF interfaces feature is supported in Cisco IOS XE Release 3.1S. |
| ISSU - HSRPv6 on VRF interfaces |
Cisco IOS XE Release 3.1S |
The ISSU - HSRPv6 on VRF interfaces feature is supported in Cisco IOS XE Release 3.1S. |
Cisco and the Cisco logo are trademarks or registered trademarks of Cisco and/or its affiliates in the U.S. and other countries. To view a list of Cisco trademarks, go to this URL: 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. (1110R)
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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