HSRP: Global IPv6 Address
IPv6 routing protocols ensure device-to-device resilience and failover. However, in situations in which the path between a host and the first-hop device fails, or the first-hop device itself fails, first hop redundancy protocols (FHRPs) ensure host-to-device resilience and failover.
The Hot Standby Router Protocol (HSRP) protects data traffic in case of a gateway failure.
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Information About HSRP Global IPv6 Address
HSRP Global IPv6 Address
This feature is supported only in Cisco IOS Release 12.2(33)SXI4.
The HSRP global IPv6 address feature allows users to configure multiple nonlink local addresses as virtual addresses, and it allows for the storage and management of multiple global IPv6 virtual addresses in addition to the existing primary link-local address. If an IPv6 address is used, it must include an IPv6 prefix length. If a link-local address is used, it must not have a prefix.
The figure below depicts a deployment scenario that uses an HSRP IPv6 global virtual interface:
In the figure above, the provider equipment (PE) devices need to inject a route to reach the customer premises equipment (CPE) from the backbone devices. Because there are two CPEs, HSRP is convenient to use. The static route will be set with a link-local next hop (FE80::1:1:1:CAFE). If this address is injected in the backbone, this route is useless with a link-local next hop, as link-local addresses only have scope within the Layer 2 local LAN space. To address this issue, the next hop of the static route toward the virtual address must be set to a nonlink-local address, so backbone devices can route packets to the PE devices. At the next-hop address resolution, the active HSRP group member will reply to neighbor solicitation (NS) messages sent to the nonlink-local address.
How to Enable HSRP Global IPv6 Address
Enabling and Verifying an HSRP Group for IPv6 Operation
In this task, when you enter the standby ipv6 command, 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.
In IPv6, a device on the link advertises in RA messages any site-local and global prefixes, and its willingness to function as a default device for the link. RA messages are sent periodically and in response to router solicitation (RS) 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. RS messages, which have a value of 133 in the Type field of the ICMPv6 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.
Configuration Example for HSRP Global IPv6 Address
Example: Configuring HSRP Global IPv6 Addresses
This example shows three HSRP global IPv6 addresses with an explicitly configured link-local address:
interface Ethernet0/0 no ip address ipv6 address 2001::DB8:1/64 standby version 2 standby 1 ipv6 FE80::1:CAFÉ standby 1 ipv6 2001::DB8:2/64 standby 1 ipv6 2001:DB8::3/64 standby 1 ipv6 2001:DB8::4/64 end
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Feature Information for HSRP: Global IPv6 Address
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.
|Table 1||Feature Information for HSRP: Global IPv6 Address|
|Feature Name||Releases||Feature Information|
HSRP: Global IPv6 Address
Cisco IOS XE Release 3.2SE
The HSRP global IPv6 address feature allows users to configure multiple non-link local addresses as virtual addresses.
The following command was introduced: standby ipv6.
- CPE --Customer premises equipment
- FHRP --First hop redundancy protocol
- GLBP --Gateway load balancing protocol
- HSRP --Hot standby routing protocol
- NA --Neighbor advertisement
- ND --Neighbor Discovery
- NS --Neighbor solicitation
- PE --Provider equipment
- RA --Router advertisement
- RS --Router solicitation
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