Configuring IPv6 OSPF
IPv6 OSPF or OSPF version 3 (OSPF v3) is a link state protocol that is used to exchange IPv6 routing information. After enabling IPv6 OSPF, you need to configure advertisement of IPv6 OSPF routes. For troubleshooting, you can limit IPv6 OSPF propagation. You can display IPv6 OSPF settings to verify the configuration.
Prerequisites for IPv6 OSPF
Before you begin configuring IPv6 OSPF, do the following:
- Make sure that you understand the IPv6 OSPF protocol.
- Install the IPv6PT license on the Citrix ADC appliance.
- Enable the IPv6 feature.
Advertising IPv6 Routes
IPv6 OSPF enables an upstream router to load balance traffic between two identical vservers hosted on two standalone Citrix ADC devices. Route advertising enables an upstream router to track network entities located behind the Citrix ADC.
To configure IPv6 OSPF to advertise IPv6 routes by using the VTYSH command line:
At the command prompt, type the following commands, in the order shown:
| Commands | Specifies |
|---|---|
| VTYSH | Display VTYSH command prompt. |
| configure terminal | Enter global configuration mode. |
| router ipv6 OSPF | Start IPv6 OSPF routing process and enter configuration mode for the routing process. |
| redistribute static | Redistribute static routes. |
| redistribute kernel | Redistribute kernel routes. |
Example:
>VTYSH
NS# configure terminal
NS(config)# router ipv6 OSPF
NS(config-router)# redistribute static
NS(config-router)# redistribute kernel
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Limiting IPv6 OSPF Propagations
If you need to troubleshoot your configuration, you use VTYSH to configure listen-only mode on any given VLAN.
To limit IPv6 OSPF propagation by using the VTYSH command line:
At the command prompt, type the following commands, in the order shown:
| Commands | Specifies |
|---|---|
| VTYSH | Display VTYSH command prompt. |
| configure terminal | Enter global configuration mode. |
| router ipv6 OSPF | Start IPv6 OSPF routing process and enter configuration mode for the routing process. |
| passive-interface < vlan_name > | Suppress routing updates on interfaces bound to the specified VLAN. |
Example:
>VTYSH
NS# configure terminal
NS(config)# router ipv6 OSPF
NS(config-router)# passive-interface VLAN0
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Verifying the IPv6 OSPF Configuration
You use VTYSH to display IPv6 OSPF current neighbors and IPv6 OSPF routes.
To view the IPv6 OSPF settings by using the VTYSH command line:
At the command prompt, type the following commands, in the order shown:
| Command | Specifies |
|---|---|
| VTYSH | Display VTYSH command prompt. |
| sh ipv6 OSPF neighbor | Display current neighbors. |
| sh ipv6 OSPF route | Display IPv6 OSPF routes. |
Example:
>VTYSH
NS# sh ipv6 OSPF neighbor
NS# sh ipv6 OSPF route
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OSPFv3 Authentication
To ensure the integrity, data origin authentication, and data confidentiality of OSPFv3 packets, OSPFv3 authentication must be configured on OSPFv3 peers.
The Citrix ADC appliance supports OSPFv3 authentication and is partially compliant with RFC 4552. OSPFv3 authentication is based on the two IPSec protocols: Authentication Header (AH) and Encapsulating Security Payload (ESP). The Citrix ADC appliance supports only the AH protocol for OSPFv3 authentication.
OSPFv3 authentication uses manually defined IPSec Security Associations (SAs) between the OSPFv3 peers and does not rely on IKE protocol for forming dynamic SAs. Manual SAs define the security parameter Index (SPI) values, algorithms, and keys to be used between the peers. Manual SAs require no negotiation between the peers; therefore, the same SA must be defined on both the peers.
You can configure OSPFv3 authentication on a VLAN or for an OSPFv3 area. When you configure for a VLAN, the settings are applied to all the interfaces that are members of the VLAN. When you configure OSPFv3 authentication for an OSPF area, the settings are applied to all the VLANs in that area. The settings are in turn applied to all the interfaces that are members of these VLANs. These settings do not apply to member VLANs on which you have configured OSPFv3 authentication directly.
Consider the following points and limitations before configuring OSPFv3 authentication on a Citrix ADC appliance:
- Make sure that you understand the different components of OSPFv3 authentication, described in RFC 4552.
- Only Authentication Header protocol is supported for OSPFv3 authentication. Encapsulating Security Payload (ESP) is not supported.
- You must define an SA with the same setting on the peer interface.
- Rekeying of manual keys is not supported.
To configure OSPFv3 authentication on a VLAN by using the VTYSH command line:
At the command prompt, type the following commands, in the order shown: OSPFv3 authentication VLAN commands.
Example:
> VTYSH NS# configure terminal
NS(config)# interface vlan2
NS(config-if)# ipv6 ospf authentication ipsec spi 256 md5 123456789ABCDEF0123456789ABCDEF0
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To configure OSPFv3 authentication on an OSPF area by using the VTYSH command line:
At the command prompt, type the following commands, in the order shown: OSPFv3 authentication OSPF area commands.
Example:
> VTYSH NS# configure terminal
ns(config)#router ipv6 ospf 30
ns(config-router)# area 1 authentication ipsec spi 256 md5123456789ABCDEF0123456789ABCDEF0
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Configuring Graceful Restart for IPv6 OSPF
In a non-INC high availability (HA) setup in which a routing protocol is configured, after a failover, routing protocols are converged and routes between the new primary node and the adjacent neighbor routers are learned. Route learning take some time to complete. During this time, forwarding of packets is delayed, network performance might get disrupted, and packets might get dropped.
Graceful restart enables an HA setup during a failover to direct its adjacent routers to not remove the old primary node’s learned routes from their routing databases. Using the old primary node’s routing information, the new primary node and the adjacent routers immediately start forwarding packets, without disrupting network performance.
Note:
Graceful restart is not supported for high availability setups in INC mode.
To configure graceful restart for IPv6 OSPF by using the VTYSH command line, at the command prompt, type the following commands, in the order shown:
| Command | Example | Command Description |
|---|---|---|
| VTYSH | > VTYSH | Enters VTYSH command prompt. |
| configure terminal | NS# configure terminal | Enters global configuration mode. |
| router-id id> | NS(config)#router-id 1.1.1.1 | Sets a router identifier for the Citrix ADC appliance. This identifier is set for all the dynamic routing protocols. The same ID must be specified in the other node in a high availability set up for graceful restart to work properly in the HA set up. |
| IPv6ospf restart grace-period <1-1800> | NS(config)# IPv6ospf restart grace-period 170 | Specifies the grace period, in seconds, for which the routes are to be preserved in the helper devices. Default value: 120 seconds. |
| IPv6 ospf restart helper max-grace-period <1-1800> | NS(config)# IPv6 ospf restart helper max-grace-period 180 | This is an optional command to limit the maximum grace period for which the Citrix ADC appliance will be in the helper mode. If the Citrix ADC appliance receives an opaque LSA with grace-period greater than the set helper max-grace-period, the LSA is discarded and the Citrix ADC is not placed in helper mode. |
| interface <VLANID> | NS(config)#interface vlan3 | Enters VLAN configuration mode. |
| ipv6 router ospf area |
NS(config-if)#ipv6 router ospf area 0 tag 1 | Starts IPv6 OSPF routing process on a VLAN. |
| exit | NS(config-if)#exit | Exits VLAN configuration mode. |
| router ipv6 ospf | NS(config)# router ipv6 ospf 1 | Starts IPv6 OSPF routing process and enters configuration mode for the routing process. |
| capability restart graceful | NS(config-router)#capability restart graceful | Enables graceful restart on the IPv6 OSPF routing process. |
| redistribute kernel | NS(config-router)# redistribute kernel | Redistributes kernel routes. |