Neighbor discovery protocol
In an IPv6 network, Citrix SD-WAN appliances periodically multicast router advertisement messages to announce their availability and convey information to the neighboring appliances in the SD-WAN network. The router advertisements include the IPv6 prefix information. Neighbor Discovery protocol (NDP) running on Citrix SD-WAN appliances use these router advertisements to determine the neighboring devices on the same link. NDP also determines each other’s link-layer addresses, finds neighbors, and maintains active neighbors reachability information.
To configure the NDP router advertisement, navigate to Configuration > Advanced Settings > NDP and click + NDP.
Choose one of the configured virtual interfaces from the Virtual Interface drop-down list. Select Enable Advertisement to enable sending periodic router advertisements and responding to Router Solicitations for the selected virtual interface.
Specify the maximum, minimum, and router lifetime intervals.
- Max Interval: The maximum time (in seconds) allowed between sending periodic unsolicited multicast router advertisements.
- Min Interval: The minimum time (in seconds) allowed between sending periodic unsolicited multicast router advertisements.
- Router Lifetime: The time (in seconds) the router is considered valid by the hosts. 0 indicates the router cannot be used as the default router
Select Managed Flag if IP addresses are available through the DHCPv6 protocol. Select Other Flag if the configuration information (other than the IP addresses) is available through the DHCPv6 protocol.
Specify the following values for the selected interface.
- Link MTU: The recommended Maximum Transmission Unit (MTU) for the interface.
- Reachable Time: The time (in milliseconds) the NDP protocol stays in the Reachable state.
- Retransmit Timer: The time (in milliseconds) between retransmission of Neighbor Solicitation messages when resolving an IP address or probing a neighbor.
- Hop Limit: The maximum number of hops to be included in the router advertisement.
Click +Prefix List and enter the following values:
- Prefix: The prefix and prefix length in Classless Inter-Domain Routing (CIDR) notation.
- Valid Lifetime: The time in seconds up to which the prefix is valid. -1 represents infinity which means the prefix remains forever.
- On-link: When selected the prefix is considered as local to the network.
- Autonomous Flag: When enabled the prefix is used by the host’s Stateless Address Autoconfiguration (SLAAC) to generate the IP address.
- Prefix Lifetime: The time (in seconds) up to which the prefix is considered as preferred.