Static hosts also need to resolve the default gateway and MAC to forward traffic. Static hosts can learn the BNG MAC using the following methods.
If the static host can use the BNG link-local as the default gateway, then the exchange of router solicit and advertisement should be able to populate the default route for the static host.
If the static host can use the BNG link-local as the default gateway but only through neighbor solicit, the BNG responds to NS only if the source address is the GUA of the host.
If the static host can only use a GUA as the default gateway, then the subscriber interface must be configured with an IPv6 address instead of a prefix.
A host’s RS or NS messages may use link-local as the source address. The host’s link-local addresses are unknown to the BNG, because the BNG only knows static hosts by their GUA. By default, unknown host’s RS or NS messages are dropped. Therefore, static hosts cannot resolve their default gateway or MAC address. There are two different methods to enable the BNG to respond to static host’s RS or NS messages. The first solution is to declare the SAP as a single-mac. When a SAP is configured as a ‟single-mac”, it is declaring that only a single host is expected on the SAP and any RS or NS sent by the host automatically populates the MAC table. The BNG in return also responds to the static host’s RS or NS. The second solution is for cases where multiple hosts are on the SAP. The RS or NS may not provide enough information to populate the subscriber host’s MAC because the source IP are link-local addresses. The BNG anti-spoof only replies to known hosts RS or NS; therefore, these static hosts’ RS or NS are dropped. The group interface has a configuration option to auto-reply to any RS or NS, which allows the static host to resolve their default gateway or route. Afterwards, the static host can send traffic to the BNG, which the BNG can use for MAC learning. To use data packets for MAC learning, the BNG has a ‟data-trigger” learning option for static hosts.