FreeBSD has added GRAND, a mechanism in which a host proactively tells the router its IPv6 and link-layer addresses. This removes address resolution from the critical path of the first packet.
To do this, the author added queueing and delayed transmission of Neighbour Advertisements, messages that map an IPv6 address to a link-layer address. Delaying several advertisements helps avoid an unnecessary traffic burst.
Claim check:
- The author implemented GRAND in FreeBSD. (confirmed by the publication itself: evidence; «GRAND fixes that asymmetry by making the host proactively advertise its address, and I implemented that mechanism in FreeBSD.»)
- In GRAND, a host proactively tells the router its IPv6 and link-layer addresses. (confirmed by the publication itself: evidence; «Gratuitous Neighbour Discovery changes the direction of information flow so that instead of waiting for the router to discover the host when the first packet arrives, the host proactively announces its IPv6 address and link-layer address using an unsolicited Neighbour Advertisement.»)
- GRAND removes address resolution from the critical path of the first packet. (confirmed by the publication itself: evidence; «This means that GRAND removes address resolution from the critical path of the first packet without claiming that the neighbour has been permanently verified as reachable.»)
- The implementation added queueing and delayed transmission of Neighbour Advertisements. (confirmed by the publication itself: evidence; «The existing implementation did not previously provide the queueing and delayed-transmission machinery needed for these behaviours. Implementing GRAND required adding that infrastructure and then using it to schedule unsolicited Neighbour Advertisements.»)
- Delaying several advertisements helps avoid an unnecessary traffic burst. (confirmed by the publication itself: evidence; «Sending all advertisements immediately could create an unnecessary burst.»)
Primary sources:
score 63.4 out of 100 · kind: guide