70 likes | 162 Views
DNAO = ROOF ((17 (P – Conf) + 2)/8) * 8. Relies on Hints means: Requires L2 hints to be able to differentiate two links. Relies on CPL means: Relies on L2 Hints and whether the prefix list is actually complete. Footnotes.
E N D
DNAO = ROOF ((17 (P – Conf) + 2)/8) * 8 Relies on Hints means: Requires L2 hints to be able to differentiate two links. Relies on CPL means: Relies on L2 Hints and whether the prefix list is actually complete.
Footnotes • Identifier Choice: Indicates which device is in charge of coordinating the identifier or identifiers used for DNA. For the CompleteRA/Landmarks • LinkID chooses one out of all prefixes, as does landmark. CompleteRA uses all the prefixes, but the combined scheme, can use either. • With landmarks, the previous link’s prefix is included in the RS. It is possible in protocol-01, to send the RS without the last prefix, in which case, no landmark response is possible, but a completeRA may be sent. • Prefix Lists are built in draft-ietf-dna-cpl-01. Once all prefixes on the link are known, reception of RAs with no prefixes in the complete Prefix List indicate change of link. CompleteRA populates a prefix list immediately to make it complete. We assume here that Landmark/CompleteRA systems always send a completeRA if the host doesn’t already know the Complete Prefix List (if not Landmark=yes). In cases without CompleteRA, the procedures in the cpl draft must be relied upon to generate the Complete Prefix List. • Landmarks need a solicitation to indicate link change. CompleteRA and LinkID do not, and can just rely on comparison of received RAs to determine change
Footnotes • While this is related to the previous slide, this line was added to show that FastRA requires RS in any case. • Single RA refers to the fact that any single received RA can be used to determine if link change has occurred. • Here, ‘Relies on L2 hint’ indicates that distinguishing between a new router and a link change requires link-layer hint reception. This is the case where the new RA has no LinkID, even if the last RA did. For CompleteRA/Landmark, this assumes that the host has received a completeRA, and that any subsequent reception of an RA can be classified as a link change (if reliable L2 hints are in use, it works, as well as if there are hints from other sources such as L3 timers). • LinkID cannot determine immediately if there is a new router, or link change has occurred unless it already has a CPL. This also requires reliable L2 hints. CompleteRA is able to identify that change has occurred immediately, but without reliable L2 hints, may have spurious change detection when a router starts on the same link
Footnotes • RA messages from non-DNA routers become indistinguishable from link change unless reliable L2 hints are available in LinkID. CompleteRAs and Landmarks both learn about non-DNA routers’ prefixes. • CompleteRAs do not have an explicit bounded size, but Landmark answers can be sent even if all prefixes do not fit in one RA (To make a completeRA).
DNAO = ROOF ((17 (P – Conf) + 2)/8) * 8 Relies on Hints means: Requires L2 hints to be able to differentiate two links. Relies on CPL means: Relies on L2 Hints and whether the prefix list is actually complete.