Relies on CPL means: Relies on L2 Hints and whether th

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Comparison of Link Identification schemes

• Objective Present the similarities and
  differences of the two schemes

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AFAIK

• Both solutions require all the routers to learn
  the set of all prefixes on the link.
• Both solutions use the set of all prefixes
  implicitly as the link identifier
• Primary difference is in the how it is
  represented in RA messages.

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Goals

• G1 Link identification and validate IP
  configuration
• G2 Minimal latency
• G3 False change detection should be avoided.
• G4 No undue signaling
• G5 Use existing signaling mechanism

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Goals (Contd.)

• G6 Use only link local scope signaling.
• G7 Compatible with SEND.
• G8 No new security vulnerabilities.
• G9 The nodes, such as routers or hosts,
  supporting DNA schemes should work appropriately
  with unmodified nodes, such as routers or hosts,
  which do not support DNA schemes.
• G10 Support nodes attached to multiple links.

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• Additional information

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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.
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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 links 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
  doesnt already know the Complete Prefix List (if
  not Landmarkyes). 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

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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 non DNA router starts on the
  same link

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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). The worst case scenario is if a link
  has one router, CompleteRA with SEND can only
  support 15 prefixes.

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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.