NHRP
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... [3]). More recently the ION working group has developed NHRP (Next
Hop Resolution Protocol [8]), a general protocol for performing
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... each Link. The MARS and NHRP protocols are NOT necessary, since
multicast and broadcast operations collapse down to an NBMA ...
... the host initiated trigger, and section 3.2.3 discusses the use of
NHRP to discover mappings for IPv6 targets in remote LLs.
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SHALL utilize NHRP as described in section 3.2.3 to ascertain a
better first-hop when a suitable flow is detected, and
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A suitable NHRP Request is constructed and sent as described in
section 3.2.3. The original NS message SHOULD be discarded.
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... host trigger has been
detected, routers SHALL use NHRP in an NHS to NHS mode to establish
the IPv6 to link ...
... Construct NHRP Requests and Replies.
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... Forward NHRP Replies towards an NHS that is topologically closer
to the requester.
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... Perform syntax translation between inbound NHRP Replies and
Redirects.
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... host initiated trigger) is used as the target for resolution in a
NHRP Request. The router then forwards this NHRP Request to the next
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... NHRP Request. The router then forwards this NHRP Request to the next
closest NHS. The process continues (as it would for normal NHRP)
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... router then forwards this NHRP Request to the next
closest NHS. The process continues (as it would for normal NHRP)
until the Request reaches an NHS that believes the IP target ...
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As NHRP resolution requests always follow the routed path for a given
target protocol address, the scope of a shortcut request will be
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... The last hop router SHALL resolve the NHRP Request from mapping
information contained in its neighbor cache for the interface ...
... router SHALL perform Neighbor
Discovery on the local interface, and build the NHRP Reply from the
resulting answer. (Note, in the case where the NHRP Request
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... local interface, and build the NHRP Reply from the
resulting answer. (Note, in the case where the NHRP Request
originated due to flow detection, there must already be a hop-by-hop ...
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The NHRP Reply is propagated back to the source of the NHRP Request,
using a hop-by-hop path as it would for normal NHRP ...
... flow detection at the
originating router, the return of the NHRP Reply results in the
following events:
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The following translation rules are meant to augment the packet
format specification in section 5 of the NHRP specification [8],
covering those packet fields specifically utilized by the IPv6 ...
... protocol addresses in the common header or CIE of a NHRP message are
always IPv6 addresses of length 16.
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When constructing an host-triggered NHRP resolution request in
response to a Neighbor Solicitation:
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... The Flags field in the common header of the NHRP resolution
request SHOULD have the Q and S bits set.
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When constructing a NHRP resolution request as a result of flow
detection, the choice of values is configuration dependent.
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A successful NHRP resolution reply for a host-triggered shortcut
attempt is translated into an IPv6 ...
... NHRP extensions currently defined in [8] have no effect on
NHRP/ND translation and MAY be used in NHRP messages for IPv6 ...
... NHRP Purge rules. ...
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Purges are generated by NHRP when changes are detected that
invalidate a previously issued NHRP Reply (this may include topology ...
... Purges are generated by NHRP when changes are detected that
invalidate a previously issued NHRP Reply (this may include topology
changes, or a target host ...
... issued Neighbor Advertisements or Router Redirects. If a NHRP Purge
is received that invalidates information previously issued to local
host ...
... Routers SHALL keep track of Neighbor cache entries that have
previously been used to generate an NHRP Reply. The expiry of any
such Neighbor cache entry SHALL result in a NHRP ...
... NHRP Reply. The expiry of any
such Neighbor cache entry SHALL result in a NHRP Purge being sent
towards the router that originally requested the NHRP ...
... architecture introduces no new protocols, but depends on
existing protocols (NHRP, IPv6, ND, MARS ...
... Luciani, J., Katz, D., Piscitello, D. Cole B and N. Doraswamy, "NBMA Next Hop Resolution Protocol (NHRP)", RFC 2332prop, April 1998. ...
... NHRP also provides mechanisms for adding optional TLVs to NHRP
Requests and NHRP Replies. Future developments of this document's
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... TLVs to NHRP
Requests and NHRP Replies. Future developments of this document's
architecture will require consistent QoS ...
... QoS extensions to both ND and
NHRP in order to ensure they are semantically equivalent (syntactic
differences are undesirable, but can be tolerated).
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... MARS control
messages share the same TLV extension mechanism as NHRP, allowing QoS
extensions to be developed as needed.
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