host
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... service, sufficient to
interconnect IPv6 routers (and even IPv6 hosts, in certain
situations). At the other extreme, NBMA networks ...
... NBMA architecture allows conventional
host-side operation of the IPv6 Neighbor Discovery protocol, while
also supporting the establishment of 'shortcut' NBMA ...
... For destinations not currently considered to be Neighbors, a host
sends the packets to one of its default routers.
...
...
Host-initiated triggering of shortcut discovery, regardless of the
existence of a packet flow, is also supported through specific
...
... flow, is also supported through specific
Neighbor Solicitations sent to a source host's default router.
...
...
The IPv6 stacks on hosts do not implement separate ND protocols
for each link layer technology ...
... IPv4 this required the definition of the Logical IP Subnet
(LIS) - an administratively constructed set of hosts that would share
the same routing prefixes (network ...
... LL). The goal is to allow both inter- and intra-LL neighbor discovery
to involve no changes to the host-side IPv6 stack for NBMA
...
... address to use as the better first hop, the associated
Neighbor Cache entry in the source host is updated and its
reachability set to STALE. Updating the cache ...
... VC was to the router, it may still be required by
other packets from the host that are heading to the router).
...
... Host-initiated shortcut request. ...
... Section 3.2.1 discusses flow-based triggers, section 3.2.2 discusses
the host initiated trigger, and section 3.2.3 discusses the use of
NHRP to discover mappings for IPv6 ...
... SHALL only track flows that originate from a directly attached
host (a host that is within the LL-local scope of one of the
router ...
... flows that originate from a directly attached
host (a host that is within the LL-local scope of one of the
router's interfaces ...
... Host Triggered Redirection ...
... host MAY also trigger a redirection to a transient neighbor.
To support host-triggered redirects, routers conforming to this
document SHALL recognize specific Neighbor Solicitation ...
... document SHALL recognize specific Neighbor Solicitation messages sent
by hosts as requests for the resolution of off-link addresses.
...
... unicast NS with shortcut limit option as a
request for a host-triggered redirect. However, actual shortcut
discovery is OPTIONAL for IPv6 routers.
...
... Redirect message identifying the router itself as the best
'shortcut', and return it to the soliciting host.
...
... The resulting Redirect message SHALL then be transmitted back to
the source host. When the Redirect message is received, the source
host ...
... host. When the Redirect message is received, the source
host SHALL update its Neighbor and Destination ...
... NHRP NAK or error indication is received for a host-triggered
shortcut attempt, the requesting router SHALL construct a Redirect
message ...
... Redirect
message identifying the router itself as the best 'shortcut', and
return it to the soliciting host.
...
...
Once flow detection has occurred, or a host trigger has been
detected, routers SHALL use NHRP ...
... flow that caused the trigger (or the target of
the host initiated trigger) is used as the target for resolution in a
NHRP ...
... validated by
the receiving host. Specifically, if the target of the resulting
short-cut is the destination host ...
... host. Specifically, if the target of the resulting
short-cut is the destination host then the ICMP Target Address
...
... Also note that egress routers may subsequently redirect the source
host. To do so, the Link Local ICMP Source Address ...
... NBMA address returned by the target host when the target host first
accepted the flow of IP traffic ...
...
When constructing an host-triggered NHRP resolution request in
response to a Neighbor Solicitation ...
... specified in the shortcut limit option included in the triggering
NS message. This ensures that hosts have control over the reach of
their shortcut request. Note that the shortcut limit given in the
option is relative to the requesting host ...
... hosts have control over the reach of
their shortcut request. Note that the shortcut limit given in the
option is relative to the requesting host, thus the requirement of
ar$hopcnt being smaller than the given shortcut limit.
...
...
A successful NHRP resolution reply for a host-triggered shortcut
attempt is translated into an IPv6 Redirect message ...
... NHRP Reply (this may include topology
changes, or a target host going down or changing identity). Any IPv6
...
... NHRP Purge
is received that invalidates information previously issued to local
host, the router SHALL issue a Router Redirect specifying the router ...
... token then one interface MUST choose another host-token. All
implementations MUST support manual configuration ...
... tokens MUST be 64 bits in length and formatted as
described in the following sections. The hosts tokens will be based
on the format of an EUI-64 ...
... A set of 2 or more 'virtual hosts' (vhosts) sharing a common
NBMA driver. Each vhost is free to establish IPv6 ...
... interfaces associated with different or common LLs. However,
vhosts are bound by the same requirement as normal hosts - no
two interfaces to the same LL can share the same interface ...
... differentiated by the LL's routing prefix. Thus, the host can re-use
a single unique interface token ...
... NBMA interfaces.
(Internally the host will tag received packets in some locally
specific manner to identify what IPv6 ...
... NBMA architecture allows conventional
host-side operation of the IPv6 Neighbor Discovery protocol, while
also supporting the establishment of 'shortcut' NBMA ...
... router based
flow detection, or host originated explicit requests. Neighbor
Discovery is used without modification for all intra-LL control
(including the initiation of NBMA ...
... C. Perkins, J. Bound, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)", Work in Progress ...
...
An IPv6 host performs address resolution by sending a Neighbor
Solicitation to the solicited-node ...
... Neighbor
Solicitation to the solicited-node multicast address of the target
host, as described in [7]. The Neighbor Solicitation message will
...
...
The solicited IPv6 host will respond to the Neighbor Solicitation
with a Neighbor Advertisement ...
...
To perform Router Discovery, an IPv6 host sends a Router Solicitation
message to the all-routers ...
... Neighbor Unreachability Detection (NUD) is the process by which an
IPv6 host determines that a neighbor is no longer reachable, as
described in [7 ...
... neighbors will be detected and handled through NUD. On each
attempt to send data from the IPv6 host to its neighbor, the node's
...
... NBMA driver
after again failing to setup the VC. The IPv6 host will therefore
never receive the solicited Neighbor Advertisements needed for
...
... deleted
from the Neighbor cache. The next time the IPv6 host tries to send
data to that neighbor, address resolution ...
... IPv6 neighbor is released, the next
time a packet is sent from the IPv6 host to the neighbor, the node's
...
... Duplicate Address Detection is performed on all addresses the host
wishes to use, regardless of the configuration mechanism used to
obtain the address ...
... node multicast address
corresponding to the host's tentative address (see 4.2. Joining a
Multicast Group ...
... tentative address (see 4.2. Joining a
Multicast Group). The IPv6 host initiates Duplicate Address Detection
by sending a Neighbor Solicitation ...
... Neighbor Solicitation to solicited-node multicast
address corresponding to the host's tentative address, with the
tentative address ...
... multicast address
corresponding to the tentative address, then the host will not
receive a Neighbor Advertisement containing its tentative address ...
... tentative address as
the target. The host will perform the retransmission logic described
in [9 ...
... Neighbor Solicitation. The processing will depend on whether or
not receiving IPv6 host considers the target address to be tentative.
...
... receiving IPv6 host's address is not tentative, the host will
respond with a Neighbor Advertisement containing the target address ...
... Neighbor Solicitation is the unspecified
address, the host sends the Neighbor Advertisement to the all-nodes
...
... IPv6 network
layer. The host performing DAD will detect that its tentative
address is the target ...
... receiving IPv6 host's address is tentative, then both hosts
are performing DAD using the same tentative address ...
... tentative address. The receiving
host will determine that the tentative address is not unique and
cannot be assigned to its NBMA ...
... IPv6 router uses a Redirect Message to inform an IPv6 host of a
better first-hop for reaching a particular destination, as described
...
... destination, as described
in [7]. This can be used to direct hosts to a better first hop
router, another host ...
... hosts to a better first hop
router, another host on the same LL, or to a transient neighbor on
another LL. The IPv6 ...
... The IPv6/NBMA driver of the IPv6 host that triggered the Redirect
will receive the encapsulated Redirect over one of it's pt-pt VCs ...
... node.
This allows NBMA hosts to be redirected off their LL to achieve
shortcut by using standard IPv6 protocols.
...
... destination as specified in the Redirect
message, but the next-hop will not be redirected to the source host.
Because no Neighbor Discovery takes place, the next-hop ...
... destination caches. However, it will continue to
transmit data back to the redirected host on the former path to the
redirected host. The next-hop ...
... transmit data back to the redirected host on the former path to the
redirected host. The next-hop node should be able to use the new VC ...
... administrator specifies the
type of autoconfiguration to use; the hosts on an LL receive this
autoconfiguration information through Router Advertisement messages ...
... IPv6 stateless address configuration is the process by which an IPv6
host autoconfigures its interfaces, as described in [IPV6-ADDRCONF].
...
... link-local address using Duplicate Address
Detection (DAD). If the IPv6 host detects that the link-local
address is not unique, the autoconfiguration process terminates. The
...
... link-local
address is not unique, the autoconfiguration process terminates. The
IPv6 host must then be manually configured.
...
...
After the IPv6 host determines that the link-local address is unique
and has assigned it to the interface ...
... and has assigned it to the interface on the Logical Link, the IPv6
host will perform Router Discovery to obtain auto-configuration
information. The IPv6 host ...
... IPv6
host will perform Router Discovery to obtain auto-configuration
information. The IPv6 host will send out a Router Solicitation and
will receive a Router Advertisement ...
... Router Advertisement, or it will wait for an
unsolicited Router Advertisement. The IPv6 host will process the M
and O bits of the Router Advertisement ...
... If there are no routers on the Logical Link, the IPv6 host will be
able to communicate with other IPv6 hosts on the Logical Link ...
... Link, the IPv6 host will be
able to communicate with other IPv6 hosts on the Logical Link using
link-local addresses ...
... layer address using Address Resolution. The IPv6 host will also
attempt to invoke stateful auto-configuration, unless it has been
explicitly configured not to do so.
...
...
An IPv6 host will invoke stateful auto-configuration if M and O bits
of Router Advertisements ...
... routers are present
on the Logical Link. An IPv6 host that is obtaining configuration
information through the stateful mechanism will hereafter be referred
to as a DHCPv6 client ...
...
An IPv6 host will be manually configured if it discovers through DAD
that its link-local address ...
... DAD
that its link-local address is not unique. Once the IPv6 host is
configured with a unique interface token ...
... routers will use the IGMPv6 protocol to periodically
determine group memberships of local hosts. In the framework
described here, the IGMPv6 protocols can be used without any special
...
... group
joined by the host. IPv6 hosts can also transmit a Group Membership
Report when the host ...
... IPv6 hosts can also transmit a Group Membership
Report when the host joins a new IPv6 multicast group. The Group ...
... An IPv6 host sends a Group Membership Reduction message when the host
leaves an IPv6 multicast group ...
... Group Membership Reduction is
sent to the multicast group the IPv6 host is leaving. The
transmission and receipt of Group Membership Reduction messages are
...
... forwarding of IPv6 packets in the absence of any other guidance
from the host.
...
... It is desirable for an IPv6/NBMA host to have some mechanism for
overriding attempts by 'the network' to optimize its internal
...
...
A non-zero FlowID might be assigned by the source host after
negotiating a preferred forwarding mechanism with 'the network' (e.g.
...
... through dynamic means such as RSVP, or administrative means).
Alternatively it can simply be assigned randomly by the source host,
and the network will provide default best effort forwarding (an IPv6 ...
... Description
The shortcut limit option is used by a host in a Neighbor
Solicitation message sent as a shortcut trigger to a default
router. It restricts the router ...
... targets
reachable via the specified number of hops. The shortcut limit is
given relative to the host requesting the shortcut. NS messages
with shortcut limit values of 0 or 1 MUST be silently ignored.
...