router
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... MLDv2. In
doing so, this document defines modifications to the host and router
portions of IGMPv3 and MLDv2 ...
... GMP
module on a host or router SHOULD have a configuration option to set
the SSM address range ...
... service, because an SSM-aware router (following the rules of this
document) will refuse to process the request, and the application
will receive no indication other than a failure to receive the
...
... version compatibility mode." This is an
exceptional (error) condition, indicating that the router(s) cannot
provide the SFGMP support needed for SSM ...
... SSM address range is changed
through configuration. A router should process such a record
according to the normal SFGMP ...
... SSM addresses, and an SSM-aware router will
ignore MODE_IS_EXCLUDE and CHANGE_TO_EXCLUDE_MODE requests in the SSM
...
... SSM range; thus, this
situation only occurs either if the router is not SSM-aware, or if
the host ...
...
In order to mitigate this problem, it must be administratively
assured that all routers on a given shared-medium network are
compliant with this document and are in agreement ...
... destination address. The transmission of such a
query likely indicates either that the sending router is not
compliant with this document or that it is not configured with the
same SSM ...
... SFGMP
protocol specifications a router would have no reason to send one,
the semantics of such a query ...
... semantics to it as described in this
section is described as an "SSM-aware" router. An SSM-aware router
...
... SSM-aware" router. An SSM-aware router
MAY have a configuration option to apply SSM semantics ...
... range.
This section documents the behavior of routers with respect to the
following types of SFGMP messages for source-specific destination
addresses ...
... SSM address range. A router SHOULD ignore a group record of either
of the following types if it refers to an SSM ...
... Filter-Mode-Change Record
A router MAY choose to log an error in either case. It MUST process
any other group records within the same report. These behaviors are
...
... range. This
specification does not explicitly prohibit such a message, although,
at the time of this writing, a router conformant to [IGMPv3,MLDv2]
...
... Queries are used within the source-specific
address range when a router receives a BLOCK_OLD_SOURCES Record for
one or more source-specific groups. These queries ...
... range could be sent by a non-SSM-aware host. A router SHOULD ignore
all such reports and specifically SHOULD NOT use them to establish IP
forwarding state ...
... IGMPv3,MLDv2]. A
router MAY log an error if it receives such a report (also a
MODIFICATION).
...
... querier election to a lower version
router must log an error, as specified by [IGMPv3,MLDv2].
...
... SSM-aware
host. A router SHOULD ignore all such messages in the source-
specific address range and MAY log an error (MODIFICATION).
...
... security
issues.
It is important that a router not accept non-source-specific
reception requests for an SSM destination address ...
... [IGMPv3] and [MLDv2] require a router, upon receiving such a
membership report, to revert to earlier version ...
... compatibility mode
for the group in question. If the router were to revert in this
situation, it would prevent an IGMPv3-capable host ...