pimGroupMappingTable

DC-PIM-MIB · .1.2.826.42.1.1578918.5.71.1.1.1.13

Object

table
The (conceptual) table listing mappings from multicast group
prefixes to the PIM mode and RP address to use for groups
within that group prefix.
          
Rows in this table are created for a variety of reasons,
indicated by the value of the pimGroupMappingOrigin object.
          
-  Rows with a pimGroupMappingOrigin value of 'embedded' are
created by the router for each Embedded-RP group-to-RP
mapping which corresponds to a group for which the PIM
router maintains protocol state.
          
-  Rows with a pimGroupMappingOrigin value of 'config' are
created and destroyed as a result of configuration of
pimStaticRP[Multi]Table being created and destroyed.
Additionally, DC-PIM creates default rows in the
pimStaticRPTable table at startup to correspond to the
SSM ranges defined by IANA.  The administrator is
permitted to modify and destroy the SSM range
configuration.
          
-  Rows with a pimGroupMappingOrigin value of 'bsr' are
created as a result of running the PIM Bootstrap Router
(BSR) mechanism.  If the local router is not the elected
BSR, these rows are created to correspond to group
prefixes in the PIM Bootstrap messages received from the
elected BSR.  If the local router is the elected BSR,
these rows are created to correspond to group prefixes in
the PIM Bootstrap messages that the local router sends.
In either case, these rows are destroyed when the group
prefixes are timed out by the BSR mechanism.
          
Given the collection of rows in this table at any point in
time, the PIM mode and RP address to use for a particular
group is determined using the following algorithm.  This
algorithm has minor aspects which are specific to DC-PIM.
          
1) If the group corresponds to the well-defined prefixes of
link-local and unroutable group addresses, it cannot be used
as a PIM group.  There are no rows in the
pimGroupMappingTable corresponding to these prefixes.
          
2) If the group corresponds to the format defined in the
Embedded-RP mechanism [RFC3956] where the RP address is
embedded in the multicast group address, the RP address is
extracted from the group address and pimGroupMappingPimMode
is 'asm'.
          
3) From the set of all rows in the pimGroupMappingTable, the
subset whose group prefix contains the group in question is
selected.
          
4) If there are no such rows, the group cannot be used for
PIM.
          
5) If there are multiple selected rows, and a subset is
defined by pimStaticRP[Multi]Table (pimGroupMappingOrigin
value of 'config') with pimStaticRPOverrideSubranges /
pimStaticRPMultiOverrideSubrngs set to TRUE, then this
subset is selected.
          
6) From the selected subset of rows, the subset that has the
greatest value of pimGroupMappingGrpPrefixLength is
selected.
          
7) If there are still multiple selected rows, the subset
that has the highest precedence (the lowest numerical value
for pimGroupMappingPrecedence) is selected.
          
8) If there are still multiple selected mappings, and a
subset is associated with the BIDIR-PIM protocol rather than
the PIM-SM protocol, this subset is selected.
          
9) If there are still multiple selected mappings, the subset
with the numerically lowest priority vector is selected.
For a BSR mapping, the priority vector is simply the RP
priority; for a configured mapping, it is whether the RP is
unreachable, then the RP priority.
          
10) If there are still multiple selected mappings, the
algorithm specified by pimTmEntRPMultipathAlgorithm is used
to select one or more mappings - unless that mechanism is
disabled (via pimTmEntBsrRPMultipathMode for BSR mappings,
or via pimTmEntBidirDataMonitorEnable for BIDIR mappings).
          
11) If there are still multiple selected rows, the highest
RP address is selected.
          
12) The group mode to use is given by the value of
pimGroupMappingPimMode from the single selected row; the RP
to use is given by the value of pimGroupMappingRPAddress.
          
This table is not used by MGMD snooping or proxy (except in
the deprecated mode enabled by pimTmEntMgmdProxy).

Context

MIB
DC-PIM-MIB
OID
.1.2.826.42.1.1578918.5.71.1.1.1.13
Type
table
Status
current
Parent
pimTables
Siblings
22
Children
1

Syntax

No syntax metadata recorded.

Values & Constraints

No enumerated values or constraints recorded.

Related Objects

Sibling Objects
Child Objects