When SSM source and group filtering is enabled (that is, when pimInterfaceUseSsmSrcAndGrpFilt is 'true'), then for groups in the SSM space the local router will - process PIM (S,G) Join messages received on this interface only if the {source, group} pair is included in the extended access list corresponding to the list index value configured for this object - only send PIM (S,G) Join messages over this interface if the {source, group} pair is included in the extended access list corresponding to the list index value configured for this object. In other words, the extended access list is a whitelist of the SSM {source, group} pairs for which DC-PIM is permitted to request or receive traffic over the interface. pimInterfaceSsmSrcAndGrpFilter defaults to 0, which indicates that no access list is specified. If the index does not correspond to a valid access list, no {source, group} pairs will match the list and therefore all PIM (S,G) Join messages will be filtered. This field is only relevant for PIM-SM. It is ignored if 'sparse' is clear for pimTmEntMode.