changes to system-max command

Several changes have been made to the system-max commands in support of Multicast Multi-VRF.

The system-max pim-mcache command has been deprecated and replaced by the system max pim-hw-mcache command.

The following new runtime commands have been introduced:

max-mcache This command is described in the “Defining the maximum number of PIM cache entries” section.

ip igmp max-group-address This command, which is described in the “Defining the maximum number of IGMP group ” section, addresses replaces the system-max igmp-max-group-address command.