Hello Nipun
In the Cisco IOS implementation of PIM, each multicast group individually operates in one of the following modes: dense mode, sparse mode, or bidirectional mode. Groups in sparse mode (PIM-SM) or bidirectional mode (bidir-PIM) use RPs to connect sources and receivers. All routers in a PIM domain need to have a consistent configuration for the mode and RP addresses of the multicast groups.
The Cisco IOS software learns the mode and RP addresses of multicast groups through the following three mechanisms: static group-to-RP mapping configurations, Auto-RP, and bootstrap router (BSR). By default, groups will operate in dense mode. No commands explicitly define groups to operate in dense mode.
The above is taken from this Cisco command reference for the ip pim rp-addresscommand.
Therefore, BSR should be capable of informing neighboring routers of the BIDIR mode when using BSR.
In the lesson, the RP was defined statically, and the bidir keyword was available. I went into the lab to check this out fpr BSR, and found that I had the bidir keyword available. Specifically:
R1(config)#ip pim rp-candidate gigabitEthernet 0/0 ?
bidir Group range treated in bidirectional shared-tree mode
group-list group-list
interval RP candidate advertisement interval
priority RP candidate priority
<cr> <cr>
The rp-candidate keyword is that used to indicate that BSR is employed.
Similarly, if you were to employ AutoRP, you have the bidir option available too.
R1(config)#ip pim send-rp-announce gigabitEthernet 0/0 scope 10 ?
bidir Group range treated in bidirectional shared-tree mode
group-list Group access-list
interval RP announcement interval
<cr> <cr>
Keep in mind that the bidir keyword is only available if BIDIR-PIM is enabled using the global ip pim bidir-enable command.
I hope this has been helpful!
Laz