PIM : How does a client discover multicast streams

multicast

I have a doubt about multicast.

Topology diagram

Multicast SEVER — R1 — R2 — R3 — PC1

From Above diagram , suppose PIM-SM is enabled on all the Routers and let us assume that R2 will be the RP.

If Multicast server sends a stream to 224.0.0.3 group , Then how does PC1 aware that it should join to that particular group .

Observations

For Example , If Multicast server sends "youtube" stream with some
video-1 , so when I type the same URL in my PC1 , how it can able to
covert that URL (youtube/video-1) to perticular multicast address ?

Who will do this conversions ?

Can anyone clarify this ?

Best Answer

The host queries a multicast catalog service to find a multicast stream (youtube video, iptv video, stocks notification service, whatever) which is mapped to that specific multicast group. The multicast catalog service is either hard-coded in the application itself, or selectable via application (say - browser) interface.

Related Solutions

PIM-SM multicast and HSRP/VRRP

PIM messages are not sourced from HSRP VIP's so the RPF check fails since the HSRP VIP is your RPF neighbor. There are two ways around this though.

Set up a dynamic routing protocol between your router and the other sides routers so HSRP is not needed.
Configure static mroutes to the other sides actual interface IP's such as:

ip mroute 0.0.0.0 0.0.0.0 1.1.1.1

Vlan – Setting up PIM Sparse mode

My questions are:

Should we setup on our core network switch OSPF with a router ID of 1.1.1.1 and then not set any OSPF settings on any other switch?

OSPF is not necessary for this implementation.

Would PIM Sparse Mode only need to be enabled on the core switches or on all of the switches in the network?

Pim-SM needs to be enabled on each L3 interface on which you want to allow the multicast traffic. For example, if you wish to contain the traffic to Vlans 15 and 14, you would have to do the following on your core:

configure
ip multicast
ip igmp
ip pim sparse
interface vlan 14
ip igmp
ip pim
interface vlan 15
ip igmp
ip pim
exit

If you want the traffic to traverse all Vlans, then you will need the appropriate interface configuration under each Vlan. Your L2 switches will need IGMP snooping turned on (ideally on all interfaces via the global configuration).

configure
ip igmp snooping 
bridge multicast filtering

For a very basic multicast setup like this, these should be the only features that you would need.