How to test multicast?

Question

Computer networks

A question for networkers. What are the multicast testing methods (IPTV)? I will give more specific questions:
1) How does mtrace work, what can be taken from its output?
2)How ping 239.0.0.2 works. That is, I am pinging a multicast group. Am I pinging everyone who subscribes to this group? And what should I get from them.
3) Are there any tools for evaluating the quality of multicast? Purely visually, when viewing iptv through a chain of routers, the sound is interrupted from time to time. Is it possible to somehow evaluate where the plug is?
For clarity, I will give a picture. It would be great if someone helped to deal with the questions posed in the example below.

Maybe you can help me deal with such issues as checking a specific channel (for example, 226.0.0.5) for operability, identifying bottlenecks due to which multicast may not work correctly. All equipment on the diagram is Cisco and Huawei, L3 switches. Routing uses PIM, OSPF.
PS If you collectively help me figure it out, I'll make it into a separate post.
Thanks in advance.

Answer 1

How does mtrace work, what can be taken from its output?

learningnetwork.cisco.com/thread/26882

How ping 239.0.0.2 works

A banal icmp echo is sent to the group. Recipients, if possible, respond with a reply where source IP equals the interface address. The sender of echo, upon receiving such a reply, displays the addresses of the senders of the reply.
Speaking of ciscos: if you configured “ip igmp join-group 239.0.0.2” on int vlan, then if PIM is configured correctly, the cisco will respond to a ping to this group from the other end of the network. And most likely, if IGMP is not messed up, any host in this VLAN will be able to listen to the group. This is a great preliminary check. If it fails, then you definitely have a problem.
I am not responsible for other vendors.

how to check a specific channel (for example 226.0.0.5) for operability

Ping is a fundamental sanity check. And then, to understand how SPT is built, go through the pieces of iron and see what's there with show ip mroute.
And yes, if you are testing IPTV, then the final stage of testing should be the same VLC or a real application. With IGMP and PIM status checking during broadcasts.
And in no case do not introduce multicast into production without getting a full understanding of what PIM, IGMP options are, how to debug and troubleshoot them.

Answer 2

It never occurred to me to ping multicast)
In general, to test multicast in my channels, I used two things:
a) VLC player for video stream + receiving it
; b) McastReceiver and McastSender utilities.

Answer 3

It looks like I have network losses. In more thorough testing, I found it often with a loss of 0.015% on UDP, 20MB. Campaign affects the quality.

Answer 4

www.bridgetech.tv/product_VB20.php The piece of iron is
expensive of course, but very convenient.