Multicast in one VLAN

Question

I need to receive multicast traffic over L2 segment on my client machine. But for some reason I am unable to do it.

To my understanding with such scheme I should receive traffic if inbetween Juniper IPTV and Qtech 2800 Client there is no igmp snooping configured in 911 VLAN (to exclude incorrect mrouter configs). And there is none. Furthermore, I can receive IGMP Membership Query and my Client host sends Membership reports back.

If I connect to the access port on Juniper IPTV directly (group 235.27.21.1), I can see IPTV stream. Can't quite wrap my head around this problem, cause I am new to multicast in general.

Bellow is igmp configuration of Juniper IPTV

protocols {
    igmp-snooping {
        vlan all {
            interface ge-0/0/17.0 {
                static {
                    group 235.27.11.0;
                    group 235.27.12.0;
                    group 235.27.21.0;
                    group 235.27.22.0;
                }
            }
        }
    }

Answer 1

I should receive traffic if inbetween Juniper IPTV and Qtech 2800 Client there is no igmp snooping configured.

You would have to make absolutely sure that this (igmp snooping disabled) is the true for all switches along the path. As long as it's not fully disabled on any of the switches, and just one fails to detect the presence of an igmp querier (i.e. has no mrouter port), it will not forward mcast traffic.

Your understanding is basically correct, but...

... remember, that with IGMP snooping disabled, switches are treating multicast as if it were broadcast ("flooding"). This might seem OK at first, but has some risks. For example: If you just add one more port in VLAN 911 from any of the aggregation switches (possibly even inadvertedly, when doing 802.1q trunking and not excluding vlan 911 from that new trunk), that port might get hammered with vlan 911's full multicast load (all streams being sent from the iptv source)

Furthermore, I can receive IGMP Membership Query and my Client host sends Membership reports back.

What now - at first, you seem to aim for IGMP snooping disabled, but then speak of IGMP membership queries and responses? That makes little sense.

IGMP snooping was invented for exactly this purpose: To allow (Layer2-)Switches to be efficient in multicast forwarding (in extenso: only replicate traffic out through switch ports beyond which a receiver has signalled interest for a given group), and not having to fall back to broadcast-like flooding of multicast.

To work properly, IGMP snooping needs an IGMP querier in the given broadcast domain.

Normally, a multicast enabled router would take this role, but L2-only multicast deployments usually don't have one (well, obviously). So the IGMP Querier feature can jump in. Check you vendor's documentation how to enable the IGMP Querier feature for the given VLAN. Usually, switches can do this, but theres other ways (small old router-on-a-stick, IP TV source itself acting also as IGMP Querier...)