IGMP Snooping

[6gnet]

Eric,

Were you able to replicate this ?

-Gregg

[Eric Stern]

I could not. But I don't have a Juniper router. So I tested it as described with the router and of course it seemed to work fine.

Can you duplicate it without the router?

[6gnet]

Yes I can:





Firmware Version
1.3.8


Board Rev
E







Multicast Source (laptop: 10.21.0.1) -(port 6, vlan121 untagged)-> WS-6-POE
WS-6-POE -(port 5, vlan 121 untagged)-> laptop running tcpdump
WS-6-POE -(port 3, vlan 121 untagged)-> laptop running VLC

IGMP Snooping off (as expected multicast stream goes to all ports):





21:12:52.863215 3c:07:54:56:f0:dc > 01:00:5e:02:2b:16, ethertype IPv4 (0x0800), length 60: (tos 0x0, ttl 1, id 59129, offset 0, flags [none], proto IGMP (2), length 32, options (RA)) 10.21.0.56 > 239.2.43.22: igmp v2 report 239.2.43.22

21:12:57.867177 3c:07:54:56:f0:dc > 01:00:5e:00:00:02, ethertype IPv4 (0x0800), length 60: (tos 0x0, ttl 1, id 59502, offset 0, flags [none], proto IGMP (2), length 32, options (RA))

10.21.0.56 > 224.0.0.2: igmp leave 239.2.43.22



21:12:57.875321 04:18:d6:c3:de:0e > 01:00:5e:02:2b:16, ethertype IPv4 (0x0800), length 60: (tos 0xc0, ttl 1, id 60185, offset 0, flags [none], proto IGMP (2), length 32, options (RA))

10.21.0.1 > 239.2.43.22: igmp query v2 [gaddr 239.2.43.22]







IGMP Snooping on (only 3c:07:54:56:f0:dc [the laptop playing using VLC] should receive the stream, however the second laptop connected [running tcpdump] also receives it as if IGMP snooping was never enabled):






21:13:51.918599 3c:07:54:56:f0:dc > 01:00:5e:02:2b:16, ethertype IPv4 (0x0800), length 60: (tos 0x0, ttl 1, id 55884, offset 0, flags [none], proto IGMP (2), length 32, options (RA)) 10.21.0.56 > 239.2.43.22: igmp v2 report 239.2.43.22


21:13:58.923519 3c:07:54:56:f0:dc > 01:00:5e:00:00:02, ethertype IPv4 (0x0800), length 60: (tos 0x0, ttl 1, id 1579, offset 0, flags [none], proto IGMP (2), length 32, options (RA))

10.21.0.1 > 239.2.43.22: igmp query v2 [gaddr 239.2.43.22]

21:14:02.419184 04:18:d6:e8:c8:b6 > 01:00:5e:00:00:01, ethertype IPv4 (0x0800), length 60: (tos 0xc0, ttl 1, id 0, offset 0, flags [DF], proto IGMP (2), length 32, options (RA))
0.0.0.0 > 224.0.0.1: igmp query v2



With IGMP Snooping enabled I dont see any queries coming from the switch mac address at all.



-Gregg

[6gnet]

So here's what I gathered

IGMP snooping works as expected IF:
1. Managment vlan (105) untagged on all ports
2. Data vlan (121) tagged on all ports
3. Multicast traffic is on Managment VLAN

IGMP Snooping works

IGMP snopping does NOT work (multicast goes to all ports) IF:
1. Managment vlan (105) tagged on all ports
2. Data vlan (121) untagged on all ports
3. Multicast traffic is on Data VLAN

IGMP Snooping does NOT work

[sirhc]

Please upgrade to v1.3.9 which is current firmware or preferably v1.4.0rc16 and confirm this is still an issue.

[6gnet]

Yes, it's the same case on 1.3.9 and 1.4.0rc16

Also in this configuration:

with IGMP Snooping enabled and multicast on Managment vlan (105), no multicast is ever forwarded

One more thing I noticed was that in the "working scenario" where multicast is on Managment vlan with all ports untagged, I do see IGMP queries coming from the switch IP address.

In any other cases, no IGMP queries are seen on connected laptops....

So I thought perhaps the IGMP snooping requires an IP address configured on the Data vlan and so I've added an IP address in the watchdog ip configuration (vlan tab) but that did not make any difference either....

I hope you guys get it fixed as it would be a shame to replace quite few Netonix switches just to get IPTV working...

-G

[6gnet]

One more possible issue (seems very odd to me):

With single management vlan, all ports untagged IGMP snooping is working but there's a strange behavior:

How to replicate:

1. On laptop1 play stream 239.0.0.1
2. On laptop2 play stream 239.0.0.2

Switch statistics report that everything is ok, same on tcpdump

3. Stop stream 239.0.0.2 on laptop2
4. Start stream 239.0.0.1 on laptop2

Switch statistics report that everything is ok, same on tcpdump

5. Stop stream 239.0.0.1 on laptop 2 (remember that laptop1 is also playing 239.0.0.1 stream during this time)
6. On laptop 2 I see IGMP leave followed by IGMP query which is normal
7. There's no more IGMP report which normal, however....

On laptop 2 stream 239.0.0.1 stops as it should for about 3 secs and then resumes without any IGMP report packets.
The switch continues to forward the stream to laptop 2 even though it should not.
Looking at statistics this incorrect forwarding is not continuous (it's being forwarded for quite few secs, then stops for about 0.5sec then continues again) and looking at the traffic dump, there are no more IGMP packets for this stream.

Stopping and starting the 239.0.0.1 stream on laptop1 fixes the issue for that particular stream.

-G

[Dave]

thanks for the detailed investigation & reporting...we will figure it out.

[gunther_01]

Does anyone know if multicast has been fixed properly in more current versions. Like 1.4.7 or even 1.4.8rcX?

[Eric Stern]

We are not aware of any issues with multicast. It would be best to try the latest version and see which is v1.4.8rc7.