IGMP snooping Puns

Could I cause impact to the active joins if I active IGMP Snooping for a VLAN?

I testing with an active join with low amount of traffic and I didn't notice any issue, I'd expected a join loss until receiver ask for a new join.

Now I should implement IGMP Snooping on VLANs with several joins and big amount of traffic.

Hey everyone , apologies if this a newbie question . I was lucky enough to get an early access dream router and looking forward to use it with my fiber connection (when it arrives that is). I have tv and a phone line through my ISP (KPN) . From what I’ve read in order to make the tv play nicely with any non-isp router it needs to support IGMP snooping . I know that the dream machine (non pro) doesn’t support that so the question is what about the dream router ? If not will the addition of a edgerouter x before the dream router be an alternative solution ?

Over the past few months, I've been moving my smart home over to Homekit from Google. I have a lot of devices, including 2 Apple TVs, 7 Homepods, and about 50 other devices on my network. I've been using my trusty TP Link Archer 5400X Tri-band router, and I've been battling to get rid of that dreaded "No Response" in the Home app. I've tried quite a few things, but it was always hit or miss. I'd tell Siri to turn something off, and it would respond that the device wasn't responding, but it would work.

My wife was getting tired of it being unreliable, so I was close to pulling the trigger on a new router. I decided to try one more thing before dropping some coin on a new one:

Enabling IGMP Snooping.

Now, your mileage may vary, but this one setting has been THE setting that woke everything up for me. After enabling this setting, and restarting everything, I haven't seen a "No Response" since. Everything is running faster, automations happen instantly, like they are supposed to. It seems that all my devices were basically flooding my network with needless traffic, causing those timeouts.

Again, your experience might differ. I've seen a lot of people saying that disabling it on Unifi switches helped them, but on my TP Link, ENABLING it has worked wonders.

Have been dealing with “No Response” intermittent issues with a fairly basic home UniFi network setup, particularly with Logi cams. Recently discovered a setting on the LAN called “IGMP Snooping” which was enabled. This setting tries to intelligently limit where multicast packets are sent. Multicast packets seem to be an important part of HomeKit networking and occasionally the UniFi switch/router was incorrectly filtering packets. After disabling the setting, in the last 7 days, I haven’t had any “No Response” issues. Hope this tip helps!

Hey all. Just wondering if there are any disadvantages to leaving IGMP snooping enabled on a converged Dante network (say 6-8 Dante devices + amplifier and system processor control) that most of the time consists entirely of unicast subscriptions but may occasionally need to make a few multicast subscriptions? Thanks in advance!

I'm trying to setup multiple switches in the network with the main switch behind the router beeing a managed switch (Zyxel XGS1210-12) and connected to the main switch are multiple clients aswell as 3 smaller, unmanaged switches (tp-link TL-SG108) with clients connected to them. Since basically every client is going to use IPTV, i wanted to make sure that IGMP snooping worked on all levels throughout the network and not just from one switch to the next or something. This is kind of new territory for me so any help would be appreciated.

EDIT: I can include a picture of the setup if the description is unclear. Just wasnt sure about the rules to include links, thats why i left it out for now.

At work we configured some equipment with igmp snooping, multicast routing, and many more things, I always look to learn new tings specially in the networking aspect. I haven't found any chapters or books on how to configure this and learning how it works. Is there a cert that touches this subject?

Hi

Is it normal that IGMP snooping doesn't work (well) with ipv6 router advertisements (radvd)?

For the last days I was looking into a problem with the IPv6 default route expiring on my client, and after a lot of experimenting with configuration changes on my client and gateway I found out that it's my CRS326 with activated IGMP snooping who blocks the periodical Router Advertisement messages from the gateway.

Is there an option on the switch that I would have to change / set the right way for this to work, or should I simply do without IGMP snooping (I only activated it because of multicast IPTV which I only rarely use)?

Thanks!

I have two USW-Flex-Mini switches that I need to switch out for a different device that has IGMP snooping capability. I want to make sure I avoid any switches that don't have this functionality but could not find a definitive list. Which UniFi devices, other than the Flex Mini should I avoid?

I am a Valcom Intercom Technician, we have a local High School as a customer. The remote network cards keep dropping multicast. It seems to work fine for months but then it always quits. I'm not sure what to tell the head of IT. Honestly, I'm not sure if its my equipment or his network. All I know is every time I bring the two cards together and patch them with a crossover they work fine.

I have heard that one of the two types of IGMP could be the problem... Is there one method that stays enabled, wether or not multicast traffic detected? I think this is the root of my issue. I've noticed a pattern that if the school is on break for a while, then comes back the cards never seem to work. I have to come out on site and power reset them. Is the network disabling multicast traffic because it's not being used at that time?

Any help will be appreciated. Thanks

Hi all, We’ve purchased a new redundant NAS storage system and the vendor has asked that we configure as follows:

“Multicast must be permitted on Storage VLAN that the NAS servers communicate on. IGMP Snooping must be either disabled OR if enabled, must have a querier”

I’m running HSRP on this VLAN and also using VPC to connect between our two Nexus 93180YC-FX’s switches and the NAS servers.

If I disable the igmp snooping on just the storage VLAN is this goes to adversely affect HSRP or VPC?

Thanks all!

Hi guys, i have been reading for a while but i have a question before buying an Ubiquiti switch.

Situation now: netgear 16 port switch, managed, IGMP Snooping enabled. This works flawless with iptv from KPN (Netherlands).

The switch is getting old, some leds dont light up anymore while connected with an utp cable. It still works but its irritating me that some leds dont work anymore.

Situation that im looking for: Ubiquiti 24 ports gen 2 (maybe with Poe).

I see people struggling with Json config files etc. I try not to use this configs, isnt there a igmp snooping function on the switch?

Thanks in advance!

Tim

Does igmp snooping do anything if the multicast source and receiver hosts are connected to the same layer 2 vlan?

I know igmp snooping limits the flood of multicast out all ports on a layer two segment, but isn’t it based on a multicast router being present? If you’re not running pim and not routing multicast across networks, then does enabling igmp snooping on the switch even do anything? The white paper on the matter says the switch monitors for igmp join group messages going to the multicast router. So now I’m wondering without said multicast router will this still work?

I have a device that requires broadcast traffic for the controller to be setup. However this device is on a different vlan than the controller software.

vlan 1 - controller vlan 2 - controller

I enabled IGMP Snooping on both vlans (Cisco SG500) Both vlans connect to an ISR 4451 through a trunk.

I assume I have to enable something on the two interfaces on the router.

I have not really done anything with Multicast Routing before so any help would be appreciated. I have found some cisco articles but I don't quite understand what this could possibly break.

Any thoughts advice would be great.

the hAP ac2 is the router connected to internet and the switch is a CSS326 connected to devices and also a Unifi Flex HD.

For proper configuration of IGMP multicast, should I be enabling IGMP snooping on the switch, router(under bridge), or just on the switch alone?

My understanding is the switch should be the main IGMP querier, but not sure if the ac2 will properly forward IGMP packets if the option isn't enabled.

with IGMP enabled I do see the IGMP list populated properly in the CSS326 SwOS panel.

thanks for the help in advance!

Does turning on snooping with UniFi also turn on a querier or do we need to bring our own querier to the party?

Can someone help explain to me why both these options should not be turned on for switching?

In reference to:

Note that "Switch > Switch Settings" Page, shows that both "IGMP Snooping" and "Flood unknown multicast traffic" Options are enabled. This makes the network vulnerable to Multicast and broadcast storms. You should disable one of these options.

Hey!

Looking for a not-too-expensive 8-10-port switch which can supply active PoE on at least 4 ports, and that supports IGMP-snooping. I'd also like it to be fan-less or at least not use the fan during normal operations.

I currently have a Cisco SG110D-08HP which is almost perfect, except that it lacks IGMP-snooping. The IPTV packets flood the network when we're watching TV. Possibly not a huge performance issue, but it annoys me :-)

Any good tips for a similar switch with IGMP snooping?

I'd prefer to stick with Cisco or possibly Ubiquiti. Can Ubiquiti switches persist these kind of configuration options across reboots, without the controller being present?

I've looked at for example Cisco SG350-10MP 10-Port, but I'm struggling to find out whether it has a fan or not.

So let's say I'm using ISP provided router that has iptv and internet on the same subnet/network. Now I know that I shouldn't use unmanaged switch to connect both internet and iptv but what about using one switch purely for internet and other one for tv? I think that should solve the problems without configuring igmp snooping am I right?

I realize this post may violate Rule #1 as it has to do with a network I use in my "home" but regardless I am posting as I hope this may eventually help someone else in a similar situation as I have been unable to find *any* information on this topic as it has to do with Aruba switches that are EOL/EOS.

I have a pair of switches, Aruba S2500 and S3500 connected via a LACP Port channel. Plugged into the S2500 is a TiVO DVR and into the S3500, is a pair of "TiVO MINI" boxes that rely on multicast to work properly it seems.

Anyway, to cut to the chase: The Aruba S2500 and S3500 seem to come with IGMP Snooping enabled by default on VLAN1. I've spent *hours* reading through crappy HP documentation for newer models of Aruba switch that does not match the commands for the S3500 nor the S2500 since these are "end of support" devices HPE no longer even has configuration PDFs available from what I can tell.

The issue is: If I disable IGMP Snooping v3 and then turn it back on, the TiVO Mini boxes connect, and they can pick up the stream from the main DVR on the 2500. However, after a short while, they stop streaming and it seems the only solution is to remove the IGMP VLAN Policy from VLAN 1 and then re-add it, and Bam, it starts working again for a short while.

Is there a way to completely disable IGMP Snooping? should I be configuring it differently? I'm sure I'm overlooking something simple, but it seems setting the policy to "no snooping" and "no snooping v3" turns it off, but again, the "Mini" boxes cannot connect until I turn it on and wait for the IGMP table to show data again.

Does anyone have documentation and/or a configuration guide on IGMP for the Aruba 2500/3500 series? or any info on how to work around this?

Thanks.

EDIT: In case this helps, here is the output of the current IGMP Membership:

-----------------------------------------------------------------------------------------

(ArubaS2500-1) #show igmp-snooping membership

IGMP Snooping Multicast Membership

----------------------------------

VLAN Group Port Expiry UpTime

---- ----- ---- ------ ------

0001 224.0.0.251Pc1 00:00:00 12:02:22

0001 224.0.0.252Pc1 00:00:00 12:02:22

0001 224.0.0.253Pc1 00:00:00 12:02:23

0001 233.89.188.1Pc1 00:00:00 12:27:17

GE0/0/0 00:02:19 12:27:17

0001 [239.255.

Hi,

I have a good understanding of basic networking, vlans, etc. I have a very simple setup with an ISP modem/router huawei hg8245h, unifi Switch and 2 AP Lite.

I have 3 IPTVs on the network. When I turned on igmp snooping in the switch, the cable went down and after checking some logs, the packets were getting discarded of some sort. I know what igmp does and it's supposed to be great for video and streaming, basically multicast.

Had this happened to someone, because unifi support is not much help really.

Background: Resilient Ethernet Protocol (REP) on Cisco IE5000 switches with IGMP snooping enabled on all switches in segment. When a fault is introduced into the REP segment, multicast traffic is interrupted for a period of approximately 4 seconds. I have narrowed it down to the IGMP snooping that is causing the disruption, learning/rebuilding etc. This is layer 2 multicast traffic. Two queriers exist on the REP segment as it stands, however, I have tried a few combinations of queriers.

Unicast traffic is only disrupted for a period of approximately 50ms.

If IGMP is disabled ring wide, no multicast interruption experienced.

Efforts: Attempted to play with IGMP timers to no avail.

Questions: Is it good practice to have IGMP enabled on a REP segment? Is there a way to improve multicasts convergence speed over a REP segment.

Hi guys,

I have some questions concerning Meraki equipment and how the MX firewall handles multicast traffic:

Example scenario: topology

1 x MX --> 3 x MS --> 5 x MR -> 5 IPTV STB Each MR AP has an IPTV STB connected.

In this test scenario, the IPTV provider has 3 channels - Channel 1 (8 Mbps), Channel 2 (8 Mbps) and Channel 3 (4 Mbps).

As IGMP snooping is available on MS Switches, each MR AP only gets the specific IPTV multicast stream, that the STB has requested. Happy network.

The MX firewall, on the other hand, doesn't have IGMP snooping (I don't understand why...), so the MX floods all STB requested IPTV multicast traffic to every directly connected MS Switch, even the switches only connected to one MR AP / STB (see topology). Not so happy network.

In our real life scenario, you have to increase IPTV provider channel nr. from 3 to 50 (3-400 Mbps total multicast traffic) and increase the amount of MS switches connected to the MX from 3 to 8, and you would have around a constant ~350Mpbs * 8 = 2.8 Gbps of multicast traffic being passed through the MX.

This causes a lot of unnecessary congestion on the network backbone link between MX & MS.

I know that setting an aggregation switch between the MX firewall and MS switches, that has IGMP snooping would solve this issue, but that's besides the point.

Would this amount of multicast traffic flooding negatively impact the MX performance, and if so, how much?

Thank you.

So I'm about to change my ISP to another one that also provides IPTV on vlan6. I already have ER-X router and I think I've figured out how to set it up (all ethernet iports will be put under switch0 and three new VIF will be created: LAN, Internet and IPTV), but since I'm gonna use it for two TVs, I have a question about IGMP snooping. Er-x does not support IGMP snooping, so what I'm gonna do is ER-X--->TP-LINK SG105E--->2x STBs.

The er-x will be configured to passthrough (not sure if that's the right word) the vlan6 only to the two ports that are actually going to need it.

So now the question is, if two TVs are showing two different channels at the same time, will they both receive the multicast data for both channels or only the one that they actually need? In other words, will IGMP snooping work? As far as I was able to understand, IGMP snooping only works if there's an IGMP querier/proxy. Does it also apply when IPTV comes on vlan? Should I also set it up on ER-X in additiom to vlan? Is that even possible?

I have CenturyLink IPTV here in Seattle and have setup a dedicated VLAN for the two set top boxes I have. Obviously there is only one port dedicated to that VLAN per switch (other than the trunk port of course). I've had IGMP snooping running on both my consumer grade switches for a while now but am wondering if it negatively impacts performance. Occasionally I'll get random block anomalies on screen or playback pauses. However, this isn't identically timed across both switches and set top boxes. In this setup is it necessary to run IGMP snooping or is it fine to turn off?

Thanks!

Edit: Failed to add "needed" to the end of the title. Oops.

Hey,

I am currently looking for a new home network setup but since I am using Magenta TV I am going to need igmp v3 snooping.

So here is my question:

Do both the US-24 and the UDM Pro support igmp v3 ?

Home network. I just realized that the 2nd Ethernet port on the MR52 doesn't actually let me bridge an MR33 to the network as a 2nd gateway, so just put a Netgear GS105PE in front of the MR52 and MR33. Network seems happier without the wireless mesh, which I didn't know was happening.

So with the GS105PE on a network where all the other hardware is Meraki, do I disable IGMP snooping? I've read some articles on it but don't really get it. I haven't changed any of Meraki's default IGMP settings, and haven't configured any specific IGMP querier?

So, I'm curious what other folks experience is. I've just added a fourth server to my cluster, and was looking to setup high availability. Whenever I would turn it on, I'd start seeing loss of quorum and guests getting moved due to fencing. When I looked at the logs I was seeing a lot of of the Totem errors ( Dec 06 12:58:05 corosync [TOTEM ] Retransmit List: 114d3ee 114d3ef 114d3f0 114d3f1 114d3f2). When I searched the Proxmox forums it indicated that corosync should be on a dedicated NIC and subnet. That surprised me since each of the nodes is connected to a USW-16-XG and it says corosync needs less than 100Mbps bandwidth, but OK.

OK, my nodes all had extra 1G NICs that I wasn't using, so that easy enough. I setup a new VLAN, added a 1G interface to each node and connected them up to ports on a USW-16-150W that was also already in the rack, and setup corosync for these interfaces. Got it all working, and bam, as soon as I setup IGMP snooping I still see the issues. If I turn it off, all is well. Ompings are always totally fine either way, but it seems that the Unifi gear is doing something with snooping that PVE doesn't like. Is there anyone using UBNT gear that is snooping and not seeing this? I'm wondering what else I can check. These 4 nodes are the only things on this new corosync subnet, so it really shouldn't be overloaded, and I can just leave snooping off, but I'd like to udnerstand it.

Has anyone deployed ganglia and enabled igmp snooping?

I've never worked with igmp at this level and when I enable igmp ganglia stops. I think it's due to the lack of an igmp router but my switches are N3k series and have igmp queriers.

Any insight would be beneficial.

Question..I just bought my own house, i currently pay cable at my parents house. I have a bridge between the two houses. I have been trying to get one of the tv box through Ethernet to go to the bridge and get a signal to have TV box at my own house. Any input? Uverse i'm using.

I'm using ubiquiti nanobean newest gen, I'm thinking buying a 5 port switch that support IGMP Snooping from the Bridge to the switch, from the switch to the TV Box. But unsure if is going to work. What do you guys think? I'm noticing that this is kind of complicated because of packets and routing. Anything helps..t.y.

Does anyone know a easier way..??

Hello All!

Just was curious what the current thinking is on these options. There is SO much conflicting info on the intertubes on these. Are they truly necessary in a modern home network? Do they conflict/are required for ApplePlay/AppleTV/Sonos?

Devices:

USW-8

USW-8-60W

Both running 3.8.11

Cloudkey running 5.5.20 FW 0.7.3

So a little bit of history with my setup. AT&T U-verse Set top boxes can be connected via Ethernet, but since the U-verse gateway only has 4 ports, when you have a DVR and 3 Set tops, they give you a Netgear switch for the TV traffic. In my case a GS108. TV traffic is unicast for about 10 seconds after you change the channel, then it joins a multicast stream from then on, until you change the channel again.

Now here is where I am having issues. Normally the gateway will direct the multicast to where it needs to go by IGMP3 snooping. Once I added my USW-8-60W to my network on the data side, (Separate network port than the netgear) the TV's would freeze after about 10 minutes and then come back a minute or two later. Looking at logs on the gateway, it was complaining about stale multicast sessions. I enabled IGMP snooping on the controller and the issue seemed to go away.

Fast forward to today. I got the bright idea of why not get an USW-8 and make that the TV switch and also have more ports to use for regular data if I need them and if I need the one POE port for something, I have that too! I mean snooping is on, it shouldn't have an issue handling the traffic right? Not so much. Back to the same issues as before, however the DVR seems fine and does not drop as before.

Even though right now I have only three devices on the switch, and each stream is roughly 5-6Mbps, is there something that I am missing when it comes to the multicast and snooping? I also tried turning on the block of multicast from LAN to WLAN to see if that helped, alas it did not.

Edit: some more clarity. And forgot the L in WLAN

So I've been reading about IGMP a lot lately, mostly RFCs (IGMP, IGMP Snooping, IGMP Proxy) and Cisco/Juniper docs. What I've found, and what I feel a bit confused about, is whether or not IGMP Snooping Querier an RFC based feature or not. It seems like it is not and it's just a feature vendors came up with, but it sounds a lot like IGMP Proxy in the RFCs.

So my core question is: are IGMP Snooping Querier and IGMP Proxy different features and what parts of the RFCs can show me that?

I have a pretty simple setup but i don't understand why the IGMP snooping Querier (The Layer 3 Switch 1) is receiving all the multicast traffic when no receivers are requesting it on that or upstream from it.

Switch 1 Layer 3(SVI) -> Switch 2 (Receivers and Sources)

If the IGMP Snooping Querier is configured on the switch with the receivers and sources the multicast traffic never leaves that switch.

If i configure the IGMP Snooping Querier on the Layer 3 Switch using a SVI, I see all multicast traffic for that vlan crossing the link between the switches. But no receivers are on switch 1.

Switch 1 - 4948E -------- Switch 2 - 3560G

Snooping groups show the following

Switch 1: Interface to Switch 2
Switch 2: Interface to Switch 1, Receivers

Hey all. First time poster to this subreddit, so apologize if I do something out of line.

Need a bit of assistance. Working a TAC Case with Cisco involving an issue with IGMP snooping. The Cisco engineer (who is a CCIE, and seems pretty knowledgeable) and I are in disagreement with the operation of IGMP Snooping. I wanted to verify that what is occurring is not intended operation.

Here's a quick drawup of the toplogy, although some inconsequential details are changed: https://imgur.com/a/whzHx

Issue: A test Set-Top Box sends a leave-group message upstream. The upstream switch receives it, and continues to forward it upstream towards the ASR9000 switch. The problem is that there is another device, on another interface of the same switch, joined to the same group. I was of the understanding that IGMP Snooping would recognize that another interface has receiver(s) for the group, and would thus not forward the IGMP Leave-Group upstream.

So, to reference the drawing. Both STBs are joined to group 225.1.1.1, and are correctly receiving the stream. The source for this multicast group is not pictured, but is transported via PIM where is hands off Layer2 at the ASR9000 Router (pictured on the far right). We leave the group (flip the channel) on STB 192.168.1.10, and a leave group is sent upstream. The ASR9000 switch (pictured left) receives the leave, and prunes the interface Gi1. At no point does it prune interface Gi2, which still has an active receiver (confirmed via show commands). Regardless, the ASR9000 switch sends a leave-group message upstream, at which point the ASR9000 Router prunes the stream completely on the LAG, thus killing the stream for the STB that was still joined on the ASR9000 switch interface. The stream eventually comes back after the ASR9000 router sends a General Query.

So it seems to me that there are 2 problems here... One is that the ASR9000 switch is sending a leave-group message upstream when it shouldn't, and the other is that the ASR9000 router is not correctly performing the last-member-query, or that it is but is not receiving a reply.

My main concern is with the IGMP Leave being sent when it shouldn't, as the ASR9000 Router is on legacy software, and is being deprecated very soon.

Talking with the Cisco engineer, he believes this is intended operation. After I asked for clarification, he reached out to 2 colleagues who indicated the same. So, I'm starting to get of the mind that I'm not processing the flow here correctly,

If IGMP Snooping is not turned on at the switch, how is multicast any different from broadcast data? I was under the impression that a host only received multicast data after joining a multicast group. Thanks

From the Wikipedia article on IGMP Snooping: A switch will, by default, flood multicast traffic to all the ports in a broadcast domain (or the VLAN equivalent). Multicast can cause unnecessary load on host devices by requiring them to process packets they have not solicited.

Is there no way to enable or disable IGMP proxying or snooping ? I believe it is causing problems with my TiVo boxes.