8. We would like to show you a description here but the site won’t allow us. Jul 7, 2022 · IGMP snooping is a method that network switches use to identify multicast groups, which are groups of computers or devices that all receive the same network traffic. 前置条件. IGMP version 1 and version 2 allow hosts to join multicast groups but they don’t check the source of the traffic. This value is used for VLANs that do not have a value specified. This is in stark contrast to Nexus switches. This might prevent the associated dynamic IGMP snooping forwarding entry from being correctly created at the data link layer and eventually cause multicast traffic As an example, if the IP address used for IGMP snooping querier is also used for another router on the segment, then there will be issues with the IGMP querier election protocol. Enable multicast router mode on the ports that uplinks to the other switches. Simple IGMP snooping should be enough. Upon receiving an IGMP general query, the switch forwards it through all ports in the VLAN except the receiving port and performs the following on the Nov 21, 2023 · You require a layer 3 switch to have an IGMP querier configured. ip igmp snooping querier enable, on page 3. IGMP Snooping is the process that allows the switch to know which multicast groups each device has subscribed to, only sending the relevant groups to each port. 40. VLAN IDs 1002―1005 are reserved for Token Ring and FDDI VLANs, and cannot be used in IGMP snooping. The DR is the device with the highest IP address on the subnet, whereas the IGMP querier is the device with the lowest IP address. "IGMP Snooping Querier" or "IGMP Querier" allows for multicast traffic to be routed between layer 3 VLANs. If I look at my IPTV clients, I see 300Mbps of multicast going to these ports, even if these are not sending IGMP messages. 100 255. Feb 16, 2024 · Quick Definition: IGMP snooping is a networking feature that allows switches to manage multicast traffic by monitoring IGMP messages. Unicast traffic in Cisco switches discovers layer 2 MAC addresses and their corresponding physical ports by looking upon You can configure an IGMP snooping querier to support IGMP snooping in subnets without multicast interfaces because the multicast traffic does not need to be routed. Values range from 1 to 25 seconds with a global default of one second. ip igmp snooping vlan querier address, on page 7. (Optional) Check the IGMP Querier Election check box to elect this device as the querier. Click Apply. When there are multiple receivers on the network then using multicast traffic is a good idea. 106: Configures a snooping querier when you do not enable PIM because multicast traffic does not need to be routed. If a multicast router supporting IGMP is not present, then the switch must assume this function in order to elicit The following items provide recommendations for configuration of a network switch for IGMP snooping: Set the IGMP query interval to 60 seconds or 125 seconds. To make multicast work correctly, you need to have IGMP snooping enabled on all the VLANs on all the switches to which your devices are IGMP Snooping. Feb 28, 2017 · The querier timeout is set to 120 seconds by default an cannot be lowered to less than 60 seconds by configuration. 5 and is intended to alleviate the load by: Nov 21, 2017 · You can configure an IGMP snooping querier to support IGMP snooping in subnets without multicast interfaces because the multicast traffic does not need to be routed. A set of hosts, routers, and/or switches that send or receive The Internet Group Management Protocol (IGMP) is a protocol that allows several devices to share one IP address so they can all receive the same data. 16. Enter system view. We have a receiver 172. Jul 30, 2017 · Enable IGMP snooping on your VLANs under the IGMP VLAN configuration. This functionality will allow an interface to join in the querier-election process. The IGMP snooping querier supports IGMP Versions 1 and 2. Jul 13, 2010 · By default IGMP snooping is Enabled and IGMP snooping querier is disabled : D7402_DC(config)#ip igmp snooping vlan 4 querier. The following example shows how to globally enable the IGMP snooping querier feature: enabled, the IGMP snooping querier uses the IP address as the query source address. [SwitchA-vlan100] igmp-snooping querier [SwitchA-vlan100] quit # In VLAN 100, specify 192. 15. 38. Set instead a Querier IP address per VLAN under the Querier VLAN configuration (VLAN10=1. Thanks! I have this problem too. 1—on the local subnet to determine whether active multicast group members exist on the subnet. (There is no multicast routing, strictly level 2). To understand IGMP proxy, let’s first look at what a UDL (Unidirectional Link) is. "IGMP Snooping" is basically used within a VLAN to control which ports get which multicast streams. The IGMP snooping querier performs querier election as described in RFC 2236. 2. 3. Since SW2 does not know where the mrouter of the group, it adds port Eth1/1 to the snooping group, and discards the packet the IGMP packet. To configure Internet Group Management Protocol (IGMP) snooping, include the igmp-snooping statement: immediate-leave ; interface interface-name {. The setup is a traditional 3-layered network design (core, distribution, access). Release Information. Now the issue: The BCC sends about 300Mbps of multicast stream into vlan 100. Once Host 1 boots, it sends an IGMP query (which is flooded over the port Observe these guidelines when configuring the IGMP snooping querier: Configure the VLAN in global configuration mode. bridge multicast filtering. Without IGMP, a network switch would forward any multicast traffic to all switchports on the switch. Enable IGMP snooping querier. For good network performance, ensure that there is only one IGMP querier in the network. When a switch is connected to a network and IGMP querier is enabled, it will assume it is the querier until it hears a General Query from another router or switch with a lower IP address. Jan 30, 2019 · If you want the devices to accept the IGMP general query messages, configure the IGMP snooping querier to run IGMPv1. Here are the new features: Mar 29, 2023 · For Querier Admin Mode, select the Enable radio button. The no form of this command disables IGMP querier on an interface. 10 and VLAN15=1. ip address 172. In this way, the device builds an IGMP snooping table that has a list of all the Mar 7, 2022 · Introduction. The first step is to enable the IGMP snooping feature on your switch. An IGMP snooping enabled Layer 2 device performs differently depending on the message type. ip igmp snooping last-member-query interval xx. 根据网络需要，可以调整查询器的以下参数：. A UDL is a link where traffic only goes one way. # Configure Switch A as the IGMP snooping querier. 5 seconds if a router fails. Click Add. It needs to see the query messages to get the information it needs to build the L2 multicast FIB. The remaining devices in the network simply ip igmp querier no ip igmp querier Description. Without IGMP snooping, the device floods the packets on every port. You can configure an IGMP snooping querier to support IGMP snooping in subnets without multicast interfaces because the multicast traffic does not need to be routed. How IGMP snooping works. The purpose of Cisco Group Management Protocol (CGMP) and Internet Group Management Protocol (IGMP) snooping is to restrain multicast traffic in a switched network. By default, a LAN switch floods multicast traffic within the broadcast domain, and this can consume a lot of bandwidth if many multicast servers are sending streams to the segment igmp-querierd is a Python implementation of IGMP Querier. This would not work well in large network The IGMP snooping querier might send IGMP general queries with the source IP address 0. Enable the IGMP snooping querier on VLAN 1. 后续任务. A multicast router port is a port where a multicast router or querier is connected. The port that receives such queries will not be maintained as a dynamic router port. Mar 11, 2018 · Hi Georg, Thanks for your reply. Configures an IGMP querier on an interface, depending on the command context you are in. IGMP is a network layer protocol used to set up multicasting on networks that use the Internet Protocol version 4 (IPv4). Note that the IP Address of the querier can be literally anything, it does not have to belong to the subnet associated with the VLAN. ip igmp snooping vlan forbidden mrouter, on page 5. If both the server and client are on the same layer-2 switch, in the same VLAN Apr 14, 2022 · The switches elect a querier based on its IP address, and the lowest IP address is elected as the querier. Select or Add an interface. Verifying the configuration. IGMP snooping is a method that network switches use to identify multicast groups, which are groups of computers or devices that all receive the same network traffic. With source filtering, we can join multicast groups but only from specified source addresses. IP manages multicast traffic by using switches, multicast routers, and hosts that support IGMP. # Enable IGMP snooping, and enable dropping unknown multicast data for VLAN 100. 1) to SW2; Because the SW2 receives the IGMP query, it will install the uplink to sw1 as mrouter port, in the snooping table. Apr 28, 2024 · II- Apply IGMP Snooping Policy under the BD. 1 Jul 17, 2023 · Before configuring IGMP snooping functions, there are certain aspects to consider. If a port spanning-tree, a port group, or a VLAN ID change occurs, the IGMP snooping-learned multicast groups from this port on the VLAN are deleted. IGMP snooping enables the device to selectively send out multicast packets on only the ports that need them. When IGMP-Snooping sees these queries (or rather, the responses), it refreshes the entries in the table. Based on the IGMP query and report IGMP snooping is the process of listening to Internet Group Management Protocol (IGMP) network traffic. Here is the key part, the endpoint device has to send a join every minute or so, or the switch cuts off the stream. It helps in managing multicast memberships by soliciting reports from hosts, thereby allowing the switch to make informed decisions about where to forward IGMP Version 2. AGR012-5K-A(config-vlan-config)# ip igmp snooping querier 172. Nov 21, 2023 · You require a layer 3 switch to have an IGMP querier configured. It sends queries to network devices, which respond with their memberships, allowing the querier to enhance the efficiency of the network. In the VLAN ID field, enter 1. The IP address used for querier functionality must also not be used for other functions, such as HSRP or VRRP. (Optional) Choose the IGMP Querier Version used if the device becomes the elected Sep 12, 2017 · Multicast may represent a heavy load for switch-routers (not mentioning the security aspect with potential DoS attacks). How IGMP operates. This property only has an effect when igmp-snooping is set to yes. Normally, a multicast router acts as an IGMP querier and sends queries every 60 seconds to the 224. The bridge will stop forwarding multicast traffic to a bridge port when an IGMP/MLD leave message is received. Apr 20, 2023 · IGMP is a protocol used by network equipment to specify which devices should receive which multicast groups. Authority Jun 3, 2012 · Multicast is new to me, but I am coming to understand IGMP snooping and the need for one of the switches to be configured as a querier. 1- Under the Bridge domain select the IGMP Snooping Policy: 2- At subnet level, enable Querier IP: III- IGMP Snooping Verification and Troubleshooting. This can usually be done through the switch’s web-based management interface or command line interface (CLI). A multicastrouter is not necessary as long as a switch is configured to support IGMP with the querier feature enabled. show vlan extended | grep <BD-NAME>. It should not flood them. IGMP is a communication protocol used by hosts and adjacent routers for multicasting communication with IP networks and uses the resources efficiently to transmit the message/data packets. The recommended setting is the default setting of the network switch. IGMP (Internet Group Management Protocol) is a Layer 3 protocol (IP protocol number 2) and is a key component (Figure 1) to IP multicast. In IGMP version 1, hosts just stop listening to the multicast group address, but they never report this to the router. Enable IGMP Snooping Status and enable IGMP Snooping Querier. " Enables IGMP/MLD fast leave feature on the bridge port. Oct 31, 2023 · Go to L2 Features -> Multicast -> IGMP Snooping . It’s more efficient than unicast since we only have to send our traffic once, this saves us precious bandwidth. Some of the switches I have seen are smart enough to wait and see if there is another querier before turning their's on. See Example below: fab4-p1-leaf1# show vlan extended | grep MV-BD. Query. The IGMP snooping querier does not The ip igmp snooping querier last-member-query-interval command specifies the global last-member-query-interval used in snooping query packets transmitted from the switch. Explanation and Examples. 4. It immediately becomes querier and starts to send query packet. Network switches use IGMP snooping to access the IGMP conversation between routers and hosts while maintaining the link with IP multicast transmission. SW2 will flood the query in the received vlan. 9. IGMP Snooping checks IGMP packets passing through the network and configures Multicasting accordingly. 2. The role of IGMP is to notify a local multicast router when a host wants to receive multicast traffic for a specific group. Under multicast support, selection Enable IGMP snooping querier. Mar 14, 2019 · When this feature is enabled, the controller snooping gathers IGMP reports from the clients, processes them, creates unique multicast group IDs (MGIDs) based on the Layer 3 multicast address and the VLAN number, and sends the IGMP reports to the IGMP querier. Step 14. Verify that all switches but the querier can receive IGMP general queries after the IGMP snooping querier starts to work. It enables switches to forward packets to the correct devices in their network. The MX can be an IGMP querier. This action causes the device to consider itself an multicast router port. Mar 19, 2018 · The host will send an IGMP request when the application starts. At that point, it becomes a "non-querier. AGR012-5K-A(config-vlan)# vlan configuration 38. By getting responses back from receivers, the switch can keep track of which receivers Mar 29, 2015 · With IGMP snooping enabled and no querier (no querier, no PIM) the switch should drop all multicast packets because of igmp snooping and no known groups. Without this, multicast will be unstable, as the snooping table aging time will expire, and remove those entries. IGMP is an internal protocol of the IP suite. # Create VLAN 100, and assign GigabitEthernet 1/0/1 through GigabitEthernet 1/0/3 to the VLAN. A message sent from the querier (multicast router or switch) asking for a response from each host belonging to the multicast group. Oct 13, 2011 · Just to complete the posting, here is the CLI command (highlighted) to enable the querier functionality within the switch; [Kswitch4cf17c#sh run. ip igmp snooping vlan 1. IGMP - Snooping Querier Election; IGMP - Snooping Querier; IGMP - access group; IGMP - fast leave; IGMP - filtering using ACLs; IGMP - ip igmp snooping querier command; IGMP - membership report; IGMP - using VLAN access maps to filter multicast traffic; IGMP Snooping internal interface; IGMP default IOS configurations; IGMP last member query Mar 25, 2018 · If an IGMP Querier later comes into the VLAN, either as a standalone router, or some switch configured for this functionality using the IGMP Snooping Querier feature, IGMP Snooping reactivate itself and will kick into action. It requires the pixel controller and sending software to operate on an Ethernet protocol that supports multicast (sACN for example). IGMP querier allows the device to proxy for a multicast router and send out periodic IGMP queries in the network. IGMP Snooping Querier is a function that can be enabled on network switches to maintain efficient multicast traffic distribution in environments lacking a dedicated multicast router. Mar 19, 2024 · IGMP Snooping Querier A multicast router must be installed in the network topology that generates IGMP queries in order to enable Snooping. # Enable the IGMP snooping feature. Apr 5, 2023 · Enable IGMP snooping. Then igmp is enabled on second device 10. Enter Name, Interface IP , and VLAN. 124( IP is likely to be different Feb 10, 2018 · Introduction. If your network has a L2 switch that is capable of IGMP snooping, but if the network does not include any L3 router or network device that can act as an IGMP Querier, the IGMP snooping function may not work as expected. Step 13. To enable IGMP snooping querier: 1. I find that when I configure a switch as a querier, all the Sep 13, 2010 · IGMP Snooping Querier functionality can be thus implemented even on a Layer2 switch. On MS120-24P is an IGMP Querier configured. When an IGMP snooping querier is enabled, it sends out periodic IGMP queries that trigger IGMP report messages from hosts that want to receive IP multicast traffic. 1/27 IGMP is enabled on interface Current IGMP host version is 2 Current IGMP router version is 2 IGMP query interval is 60 seconds IGMP configured query interval is 60 seconds IGMP querier timeout is 120 seconds IGMP configured Nov 13, 2023 · IGMP Snooping Querier is a feature in network switches that optimizes multicast traffic by maintaining multicast group memberships. exit. Note: Adding a new L3 interface on an MS390 automatically enables an IGMP querier for that VLAN. 255. 1 address (All systems on this subnet). ip igmp snooping vlan enable, on page 4. 执行本命令前需执行 igmp-snooping enable（系统视图） 命令使能全局IGMP Snooping功能。. ip igmp snooping. The IGMP querier is what coordinates the location on the network of the multicast sources. Jan 10, 2016 · IGMP snooping is configured on both switches. 0. Without a querier, it is impossible to consistently collect and update group membership tables and IGMP membership reports, which makes Snooping unreliable. IGMP Snooping Commands. 251. Statement introduced in Junos OS Release 13. All switches have IGMP snooping enabled. 2, igmp is enabled. A screen similar to the following displays. A router would receive the request and forward multicasts out the router port, and it will query out that port every query interval to see if there are still hosts interested in receiving the multicast. where # represents the PI vlan ID of your BD. Since it has not heard any query yet, it starts to send the query and once the first L3 device receives it, since the query that it received has an lower ip, it lets the 2nd device be Jan 19, 2017 · When an IGMP snooping querier is enabled, it sends out periodic IGMP queries that trigger IGMP report messages from hosts that want to receive IP multicast traffic. Feb 2, 2021 · All IPTV nodes join VLAN 100 via access ports. Jul 25, 2018 · You can validate this by running the following command. Increased security: IGMP snooping can help prevent unauthorized access to Mar 6, 2024 · Importantly, the IGMP querier is the switch/router with IGMP enabled (not to be confused with IGMP snooping) that has the LOWEST IP in that VLAN. Without IGMP snooping, switches will flood multicast traffic everywhere, treating it like broadcast traffic. Figure 1 – Summary of Multicast Components. Configure an IP address on the VLAN interface. Command did not take effect due to reason: IGMP switch querier is globally disabled. The exact process may vary depending on the switch model and vendor. ) Aside from a couple vlans that have equipment on it running a mrouter this one edge switch is really doing all the membership management. Configure the device to be an IGMP querier. 20. . It’s also more efficient than broadcast because only receivers that are actually interested in our traffic will receive About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright Feb 6, 2020 · On the upstream switch, you must configure the IGMP snooping querier on a specific VLAN and the IGMP snooping querier must match the IP in the UCS multicast policy. Examples. 7. When there is no multicast router in the VLAN to originate the queries, you must configure an IGMP snooping querier to send membership queries. Set IGMP snooping to v2 or v3. As we have seen in the IGMP snooping lesson, switches will listen to IGMP messages and learn on which interfaces they have to forward multicast traffic. 2 in the configured BD with interest to join group 239. Internet Group Management Protocol (IGMP) snooping constrains the flooding of IPv4 multicast traffic on VLANs on a device. When enabled, the IGMP snooping querier uses the IP address as the query source address. AGR012-5K-A(config)# vlan 38. Devices would be responsible for filtering out the traffic that they do not want to receive. interface vlan 1. If there is no SVI IP address, the device uses the first available IP address configured on the device. 1 as the source IP address of IGMP general queries. ip igmp snooping vlan 1 querier. group-limit limit ; host-only-interface ; immediate-leave ; multicast-router-interface; static {. show ip igmp snooping vlan #. [SwitchB] display igmp-snooping statistics Received IGMP general queries:3. Also network switches will need to have both IGMP Snooping and Querier functionality. In essence, the IGMP Snooping Querier switch sends IGMP Queries into the appropriate VLAN to facilitate the proper function of IGMP Snooping, without needing a real multicast router to send these queries. For the VLAN that you want to enable for IGMP snooping, click on the paper/pencil icon under Operation . In the Querier IP Address field, enter 10. Contents of show ip igmp interface: C897VAW#sh ip igmp interface Vlan40 is up, line protocol is up Internet address is 10. switch(config-vlan-config)# ip igmp snooping querier 172. IGMP Snooping without Router. But in general, you can follow these steps. Leave the global address at 0. By default, a LAN switch floods multicast traffic within the broadcast domain, and this can consume a lot of bandwidth if many multicast servers are sending streams to Mar 26, 2024 · To configure an IGMP querier: Navigate to Switch > Configure > Routing and DHCP. When enabled, the IGMP snooping querier restarts if you configure an IP address. ip igmp snooping vlan immediate-leave, on page 6. On a switch (or a Linux bridge), Multicast snooping sits at network layer 2. IGMP version 3 adds support for “source filtering”. Select Switching > Multicast > IGMP Snooping Querier VLAN Configuration. Click Save. There is a single central switch connected by single trunk ports to each of the other switches. The problem that I see is that there is an inefficient flow of data. The MS125 is a layer 2 switch, so that option will not be available. Jan 15, 2009 · ip igmp snooping querier timeout expiry xx. In the worst case, some multicast packets may not be delivered properly. If you are using a single VLAN (which I suspect since there are no layer 3 components mentioned), you shouldn't need an IGMP querier. IGMP Snooping Overview. That’s a problem in our environment, because there is an requirement, to limit traffic interruptions to max. Received IGMPv1 reports:0. The IGMP snooping querier disables itself if the IP address is cleared. Query messages are used to elect the IGMP querier as follows: [SwitchA-vlan100] igmp-snooping enable [SwitchA-vlan100] igmp-snooping drop-unknown # Configure Switch A as the IGMP snooping querier. Any source is able to receive traffic to the multicast group (s) that they joined. Apr 22, 2017 · IGMP snooping allows the switch to keep track of receivers on particular ports who are requesting multicast traffic. If there is no IP address configured on the VLAN interface, the IGMP snooping querier tries May 20, 2020 · IGMP Snooping Querier. Host 2 boots and sends an IGMP report, in order to join Host 1's multicast group. 52. There can only be one IGMP Querier in a network. The election of the Querier is done based on the lowest IP-address. IGMP snooping is a technique that network switches utilize to minimize flooding of IPv4 multicast traffic and optimize forwarding by sending multicast traffic only to receivers who are interested. Specifically, IGMP allows devices to join a multicasting group. Jan 27, 2022 · If there is no global IP address specified, the IGMP querier tries to use the VLAN device virtual interface (SVI) IP address (if one exists). It helps reduce unnecessary traffic, improves security, and optimizes networking traffic. group ip-address {. IGMP message types include: Query, Report (Join), and Leave Group. † If there is no IP address configured on the VLAN interface, the IGMP snooping querier does not start. The feature allows a network switch to listen in on the IGMP conversation between hosts and routers. # Display statistics for the IGMP messages on Switch B. config-if-vlan. Multicast communication can have single or multiple senders and receivers and thus, IGMP can be used Internet Group Management Protocol (IGMP) snooping constrains the flooding of IPv4 multicast traffic on VLANs on a device. 10. ip igmp snooping querier-timeout seconds Jan 28, 2022 · There is one edge switch that is designated as the IGMP snooping querier (via the command "ip igmp snooping querier". 1 Querier election process Mar 2, 2023 · IGMP snooping provides several benefits to a network, including: Improved network performance: By only forwarding multicast traffic to those devices that are interested in receiving it, IGMP snooping reduces unnecessary network traffic and improves network performance. With IGMP snooping enabled, the device monitors IGMP traffic on the network and uses what it learns to forward multicast traffic to only the downstream interfaces that are connected to interested The IGMP querier periodically sends IGMP general queries to all hosts and routers—224. Network switches play a vital role in snooping. 31. SW1 sends the IGMP general membership queries (224. 可以通过 igmp-snooping query-interval 命令配置。. IGMP snooping works pretty well but it does require a Dec 13, 2018 · A querier sends query messages to discover which network devices are members of a given multicast group. [SwitchA-vlan100] igmp-snooping general-query source-ip 192. So of course I enable it globally; and IGMP snooping querier is applied on all VLANs. May 11, 2008 · IGMP Snooping Querier. When it comes to IGMP, a network switch can have 2 roles: Querier or non-Querier. The device listens for the exchange of IGMP messages by the device and the end hosts. One of the major reasons for a new version was to improve the “leave” mechanism. The first IP address available appears in the output of the. This is what the switch should do with IGMP snooping disabled. This is due to IGMP-Snooping. 1: Verify the Receiver: IGMP Proxy allows hosts in a UDLR (Unidirectional Link Routing) topology that are not directly connected to a downstream router to join a multicast group from an upstream router by using a back channel. This example uses Switch B. These include the IGMP Snooping Querier, which is essential for enabling IGMP Snooping; the IGMP Snooping Proxy, which is an enhanced function that controls IGMP report traffic; and the IGMP Snooping Version, which refers to the version of the IGMP protocol used A Switch supporting IGMP Snooping can passively snoop on IGMP Query, Report, and Leave packets transferred between IP Multicast Switches and IP Multicast hosts to determine the IP Multicast group membership. Aug 16, 2018 · Aug 16 2018 1:24 PM. Procedure. The IP address is used as the source in messages. IGMP version 2 is the “enhanced” version of IGMP version 1. IGMP snooping listens to these IGMP reports to establish appropriate forwarding. Labels: Labels: Other Switching; May 30, 2021 · Say on device with ip 10. 查询器发送特定组查询 Sep 13, 2023 · IGMP is acronym for Internet Group Management Protocol. 168. 1. 查询器发送通用查询报文的时间间隔。. ip igmp snooping enable (Global), on page 2. Some switches magically and silently disable igmp snooping in the absence of a querier. Enable IGMP Snooping, use IGMP version 3, and forward Unknown Multicast Groups. When administratively enabled, the IGMP snooping querier moves to the nonquerier state if it detects the presence of a multicast router in the network. In a multicast network that runs IGMP, you do not need to configure an IGMP snooping querier because it may affect IGMP querier elections by sending IGMP general queries with a low source IP address. Oct 30, 2021 · IGMP snooping refers to the process of listening to the IGMP network traffic and controlling the delivery of IP multicasts accordingly. It is therefore very important that all IGMP switches have a different IP-address. Igmp snooping requires a querier somewhere on the network to function. May 5, 2020 · SW2 is configured with IGMP snooping. Enter VLAN view. Command context. With IGMP snooping enabled, the device monitors IGMP traffic on the network and uses what it learns to forward multicast traffic to only the downstream interfaces that are connected to interested receivers. The DR and the IGMP querier are selected based on different criteria and may be different devices on the same subnet. Without IGMP snooping multicast traffic is flooded out all switch ports in the VLAN. If you want to find what this value is, you can simply run the following command. Since that is the part most people forget about (or don't realize), switch manufacturers started including queriers so their snooping would always work. nf wj xp qi qq od yp fe hm kb