What is the difference between IGMP versions of S series switches


IGMP runs on the last-hop router to collect users' requests for programs. The requested multicast data is then sent from the multicast source to users through PIM.
IGMP has three versions.
1. IGMPv1
IGMPv1 defines the General Query message and Report message. A user sends Report message to request a program. After the last-hop router receives the Report message, it adds the user to the specified multicast group and sends General Query messages at intervals to maintain the membership of the user. If the router does not receive any Report message from the user within two intervals, it considers that the user does not require the multicast data and deletes the user from the multicast group.
2. IGMPv2
In IGMPv1, if a user does not require data of a multicast group, it leaves the multicast group after two intervals for sending General Query messages. Multicast data is still sent to the user in this period, wasting bandwidth. IGMPv2 improves IGMPv1 by adding two types of messages: Leave message and Special Query message.
When a user does not require data of a multicast group, the user sends a Leave message to the last-hop router. When a port of the router receives the Leave message, the router sends some Group-Specific Query messages (the quantity is specified by the robustness variable) to the interface to check whether other users in the broadcast domain on the interface require data of the multicast group. If another user requires data of the multicast group, the user replies with a Report message. When receiving the Report message, the router retains the interface. If no Report message is received, the router deletes the interface from the multicast forwarding entry.
IGMPv2 is the most widely used one on networks.
3. IGMPv3
IGMPv1 and IGMPv2 messages contain only the multicast group addresses of the requested programs. If multiple multicast sources provide data with the same multicast group address, data of all the groups is transmitted to users. Users may not see the programs they request. IGMPv3 solves this problem.
IGMPv3 adds a source list in the Report message and supports the following six types of source lists:
-Include: accepts data provided by the multicast sources in the list.
-Exclude: rejects the multicast group data provided by all sources in the list.
-ChangeToInclude: starts to accept multicast group data provided by the multicast sources in the list (previously rejects the data).
-ChangeToExclude: starts to reject multicast group data provided by the multicast sources in the list (previously accepts the data).
-AllowNew: adds a source of which the data is accepted or rejected.
-BlockOld: deletes previous sources of which the data is accepted or rejected.
IGMPv3 replaces the Leave message with the Rep
ort message and adds the Group-and-Source-Specific Query message.

Other related questions:
Clusters or stacks of S series switches
A stack or cluster of S series switches is a logical switch consisting of multiple stacking-capable or clustering-capable S series switches. In V200R001C00 and earlier versions, S series switches only set up stacks. In later versions, S series fixed switches set up stacks, and S series modular switches set up clusters. Please ask questions about specific switch models. The following information is possibly related to your question:

IGMP versions available on S series switch
S series switches support three IGMP versions: IGMPv1, IGMPv2, and IGMPv3.

How does an S series switch process IGMP messages of a later version
If the version of a received IGMP message is later than the IGMP snooping version configured on the switch, the switch processes the IGMP message as follows: - If the received message is a Report message, the switch forwards the message only to router ports and does not generate a member port or forwarding entry. - If the received message is a Query message, the switch broadcasts the message in the VLAN and sets the receiving port as a router port. After the multicast VLAN service is configured, IGMP messages are replicated and broadcast in user VLANs. If the switch receives many Group-Specific Query messages of a later version, the CPU usage may become high. If IGMP messages of a later version degrade service performance on the switch, change the IGMP snooping version to the later version.

Difference between IGMP snooping and IGMP snooping proxy on an S series switch
IGMP snooping and IGMP snooping proxy have the same functions but different mechanisms. IGMP snooping obtains required information by listening to IGMP messages; IGMP snooping proxy intercepts and suppresses IGMP requests of terminal users, and then forwards the requests to the router. The Layer 2 network device with IGMP Snooping Proxy configured functions as a server on the user side. It periodically queries user information. On the network side, this switch functions as a client and reports user information after receiving query messages. Therefore, IGMP snooping proxy can not only suppress multicast packets on Layer 2 network, but also reduce the total number of protocol packets on the network. The proxy router is required for maintaining and calculating entry status changes, so the implementation is more complex and the cost is added.

What are the differences between 802.1X and DOT1X on S series switch?
802.1X and DOT1X provide the same function.

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