Hello again, we are going to continue in this slide and discovered the important features in today's modern switches and how the switches play important role in delivering multicast traffic. But before we start with the features of the multicast, and the switch functionality, let's talk about the main important protocol which is igmp. igmp stands for internet group Management Protocol. With igmp what happens is the host use igmp to dynamically registered themselves in a multicast group on the land hosts identify group memberships by sending igmp messages to their local multicast router, or in this case, multi layer switch router And multi layers which is configured for igmp. Listen to the ICMP messages, sorry igmp messages and periodically send out queries to discover which groups are active and which groups are not active on a particular subnet, or VLAN. So I hope that's clear.
We will do a lab on this so it will be much more clear. So let's discuss the functions of the switch itself. Switches use igmp snooping to control multicast traffic igmp snooping operates on multi layer and layer two switches as we know igmp snooping sends messages between the host and the first hop multicast router or layer three switch these massive has joined and leave requests. So that's that's the function of the igmp snooping. In switches, there are three versions of igmp version one. In version one had no mechanism for receiver to leave a multicast group the router had to be taught how to time out the group membership.
And that's the only way. When igmp version two came along, they included the leaf mechanism, which was good, and it's still in use in today's implementations. igmp version three is a one step ahead of igmp version two, it supports source filtering. It is available in iOS releases 12.15 And later, but the current iOS releases still use igmp version two as a default. So I hope this is clear about how the switch really works in delivering multicast traffic. We will cover more during the lab.
And I'll go through the steps of showing all the commands that's required to basically simulate a multicast traffic. Thank you