What is Layer 2 multicast?

In the VXLAN BGP EVPN fabric, Layer-2 multicast refers to the use of IP multicast technology for transporting multicast traffic in a Layer-2 switching environment. Layer-2 multicast follows the same semantic as general Broadcast, Unknown Unicast, and Multicast (BUM) traffic.

Is multicast Layer 2 or Layer 3?

In most cases, multicast packets must pass through Layer 2 switching devices between multicast receivers and Layer 3 multicast routers. After a router forwards multicast packets to a switch, the switch forwards the multicast packets to multicast receivers. IGMP snooping is an IPv4 Layer 2 multicast protocol.

Does multicast work across VLANs?

Simply enabling the Multicast protocol on one VLAN will work if Airtames and PCs are on the same VLAN but in the case that Airtames and PCs are on different VLANs, the multicast traffic will need to cross VLANs.

What is a Layer 2 VLAN?

A virtual LAN (VLAN) is any broadcast domain that is partitioned and isolated in a computer network at the data link layer (OSI layer 2). VLANs allow devices that must be kept separate to share the cabling of a physical network and yet be prevented from directly interacting with one another.

Is IGMP a Layer 2?

IGMP messages are carried in bare IP packets with IP protocol number 2. Similar to the Internet Control Message Protocol, there is no transport layer used with IGMP messaging.

Can you multicast across subnets?

The router that is routing traffic between the subnets need to support multicast forwarding. IGMP is one such protocol that will allow multicast traffic to be routed between different IP Subnets, and is supported by Linux and most Cisco routers.

What is multicast VLAN?

Multicast VLAN registration (MVR) enables more efficient distribution of IPTV multicast streams across an Ethernet ring-based Layer 2 network. In a standard Layer 2 network, a multicast stream received on one VLAN is never distributed to interfaces outside that VLAN.

Where is Unicast used?

Unicast transmission has been in use for a long time, with well-established protocols and easy to deploy techniques. Well-known and trusted applications such as http, smtp, ftp and telnet all use the unicast standard and employ the TCP transport protocol.

Why does multicast not work in same VLAN in catalyst?

As a result, Switch 1 does not send any multicast traffic out to Switch 2. Therefore, Receiver 2 never gets any multicast traffic, even though Receiver 2 is in the same VLAN but merely on a different switch than the multicast source. The reason for this issue is that IGMP snooping is not really supported on any Catalyst platform without an mrouter.

What’s the difference between IP multicast and unicast?

In multicasting traffic recline between the boundaries of unicast and broadcast. It server’s direct single copies of data streams and that are then simulated and routed to hosts that request it. IP multicast requires support of some other protocols such as Internet Group Management Protocol (IGMP), Multicast routing for its working.

How does multicast work in a layer 2 switch?

IGMP snooping is a mechanism to constrain multicast traffic to only the ports that have receivers attached. The mechanism adds efficiency because it enables a Layer 2 switch to selectively send out multicast packets on only the ports that need them. Without IGMP snooping, the switch floods the packets on every port.

How is broadcast unknown unicast and multicast traffic transmitted?

Broadcast, unknown-unicast and multicast traffic ( BUM traffic) is network traffic transmitted using one of three methods of sending data link layer network traffic to a destination of which the sender does not know the network address. This is achieved by sending the network traffic to multiple destinations on an Ethernet network.