Contents
What is Layer 3 multicast?
A multicast routing protocol runs on Layer 3 multicast devices to establish and maintain multicast routes and correctly and efficiently forward multicast packets. Multicast routes constitute loop-free data transmission paths (also known as multicast distribution trees) from a data source to multiple receivers.
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.
What are the two supported modes for Layer 3 multicast?
Overview. When it becomes necessary to send multicast traffic between layer 3 segments, network devices typically use Protocol Independent Multicast (PIM) to build a multicast routing table. There are two modes typically used with PIM; Dense Mode (DM) and Sparse Mode (SM).
Is IGMP Layer 2 or Layer 3?
IGMP is a network layer (Layer 3) protocol used to establish membership in a Multicast group and can register a router to receive specific Multicast traffic. (Refer to RFC 1112 and RFC 2236 for information on IGMP versions 1 and 2.)
What is ACI gipo?
BD Multicast Addresses (GIPO): The BD in this case stands for Bridge Domain, which in the case of ACI is essentially a container for subnets. In this case, we’re assigning multicast addresses to the bridge domains. You may accept the default which is 225.0.
What is multicast RP?
An RP acts as the meeting place for sources and receivers of multicast data. In a PIM-SM network, sources must send their traffic to the RP. This traffic is then forwarded to receivers down a shared distribution tree.
How does layer 2 multicast and Layer 3 multicast work?
When both Layer 2 multicast and Layer 3 multicast are enabled on a switch, Layer 2 multicast interacts with Layer 3 multicast to transmit the physical port information snooped in Layer 2 multicast to Layer 3 multicast. This prevents Layer 3 multicast data packets from being broadcast in VLANs.
When to use IGMP on Layer 2 multicast?
When both Layer 2 multicast and Layer 3 multicast are enabled on a switch, IGMP snooping can be configured to implement accurate multicast forwarding at Layer 3. IGMP snooping processes IGMP messages independently regardless of whether IGMP is enabled at Layer 3.
How is multicast traffic diverted to the access switch?
Multicast traffic is diverted to the access switch through Layer 3 multicast, and then accurately forwarded to multicast receivers through Layer 2 multicast. On the network shown in Figure 1-2, the multicast source sends multicast data to SwitchA (access switch) through the multicast router.
How does the switch work on a multicast router?
The switch performs this function if there is no other device in the VLAN, such as a multicast router, to act as Querier. Although the switch automatically ceases Querier operation in an IGMP-enabled VLAN if it detects another Querier on the VLAN, you can also use the Command Prompt to disable the Querier capability for that VLAN.