thinQmaster Virtual testing partner Adaptive practice exams that find your weak spots and drill them. Every answer explained. From $69
Enroll

thinQmaster

Find your exam

Five questions free, before you decide.

Step 1 · choose a vendor

In one of our camps? Your practice exams come with the tuition — they are on your study page already.

Networking Fundamentals · Foundational

Multicast

One-to-many communication delivered only to hosts that have joined a particular group.

Definition

IPv4 multicast uses 224.0.0.0/4 and IPv6 uses ff00::/8. Hosts signal group membership with IGMP (IPv4) or MLD (IPv6), and switches can use IGMP snooping to avoid flooding multicast to every port. It is efficient for streaming, routing protocol updates and service discovery.

Example

OSPF routers send hellos to 224.0.0.5, an all-OSPF-routers multicast group.

Exam tip

Multicast goes to interested receivers only; broadcast goes to everyone on the segment.

Don't confuse it with

Related terms