IPv6 Multicast Addresses: Explained | CCNA Exam Preparation

IPv6 Multicast Addresses

Question

Which IPv6 address block sends packets to a group address rather than a single address?

Answers

Explanations

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A. B. C. D.

D.

FF00::/8 is used for IPv6 multicast and this is the IPv6 type of address the question wants to ask.

FE80::/10 range is used for link-local addresses.

Link-local addresses only used for communications within the local subnetwork (automatic address configuration, neighbor discovery, router discovery, and by many routing protocols)

It is only valid on the current subnet.

It is usually created dynamically using a link-local prefix of FE80::/10 and a 64-bit interface identifier (based on 48-bit MAC address).

The answer is D. FF00::/8.

In IPv6, a multicast address is used to send packets to a group of hosts rather than a single host. A multicast address identifies a group of devices interested in receiving the same packet. The first eight bits of a multicast address start with "1111 1111," which corresponds to the prefix FF00::/8. Therefore, any IPv6 address that starts with FF00::/8 is a multicast address.

Option A, 2000::/3, is the address block for Global Unicast addresses, which are used to identify unique interfaces that are globally reachable on the internet.

Option B, FC00::/7, is the address block for Unique Local Addresses (ULA), which are private addresses that can be used within an organization and are not routed on the public internet.

Option C, FE80::/10, is the address block for Link-Local addresses, which are used to communicate within a local network segment and are not routable beyond that segment.