In IPv6 RIP next generation (RIPng), which link-local multicast address is used by routers to send RIPng routing updates?

Introduction / Context:
Just like IPv4 routing protocols often rely on multicast or broadcast addresses to distribute routing updates, IPv6 versions of these protocols use well defined IPv6 multicast addresses. RIPng, the IPv6 version of RIP, sends its updates to a specific multicast group that all RIPng routers on a link listen to.

Given Data / Assumptions:

• The routing protocol is RIPng, not EIGRPv6 or OSPFv3.
• We are interested in the multicast destination used for routing updates.
• All candidate answers are link local IPv6 multicast addresses beginning with FF02::.
• Each address is reserved for a different routing protocol group.

Concept / Approach:
RIPng uses the IPv6 multicast address FF02::9, which corresponds to all RIP routers on a local link. Routers running RIPng send and receive updates on this multicast group. Other addresses in the options are used by EIGRPv6 and OSPFv3, so identifying RIPng relies on remembering that FF02::9 is the correct group for RIP next generation.

Step-by-Step Solution:
1. Recognize that RIPng uses an IPv6 multicast group for distributing its routing updates.2. Recall the standard mapping: FF02::9 is reserved as the all RIP routers multicast address.3. Compare this known address with the answer choices.4. Option B exactly matches FF02::9, the correct group for RIPng.5. Select FF02::9 as the correct multicast address used by RIPng.

Verification / Alternative check:
In a lab environment, if you capture IPv6 traffic on an interface where RIPng is enabled, you will observe periodic routing updates sent to FF02::9. Additionally, Cisco and other vendor documentation explicitly state that FF02::9 is the multicast group for all RIPng routers.

Why Other Options Are Wrong:
Option A, FF02::A, is used by EIGRPv6 for its control traffic. Options C and D, FF02::5 and FF02::6, are used by OSPFv3 to reach all OSPF routers and all OSPF designated routers respectively. None of these correspond to RIPng.

Common Pitfalls:
Because IPv6 multicast addresses often look similar, many learners confuse FF02::9 with FF02::A or with OSPFv3 multicast addresses. A practical tip is to remember that 9 looks like a reversed P, loosely hinting at RIP, while A can be associated with EIGRP. Developing small memory aids like this can help you recall the correct mapping during exam situations.

Final Answer:
FF02::9