Unequal-cost load balancing in EIGRP relies on finding feasible successors—backup routes whose metric is within reach of the current best path. A feasible distance (FD) is the metric of the best path, and a feasible successor is any alternative path with a metric less than that FD. The variance command sets a multiplier that expands which alternative paths EIGRP considers for load balancing. By increasing variance above 1, EIGRP accepts and can use multiple paths with metrics up to FD multiplied by the variance, enabling unequal-cost paths to share traffic. So this command is the one that governs whether feasible successors can be used for UCMP. The other options don’t control this behavior: bandwidth is an interface parameter for metric calculation, redistribute moves routes between protocols, and feasible isn’t a standalone command used this way.

IPv4 multicast at the Ethernet layer uses a specific MAC address prefix to indicate a group delivery. The first three octets must be 01-00-5E, signaling that this is a multicast MAC. The remaining 23 bits carry the lower part of the IP multicast group address, but the key identifying feature is that 01-00-5E prefix. Among the options, the one that begins with 01-00-5E is the multicast MAC. The other addresses do not use this multicast prefix (one is a broadcast address, one is a unicast-like address, and the last is not in the multicast range), so they do not represent an IP multicast MAC.

In the 2.4 GHz band, each Wi‑Fi channel is about the same width, so neighboring channels overlap. To prevent interference when you have three APs, you must pick channels whose spectral footprints don’t touch. The reliable way is to space the chosen channels by a fixed gap so there’s a guard between their bands. This spacing pattern—three channels evenly separated—ensures no overlap among the three APs’ transmissions. Other channel sets place channels too close to one another, which leads to overlapping spectra and reduced performance. So the best choice is the set that follows this even spacing of channels, guaranteeing non-overlapping operation across the three APs.

In VRRP, the group presents a shared virtual MAC address that represents the virtual router. The virtual MAC follows the pattern 00-00-5E-00-01-XX, where XX is the VRID. The address 00-00-5E-00-01-01 is the VRID 1 virtual MAC, which is used by the master VRRP router to respond to traffic addressed to the virtual MAC. Other FHRP protocols use different MAC schemes, so this specific prefix and tail belong to VRRP. That’s why the correct protocol is VRRP.

IPv6 addresses have different scopes, and which ones can be routed globally depends on that scope. Global unicast addresses are intended to be reachable on the public Internet, and their assigned prefix is 2000::/3. This range is specifically designated for globally routable addresses, covering addresses that can be routed across providers and networks worldwide. In contrast, FE80::/10 are link-local addresses that stay on the local network segment and aren’t forwarded by routers; FC00::/7 (private use) are unique local addresses meant for private networks and aren’t globally routable; FF02::/16 are multicast addresses used for one-to-many delivery, not unicast routing. So the prefix that makes an IPv6 address globally routable is 2000::/3.