Supernetting

Correct Answer: 3000::/31

When supernetting or aggregating two IPv6 networks, we inspect the network portion of the given addresses. In this case, the common portion is '3000' for the higher order 16 bits. As we are combining 3000:1000::/32 and 3000:2000::/32, the new network address starts with 3000. When we look at the third 16-bit block, it is different. This means these two networks can be combined one level up in the hierarchy. Hence, instead of a /32, we end up with a /31 prefix. Hence, the new supernet is 3000::/31. The ‘3000::/32’ and '3000:3000::/32' answers are incorrect because they retain the original /32 subnet mask. This does not represent a supernetting scenario. Answer '3000::/30' is also incorrect because it goes one level too high in aggregating the network.

Correct Answer: /22

Supernetting, also known as classless inter-domain routing (CIDR), is a method to combine multiple class C networks into a single network. Class C networks typically use a /24 subnet mask (255.255.255.0), meaning they can have up to 256 hosts. But, when superneting class C networks, we want to combine several of these small networks into a larger one, hence we need to have fewer network bits and more host bits in the subnet mask. This is why the /22 subnet mask (255.255.252.0) is the correct answer, as it allows for 1024 addresses, or 4 class C networks. The /24, /26, and /27 options represent a single class C network, a smaller segment of a Class C network, and an even smaller segment of a class C network respectively. Therefore, they can't achieve the purpose of supernetting multiple class C networks.

Correct Answer: Create a single aggregate address and mask

The best solution for an organization with multiple subnets and different CIDR values wanting to optimize routing summarization is to 'Create a single aggregate address and mask'. This is known as supernetting, a strategy that allows various small networks to appear as one large network to upstream devices, thus reducing the number of routes that a router must keep in memory. The reason the other answers are incorrect: 'Create individual aggregate addresses for each subnet' would not optimize routing, it would simply replicate the existing situation. 'Remove subnet masks from routing tables' would not be practical or effective since subnet masks are required for IP address recognition and routing. 'Increase the number of subnets' would potentially complicate routing and put additional loads on network infrastructure.