Final answer:
An example of a network ID after subnetting could be 2001:db8:abcd:1000::/64, 2001:db8:abcd:1::/64, or 2001:db8:abcd::/64, depending on the specific subnetting structure chosen within the original /48 address space.
Step-by-step explanation:
The correct answer is option b) 2001:db8:abcd:1000::/64.An IPv6 address is divided into two parts: the network ID and the host ID. When subnetting an IPv6 address, the network ID remains the same, but the host ID is divided further to create smaller networks within the main network. In this case, the network ID given is 2001:db8:abcd::/48, and after subnetting, an example network ID could be 2001:db8:abcd:1000::/64.By creating subnets within a larger network using subnetting, it allows for better organization, management, and optimization of network resources.The question posed by the student revolves around the concept of subnetting a Global Unicast Address in the context of IPv6 addressing. When an Internet Service Provider (ISP) issues a company a Global Unicast Address, this address can be divided into smaller networks or subnets. In your specific example, we're dealing with a base network which could be something like 2001:db8:abcd::/48.
This indicates that the first 48 bits of the address are used for the network prefix.Subnetting comes into play when further structuring is needed within the network. For example, option (b) 2001:db8:abcd:1000::/64 reflects a subnet of the original /48 network. This notation shows that the network has been extended to 64 bits to include additional specificity for subnetworks. The '1000' is the subnet identifier added to the original prefix. On the other hand, options (c) 2001:db8:abcd:1::/64 and (d) 2001:db8:abcd::/64 also represent possible subnets. Where (c) indicates a specific subnet with a subnet ID of '1', and (d) could be interpreted as a direct subnet of the provided address with no additional subnetting, likely the first subnet of many. Therefore, an example network ID after subnetting the provided /48 address could look like one of the provided choices (b), (c), or (d).