You own a small company and need to assign IPv6 addresses to your routers. Because you want to follow the guidelines spelled out in RFC 3177, you want to design your network with the correct prefixes. Which prefix would your ISP likely allocate to your company?
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A. B. C. D.B
RFC 3177, "IPv6 Address Allocation Management", provides guidelines for Internet Service Providers (ISPs) on how to allocate IPv6 address blocks to end-user organizations such as your small company. The goal of these guidelines is to ensure that end-users receive address blocks that are appropriate for their needs, while also minimizing the amount of address space that is consumed.
According to RFC 3177, ISPs should allocate address blocks to end-users based on the number of sites that they have. A site is defined as a network infrastructure that is located in a single geographical location, such as a building or campus. The guidelines recommend the following allocation sizes:
Therefore, if your small company has only one site, your ISP is likely to allocate a /48 prefix to you. This will give you a total of 2^80 (about 1.2 x 10^24) unique IPv6 addresses to use within your network.
Option A (47-bit prefix) is incorrect because it does not correspond to any of the recommended allocation sizes for end-users with a single site. Option B (48-bit prefix) is the correct answer for a small company with a single site, as it corresponds to the recommended allocation size. Option C (64-bit prefix) is incorrect because it is too large for a single site. Option D (128-bit prefix) is incorrect because it is the entire IPv6 address space and is not used for allocating address blocks to end-users.