Which Prefix Would Your ISP Allocate to Your Network?
Question
You own a home network connecting through an always-on connection 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 network?
Answers
Explanations
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A. B. C. D.B
From RFC 3177: This document provides recommendations to the addressing registries (APNIC, ARIN and RIPE-NCC) on policies for assigning IPv6 address blocks to end sites. In particular, it recommends the assignment of /48 in the general case, /64 when it is known that one and only one subnet is needed and /128 when it is absolutely known that one and only one device is connecting.
RFC 3177 outlines guidelines for assigning IPv6 addresses to end sites, including home networks. According to these guidelines, ISPs should allocate a /48 prefix to end sites, which provides 2^80 subnets and 2^64 addresses per subnet.
This allows end sites to have enough address space to allocate unique prefixes to each subnet, as well as enough addresses for future expansion. A /48 prefix is also consistent with the hierarchical addressing structure of IPv6, where the first 48 bits of an address represent the global routing prefix.
Therefore, the correct answer to the question is B. 48-bit prefix.
It's worth noting that ISPs may allocate different prefix lengths depending on their policies and the needs of their customers. However, a /48 prefix is the recommended allocation size for end sites in general.
