What is one of the main drawbacks to using autosummarization?

Autosummarization is a feature used in routing protocols to simplify routing by summarizing multiple subnets into a single route advertisement. One of the primary drawbacks of using autosummarization is its requirement for networks to be contiguous. This means that all the subnets being summarized must be part of the same contiguous block of addresses.

When networks are not contiguous, autosummarization can lead to improper route advertisements. For example, if there are discontinuous subnets being aggregated, some packets may get misrouted because the summarization does not accurately represent the actual structure of the network. This can complicate network design and eliminate the benefits of summarizing routes, as non-contiguous networks must be handled differently to ensure proper routing and avoid connectivity issues.

The other choices do not encapsulate the core challenge that arises from automating this summarization process—specifically, the need for contiguous networks to allow for efficient and accurate route summarization. Thus, while other factors such as routing complexity or bandwidth usage may be related to routing practices, they do not directly tie into the significant limitation that autosummarization imposes on network design with respect to contiguity.