問題文
An internet service provider is running out of public addresses for residential customers and plans a carrier-scale translation tier. An engineer proposes numbering the link between the translation devices and the customer equipment out of the shared address space reserved for that purpose. Which constraint must the design honor for that space?
選択肢
- Packets carrying those addresses must not be forwarded across provider boundaries, and the provider must filter them on ingress links.
- Devices are exempt from performing translation when identical ranges appear on two different interfaces, since the space is globally unique and so the same value can never be issued twice.
- The space must be published in the provider's external zone files, so that resolvers outside the network can map those addresses back to customer names on request.
- The space may be advertised to peering partners as long as the advertisement carries a marking that stops further propagation, because that marking prevents the partner from passing the prefix on to any network beyond its own boundary.