フリー問題

問題文

The Layer 2 connections that join two customer edge routers across a provider are being brought under graceful restart. Where does the protection for those connections come from, and which routers of the provider have to carry that protection for it to work?

選択肢

1. It comes from the restart of the protocol that distributes labels, because those connections lean on the labels that this protocol hands out for them, and it has to be switched on at the edge of the provider and inside the provider alike, with each neighbor duly helping the restart along
2. It comes from the restart of the protocol that reserves bandwidth, because those connections lean on the paths that this protocol builds for them, and it has to be switched on at the edge of the provider alone, since no router inside the provider holds any state for such connections
3. It comes from the restart of the protocol that distributes labels, because those connections lean on the labels that this protocol hands out for them, and it has to be switched on at the edge of the provider alone, since no router inside the provider holds any state for such connections
4. It comes from the restart of the protocol that reserves bandwidth, because those connections lean on the paths that this protocol builds for them, and it has to be switched on at the edge of the provider and inside the provider alike, with each neighbor duly helping the restart along