フリー問題

問題文

An engineer is reading the extension that carries a label inside the routing protocol itself, because a border device rejects the update. Which statement about the outer family that the extension covers, about the width of the label field it defines, and about what a route passed on with the next hop untouched keeps is correct?

選択肢

1. In the extension that carries a label inside the routing protocol the families it covers are those with an outer family of six or ten, the label field of its encoding is eight bits wide, and a route passed on with the next hop untouched keeps the same labels, as that extension states.
2. In the extension that carries a label inside the routing protocol the families it covers are those with an outer family of six or ten, the label field of its encoding is twenty bits wide, and a route passed on with the next hop untouched keeps the further labels, as that extension states.
3. In the extension that carries a label inside the routing protocol the families it covers are those with an outer family of one or two, the label field of its encoding is eight bits wide, and a route passed on with the next hop untouched keeps the further labels, as that extension states.
4. In the extension that carries a label inside the routing protocol the families it covers are those with an outer family of one or two, the label field of its encoding is twenty bits wide, and a route passed on with the next hop untouched keeps the same labels, as that extension states.