原文:

on a multiaccess network that has multicast capabilities,
such as Ethernet,
it is not necessary to send hello packets reliably to all neighbors individually(單獨),

EIGRP sends a single multicast hello packet containing
an indicator(指標) that informs(通知) the receivers(接收器)
that the packet need not be acknowledged(確認).

我的翻譯

多重存取網絡，具有組播功能，如Ethernet，
它沒有必要可靠地發送Hello封包給所有的鄰居

EIGRP發送一個組播hello封包，包含一個指標.
a) 這個指標 是一個通知接收器 通知封包不用被確認..
b) 這個指標 會通知接收器 說此封包不用被確認..

是a還是B還是有C的答案~~

另外...
it is not necessary to send hello packets reliably to all neighbors individually(單獨),
它沒有必要可靠地發送Hello封包給所有 鄰居
to all neighbors individually 奇怪..為何用all又用 individually(單獨),