The network administrator is trying to add Switch1 to the network， but the 802.1Q trunk is not coming up. Switch1 was previously tested in the laboratory and its trunk configuration worked fine. What are three possible causes of this problem？（） [" The trunking configuration mode on Switch1 is set to Off."," The trunking configuration mode on the other end is set to On."," The trunking configuration mode on the other end is set to Desirable."," Cisco Discovery Protocol is not running on the other end."," There is a VTP domain name mismatch."," Switch1 does not support 802.1Q"]
Which three fields are optional in an OSPFv3 external LSA？（） ["Forwarding Address","External Route","Reference Link-State ID","Option","Prefix Optio"]
酱油的调味成分有哪些？
站段自行管理的配电箱刀闸盖缺损。，属于（）问题。 ["红线","A1","A2","B"]
C口置位/复位控制字是用（）地址写入8255的。 ["PC口","PA口","PB口","控制口"]
妨碍时间
