to provide service internetworking
to support transparency for Layer 2 frames
as a connection identifier to indicate destination
as a mapping to the DLCI in service internetworking
to provide a trunk by which all VLANs can navigate from one site to one or multiple sites
第1题：
VLAN Tagging, also known as Frame Tagging, is a method developed by Cisco to help identify packets travelling through trunk links. When an Ethernet frame traverses a trunk link, a special VLAN tag is added to the frame and sent across the trunk link .How does ERS use the VLAN tag?（）
A. provide service internetworking
B. support transparency for Layer 2 frames
C. indicate destination as a connection identifier
D. map to the DLCI in service internetworking
第2题：
How does ERS use the VLAN tag?（）
第3题：
What does the text mainly tell us?
A. Tips on an important social skill. B. Importance of attending parties.
C. How to make use of associations. D. How to recite and repeat names.
第4题：
The Outer.1Q tag represents customer VLAN ID and inner.1Q tag represents Provider VLAN？（）
第5题：
–How long does the bus?-（）About half an hour.
第6题：
第7题：
（）可以给帧加上双重Tag，即在原来Tag的基础上，给帧加上一个新的Tag，从而可以支持多达4096*4096个VLAN，满足城域网对VLAN数量的需求。
第8题：
A. to provide service internetworking
B. to support transparency for Layer 2 frames
C. as a connection identifier to indicate destination
D. as a mapping to the DLCI in service internetworking
E. to provide a trunk by which all VLANs can navigate from one site to one or multiple sites
第9题：
请讲述Port-VLAN和Tag-VLAN的特点及应用环境。
第10题：
When you enter the interface command auto qos voip cisco-phone on a port at the edge of a network,how does the Cisco Catalyst switch detect if a Cisco IP Phone is connected to the port?（）