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  3. You need to decide on which trunking method to implement in the Ezonexam network. What is a characteristic of ISL and 802.1q fra

You need to decide on which trunking method to implement in the Ezonexam network. What is a characteristic of ISL and 802.1q fra

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问题 You need to decide on which trunking method to implement in the Ezonexam network. What is a characteristic of ISL and 802.1q frame tagging in a switched LAN environment?
选项 A、They are used to find the best path through a network.
B、They allow the exchange of filtering tables.
C、They specify different implementations of the Spanning-Tree Protocol.
D、They allow the exchange of routing tables
E、They provide inter-switch VLAN communication.
答案E
解析 Explanation: A trunk link is the other type of Layer 2 port supported on Cisco switches. When a trunk port is configured, it begins marking frames as they exit the port to indicate which VLAN each frame is associated with.

The trunk port can also read the markings, called tags, as they enter the trunk port. This enables the switch to send a frame only to the ports for the given VLAN associated with the incoming frame. The main purpose of trunking is to carry traffic between switches and maintain the VLAN information.

Unlike an access link, the trunk link does not belong to a single VLAN but instead can carry traffic from several VLANs over a point-to-point link between two devices that understand the protocol. Two forms of trunking are used for Cisco switches on Ethernet networks: An IEEE industry standard called IEEE 802.1Q.

This is a frame-tagging mechanism that adds a VLAN identifier to the frame by inserting a tag at Layer 2. Another form of trunking on Cisco switches is called Inter-Switch Link (ISL), which is a Cisco proprietary trunking mechanism. ISL uses a frame encapsulation method that adds a header to identify the VLAN.

Incorrect Answers:
A, D. These are the functions of routers, not switches.

B. Filtering tables can be used on certain Catalyst switches via the use of VLAN access control lists, but this information is never shared between switches.

C. A separate STP instance is created for each VLAN, but the STP implementation remains the same.
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