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10 Cards in this Set
- Front
- Back
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Name three differences between ISL and 802.1q trunk encapsulation
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ISL is Cisco proprietary and encapsulates the original frame.
Additionally ISL has no concept of a native VLAN. |
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How does ISL effect the size of ethernet frames?
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ISL adds a 26 byte header and a 4 byte trailer.
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How many FCS's are in a single ISL frame?
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2 - The original and one added at the end of the frame by the encapsulation process.
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What makes the Native VLAN different from other VLAN's?
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A native VLAN is the only VLAN that is sent out untagged when using 802.1q encapsulation.
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How can a native VLAN be encapsulated?
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By issuing the vlan dot1 tag native command in global config mode.
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What additional overhead does 802.1q encapsulation put on a frame?
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802.1q inserts a four byte tag after the source address field.
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When configuring trunks between a Cisco switch and a non Cisco switch, which trunking would you use and why?
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802.1q because ISL is Cisco Proprietary whereas 802.1q is an IEEE open standard.
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What is meant by VLAN minimization?
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Removing the native VLAN from the allowed list on a trunk.
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What is the effect of removing the native VLAN from the allowed list on a tunk?
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Data traffic will not traverse this link, however control traffic (CDP DTP etc) will continue to pass.
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What command will ensure all VLAN's are tagged when using 802.1q?
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"vlan dot1 tag native" in Global configuration
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