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CCNA3 Exploration Chapter 3. Study questions.

3.1

Why is it generally a good idea to split up a large network into smaller networks?

Splits up broadcast domains, which cuts down traffic and should improve performance. Allows different groups of users to have different facilities and security regimes.

What is the advantage of implementing subnets as VLANs rather than using routers toseparate subnets?

VLANs can be implemented using switches, which are cheaper and operate more quickly that routers. (Though a layer 3 device such as a router is still needed to route traffic between VLANs.) A VLAN can be implemented across several switches in different locations, so that a group of users with the same requirements does not have to be all together in the same place.

How manyVLANs can there be on a Catalyst 2600 series switch?

255

Which VLANs exist by default on a Catalyst 2600 switch, and which of these are intended for Ethernet networks?

VLAN 1 is for Ethernet. VLANs 1002 to 1005 also exist, but are for use on Token Ring or FDDI networks.

If you create a normal range VLAN, where will the information about it be stored?

In a file called vlan.dat whichis in flash memory. (Not in the running or startup configuration.)

A new Catalyst switch has not yet been configured. Are the Ethernet ports associated with any VLAN? If so, which one?

By default, all Ethernet ports are in VLAN 1.

Should you configure the switch IP address on VLAN 1?

You could, but it is better for security reasons to create another VLAN to be the management VLAN andassign the IP address to it. This management VLAN will be used only for managing the switch via Telnet, SSH or the web based interface.

What name is given to the type of VLAN that carries normal user traffic such as files, downloads and e-mails?

Data VLAN or User VLAN.

Which type of VLAN needs special configuration so that its traffic has priority over other traffic?

Voice VLAN.

Whatare the two methods of assigning an end device to a VLAN, and which method is more common? (Assume that voice traffic is not required.)

Port based or static VLANs are configured on switch ports and a device connecting to a port belongs to the VLAN configured on that port. Dynamic VLANs assign devices to VLANs using the MAC addresses of the devices, and these VLAN to MAC address matches need tobe stored on a server. Static VLANs are more common.

A PC attached to a switch sends out a broadcast ARP request. Which devices will receive the ARP request?

Devices on the same VLAN as the PC.

Which devices allow inter-VLAN communication?

Routers or layer 3 switches.

What is a VLAN trunk?

A link that carries traffic for more than one VLAN. It is a point to point link between twoswitches or between a switch and a router.

What is frame tagging?

It is a method of adding information to a frame to show which VLAN the frame belongs to. It is used only on VLAN trunk links.

Which protocol is now most commonly used for frame tagging, and which other protocol may still be in use?

IEEE 802.1Q is now the common protocol. Inter Switch Link (ISL) is a Cisco proprietaryprotocol that is no longer supported by newer Cisco switches, but may still be in use.

What is the purpose of the EtherType field in a frame, which is set to the hexadecimal value of 0x8100?

It signals to the device receiving the frame that this is a tagged IEEE 802.1Q frame containing VLAN information. If the frame were untagged then the device would find the length/type field in thisposition.

What does a switch port on a trunk link do if it receives a frame without a tag?

Forwards it on to the native VLAN. By default this is VLAN 1, but usually a different native VLAN is configured on a trunk link.

What is the currently approved method of creating a VLAN, number 6, called Finance, on switch SW1?

SW1(config)#vlan 6
SW1(config-vlan)#name Finance
SW1(config-vlan)#end...