Question:
The headquarter office for a cement manufacturer is installing a temporary Catalyst 3550 in an IDF to connect 24 additional users. To prevent network corruption, it is important to have the correct configuration prior to connecting to the production network. It will be necessary to ensure that the switch does not participate in VTP but forwards VTP advertisements that are received on trunk ports.
Because of errors that have been experienced on office computers, all nontrunking interfaces should transition immediately to the forwarding state of Spanning tree. Also, configure the user ports (all FastEthernet ports) so that the ports are permanently nontrunking.
Requirements:
You will configure FastEthernet ports 0/12 through 0/24 for users who belong to VLAN 20. Also, all VLAN and VTP configurations are to be completed in global configuration mode as VLAN database mode is being deprecated by Cisco. You are required to accomplish the following tasks:
1. Ensure the switch does not participate in VTP but forwards VTP advertisements received on trunk ports.
2. Ensure all non-trunking interfaces (Fa0/1 to Fa0/24) transition immediately to the forwarding state of Spanning-Tree.
3. Ensure all FastEthernet interfaces are in a permanent non-trunking mode.
4. Place FastEthernet interfaces 0/12 through 0/24 in VLAN 20.
Answer and Explanation:
*But dont enter ‘vtp mode transparent’ command at begining of configuration. if you do that you will not be able to add vlan 10 to the switch. vlan 10 is not existing in the switch and it needs to be created, it will create automatically if you follow the pass4sure answer. In transparent mode vlan creation is not possible. So, do every configuration and the last moment change the vtp mode to transparent.Switch>enable
Switch#configure terminal
Switch(config)#interface range fa0/1 - 24
Switch(config-if-range)#switchport mode access (Make all FasEthernet interfaces into access mode)
Switch(config-if-range)#spanning-tree portfast (Enables the PortFast on interface)
Next, we need to assign FastEthernet ports 0/12 through 0/24 to VLAN 20.
By default, all ports on the switch are in VLAN 1. To change the VLAN associated with a port, you need to go to each interface (or a range of interfaces) and tell it which VLAN to be a part of.
Switch(config-if-range)#interface range fa0/12 - 24
Switch(config-if-range)#switchport access vlan 20 (Make these ports members of vlan 20)
Switch(config-if-range)#exit
Next we need to make this switch in transparent mode. In this mode, switch doesn't participate in the VTP domain, but it still forwards VTP advertisements through any configured trunk links.
Switch(config)#vtp mode transparent
Switch(config)#exit
Switch#copy running-config startup-config
Multiple active paths between stations cause loops in the network. If a loop exists in the network topology, the potential exists for duplication of messages. When loops occur, some switches see stations appear on both sides of the switch. This condition confuses the forwarding algorithm and allows duplicate frames to be forwarded.
To provide path redundancy, Spanning-Tree Protocol defines a tree that spans all switches in an extended network. Spanning-Tree Protocol forces certain redundant data paths into a standby (blocked) state. If one network segment in the Spanning-Tree Protocol becomes unreachable, or if Spanning-Tree Protocol costs change, the spanning-tree algorithm reconfigures the spanning-tree topology and reestablishes the link by activating the standby path.
Spanning-Tree Protocol operation is transparent to end stations, which are unaware whether they are connected to a single LAN segment or a switched LAN of multiple segments
There is a lab about STP in Cisco CCNP 642-812 / 642-892 exam.
Spanning Tree PortFast is a Catalyst feature that causes a switch or trunk port to enter the spanning tree. Forwarding state immediately, bypassing the Listening and Lerning states. IOS-based switches only use PortFast on access port connected to end stations. When a device is connected a port, the port normally enters the spanning tree Listening state. When the Forward Delay timer expires, the port enters the Learning state. When the Forward Delay timer expires a second time, the port is transitioned to the Forwarding or Blocking state. When PortFast is enabled on s switch or trunk port, the port is immediately transitioned to the Forwarding state. As soon as the switch detects the link, the port is transtitioned to the Forwarding state (less than 2 seconds after the cable is plugged in).
