200-301 blueprint

200-301 blueprint.First, the local switch examines the new physical interfaces that have been configured to be part of the Ethernet channel, while comparing these new links to the existing links. The new physical interfaces must have the same settings as the existing links; otherwise, the switch will not add the new links to the list of those in the channel that have been verified and are working properly. This means that the physical interface is configured to always be part of the port channel, but it is not used as part of the channel and is usually in some non-working state.The list of items verified by the switch is shown below. ;, . Dependency rate. Toynon duplex. Operable access or trunk status (must be all access, or all trunk).Access VLAN is checked if an access port is available.If a trunk port is available, the list of allowed VLANs is checked (per switchporttrunk allowed command).If a trunk port is available. check the original VLAN. STP interface settings.In addition, the switch checks the settings of neighboring switches. To perform this operation, the switch needs to use PAgP or LACP (if already in use) or also Cisco Discovery Protocol (CDP) when configured manually. Adjacent switches must match all parameters in the list except for the STP setting.Let's look at an example where SW1 and SW2 are again using two links in the same Ethernet channel. Before configuring the Ethernet channel, SW1's F0/15 is given a different STP port overhead than F0/14. After the correct channel-group command is configured, as shown in Example 2-10, the switch decides whether to use F0/14 and F0/15 in the Ethernet channel.Example 2-10 Mismatched STP Overhead Results in Local Interfaces Not Being Used in an Ethernet Channel1 23:18:56.132: %PM-4-ERR_DISABLE: channel-misconfig (STP) error detected on Pol, putting FaO/14 in err-disable state