You configure a new VLAN of 22 on Switch A. You have configured a few access links with the new VLAN and they work as normal. They do not forward traffic to ports configured in the same VLAN on Switch B. All other VLANs function fine between the switches. What is the problem?

The VLAN is not allowed over the trunk because of the switchport trunk allowed vlan command. The native VLAN is used when frames are not tagged, and the problem states that traffic in the same VLAN is not being forwarded. The trunk encapsulation is set to 802.1Q, which is the default for many switches. Also, if encapsulation was not set properly, no traffic would be forwarded. VTP is not required for switching operation, although it is helpful.