Click the Exhibit button. A customer has a Cisco-based network, and you are replacing the distribution layer switches with HP E-Series switches. The customer wants you to perform the migration with…

Click the Exhibit button. A customer has a Cisco-based network, and you are replacing the distribution layer switches with HP E-Series switches. The customer wants you to perform the migration with as little downtime as possible, and you plan to connect the E-Series switches temporarily in parallel with the current distribution switches, as shown in the exhibit. As part of the migration, the customer wants you also to migrate and remove all Cisco switches to open-standard protocols rather than the proprietary Cisco order, which the exhibit shows that these switches currently use. Which Cisco proprietary protocol should you wait to migrate until after you remove the Cisco distribution switches in order to avoid connectivity issues?