
Trunk link is used to carry the different VLANs traffic on a single link. There are two different protocols are used for Ethernet trunking, 802. 1q and ISL. Trunking change the formatting of the packets. The ports need to be in agreement as to which format is being use to transmit data on the trunk, if there is different trunking encapsulation on the two ends of the link they will not able to communicate....