D-Link DXS-3400 User Manual - Page 164

DXS-3400 Series Lite Layer 3 Stackable 10GbE Managed Switch Web UI Reference Guide Link Aggregation Understanding Port Trunk Groups Port trunk groups are used to combine a number of ports together to make a single high-bandwidth data pipeline. The Switch supports up to 32 port trunk groups with up to 8 ports in each group. Figure 5-66Example of Port Trunk Group The Switch treats all ports in a trunk group as a single port. Data transmitted to a specific host (destination address) will always be transmitted over the same port in a trunk group. This allows packets in a data stream to arrive in the same order they were sent. Link aggregation allows several ports to be grouped together and to act as a single link. This gives a bandwidth that is a multiple of a single link's bandwidth. Link aggregation is most commonly used to link a bandwidth intensive network device or devices, such as a server, to the backbone of a network. The Switch allows the creation of up to 32 link aggregation groups, each group consisting of up to 8 links (ports). Each port can only belong to a single link aggregation group. All of the ports in the group must be members of the same VLAN, and their STP status, static multicast, traffic control; traffic segmentation and 802.1p default priority configurations must be identical. Port locking and 802.1X must not be enabled on the trunk group. Further, the LACP aggregated links must all be of the same speed and should be configured as full duplex. Load balancing is automatically applied to the ports in the aggregated group, and a link failure within the group causes the network traffic to be directed to the remaining links in the group. The Spanning Tree Protocol will treat a link aggregation group as a single link, on the Switch level. On the port level, the STP will use the port parameters of the Master Port in the calculation of port cost and in determining the state of the link aggregation group. If two redundant link aggregation groups are configured on the Switch, STP will block one entire group; in the same way STP will block a single port that has a redundant link. 154