Optimizing Traffic Flow with Port Controls, Port Trunking, and Filters

Port Trunking

source address to the same destination address through the same trunked link, and sends traffic from the same source address to a different destination address through a different link, depending on the rotation of path assign­ ments among the links in the trunk. Likewise, the switch distributes traffic for the same destination address but from different source addresses through different links. Because the amount of traffic coming from or going to various nodes in a network can vary widely, it is possible for one link in a trunk group to be fully utilized while others in the same trunk have unused bandwidth capacity even though the address assignments are evenly distributed across the links in a trunk. In actual networking environments, this is rarely a problem. However, if it becomes a problem, you can use the HP TopTools for Hubs & Switches network management software available from Hewlett- Packard to quickly and easily identify the sources of heavy traffic (top talkers) and make adjustments to improve performance.

Broadcasts, multicasts, and floods from different source addresses are dis­ tributed evenly across the links. As links are added or deleted, the switch redistributes traffic across the trunk group. For example, in figure 9-9-14showing a three-port trunk, traffic could be assigned as shown in table 9-8.

A

 

C1

 

W

B

Switch

C 2

Switch

X

C

C 3

Y

 

 

D

 

 

 

Z

Figure 9-14. Example of Port-Trunked NetworkTable 9-8. Example of Link Assignments in a Trunk Group (SA/DA Distribution)

Source:

Destination:

Link:

Node A

Node W

1

Node B

Node X

2

Node C

Node Y

3

Node D

Node Z

1

Node A

Node Y

2

Node B

Node W

3

 

 

 

9-32