36
13. Trunking
Port trunk allows multiple links to be bundled together and act as a single physical link for
increased throughput. It provides load balancing, and redundancy of links in a switched
inter-network. Actually, the link does not have an inherent total bandwidth equal to the sum of
its component physical links.
Traffic in a trunk is distributed across an individual link within the trunk in a deterministic
method that called a hash algorithm. The hash algorithm automatically applies load balancing
to the ports in the trunk. A port failure within the trunk group causes the network traffic to be
directed to the remaining ports. Load balancing is maintained whenever a link in a trunk is lost
or returned to service. This switch may use Port ID, Source MAC Address, Destination MAC
Address, or a combination of Source MAC Address and Destination MAC Address to be the
selection for Trunk Hash Algorithm.
Traffic pattern on the network should be considered carefully before applying it. When a
proper hash algorithm is used, traffic is kind of randomly decided to be transmitted across
either link within the trunk and load balancing will be seen.
This switch supports one trunk group, port 9 and Port 10. Trunk hash algorithm support
Source MAC, Source & Destination MAC Address.
Figure 13-1
