Technical data

BMD00136, November 2009 65
CHAPTER 4
Ports and Trunking
Trunk groups can provide super-bandwidth, multi-link connections between switches or other
trunk-capable devices. A trunk group is a group of ports that act together, combining their
bandwidth to create a single, larger virtual link. This chapter provides configuration background and
examples for trunking multiple ports together:
 ““Overview” on page 65”
 “Port Trunking Example” on page 68
 “Configurable Trunk Hash Algorithm” on page 69
 “Link Aggregation Control Protocol” on page 70
Overview
When using port trunk groups between two switches, as shown in Figure 8, you can create
a virtual link between the switches, operating up to 40 Gb per second, depending on how
many physical ports are combined. Each G8000 supports up to 52 static trunk groups (portchannels)
and up to 52 LACP trunk groups, consisting of 1-8 ports in each group.
Trunk groups are also useful for connecting a G8000 to third-party devices that support link
aggregation, such as Cisco routers and switches with EtherChannel technology (not ISL trunking
technology) and Sun's Quad Fast Ethernet Adapter. Trunk Group technology is compatible with
these devices when they are configured manually.
Statistical Load Distribution
Network traffic is distributed statistically between the ports in a trunk group. The switch can use a
combination of Layer 2 MAC and Layer 3 IP address information, present in each transmitted
frame, to determine load distribution.