Juniper Networks EX2500 - Manual (Page 59)

Trunking Overview „ 45
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.
„ Trunking Overview on page 45
„ Port Trunking Configuration Example on page 47
„ Configurable Trunk Hash Algorithm on page 48
„ Link Aggregation Control Protocol on page 49
Trunking Overview
When using port trunk groups between two switches, as shown in Figure 10 on
page 47, you can create a virtual link between the switches, operating at up to
120 gigabits per second, depending on how many physical ports are combined.
Each EX2500 switch supports up to 12 static trunk groups (portchannels) and up to
24 Link Aggregation Control Protocol (LACP) trunk groups, consisting of 1 to 12
ports in each group.
Trunk groups are also useful for connecting a EX2500 switch to third-party devices
that support link aggregation, such as 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.
NOTE: Port trunking is also known as link aggregation.