Ports And Trunking; Trunking Overview; Statistical Load Distribution - Juniper EX2500 Configuration Manual

Chapter 4

Ports and Trunking

Trunking Overview

Statistical Load Distribution

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 43
Port Trunking Configuration Example on page 45
Configurable Trunk Hash Algorithm on page 47
Link Aggregation Control Protocol on page 47
Port trunking is also known as link aggregation.
NOTE:
When using port trunk groups between two switches, as shown in Figure 10 on
page 45, 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.
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.
43
Trunking Overview