Blade ICE G8000 manual Statistical load distribution, Built-In fault tolerance

RackSwitch G8000 Application Guide

Overview

When using port trunk groups between two switches, as shown in Figure 4-1, 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 trunk- ing 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 trans- mitted frame, to determine load distribution.

Each packet’s particular MAC or IP address information results in selecting one line in the trunk group for data transmission. The more data streams feeding the trunk lines, the more evenly traffic distribution becomes.

Built-In fault tolerance

Since each trunk group is comprised of multiple physical links, the trunk group is inherently fault tolerant. As long as one connection between the switches is available, the trunk remains active.

Statistical load balancing is maintained whenever a port in a trunk group is lost or returned to service.

64 „ Chapter 4: Ports and Trunking BMD00041, November 2008