Hirschmann GREYHOUND GRS1020, Reference Manual

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Redundancy
12.5 Link Aggregation
176
UM Config GRS
Release 8.0 09/2019
12.5 Link Aggregation
Link Aggregation using the single switch method helps you overcome 2 limitations with ethernet
links, namely bandwidth, and redundancy.
The Link Aggregation Group (LAG) function helps you overcome bandwidth limitations of individual
ports. LAG lets you combine 2 or more links in parallel, creating 1 logical link between 2 devices.
The parallel links increase the bandwidth for traffic between the 2 devices.
You typically use Link Aggregation on the network backbone. The function provides you an
inexpensive way to incrementally increase bandwidth.
Furthermore, Link Aggregation provides for redundancy with a seamless failover. When a link goes
down, with 2 or more links configured in parallel, the other links in the group continue to forward
traffic.
The default settings for a new Link Aggregation instance are as follows:

In the Active column, the checkbox is marked.

In the Send trap (Link up/down) column, the checkbox is marked.

In the Static link aggregation column, the checkbox is unmarked.

In the Active ports (min.) column, the value is 1 .
12.5.1 Methods of Operation
The device operates on the Single Switch method. The Single Switch method provides you an
inexpensive way to grow your network. The single switch method states that you need 1 device on
each side of a link to provide the physical ports. The device balances the traffic load across the
group member ports.
The device also uses the Same Link Speed method in which the group member ports are full-
duplex, point-to-point links having the same transmission rate. The first port the user adds to the
group is the master port and determines the bandwidth for the other member ports of the Link
Aggregation Group.
The device lets you set up up to 2 Link Aggregation groups. The number of useable ports per Link
Aggregation group depends on the device.
12.5.2 Link Aggregation Example
Connect multiple workstations using one aggregated link group between Switch 1 and 2. By
aggregating multiple links, higher speeds are achievable without a hardware upgrade.
Figure 41: Link Aggregation Switch to Switch Network
Switch 1 Switch 2
Port 1
Port 2
Port 8
Port 6
Port 7
Port 5
Port 8
Port 6
Port 7
Port 5
Hub 1
Hub 2
Hub 3
Server 1
Hub 4
Hub 5
Hub 6
Server 2