Connecting San Switches In A Layer 2 Network - Dell PS4000 Configuration Manual

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Support for creating Link Aggregation Groups (LAG)
For non-stacking switches, the ability to bind multiple physical ports into a single logical link
for use as an inter-switch trunk (IST) is required. The switch should support designating one or
more ports for IST (via Link Aggregation Groups). The switch should support creation of LAGs
consisting of at least eight 1Gbps ports or at least two 10Gbps ports.
Note: For 1GbE SANs, using non-stacking switches to connect three or more EqualLogic
arrays into a single group may negatively impact SAN I/O throughput performance.
4.3.1

Connecting SAN Switches in a Layer 2 Network

When more than one SAN switch is required, each switch connected to the array group members will be
in the same subnet. These switches must be interconnected to provide a single switched Ethernet
fabric. Figure 9 shows the two common methods for interconnecting switches, using either stacking
switches or non-stacking switches.
Figure 9 Switch Interconnects
Stacking Switches
Stacking switches provide the preferred method for creating an inter-switch connection within a Layer
2 network infrastructure. Stacking is typically accomplished using a vendor proprietary, high-bandwidth,
low-latency interconnect that allows two or more switches to be connected in such a way that each
switch becomes part of a larger, virtual switch. A stackable switch will provide a set of dedicated
stacking ports. Installation of an optional stacking module may be required. Considerations for stacking
link bandwidth:
1Gb Switches
10Gb Switches
Dell EqualLogic Configuration Guide v11.3
The stacking link bandwidth should be at least 10Gb/s in each direction on
each wire (full-duplex) to provide adequate throughput to support an
EqualLogic SAN consisting of 1Gb arrays.
The stacking link bandwidth should be at least 40Gb/s in each direction on
each wire (full-duplex) to provide adequate throughput to support an
EqualLogic SAN consisting of 10Gb arrays or a mix of 1Gb and 10Gb arrays.
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