SGS-5220 Series User Manual

User’s Manual of SGS-5220 Series
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4.19 Stack
Using Stacking, it is possible to connect a number of switches together in a stack, which behaves as a single switch as seen
from outside the stack.
Two types of stack topologies are supported:
 Ring topology
 Chain topology (same as a disconnected ring)
Multiple PLANET SGS-5220 series devices may be connected together to constitute a ring or chain stack topology using the
STX / 10Gbps SFP+ ports as interconnect links. Dedicated stacking features built into SGS-5220 series makes all devices in the
stack operate together as a single, much larger switch. Among the stacking features are:
 Hardware controlled stack wide learning and continuous automatic MAC table synchronization
 Shortest path forwarding, providing low latency and optimal use of stacking link bandwidth
 QoS consistency across stack
 Single point of management for simple stack administration
 Low Cost and Flexible SFP+ stacking solution
 Real Plug and Play connectivity
The following figure shows an example with five devices in a ring topology stack. Each device in the stack is, in a stack context,
called a unit. The ports connecting the units are called stack ports, and the ports connecting to external hosts and switches are
called front ports.
Chain Stack: A chain of sample switches, that is, no redundant forwarding paths.
Figure 4-19-1 Chain Stack topology