Extreme Networks ExtremeSwitching 5720 Series Hardware Installation Manual page 46

SummitStack Terms
Table 15: List of Stacking Terms (continued)
Term
Active topology
Candidate node
Node role
Primary node
Backup node
Standby node
Acquired node
Data ports
46 ExtremeSwitching 5720 Series Hardware Installation Guide
Description
A contiguous set of active nodes in a stack topology plus the set of
stacking links that connect them. When an active topology consists of
more than one node, each node in the active topology is directly and
physically connected to at least one other node in the active topology.
Thus, the active topology is a set of physically contiguous active nodes
within a stack topology.
A node that is a potential member of an active topology, or an active node
that is already a member of an active topology. A candidate node may or
may not be an active mode – that is, it may or may not have joined the
control path.
The role that each active node plays in the stack – either primary, backup,
or standby.
The node that is elected as the primary node in the stack. The primary
node runs all of the configured control protocols such as OSPF (Open
Shortest Path First), RIP (Routing Information Protocol), Spanning Tree,
and EAPS (Extreme Automatic Protection Switching).
The primary node controls all of its own data ports as well as all data ports
on the backup and standby nodes. To accomplish this, the primary node
issues specific programming commands over the control path to the
backup and standby nodes.
The node assigned to take over the role of primary if the primary node
fails. The primary node keeps the backup node's databases synchronized
with its own databases in preparation for such an event.
If and when the primary node fails, the backup node becomes the primary
node and begins operating with the databases it has previously received.
In this way, all other nodes in the stack can continue operating.
A node that is prepared to become a backup node in the event that the
backup node becomes the primary node. When a backup node becomes a
primary node, the new primary node synchronizes all of its databases to
the new backup node.
When a node operates in a standby role, most databases are not
synchronized – except those few that directly relate to hardware
programming.
A standby or backup node that is acquired by a primary node. This means
that the primary node has used its databases to program the hardware of
the standby or backup node. The standby or backup node has acted as a
hardware programming proxy, accepting the instructions of the primary
node to do so.
An acquired backup node maintains the databases needed to reflect why
the hardware is programmed as it is. However, a standby node does not.
An acquired node can be re-acquired (without a reboot) by the backup
node only when the backup node becomes the primary node, and only
when both the backup and standby nodes were already acquired by the
same primary node at the time of its failure.
The set of ports on a stackable switch that are available for connection to
your data networks. Such ports can be members of a user-configured
VLAN or trunk group. They can be used for Layer 2 and 3 forwarding of
user data traffic, for mirroring, or other features you can configure. Data
ports are different from stacking ports.
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