Extreme Networks Extreme 7520 Series Hardware Installation Manual page 27

Build Stacks
Table 5: List of Stacking Terms (continued)
Term
Candidate node
Node role
Primary node
Backup node
Standby node
Acquired node
Data ports
Description
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.
Extreme 7520 Hardware Installation Guide
SummitStack Terms
27