What You Need To Know About Zystack - ZyXEL Communications X6004 User Manual

Chapter 22 ZyStack

22.1.2 What You Need to Know About ZyStack

Master/Slave in ZyStack
When you create a ZyStack, the X6004s can take on a role of a master or a slave. There can
only be one master X6004 per ZyStack. You can manage the configuration of the master and
slave X6004s by logging into the LAN or WAN IP address of the master X6004.
ZyStack Failover Mode - Active
In the active mode failover all the X6004 participating in the ZyStack are also actively
participating in the processing of phone calls. The ZyStack forms a ring with each X6004
serving as a backup for the X6004 one step higher in its hierarchy. The hierarchy is organized
in the order that each X6004 joined the ZyStack. The first X6004 is the master and it is backed
up by the X6004 that was the second member of the ZyStack. The second member is backed
up by the third and so on. Finally, the master serves as a backup to the last member to join the
ZyStack. The following figure illustrates the active mode failsafe.
Figure 250 ZyStack - Active Mode
When one of the X6004s fails, then its backup X6004 services its SIP clients.
The backup cannot, however, recreate extensions created for the analog or ISDN phones on
the X6004 that is down, nor can it recreate the outbound lines using such as the FXO or ISDN
PRI/BRI ports. You must recreate those extensions and outbound line connections in order to
be used again.
ZyStack Failover Mode - Standby
In standby mode, one of the X6004s does not actively participate in the processing of phone
calls. It only gets involved in case of a break down on one of the X6004s. When a member of
the ZyStack breaks down, the standby X6004 is ready to take the place of the downed X6004.
In this failsafe mode, all of the X6004s have the same copy of the configuration. The X6004
that was standing by, is able to replace the broken down X6004 immediately.
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