stack of x950 switches on a circuit background

VCStack Powerful Simplicity


Today’s enterprises rely on Information Technology resources and applications for accessing business-critical information and for day-to-day work. A high availability infrastructure is no longer a luxury—maintaining resource availability and data security is now of paramount importance.

Productivity is adversely affected when any of the following occur:

  • loss of access to the Internet
  • loss of access to internal servers and intranet
  • loss of IP telephony services
  • loss of customer access to public servers

It is vital, even for a small enterprise, to keep high availability considerations at the center of network design. The availability of network resources is maximized with an Allied Telesis Virtual Chassis Stacking (VCStack™) solution, providing continuous and immediate access to information when required.


VCStack enables a truly resilient network with simplified management, as multiple devices operate as a single virtual chassis. In normal operation, all bandwidth is available all the time. If a link or device fails, the network remains operational with remaining resources fully utilized.

VCStack Plus

The power of VCStack is available on the SwitchBlade x8100 Series intelligent chassis switches. Stacking two chassis provides a solution with quad resiliency—perfect for the larger enterprise business or campus network.


As well as connecting collocated switches, a VCStack can be formed over long distance fiber links for a distributed network core, or an automated disaster recovery solution for business data.

Advanced Features

As well as enabling a resilient network with simplified management, VCStack also provides advanced features such as:

  • Fast Failover: minimizes network downtime
  • Virtual MAC: maximizes network connectivity
  • Rolling Reboot: provides continuity of service
  • Provisioning: pre-configure network devices
  • Remote Login: flexible management of devices

VCStack is the network solution for today’s enterprise business. Read on to find out more.

Stacking Solutions


Network Resiliency

Prior to the advent of VCStack, high availability in enterprise networks was achieved by provisioning redundant links (with STP) and redundant routers (with VRRP). In normal operation, bandwidth and routing power would sit idle in the network.


With VCStack, Allied Telesis now provides a truly resilient network. In normal operation, all bandwidth and all routing power in the network are fully available for use all the time. If a link or device fails, some of the bandwidth or forwarding power will be lost, but the network will still be fully operational and all remaining resources will continue to be fully utilized.

Using VCStack at the core of your network allows multiple switches to appear as a single virtual chassis. This virtual chassis acts as a single switch, simplifying management.

The above diagram shows link aggregation between the core VCStack and edge switches. With link aggregation across ports on different virtual chassis members, there is no perceptible disruption in the case of a link failure, and the full bandwidth of the network is available. Link aggregation is also used to connect network resources, such as servers, across the virtual chassis members. This ensures device and path resiliency.

Virtualization of the network core ensures access to information when you need it, and this versatile solution can scale from meeting the needs of the small business right up to the larger enterprise.

VCStack Plus

Complete network core resiliency

Allied Telesis VCStack technology is now available on our SwitchBlade x8100 Series chassis switches for a powerful network core solution with quad resiliency. Two SwitchBlade x8112 chassis with dual CFC960 control cards combine to form a single virtual unit with VCStack Plus, with the simplicity of managing just one device.


Link aggregation across the two chassis to servers, network storage, and distribution switches leaves no single point of failure in this high-performing network core, ensuring device and path resiliency. Each individual chassis has PSU redundancy to ensure maximum uptime. Hot-swappable PSUs, fan trays, control and line cards allow for system maintenance and reconfiguration with no network interruption.

Real-time applications like VoIP and streaming video are assured premium service on the network, as near hitless failover between the dual control cards on each SwitchBlade x8112 means there is no perceptible disruption in the case of a problem. Even if a whole chassis is powered down, access to online resources is retained without disruption.

With the benefits of high availability, increased capacity and ease of management, VCStack Plus makes large networks reliable and simple.

Long-Distance Stacking

Distributed network core

Long distance stacking enables the VCStack solution to provide a distributed network core. The increased distance provided by fiber stacking connectivity means that members of the virtual chassis do not have to be collocated, but can be kilometers apart.


All of the benefits and powerful features of VCStack remain exactly the same—Allied Telesis long distance stacking provides a genuine distributed virtual network core.

The diagram shown here illustrates a campus where the VCStack network core is distributed across two separate buildings. By having two stack members in each location, the benefits of using link aggregation between the core and edge switches remain. The complete distributed virtual chassis provides a solution with no single point of failure, and a single management entity.

The powerful VCStack solution offers uninterrupted network access and high availability of critical resources, and yet is very simple to manage with almost plug-and-play configuration. This provides an ideal core for a data mirroring solution, where the server farm is duplicated across two sites for disaster recovery purposes.

Whether your virtual chassis is located in the same equipment rack, or distributed across the campus or the city, VCStack provides resiliency, scalability and ease of management.