Chapter 2: Virtual Chassis Stacking
VCStackTM Introduction
Features of VCStacking
The Physical Stack
A Virtual Chassis Stack (VCStack) is a group of physically separate switches that are connected so as to function as a single logical switch. In order to function as a VCStack, its component switches are connected using
Switches must be of the same product type to exist within the same stack. The principles of product / stack compatibility is shown in the Table 10.
Table 10. Stacking Compatibility by Product Type
Product | Via | |
Types |
| |
|
| |
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|
Product | Via | |
Type |
|
|
|
|
|
Product | SwitchBlade® x908 | Via either |
Type |
| speed rear chassis ports. |
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Product | x600 (all variants) | Via |
Type |
|
|
|
|
|
Creating a VCStack (or VCS) greatly eases network management, because you can configure all the stacked devices via a single IP address. Creating a VCS will often eliminate your need to configure protocols such as VRRP and Spanning Tree. VCS also enables you to create highly resilient networks. This resiliency can be applied in several ways.
Within the stack itself, switch interconnection is via two links. The second link is able to provide an alternative data path, thus the stack continues to function if a single link fails. Degraded performance might occur however, due to the reduced VCS bandwidth.
User ports can also be made extremely resilient by utilizing link aggregation. Aggregated links can span ports, modules, and even switches within the stack. Creating aggregated links that span multiple switches within a stack creates an extremely resilient configuration. Communication will still exist even if a switch and its aggregated ports fail.
Depending on the switch types used, a stack can comprise from 2 to 4 individual stack members interconnected via high speed stacking links. A stack always has a primary stack member called the “stack master”, and can contain up to 3 other stack members.
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