Cisco Stacking : All about FlexStack-Plus, FlexStack-Extended ( Fiber and Hybrid)

Today I am going to talk about the Cisco stacking technology on the access layer devices specially on the Cisco Catalyst Access switches. The terminology uses for Cisco stacking are Flex-Stack plus and Flex-Stack Extended modules. 

They have lot of differences and will be discussed in this article I will talk about them one by one and then we take it through the difference between them.

You ever heard about the famous feature of stacking in the access switching called as Cisco stack-wise with the stacking of the four Cisco 2960-S devices for a single management and the control plane. 

But there are some cases where enterprise have the more users to connect and want more stacking in order to get the more users connected in Cisco 2960-X/XR or Cisco 3850/9300. The concept of Flex-Stack plus and Flex-Stack extended came into picture.

     Cisco Flex Stack Plus and Extended modules
Fig 1.1- Cisco Flex Stack Plus and Extended modules

Modules- FlexStack Plus and FlexStack Extended
With the help of Flex-Stack Plus and Flex-Stack extended, Up to eight Cisco Catalyst 2960-X/XR and Cisco 3850/9300 Series Switches can be stacked, with a single management and control plane.

The FlexStack-Plus and FlexStack-Extended modules are simple-to-install plug-and-play modules, with no preset configuration requirements. They simplify troubleshooting of multiple switches spread over large areas of the campus.

The FlexStack-Extended module uses the same rules for stack master election as FlexStack-Plus switches. These modules can be inserted into the stack module slot at the rear of the Cisco Catalyst 2960-X/XR and Cisco 3850/9300 Series Switches

FlexStack-Plus module allows stacking over copper and provides high bandwidth of up to 80 Gbps over short distances while with the help of FlexStack- Extended module we can have the stacking over SFP+ ports and provides stacking bandwidth of up to 40 Gpbs over longer distance. 

It can be used to stack switches across wiring closets on different floors of a building or across different buildings in a campus. FlexStack Extended has two versions, FlexStack fiber Extended and FlexStack Hybrid Extended

   Configuring Flex-Stack Extended on NDNA Switch ( 2960 or 3850 )

   Check H-stack Ports

For the use of FlexStack-Extended modules, all switches in the stack require upgrade to Cisco IOS Software Release 15.2(6)E or later.

Fast convergence is not supported on stack switches with FlexStack-Extended ports. When adding a new switch to an existing stack, power off the new switch and then connect the stack cables. This is to prevent reload of the existing stack and stack master re-election.