Concept

The stack device is a logical device that is providing the actual switching effect. It gives you information about all the switch ports that are available to the stack, their addresses and so on. It is the thing that is managed on the network.

Each of the stack members are physical devices.

Staring from TKU October 2019 Discovery deliberately reports serial for stack with additional suffix "_STACK", so the serials for stack (logical device) and stack master (physical device) are different.  For example, stack serial is "123456_STACK" and serial for the stack master is "123456".

Description

The module is designed in order to do the following:

• discover stack member Network Devices;
• add additional attributes on stack and stack members; 
• create relationships between stack members and stack (as well as between interfaces on the stack device and stack members).

Supported vendors

Currently, Cisco Systems , Alcatel-Lucent, Hewlett-Packard (including Aruba and H3C), Alcatel-Lucent, Extreme, Juniper Networks, Dell EMC and Huawei Network Devices are supported.

Supported BMC Discovery versions

11.2+, TKU March 2018 +

Triggers

Product Architecture

Module consists of two patterns - StackDevice and StackRemoval.

The goal of the StackDevice pattern is to create stack member Network Devices and appropriate relationships between stack and stack members.

Pattern triggers on Discovered Chassis having hardware_type "Stack" and vendor supported (see "Supported vendors" section above). Discovered Chassis with hardware_type = "Stack" indicates that this Network Device might be a stack device.

Then pattern obtains list of Discovered Chassis with the hardware_type "Chassis" by traversing from the Discovery Access (for the stack device, each Discovered Chassis with this type represent stack member).

If the number of such chassis more then one, we know that this devices is stack and can create stack member Network Device for each chassis.

Attribute "Stack" is put on the stack device on this stage. When creating stack member Network Device pattern check if its serial number is matching the serial number of the stack device, if yes, the attribute "Stack Master" is set for this stack member.

After creating stack members pattern creates relationships between stack and stack members (Stack : DeviceStack : StackMember : NetworkDevice).

Based on the information obtained from the Discovered Cards (DDD nodes) pattern creates relationships between Network Interfaces of the stack and stack member device to whom those interfaces physically belong,

The goal of the StackRemoval pattern is to actually remove "Stack" attribute from the device which is no longer stack and also remove all the relationships to the stack member devices.  It is also responsible for "aging" of the stack members.

Below you can see the example of the stack device with three stack member devices:

... and example of the stack member device (stack master)

Additional information

Aging

Starting from TKU July 2022 stack members have aging, so they are not deleted immediately in case there is no evidence of their existence, but only get removed as stack member device reaches device aging access failures threshold.

Stack member name

Starting from March 2019 TKU name attribute for stack member devices contains name of the stack device. The format is "<stack name> - <stack member serial>".  For example "mydevice1.test.com - 123311SS".

The only exception is Cisco FEX modules. Starting from April 2020 TKU name attribute for FEX stack members is created using the following format "<fex number> - <stack member serial>".

So instead of name like "Stack Member Fex-132 Nexus2248 Chassis (1231313SS)" it is changes to "FEX-132 - 1231313SS".

Additional attributes added by module

For the stack device:

• "Stack" - Indicates that this device is stack device.

For the stack members:

• "Stack Master" - Indicates that this stack member is the device handling the stack. In this case serial number for stack and stack master will be the same.

Cisco Catalyst stack switches model names

Additional information about model naming approach for Cisco Catalyst stack switches can be found here.

Limitations

No known limitations.