Known Behaviors

The following is a limitation in Switch Engine system architecture that has yet to be resolved.

Table 1. Known Issues, Platform-Specific, and Feature Change Requests (CRs)
Defect Number Description
ExtremeSwitching 5720 Series Switches
EXOS-31419 In a 5720 stack, FDB entries of the rebooted slot remain programmed in the hardware when performing a Master failover for the 2nd time. This results in L2 traffic destined to those FDB entries being forwarded to their previously known port, rather than flooded to all ports on the VLAN.
EXOS-31633 Dynamically changing the setting of a port‘s partition can cause the JUMBO packet counters associated with that port‘s partition group to stop incrementing.


Perform a configuration save and system reboot.

EXOS-31691 If a 5720-VIM-2CE is inserted into a 5720 switch with the selected configuration file saved prior to VIM insertion, the following log messages are displayed when rebooted:

<Noti:HAL.Card.Notice> VIM 5720-VIM-2CE is detected but does not match VIM 5720-VIM-6YE needed in slot 1

<Erro:cm.sys.LoadApplCfgObjFail> "devmgr" application failed to load "card_info" configuration object: Command timedout, please try again.

<Erro:cm.sys.LoadApplCfgObjFail> "vlan" application failed to load "ports" configuration object: Port 1 out of range.

This occurs because, by default, 5720 configuration files assume either no VIM or a 5720-VIM-6YE. 5720-VIM-2CE has different port characteristics and requires reconfiguration of all port-related settings and port-VLAN assignments.


Before turning off the switch and inserting a 5720-VIM-2CE:

  1. Enter the save configuration as-script <script-name> command.
  2. Turn off the switch.
  3. Insert the 5720-VIM-2CE.
  4. Turn on the switch.
  5. Enter the run script <script-name> command.
  6. Verify the port settings are correct.
  7. Run the save configuration <file-name> command.
EXOS-32024 Extended mode operational diagnostics on the ExtremeSwitching 5720 series switch fails one of the traffic tests when run with perpetual PoE enabled. Normal mode operational diagnostics do not have this issue.


Disable inline-power perpetual before running operational diagnostics extended and re-enable inline-power perpetual after running operational diagnostics extended.

EXOS-32025 MACsec is not working on 5720-VIM-2CE ports when using the 1x100Gb partition option.
EXOS-32047 MACsec jumbo packets greater than 4K bytes can be dropped as RX Jabber errors on 5720-VIM-2CE ports when using the 1x40Gb partition option.
EXOS-32111 Connecting a Cat5 or Cat6 Ethernet cable from an Ethernet switch access port to the Console port on an active 5720 switch may cause the switch to hang in a boot cycle after reboot or power cycling the switch.


Ensure you connect the console port on the switch to the proper terminating equipment, for example, to a PC, VT terminal, terminal server, etc.

EXOS-32107 A MACsec SAK rollover issue may occur when using cipher-suite GCM-AES-256 on MACsec-enabled access ports on ExtremeSwitching 5520 and 5720 switches.
EXOS-31724 In a stack setup, the Master and Backup slots have different default FEC settings. For 25G SFP28 ports in the stack, the default FEC setting on the Master is enabled, while the default on the Backup is disabled.


Configure the 25G Backup slot ports with FEC-enabled CL91.