NSX-T BGP configuration changes are not working due to Non-Default values of BGP Timers in NSX-T Data Center

Products

• VMware NSX

Issue/Introduction

Symptoms:

• You are using NSX-T versions  3.2.0.x till 3.2.2.x or VMware NSX 4.0.x till 4.1.0.x.
• The 'Graceful Restart Timer' or 'Graceful Restart Stale timers' in T0 BGP configuration has been changed from default values. The default values of these counters on NSX are:
  Graceful Restart Timer: 180 and Graceful Restart Stale timers:600.
• In the NSX-T Policy UI, when: adding or deleting route aggregation prefixes; changing local_as; enable or disable ECMP; Inter-SR iBGP; Multipath Relax, on the T0 gateway, you will be able to see these changes but none of these changes will be applied.
• Adding or deleting route aggregation in policy mode, wont be reflected in Manager mode. 
• For example, the following ERROR's can be seen in the /var/log/proton/nsxapi.log, when editing route aggregation:
  2023-03-06T18:22:37.045Z ERROR providerTaskExecutor-90 PolicyProviderUtil 4772 POLICY [nsx@6876 comp="nsx-manager" errorCode="PM0" level="ERROR" subcomp="manager"] Created alarm Alarm [policyPath=/infra/realized-state/enforcement-points/default/routing-bgp/name/alarms/########-####-####-####-##########b7, message=Found errors in the request. Please refer to the related errors for details.,errorId=PROVIDER_INVOCATION_FAILURE, path=null, apiError=error_code=10000, module_name=ROUTING, error_message='Found errors in the request. Please refer to the related errors for details.'
  related_errors=[
  error_code=11170, module_name=ROUTING, error_message='[Routing] Graceful restart timers can not be modified when BGP is enabled.'
  ], sourceSiteId=null].

Environment

VMware NSX-T Data Center
VMware NSX-T

Cause

When the BGP Graceful Restart Timer and Graceful Restart Stale Timer are configured with non default values, this issue can occur.

Resolution

This issue is resolved in VMware NSX-T 3.2.3 (build number 21703624)
This issue is resolved in VMware NSX-T 4.1.1 (build number 22224312)

Workaround:
There are 2 workarounds for this issue:

1. In case you must use non-default values for Graceful Restart Timer and Graceful Restart Stale Timers, perhaps due to dependencies on the peer, each time the following are edited: adding or deleting route aggregation prefixes; changing local_as; enable or disable ECMP/Inter-SR iBGP/Multipath Relax, BGP on the T0 gateway needs to be disabled and re-enabled so the changes can take effect.
2. In the case where the BGP peer device supports the default values of the NSX-T Graceful Restart Timer: 180 and Graceful Restart Stale timers:600, leave NSX-T T0 gateway default timers and set the peer BGP timers to match.