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Link-flap error-disable: CLI and RESTCONF section update
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@amin-alavi
amin-alavi committed Jun 4, 2021
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Expand Up @@ -18,7 +18,8 @@ Port Link Flap Error Disable
|:---:|:-----------:|:------------------:|------------------------------------------------------|
| 0.1 | 04/14/2021 | Steven Lu | Initial version for requirements |
| 0.2 | 04/20/2021 | Steven Lu | Change feature name to Port Link Flap Error Disable |
| 0.3 | 05/11/2021 | Steven Lu | Add design details |
| 0.3 | 05/11/2021 | Steven Lu | Add design details |
| 0.4 | 05/24/2021 | Prasanth Kunjum Veettil | Add CLI and RESTCONF details |

# About this Manual
This document provides general information about the Port Link Flap Error Disable feature implementation in SONiC.
Expand All @@ -30,7 +31,7 @@ This document describes the high level design of Port Link Flap Error Disable fe
### Table 1: Abbreviations
| **Term** | **Meaning** |
|--------------------------|-------------------------------------|
| XYZ | Term description |
| xcvrd | Transceiver Daemon |

# 1 Feature Overview
The Port Link Flap Error Disable feature uses an exponential decay mechanism to prevent excessive interface flapping events from adversely affecting routing protocols and routing tables in the network. Suppressing port state change events to protect the system resources.
Expand All @@ -39,35 +40,35 @@ When Port Link Flap Error Disable is enabled, the system monitors the number of

The sampling time or window (the time during which the specified toggle threshold can occur before the wait period is activated) is triggered when the first "up to down" transition occurs.

If the port link state toggles from up to down for a specified number of times within a specified period, the interface is physically disabled for the specified wait period. Once the wait period expires, the port link state is re-enabled. However, if the wait period is set to zero (0) seconds, the port link state will remain disabled until it is manually re-enabled.
If the port link state toggles from up to down for a specified number of times within a specified period, the interface is physically disabled for the specified wait period. Once the wait period expires, the port link state is re-enabled. However, if the wait period is set to zero (0) seconds, the port link state will remain disabled until it is manually disabled and re-enabled or Port Link Flap Error Disable is disabled on this port.


## 1.1 Requirements
System shall be able to suppress interfaces state change events to protect system resources.
User shall be able to enable or disable the feature on individual interfaces and globally.
The feature must be disabled on all interfaces by default.
The feature shall be supported on physical interfaces.
There must be two sets of configuration parameters (sample-interval, waiting-period, and toggling-frequency) a per-interface set and a global set. If both global and per-interface are configured, the per-interface values are used only for given interfaces. Global values are used for all other physical interfaces.
There must be two sets of configuration parameters (sample-interval, recovery-interval, and flap-threshold) a per-interface set and a global set. If both global and per-interface are configured, the per-interface values are used only for given interfaces. Global values are used for all other physical interfaces.
If no values are specified by user, a default set of parameters are applied to all interfaces.
User shall be able to save configuration parameters (both global and per-interface).
The configuration parameters (both global and per-interface) must be preserved across device reboot.

### 1.1.1 Functional Requirements
Port Link Flap Error Disable shall use below parameters to supress and protect system.
- toggle-frequency
- flap-threshold
Specifies the number of times a port link state goes from up to down before the wait period is activated. The value ranges from 1 through 50.
- sample-interval
Specifies the amount of time, in seconds, during which the specified toggle threshold can occur before the wait period is activated. The default value is 0 and indicates that the time is forever. The value ranges from 0 through 65535.
- waiting-period
Specifies the amount of time in seconds, for which the port remains disabled (down) before it becomes enabled. The value ranges from 0 through 65535. A value of 0 indicates that the port will stay down until an administrative override occurs.
Specifies the amount of time, in seconds, during which the specified toggle threshold can occur before the wait period is activated. The value ranges from 1 through 65535.
- recovery-interval
Specifies the amount of time in seconds, for which the port remains disabled (down) before it becomes enabled. The value ranges from 0 through 65534. A value of 0 indicates that the port will stay down until an administrative override occurs.

### 1.1.2 Configuration and Management Requirements
- Port Link Flap Error Disable feature default is OFF on all physical interfaces and port-channels
- When Port Link Flap Error Disable is enabled, use below default values:
flap-threshold: 3
sample-interval: 10
toggle-frequency: 3
waiting-period: 30
- User shall be able to specify different sample-interval, toggle-frequency and waiting-period on a physical interface
recovery-interval: 300
- User shall be able to specify different sample-interval, flap-threshold and recovery-interval on a physical interface
- User shall be able to display current Port Link Flap Error Disable confiuration values.
- User shall be able to display current interface status if it was surpresed by Port Link Flap Error Disable
- User shall be able to display Link-Down-Reason if a port is disabled by Port Link Flap Error Disable feature
Expand Down Expand Up @@ -96,8 +97,80 @@ The Interface Error Disable feature exist in below modules and containers:

# 2 Functionality
## 2.1 CLI


### 2.1.1 Configuration Commands
- *link-error-disable flap-threshold <flap count> sampling-interval <interval in sec> recovery-interval <recovery interval in sec>*
Example:
```
sonic(conf-if-Ethernet0)# link-error-disable flap-threshold 10 sampling-time 3 recovery-timeout 10
```
In this example, the values for the parameters are as follows:

The flap-threshold is set at 10 times. This interval is the number of times that the port's link state goes from up to down and down to up before the recovery-timeout is activated. Enter a valid value range from 1-50. Default is 3.


The sampling-time is set to 3 seconds. This time period is the amount of time during which the specified flap-threshold can be crossed. If the flap-threshold is crossed during this sampling-time, port will be error-disabled. Enter a value between 1 and 65535 seconds. Default is 10.


The recovery-timeout is set to 10 seconds. This period of time is the amount of time the port remains disabled (down) before it becomes enabled. Entering 0 indicates that the port will stay down until an administrative override occurs. Enter a value between 0 and 65534 seconds. Default is 300.


This config command can be executed on a range of interfaces as well. Example:
```
sonic(conf-if-range-eth**)# link-error-disable flap-threshold 10 sampling-time 3 recovery-timeout 10
```
Example for disabling link-flap error-disable on a port:
```
sonic(conf-if-Ethernet0)#no link-error-disable
```
This command shall be supported on interface range as well. Example:
```
sonic(conf-if-range-eth**)#no link-error-disable
```

- *[no] errdisable recovery cause link-flap*
This is a global command to enable the link-flap error-disable feature. This is an existing command tree and link-flap CLI node is added.

Link-flap feature has to be enabled globally to start this feature even when port level configurations are already present.
When the user executes 'no errdisable recovery cause link-flap' to disable the feature at system level, the current monitoring for link-flaps on all the ports will be stopped.

```
sonic(config)# errdisable recovery cause link-flap
sonic(config)# no errdisable recovery cause link-flap
```

### 2.1.2 Show Commands

"show errdisable recovery" is an existing CLI command. This output will be updated to list the ports in recovery period.
- *show errdisable recovery*
This command displays the err-disable recovery features. Link-flap is one among the features where in err-disable recovery option can be enabled.
Example:
```
sonic#show errdisable recovery
Err-Disable Reason Timer Status
-----------------------------------
udld Disabled
bpduguard Disabled
xcvrd Disabled
link-flap Enabled
Interfaces that will be enabled at the next timeout:
Interface Errdisable reason Time left(sec)
-----------------------------------------------------
Ethernet0 link-flap 24
```
- *show errdisable link-flap*
Status and configuration details of link-flap error-disable is shown with this command.
The ports which does not have non-default error disable configurations will not be displayed in the output.

Example:
```
sonic#show errdisable link-flap
Interface Flap-threshold Sampling-time Recovery-timeout Status
---------------------------------------------------------------------------
Ethernet0 10 3 30 Errdisabled
Ethernet4 10 3 60 Not-errdisabled
Ethernet8 5 10 300 Off
```
# 2.2 Functional Description

# 3 Design
Expand All @@ -108,19 +181,19 @@ For individual physcial interface
"PORT|Ethernet124":
{
"error-disable": "on|off",
"toggle-frequency": "3",
"flap-threshold": "3",
"sampling-interval": "5",
"wait-time-period": "10"
"recovery-interval": "10"
},

### 3.2.2 APP DB
For individual physcial interface
"PORT_TABLE|Ethernet124":
{
"error-disable": "on|off",
"toggle-frequency": "3",
"flap-threshold": "3",
"sampling-interval": "5",
"wait-time-period": "10"
"recovery-interval": "10"
},

To surpress interface:
Expand All @@ -139,9 +212,9 @@ Record number of link flaps within sampling-interval:
"supress-time": time,

"error-disable": "on|off",
"toggle-frequency": "3",
"flap-threshold": "3",
"sampling-interval": "5",
"wait-time-period": "10"
"recovery-interval": "10"
}

### 3.2.4 ASIC DB
Expand Down Expand Up @@ -172,6 +245,47 @@ Can be reference to YANG if applicable. Also cover gNMI here.
Refer to Functionality

### 3.6.3 REST API Support
POST "<REST-SERVER:PORT>/restconf/data/openconfig-errdisable-ext:errdisable-port/port=<ifname>/link-flap"
Request body:
{
"openconfig-errdisable-ext:link-flap": {
"config": {
"error-disable": <string>,
"flap-threshold": <number>,
"sampling-interval": <number>,
"recovery-interval": <number>
}
}
}

Example:
```
POST "<REST-SERVER:PORT>/restconf/data/openconfig-errdisable-ext:errdisable-port/port=Ethernet24/link-flap"
{
"openconfig-errdisable-ext:link-flap": {
"config": {
"error-disable": "on",
"flap-threshold": 10,
"sampling-interval": 20,
"recovery-interval": 300
}
}
}
```

GET "<REST-SERVER:PORT>/restconf/data/openconfig-errdisable-ext:errdisable-port/port=<ifname>/link-flap/state"

Example:
```
GET "<REST-SERVER:PORT>/restconf/data/openconfig-errdisable-ext:errdisable-port/port=Ethernet24/link-flap/state"
Response data:
{
"openconfig-errdisable-ext:state": {
"time-left": 14
}
}
```

### 3.6.4 Service and Docker Management
No new service ot docker introduced

Expand Down

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