Update Command Reference with sFlow section (sonic-net#841)

doc/Command-Reference.md

@@ -86,6 +86,9 @@
     * [PFC](#pfc)
     * [Queue And Priority-Group](#queue-and-priority-group)
   * [QoS config commands](#qos-config-commands)
+* [sFlow](#sflow)
+  * [sFlow Show commands](#sflow-show-commands)
+  * [sFlow Config commands](#sflow-config-commands)
 * [Startup & Running Configuration](#startup--running-configuration)
   * [Startup Configuration](#startup-configuration)
   * [Running Configuration](#running-configuration)
@@ -4568,6 +4571,196 @@ Some of the example QOS configurations that users can modify are given below.
 
 Go Back To [Beginning of the document](#) or [Beginning of this section](#qos)
 
+## sFlow
+
+### sFlow Show commands
+
+**show sflow**
+
+This command displays the global sFlow configuration that includes the admin state, collectors, the Agent ID and counter polling interval.
+
+- Usage:
+  ```
+  show sflow
+  ```
+
+- Example:
+  ```
+  admin@sonic:~# show sflow
+  sFlow Global Information:
+  sFlow Admin State:          up
+  sFlow Polling Interval:     default
+  sFlow AgentID:              lo
+
+  2 Collectors configured:
+    Name: collector_A         IP addr: 10.11.46.2 UDP port: 6343
+    Name: collector_lo        IP addr: 127.0.0.1  UDP port: 6343
+  ```
+
+
+**show sflow interface**
+
+This command displays the per-interface sflow admin status and the sampling rate.
+
+- Usage:
+  ```
+  show sflow interface
+  ```
+
+- Example:
+  ```
+  admin@sonic:~# show sflow interface
+
+  sFlow interface configurations
+  +-------------+---------------+-----------------+
+  | Interface   | Admin State   |   Sampling Rate |
+  +=============+===============+=================+
+  | Ethernet0   | up            |            4000 |
+  +-------------+---------------+-----------------+
+  | Ethernet1   | up            |            4000 |
+  +-------------+---------------+-----------------+
+  ...
+  +-------------+---------------+-----------------+
+  | Ethernet61  | up            |            4000 |
+  +-------------+---------------+-----------------+
+  | Ethernet62  | up            |            4000 |
+  +-------------+---------------+-----------------+
+  | Ethernet63  | up            |            4000 |
+  +-------------+---------------+-----------------+
+
+  ```
+
+### sFlow Config commands
+
+**config sflow collector add**
+
+This command is used to add a sFlow collector. Note that a maximum of 2 collectors is allowed.
+
+- Usage:
+  ```
+  config sflow collector add <collector-name> <ipv4-address | ipv6-address> [port <number>]
+  ```
+
+  - Parameters:
+    - collector-name: unique name of the sFlow collector
+    - ipv4-address : IP address of the collector in dotted decimal format for IPv4
+    - ipv6-address : x: x: x: x::x format for IPv6 address of the collector (where :: notation specifies successive hexadecimal fields of zeros)
+    - port (OPTIONAL): specifies the UDP port of the collector (the range is from 0 to 65535. The default is 6343.)
+
+- Example:
+  ```
+  admin@sonic:~# sudo config sflow collector add collector_A 10.11.46.2
+  ```
+
+**config sflow collector del**
+
+This command is used to delete a sFlow collector with the given name.
+
+- Usage:
+  ```
+  config sflow collector del <collector-name>
+  ```
+
+  - Parameters:
+    - collector-name: unique name of the sFlow collector
+
+- Example:
+  ```
+  admin@sonic:~# sudo config sflow collector del collector_A
+  ```
+
+**config sflow agent-id**
+
+This command is used to add/delete the sFlow agent-id. This setting is global (applicable to both collectors) and optional. Only a single agent-id is allowed. If agent-id is not specified (with this CLI), an appropriate IP that belongs to the switch is used as the agent-id based on some simple heuristics.
+
+- Usage:
+  ```
+  config sflow agent-id <add|del> <interface-name>
+  ```
+
+  - Parameters:
+    - interface-name: specify the interface name whose ipv4 or ipv6 address will be used as the agent-id in sFlow datagrams.
+
+- Example:
+  ```
+  admin@sonic:~# sudo config sflow agent-id add lo
+  ```
+
+**config sflow**
+
+Globally, sFlow is disabled by default. When sFlow is enabled globally, the sflow deamon is started and sampling will start on all interfaces which have sFlow enabled at the interface level (see “config sflow interface…”). When sflow is disabled globally, sampling is stopped on all relevant interfaces and sflow daemon is stopped.
+
+- Usage:
+  ```
+  config sflow <enable|disable>
+  ```
+- Example:
+  ```
+  admin@sonic:~# sudo config sflow enable
+  ```  
+**config sflow interface**
+
+Enable/disable sflow at an interface level. By default, sflow is enabled on all interfaces at the interface level. Use this command to explicitly disable sFlow for a specific interface. An interface is sampled if sflow is enabled globally as well as at the interface level. Note that this configuration deals only with sFlow flow samples and not counter samples.
+
+- Usage:
+  ```
+  config sflow interface <enable|disable> <interface-name|all>
+  ```
+
+  - Parameters:
+    - interface-name: specify the interface for which sFlow flow samples have to be enabled/disabled. The “all” keyword is used as a convenience to enable/disable sflow at the interface level for all the interfaces.
+
+- Example:
+  ```
+  admin@sonic:~# sudo config sflow interface disable Ethernet40
+  ```
+
+**config sflow interface sample-rate**
+
+Configure the sample-rate for a specific interface.
+
+The default sample rate for any interface is (ifSpeed / 1e6) where ifSpeed is in bits/sec. So, the default sample rate based on interface speed is:
+
+    1-in-1000 for a 1G link
+    1-in-10,000 for a 10G link
+    1-in-40,000 for a 40G link
+    1-in-50,000 for a 50G link
+    1-in-100,000 for a 100G link
+
+It is recommended not to change the defaults. This CLI is to be used only in case of exceptions (e.g., to set the sample-rate to the nearest power-of-2 if there are hardware restrictions in using the defaults)
+
+- Usage:
+  ```
+  config sflow interface sample-rate <interface-name> <value>
+  ```
+
+  - Parameters:
+    - interface-name: specify the interface for which the sampling rate value is to be set
+    - value: value is the average number of packets skipped before the sample is taken. "The sampling rate specifies random sampling probability as the ratio of packets observed to samples generated. For example a sampling rate of 256 specifies that, on average, 1 sample will be generated for every 256 packets observed." Valid range 256:8388608.
+
+- Example:
+  ```
+  admin@sonic:~# sudo config sflow interface sample-rate Ethernet32 1000
+  ```
+**config sflow polling-interval**
+
+This command is used to set the counter polling interval. Default is 20 seconds.
+
+- Usage:
+  ```
+  config sflow polling-interval <value>
+  ```
+
+  - Parameters:
+    - value: 0-300 seconds. Set polling-interval to 0 to disable counter polling
+
+- Example:
+  ```
+  admin@sonic:~# sudo config sflow polling-interval 30
+  ```
+
+
+Go Back To [Beginning of the document](#) or [Beginning of this section](#sflow)
 
 ## Startup & Running Configuration