[Edgecore SONiC] Dynamic Port Breakout Follow

Ports can be broken out to different speeds with various lanes. E.g. If we want to change port 0 from 100G to port 0-4 with 4x25G. 

How to configure the DPB(Dynamic Port Breakout) on Edgecore SONiC.

• Dynamic Port Breakout

Support models

• Switch model name:

AS7726-32X, AS7326-56X, AS7816-64X, AS5835-54X(T), AS4630-54PE, AS9716-32D, Wedge100BF-32X

• Edgecore SONiC version:

         - Edgecore-SONiC_20201123_130028_ec202006_74

         - Edgecore-SONiC_20201229_070315_ec202006_101

         - Edgecore-SONiC_20210209_051110_ec202006_134

         - Edgecore-SONiC_20201229_070315_ec202006_bfn_65(Wedge100BF-32X)

Restriction

1. Refer to this 202006 restored guide for config restore. 
   
2. Admin status of interfaces is down by default after applying Dynamic Port Breakout setting. 
3. AS5835-54X(T), since hardware limitation, it could only set the port breakout on Ethernet48 and Ethernet60.
4. On the version "Edgecore-SONiC_20210209_051110_ec202006_134", AS9716-32D support more breakout mode "2x50G(4), 4x25G[10G](4)".

Dynamic Port Breakout

Step 1. We should remove the ip interface/ VLAN member and portchannel member on ports which we want to run the DPB.

Assume if we want to run DPB on "Ethernet48", we need to remove the ip interface on the port.

admin@sonic:~$ show ip interfaces 
Interface    IPv4 address/mask    Admin/Oper
-----------  -------------------  ------------
Ethernet48   192.168.1.1/24       up/up
docker0      240.127.1.1/24       up/down
eth0         188.188.98.25/16     up/up
lo           127.0.0.1/8          up/up
             10.1.0.1/32
admin@sonic:~$ sudo config interface ip remove Ethernet48 192.168.1.1/24

Assume if we want to run DPB on "Ethernet52", we should remove it from the VLAN member of VLAN100.

admin@sonic:~$ show vlan brief     
+-----------+----------------+------------+----------------+-----------------------+    
|   VLAN ID | IP Address     | Ports      | Port Tagging   | DHCP Helper Address   |    
+===========+================+============+================+=======================+    
|       100 | 192.168.2.2/24 | Ethernet52 | untagged       |                       |   
+-----------+----------------+------------+----------------+-----------------------+    

admin@sonic:~$ sudo config vlan member del 100 Ethernet52

Assume if we want to run the DPB on "Ethernet0", we should remove it from portchannel member of PortChannel01.

admin@sonic:~$ show interface portchannel
Flags: A - active, I - inactive, Up - up, Dw - Down, N/A - not available,
S - selected, D - deselected, * - not synced
No. Team Dev Protocol Ports
----- ----------- ----------- ------------
PortChannel01 LACP(A)(Dw) Ethernet0(D)

admin@sonic:~$ sudo config portchannel member del PortChannel01 Ethernet0

Step 2. Check breakout option availability and current breakout mode on Ethernet48.

admin@sonic:~$ show interfaces breakout
{
	...omitted...
 "Ethernet48": {
      "index": "49,49,49,49",
      "default_brkout_mode": "1x100G[40G]",  
      "child ports": "Ethernet48",
      "breakout_modes": "1x100G[40G], 2x50G, 4x25G, 4x10G",                        
      "child port speeds": "100G",
      "Current Breakout Mode": "1x100G[40G]",
      "lanes": "77,78,79,80",
      "alias_at_lanes": "Eth49/1, Eth49/2, Eth49/3, Eth49/4"
  },
.......omitted...
}


admin@sonic:~$ show interfaces breakout current-mode Ethernet48
+-------------+-------------------------+
| Interface   | Current Breakout Mode   |
+=============+=========================+
| Ethernet48  | 1x100G[40G]             |                                
+-------------+-------------------------+

Step 3. Configure dynamic port breakout

admin@sonic:~$ sudo config interface breakout Ethernet48 '4x25G'   
Do you want to Breakout the port, continue? [y/N]: y
Running Breakout Mode : 1x100G[40G]
Target Breakout Mode : 4x25G
Ports to be deleted :
 {
    "Ethernet48": "100000"
}
Ports to be added :
 {
    "Ethernet50": "25000",
    "Ethernet51": "25000",
    "Ethernet49": "25000",
    "Ethernet48": "25000"
}
After running Logic to limit the impact
Final list of ports to be deleted :
 {
    "Ethernet48": "100000"
}
Final list of ports to be added :
 {
    "Ethernet50": "25000",
    "Ethernet51": "25000",
    "Ethernet49": "25000",
    "Ethernet48": "25000"
}
Loaded below Yang Models
['sonic-acl', 'sonic-extension', 'sonic-interface', 'sonic-loopback-interface', 'sonic-port', 'sonic-portchannel', 'sonic-types', 'sonic-vlan']
Note: Below table(s) have no YANG models:
CONTAINER_FEATURE, VERSIONS, DEVICE_METADATA, FEATURE, FLEX_COUNTER_TABLE, BREAKOUT_CFG, CRM,
Breakout process got successfully completed.
Please note loaded setting will be lost after system reboot. To preserve setting, run `config save`.
admin@sonic:~$

 Caution :Be careful, please use include the mode setting with ' '.

Step 4. Show breakout current mode status and interface status

admin@sonic:~$ show interfaces breakout current-mode Ethernet48
+-------------+-------------------------+
| Interface   | Current Breakout Mode   |
+=============+=========================+
| Ethernet48  | 4x25G                   |
+-------------+-------------------------+

admin@sonic:~$ show interfaces status
  Interface            Lanes    Speed    MTU    FEC    Alias    Vlan    Oper    Admin             Type    Asym PFC
-----------  ---------------  -------  -----  -----  -------  ------  ------  -------  ---------------  ----------
... omitted
 Ethernet48               77      25G   9100   none  Eth49/1  routed    down     down  QSFP28 or later         N/A
 Ethernet49               78      25G   9100   none  Eth49/2  routed    down     down              N/A         N/A
 Ethernet50               79      25G   9100   none  Eth49/3  routed    down     down              N/A         N/A 
 Ethernet51               80      25G   9100   none  Eth49/4  routed    down     down              N/A         N/A<
... omitted

Step 5. Save configuration to startup configuration. 

admin@sonic:~$ sudo config save -y
Running command: /usr/local/bin/sonic-cfggen -d --print-data > /etc/sonic/config_db.json