Port Speed Configuration

Port Speed Configuration design

Overview

Port Speed Configuration feature allows user to specify speed for each individual switch port in the minigraph config file.
To configure port speed, user is required specify a valid port speed value in the platform specific minigraph config file.
If no speed specified, port will remain configured to the default value specified in SAI profile.

General feature design

Port Speed Configuration Data Flow

Port speed specified in the minigraph will be processed by the sonic-cfggen which using a ports configuration template will generate port configuration json file. Json file is applied using swssconfig utility after orchagent start, similar to mirror, ipinip and other configs.
Command to be executed in the run-time to fetch port properties from the minigraph and create a ports configuration json file.

sonic-cfggen -m /etc/sonic/minigraph.xml -t /usr/share/sonic/templates/ports.json.j2 > /etc/swss/config.d/ports.json

Components to be updated

Minigraph changes

Port speed property is specified in the corresponding platform specific xml file.
File location: sonic-mgmt/ansible/minigraph
In the XML hierarchy speed is under DeviceInfos/DeviceInfo/EthernetInterfaces/EthernetInterface
XML tag to set speed is Speed.
Speed should be specified in Mbits per second. E.g. for 100G need to specify 100000.

Sample of the minigraph with the speed set for port Ethernet1:

...
<DeviceInfos>
...
	<DeviceInfo>
		<EthernetInterfaces>
			...
			<EthernetInterface>
				<InterfaceName>Ethernet1/1</InterfaceName>
				...
				<Speed>40000</PortSpeed>
				...
			</EthernetInterface>
			...
		</EthernetInterfaces>
	</DeviceInfo>
</DeviceInfos>

Minigraph parser

src/sonic-config-engine/minigraph.py updated to parse new minigraph section. Result stored in the exported variable ethernet_interfaces of type list. Elements of the list are dictionaries which contains so far only two key-value records:

'name'  : '<interface name>'
'speed' : '<interface speed>'

More records will likely be added as minigraph has other values in this section (negotiation, interface type, index, priority, etc).
A new unit test in src/sonic-config-engine/tests/test_cfggen.py is added to validate new parser functionality. Unit tests for minigraph parser executed during the sonic image build.

Ports configuration JSON

Template location and name is sonic-buildimage/dockers/docker-orchagent/ports.json.j2

Sample of the ports configuration template:

[
{% for interface in interface_aux_properties %}
    {
        "PORT_TABLE:{{ interface['name'] }}": {
            "speed": "{{ interface['speed'] }}",
        },
        "OP": "SET"
    }
{% endfor %}
]

Sample of the produced ports.json

[
    {
        "PORT_TABLE:Ethernet100": {
            "speed": "40000",
        },
        "OP": "SET"
    },
    {
	...
    }
]

Applying generated configuration on the switch

Json file is applied using swssconfig utility after orchagent start similar to mirror, ipinip and other configs.
swssconfig.sh is updated to apply generated ports.json

An example of the PORT_TABLE content after applying the json:

127.0.0.1:6379> hgetall PORT_TABLE:Ethernet100
...
 7) "admin_status"
 8) "up"
 9) "mtu"
10) "9216"
11) "speed"
12) "40000"

Orchagent update

Orchagent (portsorch) handles PORT_TABLE updates.
Function PortsOrch::doPortTask(Consumer &consumer) need to be updated to handle port speed updates in PORT_TABLE table and set speed on hardware via SAI:

sai_port_api->set_port_attribute(port, SAI_PORT_ATTR_SPEED = speed)

Input validation

Before applying speed on port Orchestration Agent will perform input string validation. This includes the following:

• speed string could be converted to integer without errors
• speed value is in the list of supported port speeds (requested via SAI using attribute SAI_PORT_ATTR_SUPPORTED_SPEED). If SAI returns result indicating this attribute is not supported, orchagent will attempt to apply the speed anyway.