Interface Management Configuration Guide

Introduction

Ethernet interfaces are commonly used for carrying out business-related tasks and data transmission. They are often referred to as ports.

Numbering Scheme

The numbering scheme for Ethernet interfaces in this product series is as follows: EthernetX. Here, X represents the interface number, starting from 1 and increasing incrementally.

Default Configuration of Interfaces

Parameter	Default value
Interface management status	UP
Interface FEC (Forward Error Correction)	Disabled
Interface description	N/A
Interface MTU (Maximum Transmission Unit)	9100 bytes
Interface POE (Power over Ethernet) supply	Disabled
Interface LLDP (Link Layer Discovery Protocol) function	Disabled
Interface MAC address	Same as device MAC address

Basic Configuration of Interfaces

The product series supports interface speeds of 1G, 2.5G, and 10G.

Operation	Command	Description
Enter the system configuration view	configure
Enter the interface view	interface Ethernet ID
Set interface description	description String
Set interface speed	speed {1000\|2500\|10000}	Different types of interfaces support different configuration parameters. Please execute the speed ? command in the relevant interface view to view specific options.
Enable interface	no shutdown	By default, the Ethernet interface is on. Execute the “shutdown” command to close the interface business function and set the physical state of the interface to “down” at the same time. Note: The power supply of the POE power interface is not affected by this command.
Modify interface FEC mode	fec {rs\|fc}	By default, the FEC mode is disabled. The FEC mode must be consistent at both ends of the link for the interface to come up. Use the no fec command to disable the FEC mode for the interface.
Enable interface POE supply function	poe enable	By default, the POE supply function for the interface is disabled. Use the no poe enable command to disable the POE supply for the interface

Configuring Layer 2/3 Mode Switching for Ethernet Interfaces

By default, the device’s interfaces do not belong to any VLAN and have no IP address configured. When an interface is configured with an IP address, VRF, or other Layer 3 attributes, it automatically switches to Layer 3 mode. If you need to change the Layer 2/3 mode of an interface, you should first remove the Layer 3 attribute configurations from the interface. Afterward, execute the no router-interface command.

Operation	Command	Description
Enter the system configuration view	configure
Enter the interface view	interface Ethernet ID
Switch the interface operation mode to layer 2.	no router-interface

Maintenance Interface

Operation	Command	Description
View interface description	show interface description
View interface POE supply information	show interface poe [detail]
View interface status	show interface status
View interface module information	show interface transceiver eeprom dom [ethernet ID]
View interface statistics:	show counters interface [ethernet ID]
Clear interface statistics	clear counters interface

Port Isolation Configuration

Introduction

Port isolation allows the isolation of ports within the same VLAN. By adding ports to an isolation group, isolation between Layer 2 data packets and multicast packets can be achieved for the ports within the isolation group. Traffic between ports within the isolation group and ports not added to the isolation group is not affected by the isolation group and can flow bidirectionally.

Configuring Port Isolation Groups

Operation	Command	Description
Enter the system configuration view	configure
Create and enter isolation group view	port-isolate-group ID
Enter interface view	interface ethernet ID
Add interface to isolation group	port-isolate ID

Configuration Example

A cell has multiple users, and now requires that the users cannot interoperate with each other’s Layer 2 messages, but all can access the external network.

1.Create a VLAN and add the interface to the VLAN

sonic(config)# vlan 100
sonic(config)# port-group ethernet 1-4
sonic(config-port-group-1-4)# switchport access vlan 100

2.Create port isolation group

sonic(config)# port-isolate-group 1
sonic(config-port-isolate-group-1)# interface 1,2,3

1.View the port ioslation group configuration

sonic# show port-isolate-group
+------------+-------------+--------+
| Group ID | Interface | Mode |
+============+=============+========+
| 1 | Ethernet1 | L2 |
| | Ethernet2 | |
| | Ethernet3 | |
+------------+-------------+--------+

2.No interoperability between PCs, all PCs can access the external network

Interface Bulk Configuration

Introduction

When configuring a specific function (e.g., port shutdown) across multiple interfaces, individually entering each interface’s view and executing commands can become cumbersome. To simplify this process, the interface bulk configuration feature can be utilized to configure interfaces in batches, thereby reducing the configuration workload.

There is no upper limit to the number of interfaces that can be included in a bulk configuration, only constrained by system resources. However, if a significant number of interfaces are involved, executing commands within the bulk interface configuration view might take longer. When performing bulk interface configuration, if the interfaces listed already possess existing configurations, attempting to enter the bulk configuration view will result in failure. In such cases, the interface list needs to be reselected.

Once inside the bulk interface configuration view, you can utilize the ”?” command to explore the supported command lines for bulk configuration.

Interface Bulk Configuration

Operation	Command	Description
Enter the system configuration view	configure
Enter the interface group configuration view	port-group ethernet ID-ID	This command only supports interfaces with consecutive ID numbers for bulk configuration
Enter the lag group configuration view	port-group lag ID-ID	This command only supports lags with consecutive ID numbers for bulk configuration

Loopback Interface Configuration

Introduction

The Loopback interface is a type of virtual interface. Once created, the physical layer of the Loopback interface remains in an “up” state unless manually disabled. Due to this characteristic, the Loopback interface can be applied in the following scenarios:

Source Address for Device-generated IP Packets: Because the Loopback interface address is stable and a unicast address, it is often regarded as an identifier for the device. By allowing or prohibiting packets carrying the Loopback interface address to pass through authentication or security servers, it is possible to permit or restrict packets generated by specific devices. This simplifies packet filtering rules. However, it should be noted that when using the Loopback interface address as the source address for IP packets, routing configurations are needed to ensure the reachability of the Loopback interface to the destination route.
Dynamic Routing Protocols: In certain dynamic routing protocols, when a router ID is not configured, the Loopback interface’s IP address is used as the router ID by default. In the context of the BGP protocol, to ensure that BGP sessions are not affected by physical interface failures, the source interface for transmitting BGP packets can be configured as the Loopback interface.
In-band Device Management: The loopback interface can be utilized for device management within the network infrastructure.

Loopback Interface Configuration

Operation	Command	Description
Enter the system configuration view	configure
Enter the loopback interface configuration view	interface loopback ID
Configure the loopback interface	ip address ip-address	The IP address of the Loopback interface can only be modified and cannot be deleted