Skip to content
Any configuration changes made locally on the switch won't be synchronized with Sophos Central. We recommend making changes from the Sophos Central control panel instead.

Page permalink

Always use the following permalink when referencing this page. It will remain unchanged in future help versions.

https://docs.sophos.com/nsg/switch/help/en-us/index.html?contextId=user-guide-features-configure-port-settings-port

Port Settings

The Port Settings page allows you to change the configuration of the switch's ports to find the best balance of speed and flow control according to your preferences.

Note

Configuring Gigabit ports requires you to consider additional factors when arranging your preferences for the switch compared to 10/100 ports. See Network cable design and component planning.

Port

On the Port tab, you can see the following information about the ports:

  • Port: Shows the port number.
  • Link Status: Shows whether the link is up or down.
  • Mode: Select the speed and the duplex mode of the Ethernet connection on this port. Selecting Auto (auto-negotiation) allows one port to negotiate with a peer port automatically to obtain the connection speed and duplex mode that both ends support. When auto-negotiation is turned on, a port on the switch negotiates with the peer automatically to determine the connection speed and duplex mode. If the peer port doesn't support auto-negotiation or turns off this feature, the switch determines the connection speed by detecting the signal on the cable and using half duplex mode. When the switch's auto-negotiation is turned off, a port uses the pre-configured speed and duplex mode when making a connection, requiring you to make sure that the settings of the peer port are the same to connect.

  • Flow Control: Traffic concentration on a port decreases port bandwidth and overflows buffer memory, causing packet discards and frame losses. Flow Control regulates signal transmission to match the bandwidth of the receiving port. The switch uses IEEE 802.3x flow control in full-duplex mode and backpressure flow control in half-duplex mode.

    • IEEE 802.3x flow control sends a pause signal to the sending port, causing it to temporarily stop sending signals when the receiving port memory buffers fill.
    • Back Pressure flow control sends a "collision" signal to the sending port that mimics a packet collision status. This caused the sending port to temporarily stop sending signals and resend them later.

  • Description: The description given to the port.

To change port settings, select the ports you want to configure and click Edit.

Click Apply to save settings.

Port isolation

Port isolation lets you manually isolate ports and their connected devices from the network.

To isolate ports, select the ports you want to isolate and click Edit. Set the Status to Isolated and click Apply.

To allow isolated ports to access the network, select the ports you want to allow and click Edit. Set the Status to Not isolated and click Apply.

Port mirroring

Port mirroring forwards copies of incoming and outgoing packets from specific ports to a monitoring port. The packet copied to the monitoring port will be in the same format as the original packet.

Port mirroring is useful for network monitoring and diagnostics. Use port mirroring to send traffic to applications that analyze traffic for purposes such as monitoring compliance, detecting intrusions, monitoring and predicting traffic patterns, and other correlating events. Port mirroring is needed for traffic analysis on a switch because a switch normally sends packets only to the port to which the destination device is connected. The analyzer can capture and evaluate the data without affecting the endpoint computer on the original port. Port mirroring can consume significant CPU resources while active, so be cautious of such usage when configuring the switch.

You can configure the following settings:

  • Session ID: A number identifying the mirror session.
  • Destination port: The port to which you want to send mirrored traffic.
  • Egress: Mirrors traffic originating from the selected ports and sends it to the destination port.
  • Ingress: Mirrors traffic destined for the selected ports and sends it to the destination port.
  • Ingress and Egress: Turn on or off packet ingress to the destination port.
  • Session status: Turns the session on or off. Choose Not set to use settings configured locally on the switch.

Note

You can't mirror a faster port onto a slower port. For example, if you try to mirror the traffic from a 100Mbps port onto a 10Mbps port, this can cause throughput problems. The destination port must be an equal or faster speed port than the ingress and egress ports. The destination port and the source port can't be the same.

Click Apply to accept the changes or Cancel to exit without saving.

Jumbo frames

Jumbo frames allow the transmission of packets larger than the standard 1,500-byte ethernet maximum transmission unit (MTU), extending the Ethernet packet size to a maximum of 10,000 bytes.

To configure jumbo frames, The Size of the frame you want to use, up to 10,240 bytes. Click Apply to update the system settings.

Note

You must configure jumbo frames on all devices in the network. Make sure none of the devices exceed the maximum jumbo frame size.

LLDP

Link Layer Discovery Protocol (LLDP) is a neighbor discovery protocol that uses Ethernet connectivity to advertise information to devices on the same LAN and store information about the network.

You can configure the global LLDP settings and view local and remote device information on the LLDP tab. See Link layer discovery protocol (LLDP).

CDP

Cisco Discovery Protocol (CDP) is a Cisco proprietary protocol designed to facilitate the network management of Cisco devices by discovering hardware and protocol information about neighboring devices. Using CDP, you can gather information about neighboring network devices, including the type of hardware or equipment, software version, physical and VLAN interfaces the device uses, interface configuration, and other useful information.

You can configure the global CDP settings and view local and remote device information on the CDP tab. See Cisco Discovery Protocol.

Multicast filtering

Multicast is a form of communication that simultaneously allows multiple transmissions of multimedia and streaming data to specific recipients. Turning on Multicast filtering on your switch lets you filter selective multiple transmissions for devices connected to the network.

To turn on Multicast filtering, select Turned on for Status on the Multicast filtering tab.

EEE

Energy-Efficient Ethernet (EEE) reduces the power consumption of physical layer devices during low link utilization periods. EEE saves energy by allowing physical layer (PHY) non-essential circuits shut down when there's no traffic. Sophos Switch complies with the IEEE's EEE standard, 802.3az by using Lower Power Idle (LPI) to save power.

To turn on EEE, select the ports you want and click Edit. Set the EEE status to On and click Apply.

More resources