No relevant resource is found in the selected language.

This site uses cookies. By continuing to browse the site you are agreeing to our use of cookies. Read our privacy policy>Search

Reminder

To have a better experience, please upgrade your IE browser.

upgrade

NE20E-S2 V800R010C10SPC500 Configuration Guide - IP Services 01

This is NE20E-S2 V800R010C10SPC500 Configuration Guide - IP Services
Rate and give feedback:
Huawei uses machine translation combined with human proofreading to translate this document to different languages in order to help you better understand the content of this document. Note: Even the most advanced machine translation cannot match the quality of professional translators. Huawei shall not bear any responsibility for translation accuracy and it is recommended that you refer to the English document (a link for which has been provided).
Configuring the MTU for an Ethernet Interface

Configuring the MTU for an Ethernet Interface

MTU is the largest packet of data that can be transmitted on a network, expressed in bytes. MTU is determined by data link layer protocols, and MTU values vary with networks. A proper MTU is a prerequisite for normal communication between network devices.

Context

The size of packets is limited at the network layer. Whenever receiving an IP packet, the IP layer determines the next-hop interface for the packet and obtains the MTU configured on the interface. Then, the IP layer compares the MTU with the packet length. If the packet length is longer than the MTU, the IP layer fragments the packet into smaller packets, which are shorter than or equal to the MTU.

If unfragmentation is configured, some packets may be discarded during data transmission at the IP layer. To ensure that jumbo packets are not dropped during transmission, set an MTU on an interface to fragment these packets into smaller ones.

NOTE:
  • After changing the MTU on a specified interface, you need to restart the interface to validate the newly-configured MTU by running the shutdown and undo shutdown commands in sequence.
  • If the Ethernet interface has sub-interfaces, you need to run the undo shutdown command 15 seconds after running the shutdown command.
NOTE:
  • If the size of packets is much greater than the configured MTU value, the packets are broken into a great number of fragments. The packets may be discarded by quality of service (QoS) queues.

  • If the configured MTU value is too large, packets may be transmitted at a low speed.

  • After changing the MTU of an Ethernet interface, also change the MTU of the peer Ethernet interface to ensure that the MTUs of both interfaces are the same. If the MTUs are different, services may be interrupted.

Perform the following steps on each router:

Procedure

  • Set an IPv4 MTU for an Ethernet interface.
    1. Run system-view

      The system view is displayed.

    2. Run interface gigabitethernet interface-number

      The specified Ethernet interface view is displayed.

    3. Run mtu mtu

      An IPv4 MTU is set for the Ethernet interface.

      The MTU is expressed in bytes. The MTU value range of an Ethernet interface is determined by the device type.

    4. Run commit

      The configuration is committed.

  • Set an IPv6 MTU for an Ethernet interface.
    1. Run system-view

      The system view is displayed.

    2. Run interface gigabitethernet interface-number

      The specified Ethernet interface view is displayed.

    3. Run ipv6 enable

      IPv6 is enabled on the Ethernet interface.

    4. Run ipv6 mtu mtu

      An IPv6 MTU is set for the Ethernet interface.

      The MTU is expressed in bytes. The MTU value range of an Ethernet interface is determined by the specific device.

    5. Run commit

      The configuration is committed.

Follow-up Procedure

The length of a QoS queue is limited. If the size of packets is much greater than the configured MTU value, the packets are broken into a great number of fragments. The packets may be discarded by the QoS queue. To address this problem, you can increase the length of the QoS queue. The queue scheduling mechanism First In First Out (FIFO) is used on an interface by default. You can change the FIFO queue length. For detailed configuration of a QoS queue, see HUAWEI NE20E-S2 Universal Service Router Configuration Guide - QoS.

Translation
Download
Updated: 2019-01-02

Document ID: EDOC1100055376

Views: 15875

Downloads: 33

Average rating:
This Document Applies to these Products
Related Version
Related Documents
Share
Previous Next