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

Troubleshooting Guide

CloudEngine 16800, 12800, 12800E, 8800, 7800, 6800, and 5800 Series Switches

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).
Load Balancing Is Uneven

Load Balancing Is Uneven

Common Causes

  • The inter-chassis Eth-Trunk is not disabled from preferentially forwarding local traffic.
  • The packet type is inconsistent with the load balancing configuration.
  • ECMP is configured and the ECMP outbound interface is the Eth-Trunk.
  • The number of Eth-Trunk member interfaces is not the nth power of 2.

Troubleshooting Flowchart

Figure 6-1 Troubleshooting flowchart for uneven load balancing

Troubleshooting Procedure

  1. Check whether an inter-chassis Eth-Trunk is created.
    Run the display eth-trunk trunk-id command to check the member interface name. Check whether an inter-chassis Eth-Trunk is created.
    • If the inter-chassis Eth-Trunk is created, run the local-preference disable command in the Eth-Trunk interface view to disable the Eth-Trunk from preferentially forwarding local traffic.
    • If the Eth-Trunk is not an inter-chassis one, go to Step 2.
  2. Identify the packet type.
    1. Obtain and analyze packets.

      Perform port mirroring or packet obtaining on an interface to obtain packets. The packet obtaining function is used here.

      Run the capture-packet interface interface-type interface-number destination file file-name command in the user view to obtain packets on the Eth-Trunk.

      Parse obtained packets and determine the packet type, for example, IP packets, MPLS packets, TRILL packets, and FCoE packets.

    2. Determine the variable field.

      Check whether the MAC address, IP address, or MPLS label in packets changes.

    3. Determine the forwarding mode of packets.
      • For CE8800, CE7800, CE6800, and CE5800 series switches exclude CE6870EI and CE6875EI, hash modes can be configured for known and non-known unicast packets separately. First check whether packets are known or non-known unicast packets.
        • If packets are known unicast packets, go to Step 3.a.
        • If packets are unknown unicast, broadcast, or multicast packets, go to Step 3.b.
      • For CE6870EI, CE6875EI and CE12800 series switches, the same load balancing mode is used for known and non-known unicast packets. Skip this step and go to Step 3.a.
  3. Determine the load balancing mode.
    1. Check the hash mode of known unicast packets.
      Run the display eth-trunk trunk-id command to check the hash mode of known unicast packets.
      • If the value of Hash Arithmetic is profile X (X represents the load balancing profile name), run the display load-balance profile [ profile-name ] command to check the load balancing mode in the load balancing profile.
      • If the value of Hash Arithmetic is dst-ip, src-ip, src-dst-ip, src-dst-mac, src-mac, or dst-mac but not profile x, the load balancing mode specified by the field is used.
    2. Check the hash mode of non-known unicast packets.
      Run the display current-configuration | include load-balance unknown-unicast command on the device to check the hash mode of non-known unicast packets.
      • If the return result is empty, the load balancing mode in the load balancing profile is used.
      • If the return result is not empty, load balancing is performed on non-known unicast traffic based on the source and destination MAC addresses of packets.
  4. Check whether the packet characteristics are consistent with the load balancing mode.
    For example, packets with variable destination MAC addresses need to be forwarded but the load balancing mode is based on destination IP addresses. In this case, change the load balancing mode to destination MAC address-based.
    • If the packet characteristics are inconsistent with the load balancing mode, configure the load balancing mode to be consistent with the variable field of packets.
    • If the packet characteristics are consistent with the load balancing mode, go to Step 5.
  5. Check whether the recommended hash mode is used.
    Run the display load-balance profile [ profile-name ] command on the device to check the load balancing mode in the load balancing profile.
    • If the recommended hash mode is not used, run the eth-trunk hash-mode hash-mode-id command in the load balancing profile view to configure the recommended hash mode as prompted.
    • If the recommended hash mode is used, go to Step 6.
  6. Check whether there is the multi-level hash.

    Run the display ip routing-table command on the device to check whether ECMP is configured and whether the ECMP outbound interface is the Eth-Trunk.

    • If ECMP is configured and the ECMP outbound interface is the Eth-Trunk, run the eth-trunk universal-id universal-id command in the load balancing profile view to adjust the offset of the calculation result of the hash algorithm.
    • If ECMP is not configured, go to Step 7.
  7. Check whether the number of Eth-Trunk member interfaces is the nth power of 2.

    Run the display eth-trunk trunk-id command to check whether the number of Eth-Trunk member interfaces is the nth power of 2.

    • If the number of Eth-Trunk member interfaces is not the nth power of 2, adjust the number of Eth-Trunk member interfaces.
    • If the number of Eth-Trunk member interfaces is the nth power of 2, go to Step 8.
  8. Collect the following information and contact technical support personnel:
    • Results of the preceding troubleshooting procedure
    • Configuration file and logs of the device
Translation
Download
Updated: 2020-01-07

Document ID: EDOC1000060766

Views: 608488

Downloads: 2951

Average rating:
This Document Applies to these Products

Related Version

Related Documents

Share
Previous Next