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

Configuration Guide - Ethernet Switching

S7700 and S9700 V200R011C10

This document describes the configuration of Ethernet services, including configuring link aggregation, VLANs, Voice VLAN, VLAN mapping, QinQ, GVRP, MAC table, STP/RSTP/MSTP, SEP, and so on.
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 a MAC Hash Algorithm

Configuring a MAC Hash Algorithm

Context

A device usually uses a hash algorithm to learn MAC address entries to improve MAC address forwarding performance. When multiple MAC addresses map the same key value, a MAC address hash conflict may occur. When a MAC address hash conflict occurs, the device may fail to learn many MAC addresses and can only broadcast traffic destined for these MAC addresses. The heavy broadcast traffic increases the load on the device. In this case, use an appropriate hash algorithm to mitigate the hash conflict.

NOTE:
  • MAC addresses on an interface card are stored using the following modes:

    • Hash bucket

      The interface card that uses the hash bucket performs hash calculation for VLAN IDs and MAC addresses in MAC address entries to be stored and obtains hash bucket indexes. The MAC addresses with the same hash bucket index are stored in the same hash bucket. If a hash bucket with the maximum storage space cannot accommodate learned MAC addresses of the hash bucket, a hash conflict occurs and MAC addresses cannot be stored. The maximum number of MAC addresses learned by the interface card through the hash bucket may be not reached.

    • TCAM chip

      The interface card that uses the TCAM mode stores all learned MAC addresses in the TCAM chip in sequence. As long as the number of learned MAC addresses does not reach the maximum value, MAC addresses can be learned. In TCAM mode, the device must be equipped with the enhanced interface card that uses the TCAM chip.

    SA series, EA series, FA series, FC series, SC series, X series, EE seriescard, EH1D2X48SEC0 of the S7700&S9700 use the hash bucket, so the maximum number of MAC addresses learned by the SA series, EA series, FA series, FC series, SC series, X series, EE seriescard, EH1D2X48SEC0 of the S7700&S9700 may be not reached. Other interface cards excluding SA series, EA series, FA series, FC series, SC series, X series, EE seriescard, EH1D2X48SEC0 of the S7700&S9700 use the TCAM mode by default.

  • X series cards do not support this configuration.
  • MAC addresses are distributed on a network randomly, so the best hash algorithm cannot be determined. Generally, the default hash algorithm is the best one, so do not change the hash algorithm unless you have special requirements.

  • An appropriate hash algorithm can reduce hash conflicts, but cannot prevent them.

  • After the hash algorithm is changed, restart the card to make the configuration take effect.

Procedure

  1. Run system-view

    The system view is displayed.

  2. Run mac-address hash-mode { crc16-lower | crc16-upper | crc32-lower | crc32-upper | lsb } slot slot-id

    A hash algorithm is configured on the specified LPU.

    The default hash algorithm is crc32-lower.

Verifying the Configuration

Run the display mac-address hash-mode command to check the running and configured hash algorithms.

Translation
Download
Updated: 2019-10-18

Document ID: EDOC1000178310

Views: 285451

Downloads: 141

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