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

S1720, S2700, S5700, and S6720 V200R012(C00 and C20)

This document describes the configuration of Ethernet services, including configuring MAC address table, link aggregation, VLANs, VLAN aggregation, MUX VLAN, VLAN termination, Voice VLAN, VLAN mapping, QinQ, GVRP, VCMP, STP/RSTP/MSTP, VBST, SEP, RRPP, ERPS, LBDT, and Layer 2 protocol transparent transmission.
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

Generally, it is recommended to use the default MAC hash algorithm unless you have specific requirements.

The switch typically uses a hash algorithm to learn MAC address entries. However, conflicts may occur if two or more MAC addresses produce the same hash value. In this case, the switch may fail to learn many MAC addresses and then will broadcast traffic destined for these MAC addresses. The heavy broadcast traffic increases the load on the switch. To mitigate this issue, use an appropriate hash algorithm to mitigate the hash conflict.

NOTE:
  • The switch uses the hash bucket to store MAC addresses. The switch 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 switch through the hash bucket may be not reached.

  • The S5720HI, S5730HI, and S6720HI do not support this function.
  • MAC addresses are distributed on a network randomly, so the best hash algorithm cannot be determined. Generally, it is recommended to use the default MAC hash algorithm unless you have specific requirements.

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

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

Procedure

  1. Run system-view

    The system view is displayed.

  2. Configure a hash algorithm.

    • Run the mac-address hash-mode { xor | crc } slot slot-id command on the S1720GF, S1720GFR, S1720GW, S1720GW-E, S1720GWR, S1720GWR-E, S1720X, S1720X-E, S2720EI, S2750EI, S5700LI, S5700S-LI, S5710-X-LI, S5720I-SI, S5720LI, S5720S-LI, S5720S-SI, S5720SI, S5730S-EI, S5730SI, S6720LI, S6720S-LI, S6720S-SI, and S6720SI.
    • Run the mac-address hash-mode { crc16-lower | crc16-upper | crc32-lower | crc32-upper | lsb } slot slot-id command on other models except the S1720GF, S1720GFR, S1720GW, S1720GW-E, S1720GWR, S1720GWR-E, S1720X, S1720X-E, S2720EI, S2750EI, S5700LI, S5700S-LI, S5710-X-LI, S5720I-SI, S5720LI, S5720S-LI, S5720S-SI, S5720SI, S5730S-EI, S5730SI, S6720LI, S6720S-LI, S6720S-SI, and S6720SI.

    By default, the hash algorithm is crc on the S1720GF, S1720GFR, S1720GW, S1720GW-E, S1720GWR, S1720GWR-E, S1720X, S1720X-E, S2720EI, S2750EI, S5700LI, S5700S-LI, S5710-X-LI, S5720I-SI, S5720LI, S5720S-LI, S5720S-SI, S5720SI, S5730S-EI, S5730SI, S6720LI, S6720S-LI, S6720S-SI, and S6720SI and crc32-lower on other models.

  3. Run mac-address hash-bucket-mode { size4 | size8 | size12 | size16 }

    The hash bucket size is configured for the MAC address table.

    This function is supported only by the S1720GF, S1720GFR, S1720GW, S1720GW-E, S1720GWR, S1720GWR-E, S1720X, S1720X-E, S2750EI, S5700LI, S5700S-LI, S5720I-SI, S5720LI, S5720S-LI, S5720S-SI, and S5720SI.

    By default, the hash bucket size of a MAC address table is 4.
    NOTE:
    • A larger hash bucket size will lower device forwarding performance.

    • After you change the hash bucket size to a smaller value, you need to restart the switch.

Verifying the Configuration

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

Translation
Download
Updated: 2018-12-24

Document ID: EDOC1100038339

Views: 168190

Downloads: 701

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