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Configuration Guide - Device Management

S7700 and S9700 V200R013C00

This document describes the configurations of Device Management, including device status query, hardware management, CSS, SVF, PoE, OPS, OIDS, energy-saving management, information center, fault management, NTP, synchronous ethernet, PTP.
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New Member Joining and CSS Merging

New Member Joining and CSS Merging

Joining of a Member Switch

A new member switch can join a running single-chassis CSS. In Figure 3-9, SwitchA is running in single-chassis CSS state. After SwitchB joins the CSS, the two switches set up a new CSS. SwitchA becomes the master switch, and SwitchB becomes the standby switch.


A single CSS-enabled switch is a single-chassis CSS.

Figure 3-9  New member switch joining a single-chassis CSS
A new member switch joins a single-chassis CSS in either of the following situations:
  • After two switches are connected using cluster cables, one of the two switches is configured with the CSS function and restarted. This switch enters the single-chassis CSS state. After the other switch is configured with the CSS function and restarted, it joins the CSS as the standby switch.
  • In a running two-chassis CSS, one switch is restarted. Then this switch joins the CSS again as the standby switch.

CSS Merging

Two single-chassis CSS systems can merge into one CSS. Figure 3-10 shows two single-chassis CSS systems merging into one and electing a master switch. The master switch retains its original configuration and its standby MPU resets, without affecting services. The standby switch restarts, joins the new CSS as the standby switch, and synchronizes its configuration file with the master switch. Existing services on this switch are interrupted.

Figure 3-10  Two CSS systems merging
CSS merging occurs in either of the following situations:
  • After two switches are configured with the CSS function and restarted, they run as two single-chassis CSS systems. After they are connected using cluster cables, they merge into one CSS.

    Setting up a CSS through CSS merging is not recommended.

  • A CSS splits due to a failure of a CSS link or member switch. After this link or switch recovers, the two single-chassis CSS systems merge into one.
After two single-chassis CSS systems merge, the master switch is elected based on the following rules:
  1. The switch with longer running time becomes the master switch. This rule applies only when the two switches use SRUHs/SRUEs and set up a CSS using CSS cards. If the difference in the running time of two switches is smaller than 20s, the system considers that the two switches have the same running time.
  2. The switch with a higher CSS priority becomes the master switch.
  3. If the two switches have the same CSS priority, the switch with a smaller MAC address becomes the master switch.
  4. If the two switches have the same CSS priority and MAC address, the switch with a smaller CSS ID becomes the master switch.

Ensure that the two chassis use different CSS IDs in both new member joining and CSS merging scenarios. If their CSS IDs are the same, change the CSS ID of one switch first.

Updated: 2019-04-20

Document ID: EDOC1100065738

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