Huawei Quidway S9300 Configuration Manual page 27

Quidway S9300 Terabit Routing Switch
Configuration Guide - Device Management
standby SRU of the CSS. HA is implemented between the active and standby SRUs of the CSS.
The standby SRUs of SwitchA and SwitchB function as the candidate standby SRUs of the CSS.
If active/standby switchover is performed on SwitchA or SwitchB, the standby SRU of the switch
becomes the standby SRU of the CSS.
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Management and Traffic Forwarding in a CSS
After a CSS is set up, you can log in to the CSS through service interfaces on LPUs and the
serial port or console port on the active SRU to configure services and manage the CSS.
In a CSS, the interface view is identified by the frame ID, slot ID, subcard ID, and interface
number. You can specify any interface on the two switches to configure services on the interface.
You can also choose to specify only the frame ID and slot ID to manage the specified LPU, for
example, query information about the LPU or reset the LPU.
Different from the service traffic forwarded on a single switch, the service traffic forwarded
between the two switches of the CSS needs to pass through the switching fabric twice. Similar
to the single switch, the CSS also processes the packet content in both inbound direction and
outbound direction.
CSS Breaking
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Issue 03 (2011-12-29)
When active/standby switchover occurs on the master switch (SwitchA):
– SwitchB becomes the master switch, and the original standby SRU of the CSS becomes
the active SRU of the CSS.
– SwitchA becomes the backup switch.
– The active SRU of SwitchA restarts. The standby SRU of SwitchA becomes the standby
SRU of the CSS and synchronizes data from the new active SRU of the CSS.
When active/standby switchover occurs on the backup switch (SwitchB):
– The master switch and backup switch remain unchanged.
– The active SRU of SwitchB (namely the original standby SRU of the CSS) restarts. The
standby SRU of SwitchB becomes the standby SRU of the CSS and synchronizes data
from the active SRU of the CSS.
Cause of CSS breaking
After a CSS is set up, the active and standby SRUs of the CSS send heartbeat messages to
each other to maintain the CSS status. If a stacking cable, a stacking card, or an SRU is
faulty, communication between the two switches may fail because no stacking link is
available. In this case, the heartbeat between the two switches times out and the CSS breaks
into two independent switches.
Impact of CSS breaking
If the two switches run normally after the CSS breaks, they use the same IP address and
same MAC address to communicate with other devices on the network because their global
configurations are exactly the same. This causes faults on the entire network and conflict
of IP addresses and MAC addresses. In this case, the system displays a message, asking
you to change the IP address and MAC address of a switch or remove a switch from the
network.
NOTE
When the CSS breaks, the alarm message may be displayed only on the serial port of a switch and cannot
be sent to the NMS because of conflict of IP addresses and MAC addresses.
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2 CSS Configuration
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