H3C Technologies H3C S7500E Series Switches - Manual (Page 28)

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To do… Use the command… Remarks
Enter system view system-view —
port-group manual port-group-name
In port-group view
jumboframe enable [ value ]
interface interface-type
interface-number
Enable the
forwarding
of jumbo
frames
In Ethernet port
view
jumboframe enable [ value ]
Use any command.
By default, the switch allows
jumbo frames with the
specified length to pass
through all Ethernet ports.
The default length of jumbo
frames that are allowed to
pass is 1536 bytes.
If you set the value argument for ports of a port group in Ethernet port view or port-group view for
multiple times, the latest configuration takes effect.
Enabling Loopback Detection on an Ethernet Port
If a port receives a packet that it sent out, a loop occurs. Loops may cause broadcast storms. The
purpose of loopback detection is to detect loops on a port. When loopback detection is enabled on an
Ethernet port, the switch periodically checks for loops on the port. If a loop is detected on the port, the
switch operates on the port according to the pre-configured loopback detection actions, and sends a
trap message to the terminal.
When a loop is detected on an access port:
If the port does not support the loopback detection action setup (that is, the port doest not support
the loopback-detection action command), the switch puts the port in control mode. In this mode,
inbound packets on the port are all discarded, while outbound packets on the port are forwarded
normally. Meanwhile, the switch sends trap messages to the terminal, and deletes the
corresponding MAC address forwarding entry.
If the port supports loopback detection action setup (that is, the port supports the
loopback-detection action command), the switch operates on the port according to the
pre-configured loopback detection actions, sends trap messages and log information to the
terminal, and deletes the corresponding MAC address forwarding entry.
When a loop is detected on a trunk port or a hybrid port:
If the port does not support the loopback detection action setup, the switch sends a trap message
to the terminal. If loopback detection control is enabled on the port, the switch places the port in
control mode and discards all inbound packets on the port while normally forwarding outbound
packets on it. Meanwhile, the switch sends trap messages to the terminal, and deletes the
corresponding MAC address forwarding entry.
If the port supports the loopback detection action setup, the switch sends a trap message and log
information to the terminal. If loopback detection control is also enabled on the port, the switch