3Com 7700 Configuration Manual page 38

30 C 2: P C
HAPTER ORT ONFIGURATION
Table 6 Set the Type of the Cable Connected to the Ethernet Port
Operation
Restore the default type of the
cable connected to the Ethernet
port.
Note: The settings only take effect on 10/100Base-T and 10/100/1000Base-T
ports. The Switch 7700 only supports auto (auto-sensing). If you set some other
type, you will see the prompt "Not support this operation!". The cable type is auto
(auto-recognized) by default. The system will automatically recognize the type of
cable connecting to the port.
Setting Flow Control for Ethernet Port
If congestion occurs in the local switch after enabling flow control in both the local
and the peer switch, then the switch will inform its peer to pause sending packets.
Once the peer switch receives this message, it will pause packet sending, and vice
versa. In this way, packet loss is effectively reduced. The flow control function of
the Ethernet port can be enabled or disabled through the following command.
Perform the following configuration in Ethernet port view.
Table 7 Set Flow Control for Ethernet Port
Operation
Enable Ethernet port flow control
Disable Ethernet port flow control
Note: Ethernet port flow control is disabled by default.
Permitting/Forbidding Jumbo Frames on the Ethernet port
Using the jumbo frame enable command, you can allow jumbo frames up to
9KB to pass through the specified Ethernet port. Note that packets up to 1536
bytes, including the IEEE 802.1Q tagging are always allowed to pass through
Ethernet ports.
Jumbo frames are only allowed for Ethernet Type II frames. Most network
equipment, including NICs, switches, and routers are not capable of supporting
jumbo frames and will always discard these packets.
Perform the following configuration in Ethernet port view.
Table 8 Permitting/Forbidding Jumbo Frame to Pass Through the Ethernet Port
Operation
Permit jumbo frame to pass
through the Ethernet port.
Forbid jumbo frame to pass
through the Ethernet port.
Note: Jumbo frames are disabled by default.
Command
undo mdi
Command
flow-control
undo flow-control
Command
jumboframe enable
undo jumboframe enable