3Com Switch 7700 Configuration Manual page 38

30 C 2: P C
HAPTER ORT ONFIGURATION
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
By default, Ethernet port flow control is disabled.
Permitting/Forbidding Jumbo Frames on the Ethernet port
Using the jumbo frame enable command, you can allow jumbo frames (1523 to
to 9216 bytes) to pass through the specified Ethernet port. Note that packets up
to 1522 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.
By default, jumbo frames are disabled.
Setting the Maximum MAC Addresses an Ethernet Port can Learn
Use the following command to set a limit on the number of MAC addresses that
an Ethernet port will learn.
Perform the following configuration in Ethernet port view.
Table 9 Set a Limit on the Number of MAC Addresses Learned by an Ethernet Port
Operation
Set a limit on the number of MAC addresses
learned by an Ethernet port
Restore the default limit on MAC addresses
learned by the Ethernet port
Command
flow-control
undo flow-control
Command
jumboframe enable [ jumboframe_value ]
undo jumboframe enable
Command
mac-address max-mac-count count
undo mac-address max-mac-count