H3C Technologies H3C S5120 Series Switches - Manual (Page 83)

1-2
To do… Use the command… Remarks
Set the duplex mode duplex { auto | full | half }
Optional
auto by default.
The optical interface of a SFP port
does not support the half
keyword.
Set the transmission rate speed { 10 | 100 | 1000 | auto }
Optional
The optical interface of a SFP port
does not support the 10 or 100
keyword.
By default, the port speed is in the
auto-negotiation mode.
Shut down the Ethernet port shutdown
Optional
By default, an Ethernet port is in
up state.
To bring up an Ethernet port, use
the undo shutdown command.
Configuring an Auto-negotiation Transmission Rate
Speed auto negotiation enables an Ethernet port to negotiate with its peer for the highest speed
supported by both ends by default. If the highest speed is not desirable, you can narrow down the speed
option list for negotiation.
Figure 1-1 An application diagram of auto-negotiation transmission rate
As shown in Figure 1-1 , the network card transmission rate of the server group (Server 1, Server 2, and
Server 3) is 1000 Mbps, and the transmission rate of GigabitEthernet 1/0/4, which provides access to
the external network for the server group, is 1000 Mbps too. If you do not specify an auto-negotiation
range on the device, the transmission rate on GigabitEthernet 1/0/1, GigabitEthernet 1/0/2 and
GigabitEthernet 1/0/3 through negotiation with the servers is 1000 Mbps, which may cause congestion
on the egress interface GigabitEthernet 1/0/4. To solve the problem, you can specify the
auto-negotiation transmission rate on GigabitEthernet 1/0/1, GigabitEthernet 1/0/2, and
GigabitEthernet 1/0/3 to 100 Mbps.
Follow these steps to configure an auto-negotiation transmission rate: