1-3
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 port 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:
To do…
Use the command…
Remarks
Enter system view
system-view
—
Enter Ethernet port view
interface interface-type
interface-number
—
Configure the auto-negotiation
transmission rate range
speed
auto
[
10
|
100
|
1000
] *
Optional
z
This function is available for auto-negotiation-capable Gigabit Layer-2 Ethernet electrical ports
only.
z
If you repeatedly use the
speed
and the
speed auto
commands to configure the transmission rate
on a port, only the latest configuration takes effect.
Configuring Flow Control on an Ethernet Port
When flow control is enabled on both sides, if traffic congestion occurs at the ingress port, it will send a
Pause frame notifying the egress port to temporarily suspend the sending of packets. The egress port is
expected to stop sending any new packet when it receives the Pause frame. In this way, flow control
helps to avoid dropping of packets. Note that this will be possible only after flow control is enabled on
both the ingress and egress ports.