H3C Technologies H3C S5120 Series Switches - Manual (Page 84)

1-3
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 an interface, 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 interface, it will
send a Pause frame notifying the egress interface to temporarily suspend the sending of packets. The
egress interface 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 interfaces.
Follow these steps to enable flow control on an Ethernet port:
To do… Use the command… Remarks
Enter system view system-view —
Enter Ethernet port view
interface interface-type
interface-number
—
Enable flow control flow-control
Required
Disabled by default
Perfoming Loopback Testing on an Ethernet Port
You can perform loopback testing on an Ethernet port to check whether the port functions properly. Note
that the Ethernet port cannot forward data packets during the testing. Loopback testing falls into the
following two categories:
z Internal loopback testing, which tests all on-chip functions related to Ethernet ports. As shown in
Figure 1-2 , internal loopback testing is performed on Port 1. During the internal loopback testing,
the port sends out a certain number of test packets, which are looped back to the port over the
self-loop created on the switching chip