62 CHAPTER 3: PORT OPERATION
By default, port loopback detection and the loopback detection control function on
trunk and hybrid ports are disabled. The detection interval is 30 seconds, and the
system detects the default VLAN on the trunk and hybrid ports.
Configuring VCT
You can start the virtual cable test (VCT) to make the system test the cable connected
to the current electrical Ethernet port, and the system will return the test results in five
seconds. The test items include: whether short or open circuit exists in the Rx/Tx
direction of the cable, and what is the length of the cable in normal status or the
length from the port to the fault point of the cable.
VCT Configuration Example
Network requirements
Start VCT to make the system test the cable connected to the following port.
Configuration procedure
1Enter the system view.
<S5500> system-view
2Enter the Ethernet1/0/1 port view.
[S5500] interface Ethernet 1/0/1
3Start VCT.
[S5500-Ethernet1/0/1] virtual-cable-test
Cable status: abnormal(open), 7 metres
Pair Impedance mismatch: yes
Pair skew: 4294967294 ns
Pair swap: swap
Pair polarity: normal
Insertion loss: 7 db
Return loss: 7 db
Near-end crosstalk: 7 db
EthernetPort Security
Features
Port security is a security mechanism to control network access. It is an expansion of
the current 802.1x and MAC address authentication. This scheme controls the
incoming/outgoing packets on port by checking the MAC addresses contained in
data frames, and provides multiple security and authentication modes; this greatly
improves the security and manageability of the system.
The port security scheme provides the following features:
1NTK: Need to Know feature. By way of checking the destination MAC addresses of
the data frames to be sent from a port, this feature ensures that only successfully
Table46 Configure VCT
Operation Command Description
Enter system view system-view -
Enter Ethernet port view interface
interface-type
interface-number
-
Start VCT to make the system test
the cable connected to the current
electrical Ethernet port
virtual-cable-test Required
By default, this test is not started.