10 Gigabit Copper Cable Introduction
10Gbps Ethernet uses the MAC sublayer as defined by IEEE 802.3 to connect to devices such as 10GBase-SR, 10GBase-LX4, 10GBase-CX4, 10GBase-LRM, 10GBase-LR, 10GBase-ER, 10GBase-SW, 10GBase through a 10GB Media Independent Interface (XGMII) -LW, 10GBase-EW and 10GBase-T various physical layer entities.
Among them, 10GBase-T is 10 Gigabit Ethernet for copper medium, and has the following requirements:
(1) Only full-duplex is supported.
(2) Supports point-to-point links and structured cabling topology for star-structured LAN applications.
(3) Support 10Gbps MAC/PLS service interface.
(4) Support for copper cable media in ISO 11801-2002 (specified in detail in clause 55.7).
(5) Supports operation overall transmission distances and grades supported by a 4-pair copper twisted pair with 4 connectors.
(6) Define a single 10Gbps physical layer capable of supporting a 100m 4-pair balanced copper cabling link.
(7) The IEEE 802.3 Ethernet data frame format is maintained on the MAC client service interface.
(8) Keep the minimum and maximum frame lengths specified by the current IEEE 802.3 standard.
(9) Support automatic negotiation.
(10) Meet CISPR/FCC Class A electromagnetic compatibility requirements. The bit error rate of bg(11) is less than or equal to 10^-12 in all transmission distances and grades.
Copper cable media that support 10G include Category 6A Class Ea, Class F, and Class FA. Next, we take the 6A class Ea as an example to talk about the field test of 10G copper cable.
In the field environment, since the test is always carried out after the construction is completed, in the actual wiring system, the certification test of each cable is completed first, and then the alien crosstalk test is carried out.
Test Object Selection
The test objects include the following two:
(1) Insignificant link (Insignificant): The link is low enough to be affected by crosstalk signals and will not affect 10Gbps transmission. The IEC standard considers a link with an alien crosstalk value within the range of 100M~250MHz less than 90dB to be a negligible link, and the standard does not require reporting the test data of a negligible link.
(2) Victim: The cable that is interfered with by the surrounding adjacent links when the test line is crosstalk. After the interfering link is injected with the test signal, the field tester can measure the signal level of the victim link.
When we select the victim link for the crosstalk test, since the signal on the tested interfering link comes from at least 6 groups of interfering links, the on-site test is completed in the shortest time.
The following situations can be used as disturbing links (victim links) in cabling engineering:
(1) Select 1% or 5 (the larger value) of the total links with the largest insertion loss (the longest link).
(2) Extract 1% or 5 (the larger value) of the total links with the smallest insertion loss (the shortest link).
(3) Extract 1% or 5 (the larger value) links (medium length links) with medium insertion loss from the total links.
For example, there are 1000 links in the project, 10 longest links, 10 shortest links, and 10 middle links must be selected as the tested links. Each of the above links is tested with a certain number of links selected as sources of interference.
Select all links in the same harness or the link that most closely matches the routing location of the disturbing link. These harnesses may be on patch panels, cross-links, or piping. On the patch panel, select adjacent ports or receptacles as additional links.
When selecting the link under test, the effect of wiring on the patch panel should also be considered. The aggressor link and the interfered link should be in the same path. In this case, the alien crosstalk is more serious.
Choosing a link for testing alien crosstalk is critical and requires some knowledge of cable routing. If you do not know the direction of different links in the building (it is recommended to accurately identify the cable path during construction), since the selected interference source link is not close enough to the interfered link, no obvious crosstalk will occur, and the test results may not be accurate. precise.
Instrument Connection Method
Type A uses only the instrument mainframe, an AXT dual-port adapter and at least two AXT test terminal modules. This setup is only used to test for composite out-of-line near-end crosstalk (PS ANEXT) from the near end of the patch panel cable. Type A testing is used to quickly determine the alien crosstalk environment and can be performed quickly by a single person. Testing with a Type A setup requires connecting the right port of the AXT adapter to the link under test, and the left port of the AXT adapter to the cable that acts as the interfering link. During the test, the right port should always be connected to the link under test, and the left port should be connected to the selected interfering link respectively. The termination module needs to be connected at the far end of the cable from the link under test and the interfering link. The instrument test kit contains 12 terminal modules, and 6 interference links can be selected and connected at one time according to the link under test (the link under test occupies one terminal module), and the terminal position does not need to be changed during the test.
The B-type method needs to use the instrument host and the remote machine, and the AXT dual-port adapter needs at least one AXT terminal module. This setting is used to test the combined extra-line near-end crosstalk (PS ANEXT) and the combined extra-line attenuated crosstalk ratio (PS AACR-F) from the near-end of the link. Type B test is used when the remote ends of the wiring are far apart, and the remote units cannot access the link under test and the interfering link at the same time. To test with the B-type setup, connect the right port of the AXT adapter of the instrument host to the link under test, and the left port to the cable that acts as the interfering link. During the test, the right port should always be connected to the link under test, and the left port should be connected to the selected interfering link respectively. One end of the working area of the link under test is connected to the right port of the AXT adapter on the remote machine of the instrument. The termination module is connected to the far end of the interfering link. A maximum of 12 information sockets can be selected on one side of the work area, the terminal module can be connected at one time, and all tests can be quickly completed on the side of the patch panel.
The C-type method is the most complete alien crosstalk test, which requires the use of the instrument host and the remote unit, and the AXT dual-port adapter does not require a terminal module to completely test various possible combinations of the tested link and the interfering link. It can test near/far combined out-of-line near-end crosstalk (PS ANEXT) and near/far combined out-of-line attenuation crosstalk ratio (PS AACR-F). To test with a C-type setup, connect the right port of the AXT adapter of the instrument host to the link under test, and the left port under test to the cable that acts as an interfering link. During the test, the right port should always be connected to the link under test, and the left port should be connected to the selected interfering link respectively. The operator must pay attention to the connection of the port to avoid the wrong connection, otherwise, the wrong result will be obtained, which will cause the qualified link to fail the test.
Not all tests require the four parameters measured by the C-type connection, which should be selected according to the actual situation. The above are all tests on 10GBase-T 10G copper cables from the physical layer.