Performing tests
G. SHDSL test problemsproblems
The following section addresses questions about testing in general.
Issue
Inconsistent test results.
Resolution
Verify that your test leads are good and are connected prop-erly for the test you are performing.
G.SHDSL test problems
The following section addresses questions about G.SHDSL testing.
Issue
The modem cannot achieve sync with the remote end.
Resolution
Inability to sync can have many causes. Perform the following steps to troubleshoot:
– Disconnect the customer's G.SHDSL modem.
– Verify tester connection to the correct pair.
– Verify that the physical G.SHDSL standard is correct (G.991.2 Annex A or Annex B).
– Verify that the functional standard is correct (G.991.2, ETSI TS 101 524-1)
– Verify that the EOC standard is correct (G.991.2, ETSI TS
– Verify the asymmetric PSD setting.
– Isolate premise wiring.
– Verify the copper pair is provisioned for G.SHDSL at the CO.
– Test at the CO/Exchange on the customer pair.
– Check the DSLAM modem vendor and software version.
Issue
The HST is set up for “Adaptive” Rate Mode to match the DSLAM but the modem cannot achieve sync with the remote end. The last modem state is Check Bit Rate.
Resolution
G.SHDSL line rates are determined using the following formula: n x 64 kbps + i x 8 kbps. In this formula, the base data rate is n x 64 kbps; the sub data rate is i x 8 kbps. In synced mode, an additional 8 kbps is added for frame sync.
The modems will only sync if the sub data rate is the same.
The rates change depending on the physical standard. For all standards except TCPAM, use Table 25. For TCPAM, use Table 26.
Find the STU-C and STU-R line rates in Table 25 or Table 26.
They should be in the same “i=x” column. For example, if one side is set to a 256 payload with a line rate of 264 and the other side is set to a 384 payload with a line rate of 392, the modems will sync. However, if one side is set to a 256 payload with a line rate of 264 and the other side is set to a 328 payload with a line rate of 336, the modems will not sync.
Table 25 Valid speeds for G.SHDSL
Two Wire Four Wire
i=0 i=1 i=0
n Line
Rate Payload Line
Rate Payload Line
Rate Payload
1 72 64 80 72
2 136 128 144 136
8 520 512 528 520 1040 1024
9 584 576 592 584 1168 1152
10 648 640 656 648 1296 1280
11 712 704 720 712 1424 1408
12 776 768 784 776 1552 1536
13 840 832 848 840 1680 1664
14 904 896 912 904 1808 1792
15 968 960 976 968 1936 1920
16 1032 1024 1040 1032 2064 2048
17 1096 1088 1104 1096 2192 2176
18 1160 1152 1168 1160 2320 2304
19 1224 1216 1232 1224 2448 2432
20 1288 1280 1296 1288 2576 2560
21 1352 1344 1360 1352 2704 2688
22 1416 1408 1424 1416 2832 2816
23 1480 1472 1488 1480 2960 2944
24 1544 1536 1552 1544 3088 3072
25 1608 1600 1616 1608 3216 3200
26 1672 1664 1680 1672 3344 3328
27 1736 1728 1744 1736 3472 3456
28 1800 1792 1808 1800 3600 3584
29 1864 1856 1872 1864 3728 3712
30 1928 1920 1936 1928 3856 3840
Table 25 Valid speeds for G.SHDSL (Continued)
Two Wire Four Wire
i=0 i=1 i=0
n Line
Rate Payload Line
Rate Payload Line
Rate Payload
31 1992 1984 2000 1992 3984 3968
32 2056 2048 2064 2056 4112 4096
33 2120 2112 2128 2120 4240 4224
34 2184 2176 2192 2184 4368 4352
35 2248 2240 2256 2248 4496 4480
36 2312 2304 2320 2312 4624 4608
Table 25 Valid speeds for G.SHDSL (Continued)
Two Wire Four Wire
i=0 i=1 i=0
n Line
Rate Payload Line
Rate Payload Line
Rate Payload
Table 26 Valid speeds for TCPAM G.SHDSL
Two Wire TCPAM 32 TCPAM Auto
i=0 i=1 i=0 i=1
n Line
Rate Payload Line
Rate Payload Line
Rate Payload Line
Rate Payload
37 2376 2368 2384 2376 2376 2368 2384 2376
38 2440 2432 2448 2440 2440 2432 2448 2440
39 2504 2496 2512 2504 2504 2496 2512 2504
40 2568 2560 2576 2568 2568 2560 2576 2568
41 2632 2624 2632 2632 2632 2624 2632 2632
42 2696 2688 2704 2696 2696 2688 2704 2696
43 2760 2752 2768 2760 2760 2752 2768 2760
44 2824 2816 2832 2824 2824 2816 2832 2824
45 2888 2880 2896 2888 2888 2880 2896 2888
46 2952 2944 2960 2952 2952 2944 2960 2952
47 3016 3008 3024 3016 3016 3008 3024 3016
48 3080 3072 3088 3080 3080 3072 3088 3080
49 3144 3136 3152 3144 3144 3136 3152 3144
50 3208 3200 3216 3208 -- -- 3216 3208
51 3272 3264 3280 3272 -- -- 3280 3272
52 3336 3328 3344 3336 3336 3328 3344 3336
53 3400 3392 3408 3400 3400 3392 3408 3400
54 3464 3456 3472 3464 3472 3464
55 3528 3520 3536 3528 3528 3520 3536 3528
56 3592 3584 3600 3592 -- -- 3600 3592
57 3656 3648 3664 3656 -- -- 3664 3656
58 3720 3712 3728 3720 3720 3712 3728 3720
59 -- -- 3792 3784 -- -- 3792 3784
--Table 26 Valid speeds for TCPAM G.SHDSL (Continued)
Two Wire TCPAM 32 TCPAM Auto
i=0 i=1 i=0 i=1
n Line
Rate Payload Line
Rate Payload Line
Rate Payload Line
Rate Payload
Issue
In through mode, I’m connected to the Ethernet connector, but I’m not getting a data connection (green LED on the Ethernet connector is on, but the yellow LED is not).
Resolution
Go to the LAN Settings screen and check the Media Type. If it’s set to Auto, change it to match the specific LAN speed and duplex type that you are using.
Issue
The modem gets sync with the CO, but the rate is lower than expected.
Resolution
If the rate mode is adaptive, verify the startup margin and SNEXT margin settings.
83 5320 5312 5328 5320 -- -- --
--84 -- -- -- -- -- -- --
--85 5448 5440 5496 5448 -- -- --
--86 -- -- 5520 5512 -- -- --
--87 -- -- -- -- -- -- --
--88 5640 5632 5648 5640 -- -- --
--89 5704 5696 5712 5704 -- -- --
--Table 26 Valid speeds for TCPAM G.SHDSL (Continued)
Two Wire TCPAM 32 TCPAM Auto
i=0 i=1 i=0 i=1
n Line
Rate Payload Line
Rate Payload Line
Rate Payload Line
Rate Payload
Issue
The ping menu says pings are being sent, but the network statistics are not incrementing.
Resolution
The ping function only attempts to send a ping every second.
Depending on certain conditions, a physical ping packet may not be sent.
Check that the unit has not lost sync.
If the Ethernet protocol (not interface protocol) is being used, the device has to ARP the address first. If this fails eventually you will see a ARP HOST UNREACHABLE message. Check to see that the destination IP address and our configured IP parameters are correct.
If the Ethernet interface is being used, make sure that the cabling is correct. If the Ethernet cable is not hooked up, or is hooked up incorrectly, a packet will not be sent. Thus the Ethernet statistics will not increment.
Check the Ethernet link light on the HST-3000 Ethernet jack.
It should be green.
Issue
The ping menu says pings are being sent, but the number of replies doesn’t match the pings sent.
Resolution
Check the TX ATM PCR value on the Data settings screen. If the PCR is set too low, ping replies will be lost. This is because the “number of pings” selection (on the Ping settings) is defined as the number of pings per second and the PCR value is set as cells per second. Thus, if you are sending more pings than the PCR allows, you will not receive ping replies.
– Set the number of pings to 1 – Set the PCR to 1000 or unlimited.
Issue
The ATM total statistics are incrementing but the channel stats are not incrementing.
Resolution
Reconfigure the interface to match the VPI/VCI given in the VPI/VCI of Last Unknown Cell statistic.
Issue
The ATM channel statistics indicate that I am receiving frames but I did not get a green Data LED and pings are not working.
Resolution
Check the encapsulation and the mode. The wrong protocol may be in use.
Issue
I have a PPPoA service and I get a PPP TIMEOUT message Resolution
Verify that the VPI-VCI is correct.
Verify that the encapsulation is correct.
Verify that the addressing mode is set correctly (IPCP/Static).
Verify that the username and password are correct.
Issue
I have a PPPoE connection and I get a PPPoE FAILED message.
Resolution
Verify that the VPI-VCI is correct.
Verify that the encapsulation is correct.
Verify that the addressing mode is correct.
Verify that the user name and password are correct (including case)
Issue
I have a Bridged Ethernet connection and I get a DCHP FAILED message.
Resolution
Verify that the VPI-VCI is correct.
Verify that the encapsulation is correct.
Verify that the DHCP server isn't out of addresses. (Contact your IT department or help desk.)
Issue
I get an INVALID CONFIG message.
Resolution
Verify that a valid IP address is being used (examples of invalid IP addresses would be *.*.*.0 or 127.*.*.* or 10.0.0.1 or 192.168.0.0).
Verify that the IP address and gateway are on the same network as defined by the netmask.
Check the netmasks if Ethernet IP = DSL IP. The netmasks must be different.
Verify that the Netmask is not set to 0.0.0.0.
Issue
I have a green Data LED, but pings are not working.
Resolution
A green Data LED does not guarantee a ping (or any routed/
bridged packet) will be treated properly once it leaves the unit.
In an Ethernet bridged or IP over ATM environment with static addressing, there is no initial communication with the far end, so as soon as ATM sync occurs the interface is deemed active to pass user data.
Make sure that the VPI-VCI is correct.
Make sure that the encapsulation is correct.
Try pinging a different host.
Make sure you are not behind a firewall; they can block ping responses from reaching the host.
Check to see if the connection is unnumbered. If it is, verify that the connection is configured correctly.
View the Results>Data>Ping menu. It can often give impor-tant clues as to why the ping is not successful.
Issue
I get a message that is not listed when I am performing tests.
Resolution
You may receive an unspecified or unknown error message while you are testing G.SHDSL lines. This is because of the many different possible types of G.SHDSL modem errors. If you receive one of these messages, try the following:
Try to resync with the line.
Check the configuration of the HST-3000.
Check the configuration of the DSLAM.
Glossary
A
ADSLAM — Advanced Digital Subscriber Line Access Multi-plexer. Concentrates and multi-plexes signals at the telephone service provider location to the broader wide area network.
ATM — Asynchronous Transfer Mode. A cell-based data transfer technique in which channel demand determines packet allo-cation. ATM offers fast packet technology, real time, demand lead switching for efficient use of network resources.
Auto-Negotiation — Proce-dure for adjusting line speeds and other communication parameters automatically between two computers during data transfer.
B
BER — Bit Error Rate.
Bit error — Received bits with a value opposite that of the corre-sponding transmitted bits. Also called a test sequence error (TSE).
Bps — Bits per second.
C
CO — Central Office.
Cell — A fixed length unit of information. Most other data units can vary in length, but a cell is fixed in size. This helps cut down on network delays and variations in the delay through a network.
Crosstalk — The interference caused by signals on adjacent circuits in a network.
CPE — Customer Premise Equipment. Devices or equip-ment that the customer provides to interface with the telco.
D
Delay — A contributing measure of the carrying capacity of a link. Delay indicates how long it takes bits to find their way through a network.
Digital — Having only discrete values, such as 0 or 1.
DSL — Digital Subscriber Line.
A generic name for a family of standards allowing high-speed data transfer over telephone lines.
DSLAM — Digital Subscriber Line Access Multiplexer.
DSU/CSU — Data Service Unit/
Channel Service Unit -The inter-face device required to change one form of digital signal to another.
DTMF — Dual Tone Multi-Frequency. A voice-band tone-based method of signaling.
E
Echo — The reflecting of a signal back to its source due to a variety of reasons.
Encapsulation — The tech-nique used by layered protocols in which a layer adds header information to the protocol data unit (PDU) from the layer above.
Ethernet — A local area network (LAN) wiring scheme.
You can use the HST-3000 to emulate Ethernet terminal equipment to test connectivity.
G
Gateway — A system which does translation from some native format to another.
G.SHDSL — G.SHDSL is an