Loopback commands for testing

[rgonzaga]

I'm in the process of trying to troubleshoot the massive errors I'm receiving on one end of 3 T1s. After verifying line codes, framing and clocking with AT&T, I want to test the line with them. The problem is that they've never been able to see my equipment when they loop me. Is there a loopback command that I need to turn on to allow this? I need to turn it on for a VWIC-2MFT-T1 and WIC1-DSU. Thanks.

[rgonzaga]

in Las Vegas I'm clean. There its set to clock internal:

Hardware revision is 0.96, Software revision is 0.2,

Image checksum is 0xED22BEC5, Protocol revision is 0.1

Receiver has no alarms.

Framing is ESF, Line Code is B8ZS, Current clock source is internal,

Fraction has 24 timeslots (64 Kbits/sec each), Net bandwidth is 1536 Kbits/sec.

Total Data (last 96 15 minute intervals):

0 Line Code Violations, 23 Path Code Violations

0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 34 Degraded Mins

3 Errored Secs, 3 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

Data in current interval (640 seconds elapsed):

0 Line Code Violations, 0 Path Code Violations

0 Slip Secs, 0 Fr Loss Secs, 0 Line Err Secs, 0 Degraded Mins

0 Errored Secs, 0 Bursty Err Secs, 0 Severely Err Secs, 0 Unavail Secs

[alfonsoresendiz]

Hi!

I was reading your case, and this is a simple test that could help U:

First, U can loopback toward your router (hard loopback), and ask your SP to loop toward your router on every possible phase of the WAN cloud, and run a pattern ber test from you controller.(bert pattern 2^15) and see if errors increased on the sh controller..

Other test U can run is to put your serial´s encapsulation to HDLC and, when looped, ping your own IP addres(extended ping) this way:

a. Type: ping ip

b. Target address = enter the IP address of the interface to which the IP address was just assigned.

c. Repeat count = 1000

d. Datagram size = 1500

e. Timeout = press ENTER

f. Extended cmds = yes

g. Source Address = press ENTER

h. Type of service = press ENTER

i. Set Df bit in ip header = press ENTER

j. Validate reply data = press ENTER

k. Data pattern: 0x0000

l. Press ENTER three times.

Change the data pattern on every loop, these could helps U, and can detect the possible problem..

0x0000 - Line-code mismatches

0xFFFF - Repeater power problems

0x4040 - Timing problems

***The 0x4040 extended ping pattern also enables you to detect jitter and wander.

I hope this helps U!!

Regards!