3troubleshootingjunos

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T1 and E1 Fault Isolation

When you confirm the s ttings on both ends but problems persist, you might want to

involve the lco for line and loop testing. Before suspecting the transmission line, you

should first perform local loopback testing at each end. You also should attempt

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emote loopback requests to the far-end internal CSU.

RFC 2495

F additional information on E1 or T1 interface alarms and error conditions, you

sh uld consult RFC 2495, Definitions of Managed Objects for the DS1, E1, DS2, and

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E2 Interface Types.

JUNOS platforms also support BERT testing, as previously descr bed

n E1 and T1

interfaces. Because BERT testing is a far more definitive es , y

sh

uld c nsider

BERT testing when you suspect marginal performance or n erm

ent

perati n.

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SONET/SDH transmission syst ms incorporate a multitude of Operation,

Administration, and Maint nance (OAM) functionalities at the line, section, and path

layers. Interpretation of the SONET/SDH errors is helpful in determining the source of

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the p oblem within the SONET/SDH network. The information within the various

SONET/SDH counters is plentiful and, when properly interpreted, enables problem

localization. The following pages cover the commands available for SONET/SDH

tr

ublesh ting in the CLI.

L

calizing Errors

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chassis {

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fpc 0 {

pic 0 {

framing sdh;

}

}

}

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for

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Monitoring SONET/SDH Int rfaces

The monitor int rface command can provide useful troubleshooting

information for the SONET/SDH int rface.

The statistics in the second column are the cumulative statistics from the last time the

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clear inte faces statistics command cleared them. The statistics in the

thi d column a e the statistics from the last execution of the monitor interface

c mmand.

If the raming errors increase, check the FCS and scrambling configuration. If the

c n igurati

n is correct, check the cabling to the router, and have the carrier verify the

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integrity

the line.

If the input errors increase, check the cabling to the router, and have the carrier verify

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You can specify a custom path trace message with a set sonet-options

forpath-trace message statement at the [edit interfaces

“This byte is used to transmit repetitively a path access point identifier so that a path

receiving terminal can verify its continued connection to the intended tra smitter. A

16-byte frame is defined for the transmission of an access point ide tifier. This

16-byte frame is identical to the 16-byte frame defined in 9.2.2.2 for the description of

the byte J0. At international boundaries, or at the boundaries between the etworks of

different operators, the format defined in clause 3/G.831 shall be used unless

otherwise mutually agreed by the operators oviding the ransp rt. W thin a national

network or within the domain of a single operator, this pa h access p nt dentifier may

use a 64-byte frame.”

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