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Community Member

Leased lines troubleshooting

One of the major problems that i face alomost every day , is the problems with the WAN links.

My network is based on leased lines. When i face a problem with a link i try to correct the problem by watching the status of the serial links. Some of my actions are these:

1. Shutdown and no shut the serial links

2. Check again the ip addresses

3. Restart the routers on both sides and also the modems of leased lines.

4. Change the routers on both sides.

Usually the interfaces on both sides is showing up down.

My question is that:

Is there a way to recognise immediately that the problem is cause in my side(Routers) or on Telcos side.

Thanks a lot



Re: Leased lines troubleshooting


You can make use of any WAN Monitoring tools to detect link failures.

Those tools can give you alarams when the link goes down after which you can verify the interface status where the link is connected.

You can few parameters like errors/reliability etc which can give you a fair idea on what might have gone wrong.

I feel resetting the router or changing the routers on both the side without much of troubleshooting wont help.

Sometimes reseting the modem does the trick coz of the buffer overflow happens in the modem..

Also you can make sure by getting a physical loop from your telco and make sure that your line is fine without any errors.

Before doing you can always try a local loop from your modem towards your router interface which can give rough idea on any modem/router interface issues..


Community Member

Re: Leased lines troubleshooting


1 . check the error on the router if it is increasing then their is a problem

short run remedy : ur step 3 will be help full

long run remedy : contact ur access line provider

2. check what is the clock on the LL modem

3. take a loop from the local modem toward ur local router ( NB: some modem requires internal clock for this test , after testing revert back to network clock)

see the status in router , it should be show loopback ( give it some time say 45 sec)

ping ur own serial ip ( if interface is showing loopback) see the result

this will confirum ur conectivity between ur router and local modem

3. give a command in ur local router(CE) to get loop from ur master modem

test the result the same way as in step 2

4 take a loop from far end (CE, site 2) towards ur side (site1)

repeat the same as in step 2

5 give site 2 loops from ur side and ask the to check their router

test the result the same way as in step 2

6 if that doesn't work ask for BERT test

NB: in testing ur link will be down


plz rate this if u like

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