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New Member

ISDN SPEED

Hi,

I have configured a isdn connection to a ISA server.

The scenario is a cisco 1700 series with a ISDN S/T interface dialing to the ISA server . It is configured to dial on demand and also uses NAT.

At the ISA server the ISDN line goes to the S/T interface of a "TA adapter".The TA adapter is connected to the Serial port of the server.

I have no problems in connecting to the server, authenticating and transfering files. However the speed is very slow. At the ISA server it says that the connection is at 19,200 bps.

The knowledge I have about ISDN is that it will either connect at 64K or drop the connection(true end to end isdn).Please correct me if I am wrong.

Is there anyway for me to check the "connection speed" at the router using either SHOW or DEBUG commands.

The ISDN provider claims that the line has been tested.

I suspect that the TA is the cause?

Any comments or help greatly appreciated.

Multilink PPP is not enabled.

Thanks

Noel

3 REPLIES
Cisco Employee

Re: ISDN SPEED

There are no commands which you can use to see the total speed of the link on the router. You are right that for isdn line, one channel speed should be 64kbps. Now the best way to measure it it is using FTP from a known good server.

You can use "show interface " and see the packet stats..Make sure that there are no errors, drops etc.

New Member

Re: ISDN SPEED

Thanks tepal

We found that the problem was on the baud rate of the serial port on the ISA server which was connected to the TA adapter.

New Member

Re: ISDN SPEED

Hi Noel,

It is just a thought but have you considered looking at the bearer capability ?. The capability sent from one peer should match that recieved on the other. This can be seen when using a debug ISDN Q931.

To force the speed to 64k from a router perspective you can use the dialer isdn speed 64 command.

Cheers

Jonathan.

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