Trying to understand ISDN line

[saravanen.g]

Hi guys,

I have a 2MB PRI ISDN at my office. When i check the interface status, it shows the serial1/0:15 is always UP. Is that normal?

I've attached the output here.

Thanks.

[Richard Burts · Accepted solution]

saravanen

Yes this is normal. serial1/0.15 is the signaling channel used by the router and the phone company switch to communicate with each other and send signaling and control information. It should always be up.

HTH

Rick

[s-sheffield · Accepted solution]

for E1 lines (the one you have) serialx/x:15

is the D channel as already mentioned in the other response.

For T1 lines (1.54Mb) its serialx/x:23 for the D channel.

HTH too

Stu

[rahul0904]

saravanen said it correctly.

Serial1/0:15 is signaling channel that is used by the router & the switch at telephone company to communicate with each other by sending signaling & control information. All other channels will come up as and when you connect to other ISDN.