Question : Problem: Question in CISCO 3660 router

Hey all router gurus,

I have got this cisco 3660 router and when I check the interface by clicking on 'show interface' logging into the web management , it tells "line protocol is down'.
We called At&T and they run all diagnostic tests and everything looks successful/fine..

is there any way to debug or what exactly could be the issue

Snippets of the interface

*************
Serial2/1:1 is up, line protocol is down
  Hardware is DSX1
  Internet address is XXX.16.89.1/28
  MTU 1500 bytes, BW 1536 Kbit, DLY 20000 usec,
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation PPP, loopback not set
  Keepalive set (10 sec)
  LCP Listen
  Closed: IPCP, CDPCP

*************

All other T1 lines in the same router works fine and we are able to connect to the remote site whichever is connected to..

Any help on this will be appreciated..

SR

Answer : Problem: Question in CISCO 3660 router

router#config t
router(config)# ip route XXX.16.89.16 255.255.255.240 XXX.16.89.14  <= set more explicit route first
router(config)# no ip route XXX.16.89.0 255.255.255.0 XXX.16.89.14   <= deletes old route
router(config)#exit
router#write mem
[OK]
router#