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T1 problem or Cisco router problem?

Posted on 2008-06-11
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Last Modified: 2012-08-14
My company that has a main office and one remote office. Both offices are connected directly to us via dedicated T1's.  Users at the remote office access the Internet and file sharing servers over the point to point t1 at the main office, which is connected to a T1 for Internet access.  The problem is when users at the remote office need to download something from the Internet or file server at the main office, they are getting very slow speeds.  One test was downloading a driver from HP, at the remote office the download rate was between 10K and 15K, at the main office it was well over 200K.  

The main office and remote offices are connected via Cisco 1601 routers, and would like to know how I can see what is acting as the bottleneck here, the T1 or is one of the router's WIC cards going bad?
Here's the show interfaces for the remote office Cisco 1601:
sho interfaces
Ethernet0 is up, line protocol is up
  Hardware is QUICC Ethernet, address is 0030.80f2.5264 (bia 0030.80f2.5264)
  Internet address is 192.168.1.5/24
  MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec, rely 255/255, load 10/255
  Encapsulation ARPA, loopback not set, keepalive set (10 sec)
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input 00:00:00, output 00:00:00, output hang never
  Last clearing of "show interface" counters never
  Queueing strategy: fifo
  Output queue 0/40, 0 drops; input queue 1/75, 0 drops
  5 minute input rate 48000 bits/sec, 43 packets/sec
  5 minute output rate 394000 bits/sec, 52 packets/sec
     3978055 packets input, 1150785451 bytes, 0 no buffer
     Received 157831 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     0 input packets with dribble condition detected
     4105669 packets output, 3397442375 bytes, 0 underruns
     0 output errors, 104529 collisions, 1 interface resets
     0 babbles, 0 late collision, 24664 deferred
     0 lost carrier, 0 no carrier
     0 output buffer failures, 0 output buffers swapped out
 --More--
Serial0 is administratively down, line protocol is down
  Hardware is QUICC Serial
  MTU 1500 bytes, BW 1544 Kbit, DLY 20000 usec, rely 255/255, load 1/255
  Encapsulation HDLC, loopback not set, keepalive set (10 sec)
  Last input never, output never, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0 (size/max/drops); Total output drops: 0
  Queueing strategy: weighted fair
  Output queue: 0/1000/64/0 (size/max total/threshold/drops)
     Conversations  0/0/256 (active/max active/max total)
     Reserved Conversations 0/0 (allocated/max allocated)
  5 minute input rate 0 bits/sec, 0 packets/sec
  5 minute output rate 0 bits/sec, 0 packets/sec
     0 packets input, 0 bytes, 0 no buffer
     Received 0 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     0 packets output, 0 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
     0 carrier transitions
     DCD=up  DSR=down  DTR=down  RTS=down  CTS=down
Serial1 is up, line protocol is up
  Hardware is QUICC Serial (with FT1 CSU/DSU WIC)
  Internet address is 10.0.0.2/24
  MTU 1500 bytes, BW 512 Kbit, DLY 20000 usec, rely 255/255, load 18/255
  Encapsulation HDLC, loopback not set, keepalive set (10 sec)
  Last input 00:00:00, output 00:00:00, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0 (size/max/drops); Total output drops: 228
  Queueing strategy: weighted fair
  Output queue: 0/1000/64/0 (size/max total/threshold/drops)
     Conversations  0/20/256 (active/max active/max total)
     Reserved Conversations 0/0 (allocated/max allocated)
  5 minute input rate 370000 bits/sec, 47 packets/sec
  5 minute output rate 37000 bits/sec, 37 packets/sec
     4087816 packets input, 3355690652 bytes, 0 no buffer
     Received 25873 broadcasts, 0 runts, 0 giants, 0 throttles
     47216 input errors, 10466 CRC, 22379 frame, 0 overrun, 0 ignored, 14371 abo
rt
     3858647 packets output, 1099465220 bytes, 0 underruns
     0 output errors, 0 collisions, 43 interface resets
     0 output buffer failures, 0 output buffers swapped out
     73 carrier transitions
     DCD=up  DSR=up  DTR=up  RTS=up  CTS=up
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Question by:logicaltechs
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14 Comments
 

Author Comment

by:logicaltechs
ID: 21763495
Also, I have rebooted all my equipment several times, and have the ISP involved, however they are saying everything is OK for now....
0
 
LVL 7

Expert Comment

by:kanlue
ID: 21765634
i think that your network looks like this:
-----------
Internet <--Dedicated T1-- Main Office <--P2P T1-- Remote Office
-----------
Right?

about the 'P2P T1', between your remote office and the main one, you can try to 'clear counter' in the routers, then monitor the 'CRC' in the result of 'show int s1' of 1601 router; if it keeps going up, then either the line quality is not good, or the WIC-T1 needs to be replaced.

hope it helps.
0
 

Author Comment

by:logicaltechs
ID: 21765782
You are correct in the scenario.  How do I clear the counters on the routers? So then if I get CRC's and my ISP says my line quality is good, I can go ahead with replacing the routers since they are so old.
Also, I see from my sho int S1, that my CRC is:
"47216 input errors, 10466 CRC, 22379 frame, 0 overrun, 0 ignored, 14371 abo"
Is 22379 the number of CRC's or 10466?
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LVL 7

Expert Comment

by:kanlue
ID: 21765869
in the routers, just type in 'clear counter', then confirm. after clearing it, then you can keep 'show int s1' to monitor it.

several factors can affect CRC number. we needs to find out whether CRC keeps going up that affect the slow connection.

yes, 10466 is CRC.
0
 

Author Comment

by:logicaltechs
ID: 21804734
Sorry I have been working with the ISP back and forth regarding this, at first they say everything is clear on the T1's then the T1 goes down a day later.... So, now I am quite confident I may have a router issue as well with the 1601's.  
I cleared the counters about 18 hours ago, roughly, and here is what I have on Router 1:
Serial1 is up, line protocol is up
  Hardware is QUICC Serial (with FT1 CSU/DSU WIC)
  Internet address is 10.0.0.2/24
  MTU 1500 bytes, BW 512 Kbit, DLY 20000 usec, rely 255/255, load 19/255
  Encapsulation HDLC, loopback not set, keepalive set (10 sec)
  Last input 00:00:00, output 00:00:00, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0 (size/max/drops); Total output drops: 0
  Queueing strategy: weighted fair
  Output queue: 0/1000/64/0 (size/max total/threshold/drops)
     Conversations  0/21/256 (active/max active/max total)
     Reserved Conversations 0/0 (allocated/max allocated)
  5 minute input rate 351000 bits/sec, 47 packets/sec
  5 minute output rate 40000 bits/sec, 35 packets/sec
     1513065 packets input, 1337256282 bytes, 0 no buffer
     Received 10602 broadcasts, 0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     1222799 packets output, 204016391 bytes, 0 underruns
     0 output errors, 0 collisions, 144 interface resets
     0 output buffer failures, 0 output buffers swapped out
     1 carrier transitions
     DCD=up  DSR=up  DTR=up  RTS=up  CTS=up

On Router 2 I have:


Serial1 is up, line protocol is up
  Hardware is QUICC Serial (with FT1 CSU/DSU WIC)
  Internet address is 10.0.0.1/24
  MTU 1500 bytes, BW 1500 Kbit, DLY 20000 usec, rely 255/255, load 65/255
  Encapsulation HDLC, loopback not set, keepalive set (10 sec)
  Last input 00:00:00, output 00:00:00, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0 (size/max/drops); Total output drops: 6
  Queueing strategy: weighted fair
  Output queue: 0/1000/64/0 (size/max total/threshold/drops)
     Conversations  0/15/256 (active/max active/max total)
     Reserved Conversations 0/0 (allocated/max allocated)
  5 minute input rate 50000 bits/sec, 45 packets/sec
  5 minute output rate 387000 bits/sec, 54 packets/sec
     1288261 packets input, 211679637 bytes, 0 no buffer
     Received 11374 broadcasts, 0 runts, 1 giants, 0 throttles
     10 input errors, 1 CRC, 6 frame, 0 overrun, 0 ignored, 2 abort
     1599373 packets output, 1420112874 bytes, 0 underruns
     0 output errors, 0 collisions, 254 interface resets
     0 output buffer failures, 0 output buffers swapped out
     3 carrier transitions
     DCD=up  DSR=up  DTR=up  RTS=up  CTS=up

I now notice that there are not any CRC's on Router1 and 1 CRC on Router 2.    I also was examining the BW on the Serial Interfaces, and one is set to 512, and the other set to 1500, would this make a difference?
0
 
LVL 7

Expert Comment

by:kanlue
ID: 21805031
please make them match to test first.

and you may try to change the 'encapsulation' to 'ppp' in the serial ports of both sides.
be careful when you do so because the connection will be down while doing it. if you are in the main office, you can telnet to the remote router to change the enca first, then change the one in the main office, so that you will not lost control of the remote site.

hope it helps.
0
 

Author Comment

by:logicaltechs
ID: 21805063
That's a good idea, quick question though, if the connection was working for years before the last couple weeks, should I be changing encaps, etc.  Or should I jumpt into replacing CSU/DSU's and or the T1 WIC on this?
0
 
LVL 7

Accepted Solution

by:
kanlue earned 500 total points
ID: 21805185
good point, then no need to change enca if it's been working well for years.
if the quality of T1 is good, then i think that we can change the WIC card to test.
0
 

Author Comment

by:logicaltechs
ID: 21806218
I have obtained a replacement T1 WIC CSU/DSU card from a 1721, do i have to reconfigure the serial connection, or does the IOS just recognize it as nothing different?  ...Assuming it's in proper working condition.
0
 
LVL 7

Expert Comment

by:kanlue
ID: 21806402
it would be recognized automatically.
0
 

Author Comment

by:logicaltechs
ID: 21806457
Sweet thanks!  I am going to probly drop it in tomorrow and see what happens.
0
 

Expert Comment

by:alikuscu
ID: 21845665
I really want to find out what happened because I'm having similar issues here at my office. Please tell us if replacing the card resolved your issue.
0
 

Author Comment

by:logicaltechs
ID: 21845968
Replacing the card on either end did not help at all.  The only thing that we can do now is either change to a different ISP or start troubleshooting our switching infrastructure on the remote end.  But since this has happened before with the ISP a long time ago, we are going to find a new ISP and/or get rid of our T1 point to point circuit and get a regular T1 to the Internet and set up an IPSEC branch office VPN.
0
 

Expert Comment

by:alikuscu
ID: 21846626
Wow. Good luck.
0

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