Improve company productivity with a Business Account.Sign Up

x
?
Solved

Why input errors on my Cisco 881 Internet router?

Posted on 2013-12-16
12
Medium Priority
?
2,114 Views
Last Modified: 2014-05-20
This is using Cisco Router 881 as a Internet router, for my Internet bandwidth 100 Mbps. This is a new setup. Recently, I typed "int fastethernet4" (for the WAN interface), and found that there are few errors as follows:

  DSL#sh int fa4
FastEthernet4 is up, line protocol is up
  Hardware is PQII_PRO_UEC, address is 885a.92c2.dba0 (bia 885a.92c2.dba0)
  Internet address is xxx.xxx.xxx.xxx/23
  MTU 1500 bytes, BW 100000 Kbit/sec, DLY 100 usec,
     reliability 255/255, txload 1/255, rxload 6/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 100Mb/s, 100BaseTX/FX
  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
  Input queue: 23/75/1563/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 2358000 bits/sec, 193 packets/sec
  5 minute output rate 64000 bits/sec, 105 packets/sec
     15760684 packets input, 884649953 bytes
     Received 0 broadcasts (0 IP multicasts)
     178 runts, 0 giants, 905* throttles
     985 input errors, 1 CRC, 0 frame, 984 overrun, 0 ignored
     0 watchdog
     0 input packets with dribble condition detected
     13190300 packets output, 3412388052 bytes, 0 underruns
     0 output errors, 0 collisions, 4 interface resets
     0 unknown protocol drops
     0 babbles, 0 late collision, 0 deferred
     1 lost carrier, 0 no carrier
     0 output buffer failures, 0 output buffers swapped out

Do the following matter? As they are increasing... How about 1 lost carrier?

   178 runts, 0 giants, 905* throttles
     985 input errors, 1 CRC, 0 frame, 984 overrun, 0 ignored

Thanks in advance
0
Comment
Question by:MichaelBalack
  • 5
  • 4
  • 2
  • +1
12 Comments
 
LVL 3

Expert Comment

by:vyaradaikin
ID: 39721168
Hello. According to cisco site you got next causes:
throttles:
Packets which can increase the processor overload include IP packets with options, expired TTL, non-ARPA encapsulation, fragmentation, tunelling, ICMP packets, packets with MTU checksum failure, RPF failure, IP checksum and length errors.
overrun:
The input rate of traffic exceeded the ability of the receiver to handle the data.
I advise you to check physical connection, what type of media you use? Check the cable length to the other side. Try to change port on cisco router.
What kind of equipment on the other side?
0
 
LVL 1

Author Comment

by:MichaelBalack
ID: 39721434
Hi Vyaradaikin,

The Cisco router is connected with cat6 rj45 cable, with length in 5 meters, connected to the Internet ONT (Optical Network terminal).

The equipments on the other side is all those ISP Internet devices.
0
 
LVL 3

Expert Comment

by:vyaradaikin
ID: 39722064
So, as I see the demarcation point(point of resposibility) ends with this patchcord. You can check this by enabling some device, laptop for example to the router and then ping your router. If errors continue to appear then you may change patchcord, port and try ping again. Also you must check the ISP equipment by enabling to their equipment by laptop also. So that you can narrow circle of possible problem.
0
Worried about phishing attacks?

90% of attacks start with a phish. It’s critical that IT admins and MSSPs have the right security in place to protect their end users from these phishing attacks. Check out our latest feature brief for tips and tricks to keep your employees off a hackers line!

 
LVL 1

Author Comment

by:MichaelBalack
ID: 39725688
Hi vyaradaikin,

Users also feedback to me that certain web sites - yahoo, facebook, may delayed and and can not access as well.
0
 
LVL 3

Expert Comment

by:vyaradaikin
ID: 39725801
This also could be cause of the MTU mismatch with your ISP. You can check it by configuring tcp mss adjustment on user-side routed interface:
ip tcp adjust-mss 1380
Then try to access sites againg. If problem still exist search within physical connection. If problem is gone, then you must configure MTU your ISP support.
0
 
LVL 1

Author Comment

by:MichaelBalack
ID: 39725871
Hi vyaradaikan,

I have put in the mtu adjustment in the router VLAN1 interface as follows:

   Interface vlan1
      description office network
      ip address 192.168.100.1 255.255.255.0
      ip nat inside
      ip virtual-reassembly
     ip tcp adjust-mss 1452

My ISP is using mtu - 1452. I will monitor the status...
0
 
LVL 3

Expert Comment

by:vyaradaikin
ID: 39725878
You need decrease your mss to the value less then ISP mtu. It is because IP/TCP/UDP headers add bytes to each frame. so I recommend to try 1380 as an mss value.
0
 
LVL 31

Accepted Solution

by:
Blue Street Tech earned 2000 total points
ID: 39731355
Hi MichaelBalack,

Here is how to automate the MTU testing to size it correctly to your WAN pipe regardless of the connection type: http://www.experts-exchange.com/A_12615.html

Let me know how it goes!
0
 
LVL 1

Expert Comment

by:robertmparten
ID: 39747700
Before you go down the rabbit hole. run frames are a collision issue or you have seen an Ethernet frame of less than 64 bytes; however, you have one CRC error, so it could be from when you first connected. Here is a piece of advice:

clear counters

This will reset all your interfaces. From there, monitor to see if you have issues with CRC or runts. One more thing, some ISP equipment doesn't play nice with straight through cables, I had this issue numerous times with Verizon circuits and their equipment. Switch to a cross over cable, sadly, and verify if the ISP side is set for auto-negotiation or hard coded at 100/FULL and ensure you match on your side.
0
 
LVL 1

Author Comment

by:MichaelBalack
ID: 39747712
Sorry for the delay, let's me check and update
0
 
LVL 1

Author Comment

by:MichaelBalack
ID: 39757413
Excellent, now looks stable now
0
 
LVL 31

Expert Comment

by:Blue Street Tech
ID: 39757808
Terrific. I'm glad I could help!
0

Featured Post

Free Tool: Site Down Detector

Helpful to verify reports of your own downtime, or to double check a downed website you are trying to access.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

Join & Write a Comment

As managed cloud service providers, we often get asked to intervene when cloud deployments go awry. Attracted by apparent ease-of-use, flexibility and low computing costs, companies quickly adopt leading public cloud platforms such as Amazon Web Ser…
How to fix a SonicWall Gateway Anti-Virus firewall blocking automatic updates to apps like Windows, Adobe, Symantec, etc.
Both in life and business – not all partnerships are created equal. As the demand for cloud services increases, so do the number of self-proclaimed cloud partners. Asking the right questions up front in the partnership, will enable both parties …
Both in life and business – not all partnerships are created equal. Spend 30 short minutes with us to learn:   • Key questions to ask when considering a partnership to accelerate your business into the cloud • Pitfalls and mistakes other partners…

586 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question