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Cisco 877 not getting full ADSL speed?

Discussion in 'Routing & Switching' started by phatboy, Jan 11, 2011.

  1. phatboy

    phatboy Nibble Poster

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    Hi,

    I have got my Cisco 877w all set up and working. The only issue I have is that my speedtest results are only showing 9mb, where as when I was using a Netgear router I was getting 14mb (its a 16mb connection)

    I have updated the adsl firmware and confirmed it is being used, and the IOS. I have also tried changing the MTU on the Dialer0 interface, but it has not helped. I have also tried different dsl modes.

    I have attached my show dsl int atm0 and show run files as they are huge!

    This is my sh ver:-
    Cisco IOS Software, C870 Software (C870-ADVIPSERVICESK9-M), Version 12.4(24)T4, RELEASE SOFTWARE (fc2)
    Technical Support: http://www.cisco.com/techsupport
    Copyright (c) 1986-2010 by Cisco Systems, Inc.
    Compiled Fri 03-Sep-10 17:16 by prod_rel_team

    ROM: System Bootstrap, Version 12.3(8r)YI3, RELEASE SOFTWARE

    router uptime is 21 hours, 4 minutes
    System returned to ROM by reload at 20:52:34 GMT Mon Jan 10 2011
    System image file is "flash:c870-advipservicesk9-mz.124-24.T4.bin"
    Last reload reason: Reload Command

    Can anyone assist?

    Cheers
    Tim
     

    Attached Files:

    Certifications: CCNA R&S, CCNA Security, CCNA Voice, CCA 5.0, MCP 70-290 70-270 70-431
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  2. BosonMichael
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    BosonMichael Yottabyte Poster

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    Looks like the 877s have a maximum throughput of 12.80 Mbps. If so, you're not gonna get 16 Mbps out of it. I can't find the max throughput explicitly stated on Cisco's Web site, but there are a few threads in the support forums that seem to indicate that this is the max: link

    This might also be of interest to you... here are the technical specifications for DSL on an 870 series router according to Cisco's Product Data Sheet (red text added for emphasis):

    Might be that your 877W doesn't support your particular flavor of DSL at any faster than 8 Mbps, which is pretty close to the speed you are reporting.
     
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  3. phatboy

    phatboy Nibble Poster

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    Hi Michael,

    Thanks for the fast reply! I had a read, and I am definitly connecting ADSL2+, so I think the router can support that up to 24 Mbps?

    Further speed testing has shown best results of 10.01mb downstream, which I think is a bit too high if it was only capable of 8mb?

    The router has 128mb RAM, I wonder if this could be an issue?

    Thanks
    Tim
     
    Certifications: CCNA R&S, CCNA Security, CCNA Voice, CCA 5.0, MCP 70-290 70-270 70-431
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  4. BosonMichael
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    BosonMichael Yottabyte Poster

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    Even though ADSL2+ supports up to 24 Mbps, you're still limited to the throughput of the router.

    Dunno if it's a memory issue... typically, throughput's a CPU issue, but you never know, low memory might be a bottleneck too.
     
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  5. craigie

    craigie Terabyte Poster

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    Do you still have the NetGear router? If so plug this in and make sure you do a like for like test e.g. on wireless on NetGear and on wireless on Cisco 877 within a couple of minutes of each other.

    The reason this is important is that a normal ADSL line will offer varying levels of speed throughout the day.

    Let us know your results.
     
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  6. phatboy

    phatboy Nibble Poster

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    Ok so I checked again with the Netgear - 14mb everytime. I am very lucky with my ADSL, it always delivers well, I am told there are only 2 users on the DSLAM at present!

    Does the sh dsl int atm0 showing the downstream as 16384 mean much? I mean is it possible the router doesnt support that speed, but it knows such a speed exists?


    At the office we have another Cisco 877 and thats happily running 20mb... are there different CPU's in them or are they all going to be the same? That would eliminate the CPU as the culprit....?

    Thanks
    Tim
     
    Certifications: CCNA R&S, CCNA Security, CCNA Voice, CCA 5.0, MCP 70-290 70-270 70-431
    WIP: CCNP R&S, CCNA Wireless
  7. Sparky
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    What spec is the Netgear mate?
     
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  8. phatboy

    phatboy Nibble Poster

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    Its a DG834PN :)

    Cheers
    Tim
     
    Certifications: CCNA R&S, CCNA Security, CCNA Voice, CCA 5.0, MCP 70-290 70-270 70-431
    WIP: CCNP R&S, CCNA Wireless
  9. Sparky
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    Ahh, was expecting something more powerful!

    Anything else configured on the Cisco such as intrusion prevention etc. ?
     
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  10. phatboy

    phatboy Nibble Poster

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    Nope just a simple one, but if a crappy Netgear can do it I hope my newer Cisco can do it!!

    No IDS or anyting configured, just a straightforward setup with 2 VLANs, BVI's and SSID's.....

    Tim
     
    Certifications: CCNA R&S, CCNA Security, CCNA Voice, CCA 5.0, MCP 70-290 70-270 70-431
    WIP: CCNP R&S, CCNA Wireless
  11. Sparky
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    Strange one mate.

    Can only think there something misconfigured in the WAN interface that might be causing this.

    I take it the Netgear auto detected the ADSL settings ok? Is it possible to compare these settings (if possible) with the Cisco?
     
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  12. ThomasMc

    ThomasMc Gigabyte Poster

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    What was the reason behind upgrading to the 4.0 firmware?


    This is what I get on AMR-3.0.014.bin

    Code:
    DSL Mode:        ITU G.992.5 (ADSL2+) Annex A
    
                     DS Channel1      DS Channel0   US Channel1       US Channel0
    Speed (kbps):             0            12919             0              1016
    Cells:                    0          3638845             0        1420682692
    Reed-Solomon EC:          0            32569             0                 0
    CRC Errors:               0               53             0                 0
    Header Errors:            0               47             0                 0
    Total BER:                0E-0           3265E-10
    Leakage Average BER:      0E-0           5606E-17
    Interleave Delay:         0               40             0                 0
                            ATU-R (DS)      ATU-C (US)
    Bitswap:               enabled            enabled
    
    [​IMG]


    Also, where did yuou get the firmware from as I can't find it on ftp://ftp.cisco.com/pub/access/800/
     
    Last edited: Jan 12, 2011
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  13. phatboy

    phatboy Nibble Poster

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    Hi, I upgraded from the version you are on as I was only getting 8.5mb on that one. I got the update through a link on Google because the one on the Cisco FTP was corrupt - only 300kb where as the others were 900kb!

    Thanks
    Tim

     
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  14. ThomasMc

    ThomasMc Gigabyte Poster

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    Try it with AMR-3.0.033.bin it's in the public domain somewhere or inform Cisco your having problems downloading it, I'm sure they would send it to you.

    [added]
    I just downloaded the firmware from cisco ftp without problems
     
    Last edited: Jan 13, 2011
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  15. phatboy

    phatboy Nibble Poster

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    Hi,

    Ok I am now running AMR-3.0.033.bin, and the results are about the same. I also tried buying a superduper ADSL filter and high quality cable, but its not made a difference!

    My only other thought is CPU load? Ive done show process cpu and it shows the below:-

    CPU utilization for five seconds: 98%/37%; one minute: 24%; five minutes: 8%

    Is 98% a bad thing?! or is that normal under a speedtest?

    Im very stumped now :(

    Tim
     
    Last edited: Jan 15, 2011
    Certifications: CCNA R&S, CCNA Security, CCNA Voice, CCA 5.0, MCP 70-290 70-270 70-431
    WIP: CCNP R&S, CCNA Wireless
  16. BosonMichael
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    Considering a speedtest tries to send packets as quickly as possible, I'd say 98% is quite normal... and is (as I attempted to explain before) likely the reason why you're hitting your max throughput.
     
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  17. ThomasMc

    ThomasMc Gigabyte Poster

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    From my experience with these boxes there should be more than enough CPU to get above that speed, it would be interesting to see the full output though and see what’s using the CPU
     
    Last edited: Jan 17, 2011
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  18. BosonMichael
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    I have no idea. The only thing I know is that there are a whole bunch of people saying that the max throughput is 12.80 Mbps. Granted, the 12.80 Mbps rate is with minimum packet sizes (larger packet sizes should mean the router can send fewer packets at more than 12.80 Mbps)... but he's not even getting 12.80 Mbps. That's why it's worth checking things like ACLs and NAT to see if there's anything slowing down the throughput.

    I once had a similar situation with a group of routers that should have been able to accept faster connections... I didn't believe their theoretical maximum throughput claims. But upgrading those routers to L3 switches that handled more packets per second fixed the problem.
     
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  19. ThomasMc

    ThomasMc Gigabyte Poster

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    Nevermind about the output, just noticed they are listed in reverse order, thought it was 98% over 5 mins
     
    Last edited: Jan 17, 2011
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  20. ThomasMc

    ThomasMc Gigabyte Poster

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    I done 3 speedtests over a short period of time and this is what I got CPU wise

    CPU utilization for five seconds: 3%/2%; one minute: 12%; five minutes: 7%

    [​IMG]

    So I wonder whats taking yours up to 98%
     
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