Cisco 877 througput?

[meijbergj]

Hello,

Another wird problem. When i connect my cisco 877W to the internet (12 Mb down, 1 Mb up) i get different download results.

When i do a test (speedtest on the internet) connected to the cisco 877 LAN i get these results: max 650 kbps down and 101 kbps up.

When i am connected to the Wlan of the cisco 877 i get these results: max 375 bps down and 101 bps down.

And when i connect my Zyxel adsl2+ router i get : 1100 bps down and 101 bps up.

What's wrong with the Cisco ? Througput problem ?

Any suggestions ?

[m-haddad]

What is your internet connection?ADSL?

Let me know,

Regards,

[jackyoung]

The router should able to support up to 30Mbps at 1400 byte.

What is your current IOS ver. ? Can you upgrade to 12.4(4)T ? It supports ADSL2/2+.

Check below for info.

http://www.cisco.com/en/US/products/hw/routers/ps380/products_qanda_item0900aecd8028a982.shtml

[meijbergj]

Hello,

I have adsl2+ and the current ios is 12.4.9T.

I also installed the 12.4.9.T1, but this ios image has given me problems with the WLAN.

Any suggestions ?

[jackyoung]

Can you try to download an older ver. (i.e. 12.4(6)T3 * 12.4(4)T4) to test again. If the problem still exists, I recommend to open a TAC case w/ Cisco for further investigation.

However, can you provide the config. for reference ?

Did you turn on any security, VPN service ?

[m-haddad]

Hello,

Will you please try to set the MTU size on the ethernet interface. Use the below command:

tcp-adjust mss 1350

Also, if you are using PPOE you have to set the MTU to 1492.

I guess the above should work and it is not an IOS problem. I had similar problem and it was due to MTU problem.

Please let me know how it goes,

Thanks,

[jackyoung]

Mohamand, thanks for the info. you wake me up for this reason. Let'w wait for the testing result. :)

John, more info. for you.

http://www.cisco.com/en/US/tech/tk870/tk877/tk880/technologies_tech_note09186a008011a218.shtml

http://www.cisco.com/en/US/products/sw/iosswrel/ps1839/products_feature_guide09186a00804247fc.html

Hope this helps.

[meijbergj]

Okay, i will try this later on.

So i will set tcp-adjust mss 1350 on the ethernet interface.

I don't use pppoe so i will leave this to the default.

But what shall i put in the wlan ? Also tcp-adjust mss 1350 ?

[jackyoung]

According to the uage guidelines form second link. I could recommend below setting.

interface

ip tcp adjust-mss 1452

inteface

ip mtu 1492

Please advise the result after the test.

[meijbergj]

Hello Jack,

What value should i use for the wlan?

Later this day i will submit the results.

Thanks in advance.

John

[jackyoung]

According to the sample, there is no tcp-mss adjust required at WAN interface, so only the MTU is required. And there is no need to change the MTU but need to adjust the tcp-msss at LAN too.

Just follow my post and fill the correct interface name and number to it.

[m-haddad]

I suggest you set the MTU on the LAN

ip tcp adjust-mss 1452

On the WLAN

ip mtu 1492

I suggest to put it 1350 at first because the router you have has best throughput with packet size 1400. Therefore, setting the MTU On the LAN to 1350 can lower the processing speed for fragementation.

Please let me know how it goes,

Regards,

[meijbergj]

Thnx for all your help. But i think the problem is somewhere else (ISP).

I have doen all the settings, but it doesn't help. So i connected a linksys wap54g and it has the same problem. Only the Zyxel router haven't got the problem.

My ISP only supports the zyxel router (there default) and maybe it has something to to with this. All ther routers connect (sync) at the correct adsl2+ speed.

I noticed, by the way, that the zyxel router has an ENET ENCAP encapsulation. It also has RFC 1483 bridge, but the default is ENET ENCAP.

I will contact my ISP and hopefully they will assist me.

Thnx

[jackyoung]

Thanks for your update. RFC1483 is IP over ATM. I believe it is also using PPPoE.

Try to ask the vendor for the sample config. of Cisco router. They should have experience on it.