router cuts speed in half

[moondoggie]

I use SBC DSL PPPoE service. Advertised 384 to 1500. When I plug the modem directly to the NIC in the PC, it consistently downloads at 82kBytes. When I use the Nexland SOHO router (which is said to be a pretty good one), the speed drops to 41kBytes. Before using the Nexland, I had a LInksys BEFRS41 and the results are identical. Either router seems to cut speed in half.

My PC runs WIN XP. I get the same results with laptop running Win2K.

I've spoken with SBC and they can't help. I've played with RWIN settings until I'm blue in the face with no impact.

This thing REALLY has me perplexed. If anyone has any suggestions or advice, I'm all ears. Plus my kids would be thankful to have their PC downloading fast as well.

Many Thanks


Using Nexland SOHO ISB:

TCP options string = 020405980103030301010402
MTU = 1472
MTU is not fully optimized for broadband. Consider increasing your MTU to 1500 for better throughput.
MSS = 1432
Maximum useful data in each packet = 1432, which equals MSS.MSS is not fully optimized for broadband (although it might work well for slower connections). Consider increasing your MTU value.

Default Receive Window (RWIN) = 504064
RWIN Scaling (RFC1323) = 3 bits
Unscaled Receive Window = 63008
RWIN is a multiple of MSS
Other values for RWIN that might work well with your current MTU/MSS:
252032 (MSS x 44 * scale factor of 4)
126016 (MSS x 44 * scale factor of 2)
63008 (MSS x 44)
bandwidth * delay product:
Your RcvWindow limits you to: 20162.56 kbps (2520.32 KBytes/s) @ 200ms
Your RcvWindow limits you to: 8065.024 kbps (1008.128 KBytes/s) @ 500ms
MTU Discovery (RFC1191) = ON
Time to live left = 56 hopsTTL value is ok.
Timestamps (RFC1323) = OFF
Selective Acknowledgements (RFC2018) = ON
IP type of service field (RFC1349)= 00000000


PC logged on directly via PPPoE

TCP options string = 020405a00103030301010402
MTU = 1480
MTU is optimized for Windows XP PPoE DSL broadband. If not, consider raising MTU to 1500 for optimal throughput.
MSS = 1440
Maximum useful data in each packet = 1440, which equals MSS.MSS is optimized for Windows XP PPPoE DSL broadband. If not, consider raising MTU to 1500 for maximum throughput.

Default Receive Window (RWIN) = 504064
RWIN Scaling (RFC1323) = 3 bits
Unscaled Receive Window = 63008 For optimum performance, consider changing RWIN to a multiple of MSS.
Other values for RWIN that might work well with your current MTU/MSS:
506880 (MSS x 44 * scale factor of 8)
253440 (MSS x 44 * scale factor of 4)
126720 (MSS x 44 * scale factor of 2)
63360 (MSS x 44)
bandwidth * delay product:Your RcvWindow limits you to: 20162.56 kbps (2520.32 KBytes/s) @ 200msYour RcvWindow limits you to: 8065.024 kbps (1008.128 KBytes/s) @ 500ms
MTU Discovery (RFC1191) = ON
Time to live left = 57 hopsTTL value is ok.
Timestamps (RFC1323) = OFF
Selective Acknowledgements (RFC2018) = ON
IP type of service field (RFC1349)= 00000000

[stevebakh]

hey... I use the Linksys Befsr11 model and it works fine. When one computer is downloading and the other one ain't.. it runs at full speed. I have 256k down (35 K on average download speed) and the router doesn't split it at all! try the Linksys one again and try updatingthe firmware from the linksys website! good luck :)

[MadDoctor]

That’s weird. NIC set to half duplex on both computers? I’m not that smart… but someone smart will be along soon.

[moondoggie]

both computers set to full duplex. speed tests done with only one computer on so as not to dilute packet flow.

it is wierd.

[zxc47]

MTU = 1500
MTU is fully optimized for broadband.

MSS = 1460
Maximum useful data in each packet = 1460, which equals MSS.

Default Receive Window (RWIN) = 64240
RWIN Scaling (RFC1323) = 0 bits
Unscaled Receive Window = 64240
RWIN is a multiple of MSS
Other values for RWIN that might work well with your current MTU/MSS:
513920 (MSS x 44 * scale factor of 8)
256960 (MSS x 44 * scale factor of 4)
128480 (MSS x 44 * scale factor of 2)

bandwidth * delay product:
Your RcvWindow limits you to: 2569.6 kbps (321.2 KBytes/s) @ 200ms
Your RcvWindow limits you to: 1027.84 kbps (128.48 KBytes/s) @ 500ms

MTU Discovery (RFC1191) = ON

Time to live left = 52 hops
TTL value is ok.

Timestamps (RFC1323) = OFF

Selective Acknowledgements (RFC2018) = ON

IP type of service field (RFC1349)= 00000000

try this setting and set both nic to auto

[YeOldeStonecat]

MTU on the Nexland set to 1500? Should greatly increase your speeds. Adjust MTU on the router, not the workstations. The router does the work for you. The router is the second fastest one I've had...smokes Linksys routers, tromps Netgears too. Only one faster I've used is a 400 dollar Netopia R series (business class router)

[moondoggie]

Thanks for the advice. The max MTU for PPPoE on the Nexland is 1472. Windows XP sets it at 1492 when connected directly. But that doesn't sound like 50% to me. Appreciate the response.

[Bound]

My Mtu is 1472 on my nextland Pro800 turbo. I called support and asked about it, they told me it was my DSL provider that set it to 1472. I told then I had 1492 on my linksys and he had no answer.