Slow upload speed
 

Since getting my Superhub for my 50meg service the upload speed has dropped by nearly 50%.
I was getting about 4.8meg with the modem but the Superhub only reaches 2.4meg at best.
The latest firmware is installed so what can the issue be.

Modem stats...

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 299000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Configuration File OK
Security Enabled BPI+
Downstream Channels
Lock Status Modulation Channel ID Max Raw Bit Rate Frequency Power SNR Docsis/EuroDocsis locked
Locked QAM256 24 55616000 Kbits/sec 299000000 Hz 1.4 dBmV 42.0 dB Hybrid
Locked QAM256 25 55616000 Kbits/sec 307000000 Hz 1.5 dBmV 42.5 dB Hybrid
Locked QAM256 26 55616000 Kbits/sec 315000000 Hz 1.3 dBmV 42.3 dB Hybrid
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 0.0 dB Unknown
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 0.0 dB Unknown
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 0.0 dB Unknown
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 0.0 dB Unknown
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV 0.0 dB Unknown
Upstream Channels
Lock Status Modulation Channel ID Max Raw Bit Rate Frequency Power
Locked ATDMA 1 20480 Kbits/sec 35800000 Hz 41.2 dBmV
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
Unlocked Unknown 0 0 Ksym/sec 0 Hz 0.0 dBmV
Primary Downstream Service Flow
Downstream(0)
SFID 2238
Max Traffic Rate 53000000 bps
Max Traffic Burst 3044 bytes
Mix Traffic Rate 0 bps
Primary Upstream Service Flow
Upstream(0)
SFID 2237
Max Traffic Rate 5140000 bps
Max Traffic Burst 8160 bytes
Mix Traffic Rate 0 bps
Max Concatenated Burst 8160 bytes
Scheduling Type Best Effort
Current System Time:Mon May 02 09:11:16 2011

Re: Slow upload speed
 

There is a firmware bug on the superhub that stops you getting full upload speed when you are connected to a motorola BSR

Re: Slow upload speed
 

It could be a firmware bug on the bsr :)

Re: Slow upload speed
 

I am only getting 1.6 meg upload on the 30 meg package in Belfast.. I feel your pain as the people on the phone have no idea about this and run the same script evertime you call...have you disabled this, its your computers fault, we only gaurantee download speed. your upload speed is fine...blah blah blah...

Re: Slow upload speed
 

I get less than a meg up on 50Mb. Count yourself lucky

Re: Slow upload speed
 

Modem = fine, Superhub = poop, same BSR.

Would be interesting to see what minislot size the Pooperhub thinks it has there as 2.4Mbit/s is about what people with a minislot size of 1 were seeing before it was changed to 4 ticks.

Sadly this isn't shown on the Pooperhub GUI :(

Re: Slow upload speed
 

whats a minislot?

Re: Slow upload speed
 

It's like a regular slot but much smaller :)

Re: Slow upload speed
 

Modems request bandwidth by minislots, when they want bandwidth they ask for minislots, not bytes or bits. The size of these is in ticks of 6.25 microseconds. There's a parameter for how many ticks are in each minislot, that's the minislot size.

If the minislot size is too small the modem can't deliver full speed as each time it wants bandwidth it has to ask for it, and it can't ask enough times per second to get enough minislots for the bandwidth. With a minislot size of 1 it has to ask for 4 times as many minislots to send the same amount of data.

Modems have to run through a request - grant - send process when they want to transmit, they wait for a timed window then they send a request for upstream bandwidth, they are then given a time to send their data. This isn't instantaneous, it takes a little while, and there's a restriction on how much data a modem can request permission to send at once, 255 minislots, so the modem may not be able to go through this process enough times to get enough minislots to send the full, say, 5Mbit/s it needs to transmit on a 50Mb customer's upstream.

---------- Post added at 20:58 ---------- Previous post was at 20:57 ----------

:knock:

Re: Slow upload speed
 

So is 4 default and 1 the minimum? What is the benefit of having it set at 1? Less errors?

Re: Slow upload speed
 

Motorola as well? Or is the Cisco fixed?

Re: Slow upload speed
 

The only benefit is more efficient use of the slots. If someone has data that needs 6.25us to transmit they can request a single minislot and get just that whereas they would request a single slot and get 25us on 4.

4 is default for 6.4MHz 16QAM IIRC.

Re: Slow upload speed
 

i might have it mixed up.... again... one of them has the problem and one doesnt :erm::erm:

Re: Slow upload speed
 

The issue I'm talking about isn't a firmware bug it's a configuration error. I think this is confined to Cisco hardware.

Re: Slow upload speed
 

Both are reported to have in certain areas. This could be due to the config of the UBR/BSR.