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7350 running on 8.0.2.5

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nigelgoboom

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Feb 27^th, 2009 at 7:41pm

g'morning folks

quick question. I've got a remote site using a 7350 on idirect hub version 8.0.2.5.

the spec sheet for the 7350 claims that these modems and handle info rates upto 20m downstream and 6.5m upstream however we're not passing even close to that.

this site is on a network by itself with cir's and mir's both set to the max info rate of 6megs. and a 6m info rate on both line cards.

do any of you know if the 7350's really can pass this much data? or perhaps only in a specific mode? this is setup as a tdma not an iscpc.

thanks in advance

nigel

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Scout

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Reply #1 - Feb 28^th, 2009 at 9:34am

Hi Nigel,
Few questions.
1. What is the CIR configured for the modem?
2. Is the CIR over contended by the operator?
3. What traffic are you passing? TCP, UDP, HTTP, iperf or another test tool?
It all depends on the traffic in use, as to the results you will see, the rates promised are in a best case scenario (as with every equipment provider world wide, except iDirect can typically deliver when we test them) and I have seen them being reached, especially with the higher end modems such as you have.
With defined long packet lengths running UDP traffic (I know it's normally small UDP packets) but long packet UDP will show you much higher data rates, if you are testing TCP, there is a limitation to the bandwidth you will get with a single session, so open multiple sessions to test TCP, you will see the modem pass much more traffic.
finally, the modem is capable of these high rates for sure, but remember you have an aggregate throughput, so your total rate (downstream and Upstream) will not be the two capabilities added together but a lower number. I think you have an Aggregate throughput of 11Msps, 22 Mbps, so not the full throughput that can be achieved down and up combined.
The remotes also have a packets per secon limitation, the PPS limitation may be reached well before the bandwidth limitation, so check the pps through the remote.

To give you a full idea of what's going on, I'd need a little more info, but I hope this gives you a start point.

Scout

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Reply #2 - Feb 28^th, 2009 at 2:40pm

Quote:

g'morning folks

quick question. I've got a remote site using a 7350 on idirect hub version 8.0.2.5.

the spec sheet for the 7350 claims that these modems and handle info rates upto 20m downstream and 6.5m upstream however we're not passing even close to that.

this site is on a network by itself with cir's and mir's both set to the max info rate of 6megs. and a 6m info rate on both line cards.

do any of you know if the 7350's really can pass this much data? or perhaps only in a specific mode? this is setup as a tdma not an iscpc.

thanks in advance

nigel

When you say 6000 info rate on both cards, are you telling me that your tx card (forward carrier) is a 6MB carrier and your return is 6MBs? �(symmetrical)

What is your modulation and coding for each carrier? �

Are these carriers are on independent line cards? ��

I can assure you the 7000 series modem is capable of the data. �However, there are modulation and coding requirements to achieve the upstream throughput you are looking for (downstream, no issues)

Also, with a 6MB upstream you will more than likely be right around 5700-5800 of upstream (raw IP) throughput (somewhat dependent on the MODCOD) due to the TDMA overhead.

What kind of throughput are you seeing:

Upstream:
Downstream: