Problem with port switch?

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manny1222

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Mar 11, 2012
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Hi guys,
I just got rid of my comcast supplied gateway for internet and replaced it with a Netgear CM700 modem and a Netgear R7000 router. I did a speedtest.net test on my phone using wifi and I was getting 118 down and 12 up.This is better than 90 down and 12 up I was getting previously. I tried speedtest on my desktop that is hardwired and got same as I was getting previously (90 down, 12 up). I moved the desktop from my port switch (Netgear JGS524) to the router directly and I got 119 down and 12 up.
Is there a problem with my switch or is there some setting that I haven't toggled on? I only have one cable coming from the router to the port switch, and as far as I know, they are all gigabit capable. Thanks for the replies.
 
It sounds like you are getting the speeds you are paying for...

Have you verified the port speed settings the switch or from the router to the switch to make sure it is not set to FastEthernet or 100Mbit?
 
Thanks for the reply. The port doesnt have any physical switches that i see, and it doesnt have any management software.
As far as i know its all gigabit enabled. The differences in speed happens regardless of where i plug them in on the router.
 
Are you getting near gigabit speeds within the switched network? Like, from host to host without the router in the equation?
 
So when hanging off of your gigabit switch, you can't break 100mbit, but plugged directly into the R7000 you can? You should be able to look at the lights on the front of that netgear and determine that something is up. Chances are good that the connection between the switch and the router is only 100mbit. So you'll see gigabit on your desktop because you have gigabit between that and the switch, but the uplink is throttling you. If it's showing up on the netgear switch, you should see one of the speed lights as a yellow light. If they are all green then it's probably not anything on the switch.
 
bman212121 said:
So when hanging off of your gigabit switch, you can't break 100mbit, but plugged directly into the R7000 you can? You should be able to look at the lights on the front of that netgear and determine that something is up. Chances are good that the connection between the switch and the router is only 100mbit. So you'll see gigabit on your desktop because you have gigabit between that and the switch, but the uplink is throttling you. If it's showing up on the netgear switch, you should see one of the speed lights as a yellow light. If they are all green then it's probably not anything on the switch.
Click to expand...

This was my thought as well, until I looked at the modem the OP provided, and it's a 1GbE port on it. There's obviously something going on, but who knows....
 
Cmustang87 said:
This was my thought as well, until I looked at the modem the OP provided, and it's a 1GbE port on it. There's obviously something going on, but who knows....
Click to expand...

No, not the modem port. The connection between the modem and the router is fine. The connection between the router and the switch is likely bad.
 
Suspects: Bad cable between modem and switch. Router set for jumbo packets, switch isn't or can't. The switch and router just won't play well together.
 
Check that switch and see what it is negotiating for--gigabit or fast ethernet. My bet is fast ethernet.
 
If the cable between the Modem and Router is fast E or going bad then all devices will experience the same fluctuation. One other thing to consider here is that if your service that you are paying for is not more than 100Mbp/s, than FastE ( I.E. 100Mbp/s connection) is more than enough to handle it.
You are also on a Cable connection. There is going to be quite a bit of fluctuation on your experience depending on how many people are on the main feed for your apartment/neighborhood and sometimes even City. During peak hours and holidays you will definitely see a drop in performance. I pay for 100/10 and over thanksgiving break I saw my speed dip down to 50-60 dl.

You have 24 ports on that switch, you can always try moving it to another port and see if that improves things, but my guess is that the 119 down that you are seeing is burst speed, not continuous throughput.

I burst up to around 115-122 at times during speed tests but continuous I average around 80-95 ( which if you do the math for overhead) is right at the max. The reason you get bursting is the ISP CO switch gets requests that are above its configured QOS bandwidths, so it will temporarily increase allocated bandwidth to accommodate the requests to minimize packet loss. The average ISP ( at least according to a few colleagues that work for a few different ISPs) uses a 25% QOS burst ratio.

Ethernet efficiently can only hit at about 97% ( due to TCP/IP overhead of 2.74%) and if you add on VLAN tagging you have a theoretical limit of 94.68. Getting 90 down with a theoretical max of 94.68 ( that is if you have 100 DL) means you arent doing too bad.


To all the people that are saying its a 100/1000 negotiation issue; you simply do not need to have the port set to 1Gbp/s to see your "max speeds" if you are not paying for service above 100 in either direction. If you are paying for 100+, then yeah there could be a port negotiation or cable issue. Cables are cheap to replace as a starting point. Jumbo frames only do you good if all the devices you are transferring between are using Jumbo frames. There is no guarantee that your ISP is using Jumbo frames which means that your router would have to due more overhead to split/unsplit those 9k frames. I've only ever seen IMIX which makes sense because if they were using 9K and had frame loss, then 9k size packets are having to be resent rather than 64k or 1500k sized packets. Less efficient.

I also have the Netgear CM700 modem going to a FastE port on my Cisco 2901 Router with my 100Mb service and again average 80-95 Mb DL. I also live in Dallas so there is a lot of population and congestion and am happy with that. Thats why ISPs say your service is up to 100Mbp/s, not guaranteed.
 
I still think it's a FE vs GE negotiation issue on the port. Otherwise, the 119 test wouldn't even happen, and should still be 119 even with the switch/router (unless the router can't handle that much wan to lan--then that's the issue).
 
Sure it can. On a 100Mbp/s connection you can see 12MBp/s download. That comes out to roughly 120Mbp/s. I see it day in and day out. It doesn't stay there, but it can achieve it.

OP can set the speed manually on the router and see what happens. If the connection to the modem dies, then there is something funky with that Modem and I would get it replaced.
 
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Daedalus0101101 said:
Sure it can. On a 100Mbp/s connection you can see 12MBp/s download. That comes out to roughly 120Mbp/s. I see it day in and day out. It doesn't stay there, but it can achieve it.

OP can set the speed manually on the router and see what happens. If the connection to the modem dies, then there is something funky with that Modem and I would get it replaced.
Click to expand...
With the overhead that internet connections have I haven't seen >85Mbits even with a 200Mbps+ connection. I haven't even seen >94Mb on a LAN using iperf between a GE and FE system.

I'm still betting on the FE vs GE issue.
 
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