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802.3ad LAG Question on 2808 vs. 2716
Hello,
Disclosure: I have a moderate amount of IT knowledge but am a newbie when it comes to networking and all the various IEEE protocols.
I need a new Gigabit switch for my network to replace a 2716 that died on me. I was all set to order a 2808 when I came across another post on this forum that has me concerned that the 2808 will not work for me (en.community.dell.com/support-forums/network-switches/f/866/t/19541840.aspx ). I have a Synology DS412+ NAS that has 2 gigabit ports that I connected to the switch and configured with Link Aggregation. A few days ago I needed to physically move the 2716 from one rack to a different one. When I unplugged the power the switch just died. It would not turn back on. I assume the PSU couldn't handle the power cycle.
Needing a switch right away I ran to the nearest Fry's and purchased a NetGear switch. When I tried to configure my NAS with LAG I was disappointed to receive an error message that my switch does not support 802.3ad. I decided to keep the NetGear for a few days while I order a new PowerConnect. This network is small - I only use 5 ports. I was planning on buying the 2808 as I see it is listed as supporting 802.3ad. Then I came across the above post that seems to say it supports some form of LAG, but not LACP 802.3ad.
Can someone please tell me in non technical terms what features are different (besides the number of ports) between the 2716 and 2808? Will the 2808 work in LAG with my DS412+? I should point out that my 192.168.1.xxx network is configured with fixed IP addresses. I do not use DHCP. Does that make a difference?
If the 2808 will not meet my needs, can you recommend other PowerConnect models that would be in the $150 price range that would? If need be I can buy a used 2716 on eBay. I would prefer buying a new switch to avoid having any problems down the road.
P.S. I do not recall ever configuring my 2716. If I buy the 2808, would I need to configure it or can I just "plug it in"?
Anonymous
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January 26th, 2015 06:00
Both the 2700 and 2800 switches have very similar management interfaces. They both support static link aggregation. This means that the LAG will not negotiate with the device on the other end. The LAG will presume that the other device is setup the same.
There are two possibilities here. The first is that the DS412+ was setup with an active/passive configuration. In this case I don’t think there is a need for any switch configuration.
The other possibility is that there was a LAG created. It is easy to configure a LAG, so you may have just forgot about making it. Page 131 of the user guide details the creation of a LAG.
http://bit.ly/1yVd64i
You may also be able to look at the DS412+ to see how the NICs are configured, that would give you a better idea of how you need to configure the switch.
Keep us posted.
MrChip
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January 26th, 2015 09:00
One more question, I ran LAN Speed Test (Lite) to test the speed from my PC to first my server and second my NAS. Here are the results with a 1.2GB file:
To Server:
Writing (Upload) = 176.3 Mbps
Reading (Download) = 265.8 Mbps
To NAS:
Writing (Upload) = 701.9 Mbps
Reading (Download) = 358.6 Mbps
Do these speeds seem correct for gigabit NICs using a gigabit switch and CAT 6 wires? I wonder why NAS writing is so much higher than all the others?
MrChip
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January 26th, 2015 09:00
Hi Daniel,
Thank you for helping me out with this. I will have a chance to look into your questions in a few hours. I have some fundamental questions about LAG.
The DS412+ gives me two option for using both of its gigabit NICs. One is in a LAG mode and the other is more for fault tolerance. My assumption was that using LAG would roughly double the transmission speed of the NAS from 1Gbps to 2 Gbps. This weekend I have seen some posts that indicate that with my current setup I may not see this benefit.
95% of the time I am the only user accessing the NAS. My new server has only 1 NIC and although my primary PC has two, I only use one NIC. Assuming I get the NAS to run in LAG mode. Am I correct that this would mean it would send/receive 2 Gbps to the switch, but my server and PC will still be limited to 1 Gbps unless I have dual NICs set up in LAG on them? So in effect LAG will not give me any performance benefit?
Let's assume I installed a second NIC on my server and configured them in LAG, would my server backups to the NAS run faster then?
Thanks!
Anonymous
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January 26th, 2015 11:00
Teaming/LAG the two ports together creates the ability for multiple connections to achieve higher speeds Vs. non LAG connection. It will not increase the speed of one connection to the NAS. Here is a post on the Synology forums about link aggregation.
http://bit.ly/1Db4i9J
That users conclusion was that the LAG is not going to benefit a single connection to the NAS.
On your server, depending on the hardware and OS, I believe there are some specific configurations that would enable a single connection to the server to aggregate bandwidth for a single connection.
When testing transfer speeds from one device to another there is more that is factored in. such as disk read and write speeds. The NAS may have a higher read and wrtie speed to it's disks than the server does. Using software specific to testing network throughput may net more constant results.