We have a rather peculiar problem with internet speed in our office. Recently, we switched to a fiber-optic connection. We're supposed to have a 100Mbit connection (up and down). Here's how it has been set up (we're in a building with multiple tenants but just one fiber-optic connection, that's why we're using static IP routing so every tenant has their own IP):

  1. Vigor 2130n router where the cable comes into the building
  2. Vigor 2130n router in server room (connected to router #1 via WAN port w/ patch cable)
  3. 100M network switch connected to router #2 LAN port
  4. Vigor 2130 router connected to switch #3 via WAN port, using Static IP routing
  5. Gigabit network switch connected to router #4
  6. My computer connected to switch #5

Now the funny thing is, that when I connect router #4 to switch #3 using a LAN port (which is of course exactly the same as plugging switch #5 into switch #3) I have a 100 Mbit internet connection (according to Speedtest.net). However, when I connect router #4 to switch #3 using the router's WAN port (which is necessary for the static IP), I only get about 48 Mbits up and down the line.

The Vigor 2130n and 2130 have gigabit WAN and LAN. The (n) version also has WLAN.

When I log into router #1, it says that its WAN port uses a 1Gfdx connection. Router #2 I don't have access to. Router #4 says its WAN port uses a 100Fdx connection.

Can anyone explain why we might be getting a lower speed when using the WAN port? I've proposed to the building manager to test if switch #3 is the culprit by bypassing it and connection router #4 to router #2. In the meanwhile, I'm hoping someone can shed some light on this issue.

  • 2
    Why do you even still have a 100M switch? That aside, I'd check your duplex settings on router #4, and also ensure that the WAN settings on router 4 are not throttling the connection (bandwidth control, etc). – NickW Apr 4 '14 at 9:48
  • Well, we're just one of the tenants and the owners own the stuff. They have no IT people at all, and the manager literally told me that he believed the speed test was wrong because his connection was certainly faster than it used to be... He has agreed to test the connection with our switch later today; I'm sure if that gives the higher speed, he'll ditch his old 100M one. I'll double check the router settings, but I'm pretty sure that's not it. – Knelis Apr 4 '14 at 9:56
  • 1
    Make sure the WAN connection is 100 Full Duplex.. – NickW Apr 4 '14 at 9:57
  • Its current status is 100fdx – Knelis Apr 4 '14 at 10:01
  • 1
    I think the skipping of the 100M switch will be the test you need to prove who the culprit is.. – NickW Apr 4 '14 at 10:15

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