Poor network performance on SG500-52 ports

[michel.laurent1]

Here is the Scenario:

- Cable Modem connected to ISP with 100Mbit/s Speed.

- Cisco Router RV325 connected to Cable Modem on WAN1 port. Router acts as DHCP Server with 5 VLANs.

- SG500-52 Switch (In router Mode) connected via trunk port to LAN2 port of the RV325. Ip route was set to the ip address of the RV325 Router.

Now here is my problem.

Every client connected to the SG500 Switch can only download with download with 0.4 Kbit/s, upload is 6Mbit/s. Browsing the internet is nearly impossible.

Clients connected to the RV325 LAN port directly can download 90Mbit/s and upload 6Mbit/s.

I cannot understand why there is a so significant loss in performance.

Any help is much appreciated.

[Tom Watts]

Hi Michael, I think there are 2 concerns to express. The first being since the RV325 supports VLANS, I wouldn't see a good reason for basic use to have your switch in layer 3 mode. Second concern and is more applicable, it is possible the way your host connections are set up it is packet switching instead of hardware switching.

I'm quite certain if your switch is layer 2 mode that your problems will go away. If you want to leave it as it is, I am quite certain if you ensure you're not locally routing your hosts on the switch IP interfaces but instead to the RV325 interfaces, it will switch much faster.

[michel.laurent1]

Hi Tom, thanks for the quick response. Meanwhile I had the opportunity to follow your advice and to change the SG500 to system mode switch (layer 2).

Unfortunately this didn't fixed the issue. 

I did some further investigation and I found out that only 2 ports (port 3 and 4) are showing the slow packet send issue. So every device connected to port 3 or 4 is slow.

For now I have found a workaround by connecting the computers to other port than 3 or 4 and the the performance is good.

I assume that there is a hardware issue with the switch. 

I will contact CISCO support.