Asked this question previously, but it wasn't as detailed as this.

I had my network speed improved by my ISP, I tested the network speed from the Fiber media converter, the speed was awesome, tested it in some offices (both wireless and LAN ports) the network was still fine, but in some parts of the same building, the network is dead slow, as first I suspected coverage, that's for the wireless, but I tested the LAN ports, they were also slow. Can someone please help out on what might be the cause of this.

So this is the flow below

ISP => Media Converter => Juniper Router (SRX 550) => Cisco Switch => AP Access Points

NOTE: VLAN hasn't been setup on any of the switches.

I'll also appreciate an advice on how I can improve on my flow to better the security architecture of my network.

Thanks in anticipation.

  • Can you add the model of Cisco switch? Are you familiar with its command-line interface, accessed using SSH, Telnet, or serial console? Have you checked the CLI in the Cisco for errors, e.g. show interface ? – Jeff Wheeler Sep 19 '20 at 15:08
  • Are the interfaces rated for your speeds? Is there QoS applied? VLAN segmentation? Faulty cabling? STP or any errors on the switches? – DankyNanky Sep 20 '20 at 13:06

Connecting directly into the switch, use the wired network to see if the problem is still there. If not, it's the wireless network - interference, thick walls, long range, overload, ...

If the problem persists directly on the switch, check the switch's interface counters for errors. FCS, giants, runts indicate cabling problems on that port. If any port reports collisions it's not configured correctly (use Auto Negotiation at all times and DON'T force the port into any speed or duplex mode).

If the switch counters don't show anything check the Juniper port for anomalies. Try a laptop connected directly to the firewall. If performance is bad it's the Juniper - configuration, firewall overload, congestion, ...

If you're not monitoring your network and the Internet link at all, it's also quite possible that some user is running software that just seriously eats up bandwidth and slows the network for anyone else. It's not unheard of to run P2P file sharing from the office...

As to security, monitoring your network is usually one part. For details, you'd need to tell us what problems you see and what your requirements are.

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