Seeking Urgent Help with Network Issues in My Tree Topology!

[ultimatepie]

Dear all,

 

I am facing significant network issues in my current tree topology setup and believe that transitioning to a star topology might help alleviate the problems. Unfortunately, my attempts to address the issues through the implementation of VLANs (Virtual Local Area Networks) and QoS (Quality of Service) have not yielded the desired results. Despite these conventional solutions, my VoIP service still experiences interference during peak times, and I suspect that my CCTV RTP traffic might be contributing to the overall network instability.

 

I have already tried using VLANs to segregate network traffic and prioritize VoIP packets, but it hasn't resolved the issues. Similarly, my attempts at implementing QoS to allocate bandwidth appropriately and prioritize specific traffic flows have not been successful. I find it frustrating that these conventional approaches have not provided the relief I expected.

 

Given the circumstances, I am now seeking alternative ideas and unconventional approaches to tackle this situation. If VLANs and QoS are not effective, what other strategies or techniques could I explore? Are there any specialized network equipment or configurations that might be better suited to my specific scenario? Additionally, are there any additional considerations or factors that I might have overlooked?

 

I am truly at a loss and would greatly appreciate any out-of-the-box suggestions or expertise you can offer. Your insights and experience in troubleshooting network problems would be invaluable in helping me overcome these challenges.

 

Thank you for taking the time to read my plea for assistance. Your support could make a tremendous difference in resolving these network issues. All of our switches are gigabit, support layer 2 and layer 3, and are not unmanaged.

 

The ISP has informed me that the issue does not lie with them, and we have a 1 Gbps line and Microsoft intuned devices no more AD

 

Thank you once again for your attention and assistance.

Edited May 19, 2023 by ultimatepie

[bald_pig]

What speed is your backbone?

[soapyfish]

Have you used Wireshark to do some packet capture and see whats actually happening?

[Davit2005]

CCTV and VOIP should be kept separate, I wouldn't go back on that TBH. CCTV should be on it's own vlan and if you have VOIP (unless it's teams) it should be on it's own network. The same to be said for BMS, Door Access too as they can be quite noisy.

 

I've seen printer cause a lot of issues on the same vlan as VOIP phones before now even to the point that the phones were nearly un-usable.

[ultimatepie]

our network backbone utilizes single fiber, Cat5, or Cat6 links to connect to the cabinets. There is no additional trucking involved in the network infrastructure only been at the school for 10 months, no investment in this area at all

[ultimatepie]

when i start shit loads of stp traffic found 6 loops in my first 3 weeks

[mavhc]

What models switches, check the cpu and ram usage on them. You can always try overloading the switches with some extra traffic using iperf or similar

[Davit2005]

when i start shit loads of stp traffic found 6 loops in my first 3 weeks

 

Depending on the switches I'd deploy loop protection, some form of spanning tree MSTP, RSTP or similar. Ideally You need to keep the same type of spanning tree across all of the switches that connect to each other otherwise you can create issues.

 

vLANs also help with spanning tree as it will isolate a loop to a section of the network rather than effecting the whole network.

[ultimatepie]

cisco SG200-50P x18 dell 5548p x2

[ultimatepie]

rstp is enabled, but STP Loopback Guard is not

[mavhc]

For Cisco, according to google "under the Admin -> Diagnostics you may check CPU utilization"

 

On dell see page 86 of https://dl.dell.com/Manuals/Common/PowerConnect5500_CLIRef_en-us.pdf

 

The service cpu-utilization Global Configuration mode command enables

measuring CPU utilization. Use the no form of this command to restore the

default configuration.

 

service cpu-utilization

 

 

Use the

 

show cpu utilization

 

Privileged EXEC command to view

information on CPU utilization

[ultimatepie]

cpu usage is low

[mavhc]

also check for packet errors, spanning tree errors etc

 

Obviously need to check cpu when the problems are happening, and/or find a reliable way to cause the issue for testing

[5tu]

Can you share a diagram of your topology?

[RedwayNetworks_Michael]

Hi, One of our engineers has had a look at this for you and has given the below

 

Many useful suggestions have already been mentioned in this thread, and I would like to add my own thoughts:

 

Firstly, you mentioned that you suspect CCTV traffic may be causing issues. What is the path of CCTV traffic in the network? Does all CCTV traffic go back to one location through a single switch/NVR, or is it dispersed around the network?

 

Since the network has a tree topology, traffic will likely have to pass through several switches before reaching its destination. If your current switches are limited to a 1Gbps uplink, they may become saturated. Here are some tests you could perform:

 

1. Run a speed test from each switch to establish a benchmark for performance. How close are you able to achieve to the Gigabit speeds? Does one switch perform better than another? This may help you identify any bottlenecks in your network.

2. Conduct a ping test from each switch. Multiple hops or high uplink utilisation may cause high latency, which will be problematic for VoIP.

3. Are QoS settings being preserved throughout the network? Performing a packet capture from different locations will allow you to see if QoS markings are carried through the entire network and in both directions.

 

Is it possible to use LACP to increase bandwidth between switches, servers, NVRs, or other high-bandwidth areas in the network?" Or use separate uplinks and split VLANs across the different uplinks?