troubleshooting Question

Network Devices drop off then come back

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CMITStamfordFlag for United States of America asked on
RoutersWireless NetworkingNetworking Hardware-OtherNetwork AnalysisDHCP
15 Comments1 Solution225 ViewsLast Modified:

Thank you for taking the time out to read my question. Your time and expertise is greatly appreciated.

I recently took over mgt of a network that has several VLAN's. The last provider setup the network then disappeared. The client is now having issues:

- Cameras drop off the network, then comeback. When it comes back another one drops off. (These devices have static IP's)
- Devices on Data VLAN will loose internet connection. For example a laptop on wifi will lose connection and then won't be able to connect back. Says limited connection and device does not get an IP address.

I've only so far noticed this issue on VLAN1 & VLAN4

These are the VLAN's:

VLAN1: Management, Security (NAS, POE Cameras)  (static IP)
VLAN2: Voice  (DHCP)
VLAN3: Video Streaming  (DHCP)
VLAN4: Automation, DATA, WIFI (DHCP)
VLAN5: Not Used
VLAN6: Future Guest Wifi (currently not used)

Everything in the building is IP controlled (lights, hvac, security, alarm, doors, shades, TV's, sound) All the networking hardware is from Control4 

VLANS and DHCP is coming off the router. There are a total of 6 24 port gigabit switches that I found so far. I far as i can tell the entire network is gigabit.

I automatically suspected that there are issues with DHCP. However, both static and dhcp devices on VLAN1 and VLAN4 suffer from this issue. I did review all the DHCP scopes and they look fine.

Yesterday i had to reboot the router b/c several wireless laptops (including mine) dropped off the network and would not connect back. I then patched my laptop into VLAN1 on one of the switches and was not able to get an IP there either. I finally had to reboot the router. Once i did that, the devices were able to connect including my laptop which was patched into one of the switches on VLAN1.

I used wireshark to perform a packed capture on VLAN1 hardwired and VLAN4 wireless. At the moment I lack the expertise to analyze the packet capture. They are located here Please review it if you can and tell me if you can spot any evident issues.

My next steps:
 - reboot entire network including all network devices
 - review VLAN tagging on all switches
 - enable spanning tree on managed switches

Any and all constructive feedback/recommendations are greatly appreciated ahead of time.

Please let me know if you need more info or have additional questions.

Thank you advance.

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