M and MSM Series

Wireless intermitent comunication problems

Occasional Advisor

Wireless intermitent comunication problems

Hello all,


I'm having an issue that I cannot pinpoint the problem.




1x MSM720

9x MSM430 Access Point

2x HP 5120 IRF switch

5x HP v1910-48 switch

2x HP v1910-24 switch


The HP 5120 (IRF) switch is the switch core of the network. This switch has all the VLAN configured and they are as follows:


VLAN1 -> – Servers and workstations (DHCP+DNS are on this subnet)

VLAN2 -> – Printers, MSM720 and MSM430

VLAN3 -> – Wireless Guest (access to other subnets controlled by ACL)

VLAN4 -> – Wireless LAN

VLAN5 -> ISCSI subnet (no routing)

VLAN7 -> 192.9.203./24  - Telephones




When all wireless devices connect they receive IP without any problems and they get IPs from the VLAN4 (


At this point they're able to communicate with devices on other VLAN.


Problem starts when, for a yet unclear reason, wireless devices stop reaching other VLAN. They still can reach other devices on same VLAN ( but they're unable to reach devices on other subnets.


Things can be resolved in a simple manner, so simple as release/renew IP.


But what bothers me is this behavior.


I already checked the core switch logs, MSM720 logs with no luck. Nothing shows there. I can share these logs if needed.


This is why I come to you.


I'm running out of ideas, because if this was a constant problem, something should be wrong with routing tables, maybe.


But it's not a constant problem. It's intermitent and random around all APs.


Can anyone shed some light on this? Or at least give some ideas on what to check?


Any help is appreciated.


Thank you in advance




Frequent Advisor

Re: Wireless intermitent comunication problems



Since the different VLAN need to be routed, you probably right on the routing.


Where is the default router?


Usually when you renew dhcp the default route get installed i.e. the route.


I would try to see the route to the gw is reachable, and on the router/gateway you do need to see the route to the different subnet/VLAN.


I think there is nothing wrong with the wifi but more on routing like your first hunch.


Sometime, some router may icmp-route-redirect, this would alter your default route.