OT: every 180 seconds 2 pings lost in Network

[nobody]

Anyone here with a good idea with this strange problem?
Network with 2 switches (zyxel XGS2210). Servers, 3CX phone system connected to switch one. Phones, PCs connected to switch two.
Every 3 minutes a ping from the 3CX and other devices connected to switch one to a device at switch two, two pings are lost. Not exactly every three minutes maybe 175 seconds. So, if a call is going on, there will be about 5 seconds of silence every three minutes, the call is not dropped.
pings to devices withing the switch one are ok.
No errors are recorded in the system log of the switches.
Besides of unplugging every device connected to switch two one after the other, what can be done to find the problem?

 

[eddv123]

ZyXEL XGS switches are good quality switches - these are the layer 2 models so you don't get the layer 3 functionality like the core XGS range but they are still pretty good.

Are you using any VLAN's (802.1q) or QoS priority (802.1p) settings on these switches, if not I would recommend prioritizing your voice traffic on both switches and see if the issue occurs.

Common things that may cause packet loss would be bottlenecks, router queues, over-utilized devices, poor cabling etc. Since you are connecting these switches together you have what is called an inter-switch shared link - if you have low bandwidth or a high amount of of packets on the network it could be a potential bottle-neck.

Is the inter-switch link simply connected via copper or is it using a gigabit fiber link ?

Since you aren't getting any logging, here are a couple of useful ping tools which will complement your standard ping - as standard an acceptable quality level for both way ping time is around 100-160 ms.

http://www.nirsoft.net/utils/multiple_ping_tool.htmlhttps://tools.pingdom.com/

 

[nobody]

These switches are connected using 10GBE links (10GBE-T, 2m distance). It cannot be utilization, since it appears so excactly every 3 minutes. It is unlikely the connection between the switches is the culprit because of the same reason. Of course this is a guess.
Interestingly the problem went away after everyone left the office (phones stayed on, PCs where shutdown).
Problem is everything there is brand-new, except the PCs: New building, new phone system, new cabling, new switches. Not easy to decide where to start to search.

 

[eddv123]

If it goes away when everyone leaves the office then it must be a traffic related issue on the local LAN. I guess this issue has an effect on both LAN to LAN calls and those traversing the WAN link.

Could someone be hogging the bandwidth - such as streaming videos or something like that.

Simple answer deploy QoS techniques, here are some examples on the ZyXEL knowledgbase:

https://support.zyxel.eu/hc/en-us/a...tch-Video-Tutorial-Series-VLAN-Configuration-https://kb.zyxel.com/KB/searchArticle!gwsViewDetail.action?articleOid=014054&lang=EN
For full QoS this must be configured on both Layer 2 and 3 (switches and router):
https://kb.zyxel.com/KB/searchArticle!gwsViewDetail.action?articleOid=006433&lang=EN
I would go for configuring DSCP codes on the phones - if using a supported device this can be auto-configured from 3CX: https://www.3cx.com/sip-phones/vlan-configuration/

Code 46 is commonly used for IP endpoints.

The configured VLAN's on the switches 802.1q and p. But when passed to the routers the Layer 2 information is stripped so you must configure a DSCP value on the router also - you can see this on the guide sent above.

 

[nobody]

eddv123. Thank you for your input.
The Zyxel links are helpful.
I think (and meanwhile zyxel support also thinks the same) the problem is not related to bandwidth but a misbehaving Ethernet card lives in the network.
But I like to explore the option of a dedicated VLAN for the phones with 3CX.
How will the PBX behave when I add the second Lan Card to the VM?
Vlan1: PCs, Internet, 3CX connection to the Internet.
Vlan2: Phone Network
I would create a VLAN based on the Manufactures MAC - all phones are yealink, so any yealink phone will automatically go into the Voice Vlan.
Will dialling from the PCs (windows native client) still work ok?
Should I enable routing between Vlan1 and Vlan2 (I would say, no)
Are the any other problems to expect with a multi-homing 3CX installation on Windows?

 

[eddv123]

Ethernet card lives in the network.

OK it would make sense however it isn't that regular an occurrence, but you never know. Have they identified how you would troubleshoot this ?

How will the PBX behave when I add the second Lan Card to the VM?

This is mostly covered in this guide here. https://www.3cx.com/blog/docs/network-configurations-supported-3cx-phone-system/ it also covers segrated networks but not VLAN's specifically.

How many users are in the organisation ? if the amount is low an bandwidth availability is good then you shouldn't need QoS (if of course you do find this issue to be related to the NIC card).

If you do want to do this however then it isn't too hard to configure. Just split the VLAN's into data voice, your data traffic can be left at default and the 802.1p priority for voice is normally set at 5.

In fact and if I recall (it is worth checking specifically on the model you have) ZyXEL switches support the "voice VLAN" feature, some info on voice VLAN here:

https://www.zyxel.com/uploads/tech-lib/VOIPGuideUsingZyXELSwitch.pdfhttps://kb.zyxel.com/KB/searchArticle!gwsViewDetail.action?articleOid=014405&lang=EN
Ensure that any links (such as uplink ports or ports on the router if using sub interfaces) are set to be trunk ports also - trunk ports mean that the port will accept traffic from both VLAN's.

 

[nobody]

OK it would make sense however it isn't that regular an occurrence, but you never know. Have they identified how you would troubleshoot this ?

They have no better method to offer then what I thougt of myself: unplug one after the other. They will ask in TW but that might take a little time.
I think if its related to the switch, someone must know when hears "every 180 seconds" where to look for.

 

[eddv123]

Ive dropped you a PM.