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Author Topic: Performance issues with VLANs tunnelled over Mint Level 2?  (Read 2446 times)

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Offline VeniVidiVidic

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Performance issues with VLANs tunnelled over Mint Level 2?
« on: March 03, 2017, 01:03:23 PM »

Hi all - looking for advice or any shared knowledge/experience please!,

I've noticed a strange issue with client throughput performance through AP6532's (Haven't been able to test on a site using AP7522's yet but plan to) but only on tunnelled WLANs. This is back to RFS7000 cluster running WiNG v5.5.5, we are planning to upgrade to v5.8 soon due to a "comms error" bug too for reference.

My basic test (From various clients with the same results) is internet downloads from my HQ site via our central internet breakout through the Data Centre. I can get nearly 100Mbps downstream consistently on a local WLAN via this path. On the exact same client when I join a Tunnelled WLAN whereby the data path would be identical (Same LAN/WAN routes, same FW to reach the net) apart from the termination onto the controller at the same DC my Local WLAN traffic egresses from I instead am seeing 3Mbps with absolute consistency!

Deep review of packet traces shows increased latency between packets being received on the Tunnelled WLAN on an order of magnitude lower on the Local WLAN so the TCP throughput is an order of magnitude higher as it never builds up mutilple sent packets before waiting for an ACK. I also see lot's more duplicate ACKs I think relate to the delays causing confusion to the client.

I'm not expecting the performance between locally bridged and tunnelled WLANs to be identical as appreciate the reduced MTU on the tunnelled WLANs and overhead of (De)encapsulation the local RFDM and the RFS7000 but not to this degree. If it was 25% of the speed I would probably live with it but 3Mbps vs nearly 100 is very sluggish to see.

Anyone had any experience with Mint Level 2 tunnelling and this type of behaviour? Some relevant config extracts below for context...


On RFS Profiles:

mint-policy global-default
 mtu 1364

bridge vlan 123
  bridging-mode tunnel
  ip arp trust
  ip dhcp trust

On WLAN Profiles:
 vlan 123
 bridging-mode tunnel

Offline jcoehoorn

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Re: Performance issues with VLANs tunnelled over Mint Level 2?
« Reply #1 on: March 03, 2017, 01:09:58 PM »
Do file transfers within your network show similar performance differences?

Offline VeniVidiVidic

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Re: Performance issues with VLANs tunnelled over Mint Level 2?
« Reply #2 on: March 03, 2017, 06:21:36 PM »
Yes - reaching across from the Tunneled VLAN (DMZ) into the Datacentre to reach a server for example suffers the same issue of sluggish performance and again hitting the same server from the same AP on a locally bridged WLAN is extremely responsive. This is the first time performance has been noticeable for a tunneled WLAN as previous use was for very low bandwidth applications so never hit the 3Mbps limit and thus never noticed the issue.

Appreciate Extreme support will likley just point to Firmware until we move to 5.8 so just wondered if anyone else knew about it as a "known limitation". I can't find anything in the vendor materials around performance for tunneled WLANs in terms of throughput only number of WLANs and we are only running 4 or 5 WLANs in tunneled mode on the whole RFS7000 cluster with sub 30% CPU on average. A real mystery..

Offline McNulty

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Re: Performance issues with VLANs tunnelled over Mint Level 2?
« Reply #3 on: March 11, 2017, 06:59:05 PM »
If you haven't already, I suggest checking the QoS setup across your WAN. Remember that the tunnelled traffic will show up as MiNT traffic and be dealt with accordingly. So you may have a device in your network limiting "unknown traffic type" to 3mbps