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ASA 5505 hosted VoIP QoS

Austin Rivet
Level 1
Level 1


I realize there have been many posts about QoS on the ASA before, but I'm hoping to gain some further clarification/insight on a specific situation.

For starters, I have an ASA 5505 on 9.1(2) code. I have two VLANs configured (inside and outside). My internal LAN has a mix of roughly PCs and 7 IP phones on a single /24 subnet. My WAN connection is business cable connection (50 Mbps down and 20 Mbps up). We are using a hosted VoIP solution.

I am getting complaints that audio during voice calls is choppy and sometimes calls drop totally. I suspect that the culprit is a couple of users who are using up most of the bandwidth. I fully understand that once traffic leaves the ASA I have no control over latency, delay, etc to the VoIP provider due to the fact that this is a best effort WAN service. That said, I would like to configure QoS on the ASA to at least do what I can to fix this on my end.

I have read quite a bit on the subject of applying QoS on the ASA, including:

-ASA QoS Doc

-QoS on ASA configuration examples

-ASA CLI config guide: QoS

This is all very good information, but it seems like these documents are all focused only on applying QoS to outbound traffic. I need to be able to do outbound/inbound QoS. In other words, in addition to applying QoS to outgoing traffic, I need to ensure that incoming VoIP traffic does not get dropped because a couple of users are consuming all of the download bandwidth.

My question is would policing on both the inside and outside interface combined with priority queuing (as described in this blog) accomplish this?  If not, what is the correct approach to this scenario.

Any help would be greatly appreciated.


1 Reply 1

Philip D'Ath
VIP Alumni
VIP Alumni

Apply a QoD policy to your "inside" interface as well.  You can do this to limit users downloading traffic (aka downloads flow in the "outside" interface and out the "inside" interface).

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