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QoS + VOIP, SIP client phones to Internet server

Straeter

So I've read and read, and read some more all sorts of different posts and none of them are real clear.  QoS on the UTM seems to be all about throttling and limiting.  Is there a way just to use QoS prioritization like cheap routers/firewalls will and all the other commercial ones will?

I have 4 Cisco SPA525G VOIP phones using SIP + RTP to communicate to my cloud hosted "pbx".  If we're not using the internet everything works well.  However, if I decide to upload a file to dropbox or exchange or whatever, the phones degrade horribly, downloading seems to not affect it as much.  I have an 18Mbit down, 1.5Mbit up connection.  According to my VOIP provider, "marking OSI Layer 2 packets with high-priority (5) class tags (802.1p and IP Precedence)", and they tag all of their voice packets with DSCP value of 46. 

So what settings are required to give these packets absolutely priority over everything else.  I shouldn't have to set guaranteed bandwidth with priority being given to them.  If priority is utilized it should just put them to the front of the line no matter if I have 1 phone in use or all 4 of them.

EDIT: SG135W running 9.412-2 if that matters.

Thanks!



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  • 0

    When it comes to QoS, it helps to describe what you're observing that makes you ask questions.  Before we assume that it is QoS, see #1 in Rulz and confirm that you're not seeing an issue with Anti-UDP Flooding activity.

    If your ISP doesn't support TOS and DSCP bits, you have no choice other than to use Download Throttling rules to reserve bandwidth for inbound VoIP traffic.  On the External interface, limit inbound VoIP traffic to 100Mbps followed by a rule that limits all traffic to 17.5Mbps.

    Also, on the External interface, create a Bandwidth Pool guaranteeing outbound VoIP traffic 0.5Mbps.

    Cheers - Bob

     
    Sophos UTM Community Moderator
    Sophos Certified Architect - UTM
    Sophos Certified Engineer - XG
    Gold Solution Partner since 2005
    MediaSoft, Inc. USA
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  • 0

    When it comes to QoS, it helps to describe what you're observing that makes you ask questions.  Before we assume that it is QoS, see #1 in Rulz and confirm that you're not seeing an issue with Anti-UDP Flooding activity.

    If your ISP doesn't support TOS and DSCP bits, you have no choice other than to use Download Throttling rules to reserve bandwidth for inbound VoIP traffic.  On the External interface, limit inbound VoIP traffic to 100Mbps followed by a rule that limits all traffic to 17.5Mbps.

    Also, on the External interface, create a Bandwidth Pool guaranteeing outbound VoIP traffic 0.5Mbps.

    Cheers - Bob

     
    Sophos UTM Community Moderator
    Sophos Certified Architect - UTM
    Sophos Certified Engineer - XG
    Gold Solution Partner since 2005
    MediaSoft, Inc. USA
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  • 0 in reply to BAlfson

    UDP Flood is disabled.

    Downloading files doesn't degrade the connection.  Only uploading of files does that.  And doing what you are suggesting is bandwidth reservation or throttling, not QoS and prioritization.  Which most residential grade firewalls / routers costing over $100 bucks will do with a checkbox.  Let alone other commercial grade firewalls that will do with QoS priority levels without ever having to touch throttling or bandwidth rules.

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