Using QoS to prioritize traffic

Discussion in 'Cisco' started by ESM, Oct 20, 2005.

  1. ESM

    ESM Guest

    I have a 10mbs link between 2 sites. One end has a Cat6513 Hybrid and the
    other a Cat3560. I am running Voice traffic (SIP) across this link

    I am trunking between these two sites. I am using auto qos in both
    switches, using trust cos on trunked links and trust dscp on non-trunked

    When I do pacture captures with Etheral I'm seeing all my UDP/RTP voice
    traffic as 'ef' and some other non UDP/RTP traffic as 'cs2'

    I want to prioritize SQL traffic across this link so it is higher then
    default dscp of 0, but still below voice traffic priorities. I need to do
    this because one of my applications that talks to the SQL server keeps

    To do this, I setup a policy map on the 3560 that matches tcp/1433 and
    defined this class is as dscp 28, which is af32. I applied this inbound on
    interface where computers are connected that use the application in

    When I do a packet capture on the 6513,s panning the port that connects to
    this remote site, I'm seeing SQL traffic from the computers showing a dscp
    of af31. This is where I get confused. If the switch is set to tag this as
    af32, why is it coming across as af31? The ISP is not re-tagging any
    traffic. They are doing Q-in-Q tunneling (encapsulating my encapsulated
    packet, sending it across, then removing the extra encapsulation, leaving my
    original packet).

    Do I have something setup improperly? The reason I'm concerned is because I
    typically see QoS examples for voice traffic matching af31 and ef for RTP.
    Since I'm not seeing af31 on my RTP traffic, but ef, I assume it's not a
    huge issue, but I really do not fully understand the priority queues and how
    and their precedence. The goal is to have highest priority to all my voice
    traffic, then give priority to SQL traffic, then give everything else
    default 0.
    ESM, Oct 20, 2005
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  2. ESM



    can u post out the configs related to qos and the service policy ??

    , Oct 26, 2005
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  3. ESM

    ESM Guest

    I ended up opening a TAC case. Found out the sup2 can only apply an acl on
    egress on a vlan (even though the help says you can specify inbound or
    outbound, perhaps the 720 can do ingress). An ACL on a switch is always

    So basically TAC said I need to apply an ACL for TCP/1433 on the ports that
    the SQL server is connected to, and define the ACL with a destination
    network segment so it only tags the traffic destined for the remote sites

    <> wrote in message
    > hi
    > can u post out the configs related to qos and the service policy ??
    > regds
    ESM, Oct 27, 2005
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