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DSCP setup

I'd like to submit this config for review. My goal is to have outbound latency sensetive traffic(acl 101) and outbound lantency in-sensetive traffic(acl 102) get marked w/ dscp values on the internal interface, fa0.

Once this traffic is marked have the outbound interface give preference to the AF11 class(w/ priotity queueing), and AF13 getting dropped sooner and sent later.

#acl for latency sensetive traffic

access-list 101 permit udp any any range 26000 29000

access-list 101 permit udp any any range 5998 9000

access-list 101 permit udp any any range 2300 2400

access-list 101 permit udp any any eq 4000

access-list 101 permit udp any any eq 14567

#acl for latency insensetive traffic

access-list 102 permit tcp any any eq 8080

access-list 102 permit tcp any any eq 443

access-list 102 permit tcp any any eq ftp-data

access-list 102 permit tcp any any eq ftp

access-list 102 permit tcp any any eq www

#class maps to classify inbound traffic on the #internal interface

class-map match-any sensetive

match access-group 101

class-map match-any insensetive

match access-group 102

#class maps to match packets w/ diffserv values

#on WAN interface s0

class-map match-all high

match ip dscp af11

class-map match-all low

match ip dscp af13

#set acl 101 w/ dscp values of Af11 & acl 102 w/ Af13

policy-map setdscp

class sensetive

set dscp af11

class insensetive

set dscp af13

#give acl 101 w/ dscp value af11 70% of out going #bandwidth and acl 102 w/ dscp value af13 the #remaining 30%

policy-map manage

class high

priority percent 70

class low

bandwidth remaining percent 30

inter fa0

desc internal interface

service-policy input setdscp

inter serial0

desc WAN interface

service-policy output manage

Can anyone spot anything wrong with this? I'm worried about QoS. DSCP should give prefence to acl 101 but I'm not sure as this is my first foray into dscp.

Should I just dump DSCP and opt for GTS?

Also once packets marked w/ DSCP leave my network - do routers further downstream reset those bits to 0? If thats the case Dscps value goes down signifigantly.

Thanks for any feedback, I've found QoS to be very foggy...

1 REPLY
Silver

Re: DSCP setup

Even in the case of DSCP if the last bit is "0" it falls under standard implementation wherein the first three bits automatically gets copied on to the EXP field of the MPLS shim header. For more info, refer : http://www.cisco.com/en/US/products/sw/iosswrel/ps5207/products_command_reference_chapter09186a00801a7f28.html#wp1060776

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