From: Niche (jackyliu419@gmail.com)
Date: Fri Sep 16 2005 - 04:01:04 GMT-3
Hi,
May be you can try this,
Assume the incoming packet do not have any cos value pre-define,
mls qos
int fa0/1
wrr-queue bandwidth 4 3 2 1
wrr-queue cos-map 1 0 1 2 3
wrr-queue cos-map 2 4
wrr-queue cos-map 3 6 7
wrr-queue cos-map 4 5
int fa0/2
service-policy input icmp-cos
access-list 100 permit icmp any any
class-map icmp
match access-group 100
policy-map icmp-cos
class icmp
set cos 5
The 4th queue will be assigned 4/10 of the total bandwidth of the fa0/1
according to this configuration. "mls qos" in global configuration is a must
before any cos, dscp or ip precedence qos configuration go active.
If you want to go 1 step further, you can configure priority queue (queue 4
is default priority queue) at int fa0/1 so all cos 5 packets will be served
before any other type of packets.
Please correct me if I get anything wrong =), I am still learning..
Cheers~
Jacky
On 9/15/05, chrlewis@cisco.com <chrlewis@cisco.com> wrote:
>
> Consider the following:
>
> Traffic classified in class cos gets a cos value of 5
>
> What does this mean?
> If the traffic coming in is not tagged with a .1q or ISL header what
> relevance does this have?
> The CoS value is actually determined by the internal DSCP value, so you
> need to determine how that internal DSCP is set.
>
> With wrr-queue cos-map 1 5 you are sending cos 5 (derived from internal
> DSCP) in to queue 1.
>
> With wrr-queue bandwidth you are giving 1/91 parts of the bandwidth with
> queue 1, is this what you want?
>
> As a further exercise, are you clear on how you would configure priority
> queueing for a different CoS on top of this?
>
> Good show commands to become familiar with are
>
> Show wrr-queue bandwidth
> Show wrr-queue cos-map
> And for extra credit know show mls qos map dscp-cos, this becomes useful
> when you have to configure the switch to set egress cos to a non-default
> value based off internal DSCP.
>
> Chris
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Ahmed Ossama
> Sent: Thursday, September 15, 2005 5:31 AM
> To: ccielab@groupstudy.com
> Subject: CAT 3550 switch again
>
> Dear All,
>
> I am confused about some quality of service principles.
>
> 1st If I want to give ICMP traffic the higher priority ( for example), I
> have 3550 switch, the ingress port is fast 0/2 and the egress port fast
> 0/1.
>
> Shall I match the input packets with policy map then set the cos to 5
> then using wrr-queue bandwidth 1 30 30 30, wrr-queue cos-map 1 5
>
>
>
> Configuration will be as follow:
>
>
>
> interface FastEthernet0/1
>
> switchport access vlan 3
>
> switchport mode access
>
> no ip address
>
> wrr-queue bandwidth 1 30 30 30
>
> wrr-queue cos-map 1 5
>
> wrr-queue cos-map 2 1 2
>
> wrr-queue cos-map 3 0 3 4 6
>
> wrr-queue cos-map 4 7
>
> spanning-tree portfast
>
> !
>
>
>
> interface FastEthernet0/2
>
> switchport access vlan 3
>
> switchport mode access
>
> no ip address
>
> service-policy input cos
>
> end
>
> !
>
> Switch#sh policy-map cos
>
> Policy Map cos
>
> class cos
>
> set cos 5
>
>
>
>
>
> Or I must use a dscp -to-cos map and at the ingress set a dscp values as
> shown:
>
>
>
> interface FastEthernet0/2
>
> switchport access vlan 3
>
> switchport mode access
>
> no ip address
>
> service-policy input cos
>
> !
>
> Switch#show policy-map cos
>
> Policy Map cos
>
> class cos
>
> set ip dscp 5
>
> !
>
> mls qos map dscp-cos 45 to 5
>
>
>
> Or the two solutions are valid.
>
>
>
> Thanks ,
>
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