From: MMoniz (ccie2002@tampabay.rr.com)
Date: Mon May 10 2004 - 20:17:32 GMT-3
Yasser I will try to provide
For Q2 read this
http://www.cisco.com/univercd/cc/td/doc/product/lan/c3550/12119ea1/3550scg/s
wqos.htm#1152559
An excerpt
Configuring the DSCP Trust State on a Port Bordering Another QoS Domain
(another switch)<<<< I wrote
If you are administering two separate QoS domains between which you want to
implement QoS features for IP traffic, you can configure the switch ports
bordering the domains to a DSCP-trusted state as shown in Figure 29-10. Then
the receiving port accepts the DSCP-trusted value and avoids the
classification stage of QoS. If the two domains use different DSCP values,
you can configure the DSCP-to-DSCP-mutation map to translate a set of DSCP
values to match the definition in the other domain
.......Since they should both use the same mapping, mutilation shouldn't be
needed!!!
for Q3 this is only a match all traffic scenario, but as I am sure you know
with policy maps
you can use multiple class maps
class-map match-all test
match access-group 101
class-map match-all vlan
match vlan 12
match class-map test
!
!
policy-map prec5
class vlan
set ip precedence 5
interface FastEthernet0/13
switchport access vlan 12
switchport mode access
mls qos monitor dscp 40
mls qos monitor packets
service-policy input prec5
spanning-tree portfast
Mike
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Yasser Aly
Sent: Monday, May 10, 2004 7:02 PM
To: ccie2002@tampabay.rr.com; ccielab@groupstudy.com
Subject: RE: End-to-End Switch QoS
Thanx Mike for your feedback.
I agree with your openion for question 1.
For question #2 I have never seen a scenario where QoS was configured over
the two switches. Need to hear others feedback about this point.
For your answer in Q3: Would you kindly provide a sample configuration about
how to acheive so.
Regards,
Yasser
===================
Well I will attempt to
Q1. Priority extend is for traffic originating on a phone switchport..so it
is not the same
as cos 1 cos overide. If you do both and do have a phone connected, the
overide will take precedence.
Q2. You shouldn't have to do anything on the egress port connecting the
switches, as they should use
the same dscp map info by default. You will most likely need to do trust
COS on the ingress of the other switch.
Q3. You can do policy map QOS to distinguish between the different traffic.
(just learned that it actually works
even though show commands for it are not going to work unless you do mls
qos monitor on the ports)
Well that is my opinion.
mike
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Yasser Aly
Sent: Monday, May 10, 2004 5:39 PM
To: ccielab@groupstudy.com
Subject: End-to-End Switch QoS
Hello,
Scenario is as follows: VLAN 4 is configured on many ports on the switch.
One of the ports is connected to a server providing multicast feeds with a
CoS value of 4.
Required:
1) Maintain multicast feed CoS value received at this port as it enters the
switch block.
2) Other ports that belongs to VLAN 4 should be marked with a CoS value of 1
to avoid getting any better treatment.
Solution Provided:
---------------
mls qos
!
int f0/4 ( Where the server is connected )
mls qos trust cos
!
int f0/8 ( Other port belongs to VLAN 4 )
mls qos cos 1
mls qos cos override
-----------------
My questions:
1) Will there be a difference if I used switchport priority extend cos 1
instead of using mls qos cos 1 + mls qos cos override on other ports
that belongs to this VLAN other than the server port ?
2) If the scenario has 2 switches and this VLAN has ports on both switches,
will there be any configuration needed to the trunk ports to maintain the
CoS value or I just need to care about the entry point and that's it ? What
are the guarantees that the CoS values will be maintained between both
switches ?
3) Finally, on the port having the server. Is it possible to assign two
differnt CoS values on the same port ( One for the mcast feed, and other for
the rest of traffic ) ?
Your feedback is highly appreciated.
Yasser
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