From: Kenneth Wygand (KWygand@customonline.com)
Date: Thu Apr 22 2004 - 22:48:40 GMT-3
Ahmed,
COS "0" is the same as best effort. They both indicate the COS bits
have not been turned on.
Kenneth E. Wygand
Systems Engineer, Project Services
CISSP #37102, CCNP, CCDP, ACSP, Cisco IPT Design Specialist, MCP, CNA,
Network+, A+
Custom Computer Specialists, Inc.
"The only unattainable goal is the one not attempted."
-Anonymous
-----Original Message-----
From: Ahmed Mustafa [mailto:ahmed.mustafa@sbcglobal.net]
Sent: Thursday, April 22, 2004 9:40 PM
To: ccie2be; Kenneth Wygand; Group Study
Subject: Re: QoS on 3550
Kenneth,
if mls is not enabled then the COS value will be rewritten to 0.
if msl is enabled then the COS value will be set as best effort, unless
one
enables the command "mls qos trust cos.
Is COS 0 and BE are same or different?
Regards,
Ahmed
----- Original Message -----
From: "ccie2be" <ccie2be@nyc.rr.com>
To: "Kenneth Wygand" <KWygand@customonline.com>; "Group Study"
<ccielab@groupstudy.com>
Sent: Thursday, April 22, 2004 1:15 PM
Subject: Re: QoS on 3550
> Good job Ken,
>
> Now, just to spell out your findings.
>
> 1) To set any QoS values (cos, ip prec, dscp, or tos) on incoming
frames
to a
> regular layer 2 access port on a 3550, mls qos has to be enabled. If
mls
qos
> isn't enabled, setting qos values either does no good or just can't
done.
>
> 2) Per an earlier post, if mls qos is enabled, any qos values that
were
set in
> the packet prior to reaching the 3550 will, by default, be reset to
"best
> effort". If this behavior isn't wanted, the port must be changed from
> untrusted to trusted.
>
> 3) Any QoS settings made to incoming frames (or pkt's) on a regular
layer
2
> port are carried intact to the outgoing port whether or not the
outgoing
port
> is a regular layer 2 port or a trunk.
>
> If anyone disagrees with these conclusions, please let us know which
> conclusions you disagree with and why.
>
> Thanks, Tim
> ----- Original Message -----
> From: Kenneth Wygand
> To: ccie2be ; Group Study
> Sent: Thursday, April 22, 2004 2:41 PM
> Subject: RE: QoS on 3550
>
>
> I just tried this out. You need to enable "mls qos" to do anything
with
COS
> or TOS values. COS or TOS will not "pass through" the switch unless
you
have
> this configured globally.
>
>
>
> Yes, COS does automatically map to IP Precedence values by default
through
> "mls qos cos-to-dscp" (COS 5 maps to DSCP 40 which is backwards
compatible
> with IP Precedence 5.
>
>
>
> Yes, you can set the _raw_ value of the TOS field through an
extended
ping.
> However since this is the raw value, IP Precedence of 5 is represented
through
> "160" and DSCP EF is represented through "184" (you need to do the
binary
> conversion).
>
>
>
> I think I answered all the questions here. If anyone else has any
other
> questions, let me know and I'll try to answer!
>
>
>
> Thanks!
>
>
>
> Kenneth E. Wygand
> Systems Engineer, Project Services
>
> CISSP #37102, CCNP, CCDP, ACSP, Cisco IPT Design Specialist, MCP,
CNA,
> Network+, A+
> Custom Computer Specialists, Inc.
>
> "I am not really smart. I just stick with problems longer."
> -Albert Einstein
>
>
>
> Custom Computer Specialists, Inc.
>
> "Celebrating 25 Years of Excellence"
>
>
>
> -----Original Message-----
> From: ccie2be [mailto:ccie2be@nyc.rr.com]
> Sent: Thursday, April 22, 2004 12:52 PM
> To: Kenneth Wygand; Group Study
> Subject: Re: QoS on 3550
>
>
>
> Hey Ken,
>
>
>
> I don't think this can be fully tested by marking pkts on the 2500.
I
think
> you have to test this on the 3550.
>
>
>
> Can you set this up? rtr1 ----> sw1--trunk sw2 ---> rtr2 or
rtr1 -->
> sw --> rtr2
>
>
>
> Try setting the 3550 port connected to rtr1 to mark icmp pkts to cos
5.
> Then configure logging on rtr2 connected to the 3550 using an
access-list
that
> logs all icmp pkts with a ip prec = 5. (On the 3550, frames marked
with
cos =
> 5, I think are automatically mapped to ip prec = 5.)
>
>
>
> I think, but I'm not sure, that mls qos has to be enabled on the
3550
for
> this to work. Maybe you can confirm this.
>
>
>
> Now, ping the 2nd rtr, and see what pkts are logged.
>
>
>
> After testing what happens with frames marked on the 3550 with cos
settings,
> try changing the marking to ip prec, and then dscp, and repeating
experiment.
> If you do this, don't forget to change the log access-list on the 2nd
rtr
so
> that you can see what the 3550 does in each case.
>
>
>
> HTH, Tim
>
> ----- Original Message -----
>
> From: Kenneth Wygand
>
> To: ccie2be ; Group Study
>
> Sent: Thursday, April 22, 2004 12:21 PM
>
> Subject: RE: QoS on 3550
>
>
>
> I'm trying to test this out as we speak. I'm trying to set the IP
> Precedence in a route map assigned to a local policy in a 2500 series
router,
> but I'm receiving the following. is this because I cannot set ISL or
DOT1Q
> encapsulation on a 2500-series router? I believe I should be able to
set
the
> TOS bit on any platform because there is a TOS field in all IP
packets.
>
>
>
> <snip>
>
> ip local policy route-map SETFLASH
>
>
>
> route-map SETFLASH permit 10
>
> set ip precedence flash
>
>
>
> r1#ping 10.0.0.2
>
> *Mar 1 00:12:43.951: %SYS-5-CONFIG_I: Configured from console by
console
>
>
>
> Type escape sequence to abort.
>
> Sending 5, 100-byte ICMP Echos to 10.0.0.2, timeout is 2 seconds:
>
>
>
> *Mar 1 00:12:47.163: IP: s=10.0.0.1 (local), d=10.0.0.2, len 100,
policy
> match
>
> *Mar 1 00:12:47.167: IP: route map SETFLASH, item 10, permit
>
> *Mar 1 00:12:47.171: IP: s=10.0.0.1 (local), d=10.0.0.2, len 100,
policy
> reject
>
> ed -- normal forwarding.
>
> *Mar 1 00:12:49.163: IP: s=10.0.0.1 (local), d=10.0.0.2, len 100,
policy
> match
>
> *Mar 1 00:12:49.167: IP: route map SETFLASH, item 10, permit
>
> *Mar 1 00:12:49.167: IP: s=10.0.0.1 (local), d=10.0.0.2, len 100,
policy
> reject
>
> ed -- normal forwarding.
>
> *Mar 1 00:12:51.163: IP: s=10.0.0.1 (local), d=10.0.0.2, len 100,
policy
> match
>
> *Mar 1 00:12:51.167: IP: route map SETFLASH, item 10, permit
>
> *Mar 1 00:12:51.171: IP: s=10.0.0.1 (local), d=10.0.0.2, len 100,
policy
> reject
>
> ed -- normal forwarding.
>
> *Mar 1 00:12:53.163: IP: s=10.0.0.1 (local), d=10.0.0.2, len 100,
policy
> match
>
> *Mar 1 00:12:53.167: IP: route map SETFLASH, item 10, permit
>
> *Mar 1 00:12:53.167: IP: s=10.0.0.1 (local), d=10.0.0.2, len 100,
policy
> reject
>
> ed -- normal forwarding.
>
> *Mar 1 00:12:55.163: IP: s=10.0.0.1 (local), d=10.0.0.2, len 100,
policy
> match
>
> *Mar 1 00:12:55.167: IP: route map SETFLASH, item 10, permit
>
> *Mar 1 00:12:55.167: IP: s=10.0.0.1 (local), d=10.0.0.2, len 100,
policy
> reject
>
> ed -- normal forwarding.
>
> Success rate is 0 percent (0/5)
>
> </snip>
>
>
>
> Any ideas?
>
>
>
> Kenneth E. Wygand
> Systems Engineer, Project Services
>
> CISSP #37102, CCNP, CCDP, ACSP, Cisco IPT Design Specialist, MCP,
CNA,
> Network+, A+
> Custom Computer Specialists, Inc.
>
> "I am not really smart. I just stick with problems longer."
> -Albert Einstein
>
>
>
> Custom Computer Specialists, Inc.
>
> "Celebrating 25 Years of Excellence"
>
>
>
> -----Original Message-----
> From: ccie2be [mailto:ccie2be@nyc.rr.com]
> Sent: Thursday, April 22, 2004 11:57 AM
> To: Group Study
> Subject: QoS on 3550
>
>
>
> Hi guys,
>
>
>
> I'm trying to understand something which has me confused.
>
>
>
> Recall these facts:
>
>
>
> At layer 2, only ISL or 802.1q trunks have fields to carry layer 2
QoS
> info.
>
>
>
> Regular ethernet frames don't and can't carry any QoS info.
>
>
>
> Given the above,
>
>
>
> Q1) Can cos be set on frames coming into or going out of regular
access
> port on a 3550?
>
>
>
> Q2) If so, how does this work?
>
>
>
> Q3) Can someone confirm that's there's no problem or Gotcha's on
setting
> layer 3 QoS on frames coming into or leaving a regular access port?
>
>
>
> Thanks in advanced, Tim
>
> [GroupStudy removed an attachment of type image/gif which had a name
of
image001.gif]
>
>
This archive was generated by hypermail 2.1.4 : Mon May 03 2004 - 19:48:53 GMT-3