Ian,
I agree with you that the box shud retain its TOS/DSCP value but I dont
think Cisco 6509 retains the TOS value with QoS turned Off,
I chatted with a couple of freinds and thye have experienced same, but need
some documented proof.
SH
-----Original Message-----
From: Ian Cox [mailto:icox@cisco.com]
Sent: Monday, April 22, 2002 5:53 PM
To: Hassan, Shehzad; Cisconsp (E-mail)
Subject: Re: [nsp] TOS/DSCP marking on 6509 SUP
At 10:44 PM 4/21/2002 -0400, Hassan, Shehzad wrote:
>I would like to start with a couple of very simple questions on 6509
running
>Hybrid Code CATOS 6.3.3 and MSFC code 12.1aE5.
>
>1. The default behavior of 6509 is QoS disabled,
> considering a lab scenario, if TOS=7 data is entering FE-port
3/25-VLAN100
>and exiting port 2/25-VLAN21 (WS-X6348-RJ-45-48 Port FE), will the TOS
value
>be retained ?
Yes, IP Tos and DSCP values are preserved when QoS is disabled.
>2. IF QoS turned on, no QoS attached to any of the VLANs or ports, if a
>packet with TOS=7 enters and exits the ports/vlans mentioned above, will
the
>TOS value be retained ?
No, all packets on ports that are untrusted, (which is the default) will
have there ToS / DSCP values rewrititten to 0.
>I have a similar scenario setup in my Lab and somehow every packet (I'm
>sending ICMP TOS=7 packets) is getting stamped to TOS=0 whether I turn QoS
>ON or OFF.
If you disable QoS it should revert back to not modifying the ToS/DSCP
value.
>* If I turn on QoS, match for ICMP packets and re-stamp to another TOS
value
>it works as expected.
After a reboot, with qos disabled does the switch correctly pass the packet
without changing the ToS/DSCP value?
Ian
>I did some search on CCO and found following:
>
>Configuring Quality of Service (release 6.3)
>http://www.cisco.com/univercd/cc/td/doc/product/lan/cat6000/sw_6_3/confg_gd
/
>qos.htm
>QoS Default Configuration
>Table 41-3 shows the QoS default configuration.
>Note:
>With QoS enabled and all other QoS parameters at default values, QoS sets
>Layer 3 DSCP to zero and Layer 2 CoS to zero in all traffic transmitted
from
>the switch.
>This answers my 1st question,
>
>But my problem is even though the QoS is turned off everything is getting
>stamped with TOS=0,
>
>Any comments/experiences ?
>
>SH
This archive was generated by hypermail 2b29 : Sun Aug 04 2002 - 04:13:41 EDT