12-05-2013 01:49 PM - edited 03-07-2019 04:57 PM
Hi,
I've just added the following commands to my 6509 switch -
mls qos
interface GigabitEthernet3/24
description *** DATA VLAN 35 - VOICE VLAN 34 ***
switchport
switchport trunk native vlan 33
switchport trunk allowed vlan 32,33
switchport mode trunk
mls qos trust dscp
no cdp enable
spanning-tree portfast trunk
!
I have a phone connected to this port and when I make calls the wireshark output (sniffing on same VLAN) show the markings as being present (e.g. DSCP = 46)
The upstream router (a Cisco 3845) has the following configuration:
!
class-map match-all IPVoice-Priority
match ip dscp ef
!
!
policy-map WAN_QoS
class IPVoice-Priority
priority 30000
class class-default
fair-queue
!
interface FastEthernet2/1
service-policy output WAN_QoS
when I make a VoIP call (that I know is traversing the WAN link connected to fa2/1) and run the command
show policy-map interface fastEthernet 2/0
The packet count isn't incrementing i.e. the traffic is not being identified and prioritised. (I believe the DSCP markings are being set back to zero by the switch before the traffic leaves for the router)
The interesting thing is that if i remove the mls qos configuration from the 6509 switch the markings are left in tact and are making it to the upstream router and onwards on the WAN link.
My theory is that the switch is resetting the CoS or DSCP values before sending the traffic onwards to the router.
Can anybody tell me where I am going wrong? i.e. how can I get the switch to trust CoS/DSCP markings as they leave the local VLAN on the 6509 switch?
12-05-2013 01:50 PM
And... thank you!
12-05-2013 02:17 PM
I don't know if this could be playing a part but the 6509 switches are set up as a redundant pair with a port-channel connecting them.
I'm just wondering - if the traffic on the VLAN was leaving switch A to go via switch B if the port the traffic left switch A on could be setting the DSCP markings to zero?
12-05-2013 02:35 PM
Please let me know if the problem isn't clear!?
Many thanks,
Andy
12-05-2013 03:11 PM
Andy
I'm just wondering - if the traffic on the VLAN was leaving switch A to go via switch B if the port the traffic left switch A on could be setting the DSCP markings to zero?
Do you have mls qos trust dscp on the port channel config on switch B. Because that is an ingress port so it could be resetting it.
Jon
12-06-2013 03:13 AM
Hi Jon,
Thanks for your response.
I don't think the traffic is going via the other switch (B) but the other switch hasn't got the 'mls qos' command configured so it shouldn't be doing anything to the traffic.
I need to do some more granular troubleshooting I guess to figure out exactly where the markings are being reset to zero.
Do you know any debug command that will show the exact point where the makrings are being removed? or anybody on the forum!?
Thank you,
Andy
12-06-2013 05:21 AM
Andy
Don't know of any debugs that can be used but i'll have a quick check.
Which module is this trunk connected to ?
Which supervisor ?
Which IOS ?
Perhaps you can post the entire config of the 6500 ?
Jon
12-11-2013 03:08 AM
Hi Jon/all,
Sorry for the delay. I've been away from the office.
The trunk is connected to module 3.
6509E-DIST-01#show module 3
Mod Ports Card Type Model Serial No.
--- ----- -------------------------------------- ------------------ -----------
3 48 SFM-capable 48 port 10/100/1000mb RJ45 WS-X6548-GE-TX SAL09496X50
Mod MAC addresses Hw Fw Sw Status
--- ---------------------------------- ------ ------------ ------------ -------
3 0016.47d6.7680 to 0016.47d6.76af 10.2 7.2(1) 8.7(0.22)BUB Ok
Mod Sub-Module Model Serial Hw Status
---- --------------------------- ------------------ ----------- ------- -------
3 IEEE Voice Daughter Card WS-F6K-GE48-AF SAL09518EAA 1.2 Ok
Mod Online Diag Status
---- -------------------
3 Pass
6509E-DIST-02#show module 3
Mod Ports Card Type Model Serial No.
--- ----- -------------------------------------- ------------------ -----------
3 48 SFM-capable 48 port 10/100/1000mb RJ45 WS-X6548-GE-TX SAL1003APZF
Mod MAC addresses Hw Fw Sw Status
--- ---------------------------------- ------ ------------ ------------ -------
3 0016.9de0.eb78 to 0016.9de0.eba7 10.2 7.2(1) 8.7(0.22)BUB Ok
Mod Sub-Module Model Serial Hw Status
---- --------------------------- ------------------ ----------- ------- -------
3 IEEE Voice Daughter Card WS-F6K-GE48-AF SAL1003AR3J 1.2 Ok
Mod Online Diag Status
---- -------------------
3 Pass
6509E-DIST-01#show module 5
Mod Ports Card Type Model Serial No.
--- ----- -------------------------------------- ------------------ -----------
5 2 Supervisor Engine 720 (Active) WS-SUP720-3B SAL09232SMZ
Mod MAC addresses Hw Fw Sw Status
--- ---------------------------------- ------ ------------ ------------ -------
5 0013.7f0d.3c1c to 0013.7f0d.3c1f 4.4 8.1(3) 12.2(33)SXH4 Ok
Mod Sub-Module Model Serial Hw Status
---- --------------------------- ------------------ ----------- ------- -------
5 Policy Feature Card 3 WS-F6K-PFC3B SAL09232N80 2.1 Ok
5 MSFC3 Daughterboard WS-SUP720 SAL09211PZ8 2.3 Ok
6509E-DIST-02#show module 5
Mod Ports Card Type Model Serial No.
--- ----- -------------------------------------- ------------------ -----------
5 2 Supervisor Engine 720 (Active) WS-SUP720-3B SAL09222278
Mod MAC addresses Hw Fw Sw Status
--- ---------------------------------- ------ ------------ ------------ -------
5 0013.7f0d.3020 to 0013.7f0d.3023 4.4 8.1(3) 12.2(33)SXH4 Ok
Mod Sub-Module Model Serial Hw Status
---- --------------------------- ------------------ ----------- ------- -------
5 Policy Feature Card 3 WS-F6K-PFC3B SAL0922281C 2.1 Ok
5 MSFC3 Daughterboard WS-SUP720 SAL09222DPX 2.3 Ok
Mod Online Diag Status
---- -------------------
5 Pass
6509E-DIST-01#show version
Cisco IOS Software, s72033_rp Software (s72033_rp-IPSERVICES_WAN-M), Version 12.2(33)SXH4, RELEASE SOFTWARE (fc1)
6509E-DIST-02#show version
Cisco IOS Software, s72033_rp Software (s72033_rp-IPSERVICES_WAN-M), Version 12.2(33)SXH4, RELEASE SOFTWARE (fc1)
I can send the config over to you Jon.. My email is casabas at hotmail.co.uk
Thank you.
Andy
12-11-2013 06:15 AM
Andy
Sorry to keep asking for outputs but can you post output of -
"sh queueing int gi3/24"
Note also that a way to guarantee the DSCP markings are preserved is to disable the DSCP rewrite command ie.
"no mls qos dscp rewrite ip dscp"
which tells the switch to leave any DSCP marking in the packet untouched. However as far as i am aware if you use the "mls qos trust dscp" command on an interface you should not need to do this as the internal DSCP value is simply the one that was received on the port and then is written into the TOS header on egress.
Is there any other QOS config on the switch in terms of policy maps or have you modfied any of the QOS maps on the 6500 ?
Jon
12-11-2013 08:29 AM
Hi Jon.
Thank you. Whatever helps - It's very kind of you to take your time out to assist.
The only mls config that shows up when searching for it is as follows:
RS03-6509E-DIST-ML-01#show mls qo
RS03-6509E-DIST-ML-01#show run | inc mls
mls netflow interface
no mls flow ip
mls qos map cos-dscp 0 8 16 24 32 46 48 56
mls qos
mls cef error action reset
mls qos trust dscp
mls qos trust dscp
mls qos trust dscp
RS03-6509E-DIST-ML-01#
And the output for 'sho queueing interface gig 3/24' -
RS03-6509E-DIST-ML-01#sho queueing interface gig 3/24
Interface GigabitEthernet3/24 queueing strategy: Weighted Round-Robin
Port QoS is enabled
Trust state: trust DSCP
Extend trust state: not trusted [COS = 0]
Default COS is 0
Queueing Mode In Tx direction: mode-cos
Transmit queues [type = 1p2q2t]:
Queue Id Scheduling Num of thresholds
-----------------------------------------
1 WRR low 2
2 WRR high 2
3 Priority 1
WRR bandwidth ratios: 100[queue 1] 255[queue 2]
queue-limit ratios: 70[queue 1] 15[queue 2] 15[Pri Queue]*same as Q2
queue random-detect-min-thresholds
----------------------------------
1 40[1] 70[2]
2 40[1] 70[2]
queue random-detect-max-thresholds
----------------------------------
1 70[1] 100[2]
2 70[1] 100[2]
queue thresh cos-map
---------------------------------------
1 1 0 1
1 2 2 3
2 1 4 6
2 2 7
3 1 5
Queueing Mode In Rx direction: mode-cos
Receive queues [type = 1q2t]:
Queue Id Scheduling Num of thresholds
-----------------------------------------
1 Standard 2
queue tail-drop-thresholds
--------------------------
1 100[1] 100[2]
queue thresh cos-map
---------------------------------------
1 1 0 1 2 3 4 5 6 7
1 2
Packets dropped on Transmit:
BPDU packets: 0
queue thresh dropped [cos-map]
---------------------------------------------------
1 1 0 [0 1 ]
1 2 0 [2 3 ]
2 1 0 [4 6 ]
2 2 0* [7 ]
3 1 0* [5 ]
* - shared transmit counter
Packets dropped on Receive:
BPDU packets: 0
queue thresh dropped [cos-map]
---------------------------------------------------
1 1 0 [0 1 2 3 4 5 6 7 ]
RS03-6509E-DIST-ML-01#
Thank you.
Kind regards,
Andy
12-11-2013 10:27 AM
Andy
Can you post complete list of modules in your chassis ? Do you have any service modules in there ?
Your last output shows that the port is showing as trusted so i can't see anything wrong there.
Jon
12-12-2013 04:02 AM
HI Jon,
Please see below.
Thanks again,
Andy
6509E-DIST-01#show module
Mod Ports Card Type Model Serial No.
--- ----- -------------------------------------- ------------------ -----------
1 48 48-port 10/100/1000 RJ45 EtherModule WS-X6148A-GE-45AF SAL1031WYF9
2 48 48 port 10/100/1000mb EtherModule WS-X6148-GE-45AF SAL1022PYEH
3 48 SFM-capable 48 port 10/100/1000mb RJ45 WS-X6548-GE-TX SAL09496X50
4 48 48-port 10/100/1000 RJ45 EtherModule WS-X6148A-GE-45AF SAL1032XC3H
5 2 Supervisor Engine 720 (Active) WS-SUP720-3B SAL09232SMZ
6 2 Supervisor Engine 720 (Hot) WS-SUP720-3B SAL09232SQ5
7 48 SFM-capable 48 port 10/100/1000mb RJ45 WS-X6548-GE-TX SAL09169GN4
8 48 SFM-capable 48 port 10/100/1000mb RJ45 WS-X6548-GE-TX SAL09169GG9
9 48 SFM-capable 48 port 10/100/1000mb RJ45 WS-X6548-GE-TX SAL09232VBT
Mod MAC addresses Hw Fw Sw Status
--- ---------------------------------- ------ ------------ ------------ -------
1 0018.b973.2f10 to 0018.b973.2f3f 2.0 8.4(1) 8.7(0.22)BUB Ok
2 0018.1856.2ae8 to 0018.1856.2b17 7.0 7.2(1) 8.7(0.22)BUB Ok
3 0016.47d6.7680 to 0016.47d6.76af 10.2 7.2(1) 8.7(0.22)BUB Ok
4 0019.0684.1dc0 to 0019.0684.1def 2.1 8.4(1) 8.7(0.22)BUB Ok
5 0013.7f0d.3c1c to 0013.7f0d.3c1f 4.4 8.1(3) 12.2(33)SXH4 Ok
6 0012.dae4.5f94 to 0012.dae4.5f97 4.4 8.1(3) 12.2(33)SXH4 Ok
7 0013.c37a.6178 to 0013.c37a.61a7 10.1 7.2(1) 8.7(0.22)BUB Ok
8 0013.c312.6e60 to 0013.c312.6e8f 10.1 7.2(1) 8.7(0.22)BUB Ok
9 0009.125c.704c to 0009.125c.707b 10.1 7.2(1) 8.7(0.22)BUB Ok
Mod Sub-Module Model Serial Hw Status
---- --------------------------- ------------------ ----------- ------- -------
1 IEEE Voice Daughter Card WS-F6K-48-AF SAL1030WC3F 2.0 Ok
2 IEEE Voice Daughter Card WS-F6K-GE48-AF SAL1022PVC8 1.3 Ok
3 IEEE Voice Daughter Card WS-F6K-GE48-AF SAL09518EAA 1.2 Ok
4 IEEE Voice Daughter Card WS-F6K-48-AF SAL1032XH3U 2.1 Ok
5 Policy Feature Card 3 WS-F6K-PFC3B SAL09232N80 2.1 Ok
5 MSFC3 Daughterboard WS-SUP720 SAL09211PZ8 2.3 Ok
6 Policy Feature Card 3 WS-F6K-PFC3B SAL09232N7J 2.1 Ok
6 MSFC3 Daughterboard WS-SUP720 SAL09232QUS 2.3 Ok
7 Cisco Voice Daughter Card WS-F6K-VPWR-GE SAL091594AR 1.1 Ok
8 Cisco Voice Daughter Card WS-F6K-VPWR-GE SAL09127A2H 1.1 Ok
9 Cisco Voice Daughter Card WS-F6K-VPWR-GE SAL09232SWH 1.1 Ok
Mod Online Diag Status
---- -------------------
1 Pass
2 Pass
3 Pass
4 Pass
5 Pass
6 Pass
7 Pass
8 Pass
9 Pass
6509E-DIST-01#
12-12-2013 08:37 AM
edited
12-12-2013 08:39 AM
Andy
No, nothing there. I did find some bugs related to service modules (FWSM, IDSM) removing the DSCP marking but you don't have any of those.
Possible workarounds for you -
1) "no mls qos rewrite ip dscp" - this will ensure the switch does not rewrite the DSCP value, assuming you are not actually wanting to change any DCSP markings on your switch ?
The problem with this command though is that it applies to all ports. So if someone connected a laptop to a port on your switch and marked all their traffic as DSCP 46 then the switch would simply pass on those packets to the router unchanged. So it removes the trust boundary if you see what i mean. The likelihood of someone doing this is probably very slim but it is worthbearing in mind.
2) remark the packets on the ingress interface of the router. The general rule with QOS is to mark as close to the source as possible so this is not ideal. In addition if you want the voice packets to go to a specific queue on the egress interface of the switch then the marking may have already been lost by then. You would also need to know the ports used by the VoIP phones to match them in a policy map.
Couple of quick questions -
1) are you sure that traffic is going from switch A direct to the router ?
2) how is the router connected to the switch ie. is it just a routed port connection between the two ?
Jon
12-12-2013 09:25 AM
Andy
Is the packet from the phone being marked with a CoS value as well ?
If so which value is it, presumably CoS 5.
Jon
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