From: Alex Steer (alex.steer@eison.co.uk)
Date: Wed Nov 07 2007 - 10:08:18 ART
I'm abit baffled as the the outcome of this. If you ping the SVI on the
switch no rewrite seems to occur. However if you ping another device on
the switch a rewrite does occur. Presumably on egress.
Apparently "no mls qos rewrite ip dscp" (default command being the -no
variant) is supposed to produce this behaviour. I have not configured
it so the rewrite should be happening on ingress.
I've labbed this same scenario using the alternative configuration of a
3550 using nested class-maps and it does rewrite the ip dscp on ingress.
The svi on the 3550 does see ef packets.
Can anybody think of a cause for this as I was under the impression that
no mls qos rewrite ip dscp would cause this behaviour IF I had
configured it.
Thanks in advance
Alex
Btw: the config below is hand written not from the lab so if is isn't
perfect then that's my typing, it's here purely to show the scenario.
Here is the scenario,
R5-----Sw1-----R3
Router3
Access-list 101 permit ip any any dscp 0
Access-list 101 permit ip any any dscp ef
Access-list 101 permit ip any any
Int e0/0
Ip address 10.0.0.3 255.255.255.0
Ip access-group 101 in
Router5
Access-list 101 permit ip any any dscp 0
Access-list 101 permit ip any any dscp ef
Access-list 101 permit ip any any
Int e0/0
Ip address 10.0.0.5 255.255.255.0
Ip access-group 101 in
Switch1
Access-list 101 permit ip any any dscp 0
Access-list 101 permit ip any any dscp 46
Access-list 101 permit ip any any
Access-list 110 permit ip any any
Class-map vlan5
Match access-group 110
Policy-map vlan5
Class vlan5
Set dscp ef
Int fa0/3
Mls qos vlan-based
Swi mode acc
Swi acc vlan 5
Int fa0/5
Mls qos vlan-based
Swi mode acc
Swi acc vlan 5
Int vlan 5
Ip address 10.0.0.7 255.255.255.0
Ip access-group 101 in
Service-policy input vlan5
Router5
Ping 10.0.0.7 repeat 1000
Ping 10.0.0.3 repeat 1000
Switch1
Show access-list 101 | inc matches
10 permit ip any any dscp default (1000 matches)
Router3
Show access-list 101 | inc matches
10 permit ip any any dscp ef (1000 matches)
This archive was generated by hypermail 2.1.4 : Sat Dec 01 2007 - 06:37:28 ART