why does this guy say native vlan 101 when it is the data vlan?

itdaddy

This is the only QOS methods on our switches using Mitel phone system with Cisco gear.
If you look at the access interface, he uses a (native vlan 101 command?)
The switches are connected to the phones(mitel) and then the pc is connected to the phone.
so here are my questions?
1. (fact only) the phones are set to cos value of 6 that I am sure of
cause i am the one who sets the TCP settings and the cos value of 6.
questions:
2. does the phone tag the pc with vlan 0 or cos 0?
3. why does this guy put the command (native vlan 101 on the access port?)
why native vlan? what does that do? not tag it? huh why.
if you take the command out what willl happen???
4. why does this guy set the command with cos 5? there no cos 5 on our network?
but there is cos 6 since the phone are all configured with cos 6.

5. why is there 0-7 dscp values when there is only 1 cos value mapped? huh?

mls qos srr-queue input cos-map queue 1 threshold 1 5
mls qos srr-queue input cos-map queue 2 threshold 1 6

mls qos srr-queue input dscp-map queue 1 threshold 1 40 41 42 43 44 45 46 47
mls qos srr-queue input dscp-map queue 2 threshold 1 48 49 50 51 52 53 54 55

mls qos srr-queue output cos-map queue 1 threshold 1 6
mls qos srr-queue output cos-map queue 4 threshold 1 5

mls qos srr-queue output dscp-map queue 1 threshold 1 48 49 50 51 52 53 54 55
mls qos srr-queue output dscp-map queue 4 threshold 1 40 41 42 43 44 45 46 47
mls qos

interface FastEthernet0/4
switchport access vlan 101
switchport trunk encapsulation dot1q
switchport trunk native vlan 101
switchport trunk allowed vlan 101,121
switchport mode trunk
priority-queue out
mls qos trust cos
spanning-tree portfast

instant000

Disclaimer: I'm not a voice person.


Also, according to the port config, it just takes on whatever the phone sends. You put in there "trust cos".

---

1. You stated this, no comment necessary.
2. 0 is the default, so the PC should be 0
3. it's a trunk port "switchport mode trunk"
4. In case you migrate to Cisco in the future?
5. Cisco Catalyst 3750 QoS Configuration Examples - Cisco

In the table, you can see that multiple DSCP values map to a SINGLE cos value. It's kind of by design.

It would probably be more helpful if they showed it in binary, so you could see the common bits.

I can't find a link that says so, at the moment, but I'm sure if you saw the binary comparing the two, it'd make perfect sense.

===========

Your thread title was a question too:

Back in the day, I heard that you had to configure ports as trunk when hooking them up to cisco phones. (Some voice person told me that.)

Even now, if you configure a voice vlan, it's still a "special" kind of trunk, as you will note that the Cisco phones have a switch inside them.

Look at this reference:

Catalyst 3550 Multilayer Switch Software Configuration Guide, 12.1(19)EA1 - Configuring Voice VLAN [Cisco Catalyst 3550 Series Switches] - Cisco

As you can see from the diagram, the switch inside the phone is where the magic happens.

itdaddy

instant000
wow great reference and explain. thank you. hey but I wonder why he said in his command Native vlan 101 when 101 is the data pc vlan and vlan 121 is the local voice van? why ? why untag he vlan 101 weird to me?

itdaddy

SOLVED! yeah this is why the do the command Native vlan 101 (for the data vlan) cause it remarks
the COS and DSCP values to zero ; this is how the data vlan is set to zero COS/DSCP value thank you
instant000 for this great QOS reference:


interface GigabitEthernet1/0/3
description **** Trunk Port ****
switchport trunk encapsulation dot1q
switchport mode trunk
switchport trunk native vlan 5
switchport trunk allowed vlan 5,10,20,30,40,50
mls qos trust cos end

interface GigabitEthernet1/0/12
description **** Cisco IP Phone ****
switchport access vlan 10
switchport mode access
switchport voice vlan 20
mls qos trust cos
spanning-tree portfast end

!--- The Cisco IP Phone uses IEEE 802.1Q frames for Voice !--- VLAN traffic.

Example 3: If the port is a dot1q trunk port and the port is configured with the mls qos trust cos command, native VLAN frames will have CoS and DSCP values as 0. Because native VLAN frames are untagged and the frame is tagged after it enters the switch, the switch will set the default CoS value to 0 and the CoS-to-DSCP table sets the DSCP value to 0.
Note: The DSCP value of the packet coming from native VLAN will be reset to 0.