3750 QOS per vlan

[khaled alodat]

Hi,

I've a scenario but I don't know it its doable or not, can some please tell me if I can apply it ?

I will make it simple.

two vlan in an office, the office is connected to the data center via point to point fiber line.

What I need to do is reserve 20% of the line speed for vlan 1 end 80% for everything else, and apply this config on a Trunk port.

It look simple but I could not think of anything that allow QOS to be applied on a trunk port.

Thanks,

[Joseph W. Doherty]

Disclaimer

The  Author of this posting offers the information contained within this  posting without consideration and with the reader's understanding that  there's no implied or expressed suitability or fitness for any purpose.  Information provided is for informational purposes only and should not  be construed as rendering professional advice of any kind. Usage of this  posting's information is solely at reader's own risk.

Liability Disclaimer

In  no event shall Author be liable for any damages whatsoever (including,  without limitation, damages for loss of use, data or profit) arising out  of the use or inability to use the posting's information even if Author  has been advised of the possibility of such damage.

Posting

Yes, you're correct - it's simple.

You mark VLAN1 frames or packets differently from all other traffic (or the converse) and you use two egress queues, one allocated 20% and the other 80% (with, of course, VLAN1 mapped to the former and everything else to the latter).

Since you'll be using a trunk port, you could use the L2 CoS unless you want to treat VLAN1 traffic special further along.  Then you should use DSCP.

[khaled alodat]

Hi Joseph,

I have two points :

1- for a security reason there is no interface vlan configured on the 3750 , can we still use your suggestion if we create interface vlan with no ip address?

2- as far as I know ,the 3750 don't support Egress Qos..

Let me describe exaclty what i need to do:

we have more than 50 routable vlan and one vlan for wireless, all 50 vlans are going through the point to point link (to our data center), the wireless vlan is connected to a cheap adsl in the same office (DHCP configured on the ADSL router).

There is no SVI for the wireless vlan ( layer to security ), the other 50 vlan's don't know about the wireless and the wireless don't know about the other vlan's.

I need a way to redirect the wireless vlan through the Point to point link (still a I don't want the vlan to be routable ) and to use only 20% of the link speed.

Thanks,

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

#2 first.  The 3750s most certainly support egress QoS.  Find your installed QoS version, and perhaps start with the config guide chapter on QoS, for example: http://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750x_3560x/software/release/12-2_55_se/configuration/guide/3750xscg/swqos.html

#1 if your wireless traffic is ingressing on "exclusive" port or ports, you can tag the frames at the port level.  If the wireless traffic is ingressing on a trunk, you might be able to write an ingress port policy to match the vlan tag and tag the frame's CoS.

[khaled alodat]

Hi Joseph,

I'm sorry but Qos is not my favorite toppic.. so

Sw1 is office , SW2 is our data center, vlan 300 is for wireless( vlan 300 is only on sw1)

Basic picture, C1 is access point ,  we marked the traffic coming on port 2 in SW1, and policy to match the traffic (already marked on port 1 Sw2), my problem still on port 1 SW1. (the most important port)

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

So you're saying both sw1's port 2 and sw2's port 1 have ingress policies that match your wireless traffic?  The latter, though, using some special marking set on sw1's port 2?  That's fine.

If you can tag the wireless ingress on sw1's port 2, you can use that for sw1's port 1 egress treatment.

PS:

What might be throwing you off, on a 3750, you can have an ingress policy similar to what's on a router, but for egress you need to map frames/packets to one of 4 egress queues.  There's no similar egress policy.