Ethernet Switches & Routers

Reply
Occasional Contributor
Posts: 7
Registered: ‎06-14-2013

QOS - layer 2 FCX switches

I have a fairly straight forward network topology.

1. Two (2) FCX 48-port running layer 3 code. These are NOT stacked and have a 4-port tagged trunk between them. These switches run VE interfaces as default gateways for allof the VLAN's ont he network.

2. Five (5) FCX 48-port running lay 2 code. These are not stcaked and have 1-port tagged headed to the first core switch and a 2nd-port tagged headed to the second core switch (dual-homed as they would).

3. RSTP is running on the entire LAN, core switch #1 is the root, all of the layer 2 switches are forwarding to the root on their first port.

We want to implement QOS for VOIP utlilizing DSCP values. The phones are confgiured to send DSCP EF bits with value 46 as expected.

1. I can configure all layer 2 FCX switches with "trust dscp" on all the end station ports.

Questions:

1. For the ports on the layer 2 switches that are uplinking to the core, what can I do for QOS egress here as the packets leave the layer 2 switch and head to the core?

2. For the layer 3 core switches, do I simply need to enable "trust DSCP" on the links to the layer 2 switches?

3. For the layer 3 core switches, how do I get the QOS egress configured for packets headed outbound to the internet from there?

Occasional Contributor
Posts: 7
Registered: ‎06-14-2013

Re: QOS - layer 2 FCX switches

Has anyone implemented this as above?  Hoping to find some answers before the weekend. 

Frequent Contributor
Posts: 118
Registered: ‎06-15-2009

Re: QOS - layer 2 FCX switches

9146fan,

Please find comments inline.


1. For the ports on the layer 2 switches that are uplinking to the core, what can I do for QOS egress here as the packets leave the layer 2 switch and head to the core?

Assign higher weight to voip traffic.

2. For the layer 3 core switches, do I simply need to enable "trust DSCP" on the links to the layer 2 switches?

‘trust DSCP’ usage not recommended. Its better to use acl to map voip traffic to priority 2-4,  and assign higher weight ( using “qos profile” command) to the queue which voip traffic should go.  

3. For the layer 3 core switches, how do I get the QOS egress configured for packets headed outbound to the internet from there?

If it is desired to change .p or dscp before going to internet, use qos marking through acl.  There shall not be anything else except assigning higher weight to voip traffic.


Hope this helps,

Deepti


Occasional Contributor
Posts: 7
Registered: ‎06-14-2013

Re: QOS - layer 2 FCX switches

Thanks for the response. We are looking to implement towards RFC2474 (DSCP) as it is the newer "standard" (yes, not ratified as a whole by IETF yet).

1. It sounds like (even on layer 2 switch code), that I need to mark traffic with ACL on the outbound interfaces headed to the core switches.

2. Sounds like you are saying I should have an INPUT ACL on the links coming from the closet switches to mark traffic as needed.

3. Sounds like I need an OUTPUT ACL to mark traffic internet bound (headed out of the core to the internet).

It seems that I will want to be sure to mark traffic in both directions also (return traffic).

Frequent Contributor
Posts: 118
Registered: ‎06-15-2009

Re: QOS - layer 2 FCX switches

9146fan,

Yes to all the points above.

thanks,

Deepti

Join the Community

Get quick and easy access to valuable resource designed to help you manage your Brocade Network.