3560 QoS SRR bandwidth shape/share

[asus zowey]

i have the following setup

Core Stack(3750)--- Distribution Stack(3750)----Access switches (3560)--- end devices

i want to implement the srr-queue bandwidth shape/share on the interface

my question is

1- on which interfaces should i implement the command and on which boxes ?

[Rasika Nayanajith]

Hi Asus,

Also, what if i want toconfigure a port between a router and a switch to be trust for ip phones only but remark other services. How is that done ?

This can be done by a service policy apply to the switchport where it connect to the router. Here is an example for that where only voice traffic will go with the given DSCP value & all other traffic go as "class-default which is DSCP 0". First you need classify voice traffic (RTP media & Signalling) & then you can mark them appropriately. If you want to remark other traffic then you need to define those ACLs & give required DSCP marking under policy map. Then you can apply this to switchport connected to the router in ingress direction.

ip access-list extended VOIP-RTP

remark VoIP traffic

permit udp any any range 16384 32767

!

ip access-list extended VOIP-SIGNALLING

remark VOIP-SCCP Traffic

permit tcp any any range 2000 2002

permit tcp any range 2000 2002 any

remark VOIP-SIP Control Traffic

permit udp any any range 5060 5061

permit udp any range 5060 5061 any

permit tcp any any range 5060 5061

permit tcp any range 5060 5061 any

!

class-map match-all VOIP-TRAFFIC

match access-group name VOIP-TRAFFIC

!

class-map match-all VOIP-SIGNALLING

match access-group name VOIP-SIGNALLING

!

policy-map INGRESS-POLICY

class VOIP-TRAFFIC

set ip dscp ef

class VOIP-SIGNALLING

set ip dscp cs3

!

Interface Gig x/x

service-policy input INGRESS-POLICY

HTH

Rasika

*** Pls rate all useful responses ****

[asus zowey]

i can't thank you enough

[Jon Marshall]

Rasika

Thanks for that. Wasn't trying to pick fault because you are spot on with your answers just wanted to give the full picture in terms of some switches/linecards.

Jon

[Rasika Nayanajith]

Hi Jon,

I perfectly understand that  & it is great that you pointed out that. So it helps someone to understand topic in detail.

Regards

Rasika

[Joseph W. Doherty]

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Posting

I just wanted to mention, when you enable QoS on the 3560/3750 series switches, their smallish buffer resources often cause drops not seen before QoS was enabled.  Buffer tuning, i.e. changing from the defaults, can sometimes mitigate this; sometimes not too.

Cisco has (finally) documented that 3750-X series has 2 MB per 24 downlink ports, and 2 MB per uplink ports.  So, for really busy ports, uplinks ports allow for more physical buffers per port.  Cisco hasn't, to my knowledge, documented buffer memory for other models in the series, but I would suspect uplink ports might have more physical buffers on other models too.

BTW, at LAN bandwidths, often prioritization isn't as important as drop management.  So, often on these switches you might just leave QoS disabled.