Looking for a Cookie-cutter QoS configuration

[Peter Marshall]

Anyone keen on QoS care to give a critique to what I've come up with here?

Router Configuration:

class-map match-any DATA
 match dscp af43
 match dscp af31  af32  af33
 match dscp af21  af22  af23
 match dscp af11  af12  af13
class-map match-any SIGNAL
 match dscp cs3
 match dscp cs2
 match dscp cs6
 match dscp cs7
class-map match-any VIDEO
 match dscp cs4
 match dscp af41 af42
class-map match-any VOICE
 match dscp ef
 match dscp cs5
class-map match-all SCAVENGER
 match dscp cs1

policy-map ASE
 class VOICE
  priority percent 22
 class VIDEO
  bandwidth percent 5
 class SIGNAL
  bandwidth percent 5
 class DATA
  bandwidth percent 42
  fair-queue
  random-detect dscp-based
 class SCAVENGER
  bandwidth percent 1
  random-detect dscp-based
  fair-queue
 class class-default
  set dscp default
  bandwidth percent 25
  fair-queue
  random-detect dscp-based

Switch Configuration:

CDP is globally disabled, the IP phones and digital PBX are in their own VLAN.

mls qos

auto qos srnd4

The default gateway is on the data VLAN.

Here's a switchport for an IP phone or PBX:

interface GigabitEthernet1/0/21
 switchport access vlan 7
 switchport mode access
 switchport nonegotiate
 power inline never (optionally this could be enabled for an IP phone)
 speed auto
 srr-queue bandwidth share 1 30 35 5
 priority-queue out
 authentication port-control auto
 mls qos trust cos
 auto qos trust
 spanning-tree portfast
 spanning-tree bpduguard enable
 spanning-tree guard root

Here's a switchport for a device, such as a workstation:

interface GigabitEthernet1/0/20
 switchport access vlan 17
 switchport mode access
 switchport nonegotiate
 power inline never
 speed auto 100
 spanning-tree portfast
 spanning-tree bpduguard enable
 spanning-tree guard root

Here's the trunk (up to the router or to another switch):

interface GigabitEthernet1/0/1
 description Uplink_RTRA
 switchport trunk allowed vlan 7,17,21
 switchport mode trunk
 switchport nonegotiate
 power inline never
 spanning-tree portfast trunk

[Philip D'Ath]

There are a multitude of "correct" answers just with different merits, and this is one of them.  It looks fine to me.

I would personally leave PoE enabled.  Assuming your switches have enough power to driver every port anyway.

Often voice signalling (cs5) is not lumped in with the RTP stream, and is assigned to a small non-priority queue.

[Peter Marshall]

Thanks, p.dath. Exactly the kind of feedback I'm looking for. I should have noted that I'm using 1921 routers and 2960X switches. I also should have noted that PoE wasn't required, so that's why it's globally disabled. CDP is also globally disabled since there are no Cisco IP phones or APs - I may enable CDP on my uplinks.

The 2960X-24PS-L &  2960X-48LPS-L can power up to 12 ports up to 30W each or 24 ports up to 15.4W each. So, the 48-port switch doesn't allow PoE on all ports. The only problem with the chart in the data sheet is that it doesn't address the 802.3af Class 0 through 4 requirements for devices that draw less than 15.4W. However, that would be easy to figure out.

http://www.cisco.com/c/en/us/products/collateral/switches/catalyst-2960-x-series-switches/data_sheet_c78-728232.html

I could easily move cs5 to the SIGNAL queue since that will also keep the VOICE queue pure.