CISCO QoS for Dummies

By brendon on February 5th, 2010

Hey, for all those out there who have as much trouble with the CISCO QoS implementation as I do…. Here are 4 no so easy steps to configure.

Step 1. Access List

NOTE: You can specify IP addresses or traffic types here.

ip access-list extended <VOICE>
 permit udp any any range 16384 32767
ip access-list extended <VOICE-CONTROL>
 remark Match VoIP Control Traffic
 remark SIP
 permit tcp any any range 5060 5061
 permit udp any any range 5060 5061
 remark SCCP
 permit tcp any any range 2000 2002
 remark H323 Fast Start
 permit tcp any any eq 1720
 remark H323 Slow Start
 permit tcp any any range 11000 11999
 remark MGCP
 permit udp any any eq 2427

Step 2.  Class Map

NOTE: The ‘match-all’ or ‘match-any’ commands are like using AND/ OR for the access lists specified.

class-map match-all <VOICE-CONTROL>
 match access-group name <VOICE-CONTROL>
class-map match-any <VOICE>
 match access-group name <VOICE>
 match ip dscp ef
 match ip precedence 5

Step 3.  Policy Map

NOTE: The ‘priority’ command is the same as bandwidth but gives this traffic first access to bandwidth. You can only specify this command once.

policy-map <VOICEWAN>
 class <VOICE>
    priority <number-kbit>
 class <VOICE-CONTROL>
    bandwidth <number-kbit>
 class class-default
    fair-queue

Step 4. Interface Configuration

interface <outside_interface>
 bandwidth <number-kbit>
 bandwidth receive <number-kbit>
 service-policy output <VOICEWAN>

What’s so hard about that?