cisco qos--How Are Conversation Numbers Allocated?

http://www.cisco.com/c/en/us/support/docs/quality-of-service-qos/qos-congestion-avoidance/10107-showpolicy.html

This section explains how your router allocates conversation numbers for the queues created when the service policy is applied.

Router# show policy-map interface s1/0.1 dlci 100 
 Serial1/0.1: DLCI 100 - 
 output : mypolicy 
  Class voice 
   Weighted Fair Queueing 
       Strict Priority 
       Output Queue: Conversation 72 
         Bandwidth 16 (kbps) Packets Matched 0 
        (pkts discards/bytes discards) 0/0 
  Class immediate-data 
   Weighted Fair Queueing 
       Output Queue: Conversation 73 
         Bandwidth 60 (%) Packets Matched 0 
         (pkts discards/bytes discards/tail drops) 0/0/0 
         mean queue depth: 0 
         drops: class  random   tail     min-th   max-th   mark-prob 
                0      0        0        64       128      1/10 
                1      0        0        71       128      1/10 
                2      0        0        78       128      1/10 
                3      0        0        85       128      1/10 
                4      0        0        92       128      1/10 
                5      0        0        99       128      1/10 
                6      0        0        106      128      1/10 
                7      0        0        113      128      1/10 
                rsvp   0        0        120      128      1/10 
  Class priority-data 
   Weighted Fair Queueing 
       Output Queue: Conversation 74 
         Bandwidth 40 (%) Packets Matched 0 Max Threshold 64 (packets) 
         (pkts discards/bytes discards/tail drops) 0/0/0 
  Class class-default 
   Weighted Fair Queueing 
       Flow Based Fair Queueing 
       Maximum Number of Hashed Queues 64  Max Threshold 20 (packets)

The class-default class is the default class to which traffic is directed, if that traffic does not satisfy the match criteria of other classes whose policy is defined in the policy map. The fair-queue command allows you to specify the number of dynamic queues into which your IP flows are sorted and classified. Alternately, your router allocates a default number of queues derived from the bandwidth on the interface or VC. Supported values in either case are a power of two, in a range from 16 to 4096.

This table lists the default values for interfaces and for ATM permanent virtual circuits (PVCs):

Default Number of Dynamic Queues as a Function of Interface Bandwidth

Bandwidth Range	Number of Dynamic Queues
Less than or equal to 64 kbps	16
More than 64 kbps and less than or equal to 128 kbps	32
More than 128 kbps and less than or equal to 256 kbps	64
More than 256 kbps and less than or equal to 512 kbps	128
More than 512 kbps	256

Default Number of Dynamic Queues as a Function of ATM PVC Bandwidth

Bandwidth Range	Number of Dynamic Queues
Less than or equal to 128 kbps	16
More than 128 kbps and less than or equal to 512 kbps	32
More than 512 kbps and less than or equal to 2000 kbps	64
More than 2000 kbps and less than or equal to 8000 kbps	128
More than 8000 kbps	256

Based on the number of reserved queues for weighted fair queuing, Cisco IOS assigns a conversation or queue number as shown in this table:

Conversation / Queue Number	Type of Traffic
1 - 256	General flow-based traffic queues. Traffic that does not match to a user-created class will match to class-default and one of the flow-based queues.
257 - 263	Reserved for Cisco Discovery Protocol (CDP) and for packets marked with an internal high-priority flag.
264	Reserved queue for the priority class (classes configured with the priority command). Look for the "Strict Priority" value for the class in the show policy-map interface output. The priority queue uses a conversation ID equal to the number of dynamic queues plus eight.
265 and higher	Queues for user-created classes.

Confirming Your Service Policy