
Chapter 4
IP QoS Framework Overview
E-NIT-CTC-20041213-0013v0.5 27
4.2 Resource ManagementIntroduction The RM module reserves memory for four independent traffic classes. Resources are 
reserved for each RM-class, both in the upstream and in the downstream direction (8 
reservations in total). The figure below shows the Resource Management 
reservations.
For incoming data towards the IP host, this module copies the VLAN user priority 
field into the packet internal class indication. The module also sets (or raises) the 
internal class indication based upon the ATM VP/VC QoS category for reassembled 
frames.
As a result, incoming low priority UBR (Unspecified Bit Rate) traffic will not be able to 
consume all resources because resources are reserved for VBR (Variable Bit Rate) 
and CBR (Constant Bit Rate) data. Similarly, low priority VLAN frames won't be able 
to consume all resources because resources are reserved for high priority (based 
upon the VLAN user priority field) VLAN frames.
resource 
reservation
0 1 2 3
UPSTREAM
0 1 2 3
DOWNSTREAM
Dynamic Memory Pool