Ericsson EFN324, User Manual, Page: 46 / 176

IndexIndex
5.5.1 Ingress Quality of Service
The following Quality of Service actions are performed at the ingress:
1.
Connection Bandwidth Limitation
The packets are processed by the bandwidth limitation function for the
connection
. If the bandwidth limit is exceeded, the packet is discarded. The
bandwidth limitation applies to all the incoming traffic of the VLAN with no
regards to flow, or priority.
1.
Flow Selection
The flow to which the packet will be directed to is determined by the Flow
selection criteria
and
the value of either p­bit or dscp bit
. The p­bit/dscp bits are
hard coded to the four global flows as given above. The following can be
use as determination criteria (based on the packet header):

P­bit

DSCP
 None (all traffic will be directed to the connection flow)
2. Quality of Service per Flow
For QoS processing, each packet is processed in the flow to which it
belongs. For each flow, the following actions are performed:

The out­queue buffer memory is checked. If, for the flow reliability , the current
remaining memory space is too low, the packet is discarded. Overflow situations
might occur if, for example, a flow exceeding 100 Mbps from an uplink is directed to a
single FE downlink. The buffer availability check is related to out­queue handling.
Please refer to step 3 on page 43 for more information.

The ingress flow priority is used to assign the egress priority queue. The egress
queue selection (queue Highest, High, Medium and low) is thus not dependent on
the p­bit of packet, but only depends on the priority configured for the ingress flow.
See the dashed arrow line in Figure 21 on page 41, and step 3 on page 43.
 The flow marking is determined, and is used in the egress p­bit translation. For each
flow, a p­bit, to overwrite the existing p­bit in the outer VLAN, can be configured. If