Glossary
none is selected, the EFN handles the outer VLAN p-bit transparently. See the
dashed arrow line in Figure 21 on page 41, and step 2 on page 43.
5.5.2 Egress Quality of Service
The following Quality of Service actions are performed at the egress:
1. Connection Bandwidth Limitation
If a bandwidth limit is configured for the egress connection, the current
bandwidth utilization is checked. If forwarding the packet would exceed the
configured limit, the packet is discarded. The bandwidth limitation applies
to all the traffic of the VLAN with no regards to flow, or priority.
2. p-bit Translation
If configured, the packet is given a new p-bit, based on the marking
determined at ingress processing (see marking in step 2 on page 42 ).
3. Port Traffic Handling
The port traffic handling applies for all the traffic that is to be sent out of
the port (traffic from all VLANs and all flows).
Overflow handling
As has already been described under ingress quality of service, if the
memory buffers are filled over certain limits, the packet may be
discarded, depending on the reliability setting for the ingress
connection.
Once placed in the queue, packets will not be removed. Instead,
packets that are to be placed in the queue can be discarded under
certain conditions.
When there are many packets in the out queue already and the out
queue approaches its upper limit, packets that are to be placed in the
queue start to be discarded. To begin with, only packets with the
lowest priority are discarded. After this, packets with gradually higher
priorities are discarded, if the free space in the out queue continues to
decrease.
There is a common memory area for all out-going packets in the EFN,
for all ports and priorities. If there is more than one packet to be sent
in a certain queue, a queue of packets to be sent through that port is
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