Interface Groups - Nortel 2000 Using Manual

286 Chapter 4 Policy-enabled networks
There are 2 sets of external ports. The first set contains 24 10/100 Mb/s ports.
Each port in this set has a set of 4 queues. The first queue holds the highest
priority and is serviced in an absolute priority fashion, meaning that this queue is
serviced first until all the queued packets are transmitted. The other three queues
are serviced using a WRR scheduler.
The second set contains the MDA front panel ports. There are two types of MDAs.
The Gigabit MDA has 1 uplink with 2 queues that are serviced in an absolute
priority fashion. However, each port on the BPS2000-4TX MDA, BSP2000-4FX
MDA, and BPS2000-2FX MDA has a set of 4 queues. The first queue holds the
highest priority and is serviced in an absolute priority fashion, meaning that this
queue is serviced first until all the queued packets are transmitted. The other three
queues are serviced using a WRR scheduler.
You cannot change the characteristics of these queue sets (such as the service
discipline, packet or buffer thresholds, and queue weights for WRR scheduler).
You can change the default IEEE 802.1p to queue mapping and the default DSCP
to IEEE 802.1p mapping using the Web-based management interface, SNMP, the
CLI, or DM. Note that the IEEE 802.1p to queue mapping for an interface (port)
depends on the number of queues available at that interface. This number depends
on the queue set associated with the interface.

Interface groups

Every port should be assigned to an interface group, which is used to apply
policies to traffic received by this port. And, each port can belong to only one
interface group. The Web-based interface for Advanced QoS uses the term
"Interface Configurations" for this function.
All ports that have the same interface group (role combination) have the same set
of filters installed on them. When you move a port to another interface group (role
combination), the filters associated with the previous interface group are removed
and the filters associated with the new interface group are installed on the port.
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