User's Manual

CHAPTER 2. System Overview
2-6
© SAMSUNG Electronics Co., Ltd.
QoS Support Function
To maintain the QoS constraints given to each QoS class or service flow, the SPI-2L10
assigns a queue within the modem to each service flow and performs a scheduling
according to the priorities of those service flows. Because real-time traffic has a higher
priority than non-real-time traffic, a strict priority scheduling is used to schedule real-time
traffic first.
All real-time traffic is scheduled considering its transmission delay. All non-real-time
traffic is scheduled using the Proportional Fair (PF) scheduling considering efficiency and
fairness of air resources. The scheduled air resource assignment is sent to the MS using the
MAP. When receiving the MAP, the MS checks the air resources assigned to it and then
modulates or demodulates the downlink packets or sends the uplink packets to the assigned
uplink area.
Meanwhile, the SPI-2L10 can monitor the throughput statistics per service flow and the
Service Flow Addition (SFA) statistics per service flow, and provides the statistics for
admission control rejection.
2.2.3 IP Processing Functions
IP QoS Function
The SPI-2L10 supports 8-class DiffServ and mapping between the services classes of the
user traffic received from the MS and DiffServ classes. In addition, the SPI-2L10 supports
mapping between the Differentiated Services Code Points (DSCP) and the 802.3 Ethernet
MAC service classes.
However, to support the backhaul QoS function, the SPI-2L10n must interoperate with an
ACR that can support the function above.
Ethernet/VLAN Interface Function
The SPI-2L10 provides Ethernet interfaces and supports the Virtual Local Area Network
(VLAN) function and the Ethernet CoS function. Here, the MAC bridge function defined
in IEEE 802.1D is not supported.
The SPI-2L10 allows multiple VLAN IDs to be set for an Ethernet interface. To support
Ethernet CoS, it maps the DSCP value of the IP header to the CoS value of the Ethernet
header for Tx packets.
Operating Networks Separately
The SPI-2L10 allows configuration of two logical VLAN interfaces in a physical interface
to support the network operation method in which the network for common user traffic and
the network dedicated to management are separated. In this case, the IP address of each
VLAN interface must have a different subnet.
Of the two VLAN interfaces, one is used for management and the other is used for user
traffic. At this time, the SPI-2L10 provides the static routing table configuration function to
separate the traffic of two VLAN interfaces and control each traffic path.
When the network for common user traffic and the network dedicated to management are
not separated, no VLAN interface is used or only one VLAN interface can be used.