Red
MAX
™
Base Station
user manual
Doc. #70-00058-01-01-DRAFT
Proprietary Redline Communications © 2006
November
29,
2006
Page 22 of 106
2.7 Service
Flows
Service flows are a key feature of the 802.16 standard.
A service flow represents a unidirectional data flow. Transmitting bidirectional traffic
requires that two service flows be defined: one for the uplink, and another for the
downlink. These service flows can have different QoS settings.
The base station allows multiple service flows to be configured for each subscriber in a
sector. This allows service providers to offer different services, and segregate traffic
flows having different QoS requirements.
2.7.1 Service
Flow
Classification
Data packets are forwarded by the base station based on classification rules.
Classification rules require examining each packet for pattern matches such as destination
address, source address, or VLAN tag. All classification is defined at the base station and
the classification parameters are downloaded to the subscriber.
A service flow is partially characterized by the following attributes:
1. A 32-bit Service Flow ID (SFID) is assigned to all existing service flows. The SFID
serves as the principal identifier for the Service Flow and has an associated direction.
2. A 16-bit Connection ID (CID) is associated with each active SFID (connection
active).
3. A set of QoS parameters specifying the required resources. The principal resource is
bandwidth, but the specification may also include latency requirements.
4. A set of QoS parameters defining the level of service being provided.
2.7.2 Dynamic Service Addition
Service flows are defined and stored in the base station. For each service flow to be
established, the base station sends a setup message to the subscriber specifying the
required set of QoS parameters. The subscriber responds to each request by accepting or
rejecting the setup message.
A service flow may be pre-provisioned or can be dynamically created and deleted
without service outage. This is useful for supporting multiple subscribers in a single
sector. New subscribers can be added and existing subscribers can be removed or have
service levels modified.
Setup messages are sent by the base station following any subscriber power-cycle, loss
and recovery of the wireless link to a subscriber, or any service flow add/delete operation
at the base station.
2.7.3 Default
Service
Flows
Default UL/DL service flows are created automatically for each registered subscriber.
These service flows are used to pass all traffic not matching any user-defined service
flow (such as broadcast ARP) between the base station and subscribers. The default
service flow capacity is limited for each subscriber.