Configuring Your SmartRG™
- Common Use Cases
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Use Case: Applying Quality of Service (QoS) to VoIP and IPTV LAN Traffic
When deploying time critical services such as VoIP and IPTV comingled with common data services,
it becomes necessary to prioritize the time critical, upstream LAN traffic over common data traffic
(e.g Internet data and file transfers). Time critical traffic commonly includes SIP signaling (VoIP call
setup/teardown) and IGMP signaling (IPTV channel change). The SmartRG line of gateways
prioritizes time critical
traffic using the “Differentiated Services Code Point” field in the IP hea
der
as defined by RFC 2474.
NOTE
The residential gateway plays no part in the prioritization of downstream traffic.
Traffic generated by LAN hosts such as VoIP phones, IPTV STBs and PCs is identified
by “classifiers”
and placed into prioritization “queues.” Queues are emptied through the routed WAN connection
based on queue priority. Classifiers can identify traffic based on a number of criteria including:
source/destination MAC address, source/destination IP address, protocol, DSCP mark, etc. This
section describes a
typical
QoS configuration to prioritized upstream VoIP and IPTV traffic.
A
typical
VoIP/IPTV/data QoS configuration is shown below:
Figure 38 Typical QoS Configuration to Support VoIP and IPTV Services
VoIP traffic is identified by its source MAC/Mask (VoIP user agent OUI) and IPTV traffic is identified
by the DSCP mark in its IP header. All remaining traffic is placed in the data (default) queue.
NOTE
Mediaroom based IPTV STBs place the DSCP18 mark on all upstream traffic.
The QoS configuration process is comprised of three main steps:
Enable QoS on the routed WAN connection and enable QoS processing
Create traffic queues to prioritize the different types of traffic
–
and-
Create traffic classifiers to identify the different types of traffic
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