ZyXEL Communications OMC-2301, User Manual

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Chapter 6 Basic Setting
OMC-2301 User’s Guide
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Figure 20 IGMP Proxy Network Example
The system will not respond to IGMP join and leave messages on the upstream interface. The
system only responds to IGMP query messages on the upstream interface. The system sends
IGMP query messages to the hosts that are members of the query VLAN.
The system only sends an IGMP leave messages via the upstream interface when the last host
leaves a multicast group.
The Ethernet port on the line card acts as the upstream interface. By default, the PON port is
set as a downstream interface.
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The OLT does not allow a PON port to send multicast traffic (except static
multicast traffic) to an uplink port. Only the uplink port can forward multicast
traffic to the PON port.
6.7 DBA (Dynamic Bandwidth Allocation)
In an EPON network, to prevent network congestion, dynamic bandwidth allocation allows
the OLT to quickly re-assign unused bandwidth based on traffic requirements. The OLT
periodically broadcasts discovery messages to all ONUs. The ONUs then can register and send
report messages to request bandwidth for data transmission. The OLT bases on the registered
ONU’s RTT (Round Trip Time) and bandwidth request to decide when and how long the ONU
can transmit data. Bandwidth re-assignment can be for an ONU or for the priority-level
queues. In addition to reassigning bandwidth on the go, DBA helps to ensure quality of service
on the network.
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A PON port allows only one ONU to transmit data at a time.
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