ZyXEL Communications NWA1100-N User Manual
Chapter 6 Wireless Settings Screen
NWA1100-N User’s Guide
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On APs without WMM QoS, all traffic streams are given the same access priority to the wireless
network. If the introduction of another traffic stream creates a data transmission demand that
exceeds the current network capacity, then the new traffic stream reduces the throughput of the
other traffic streams.
network. If the introduction of another traffic stream creates a data transmission demand that
exceeds the current network capacity, then the new traffic stream reduces the throughput of the
other traffic streams.
The NWA uses WMM QoS to prioritize traffic streams according to the IEEE 802.1q or DSCP
information in each packet’s header. The NWA automatically determines the priority to use for an
individual traffic stream. This prevents reductions in data transmission for applications that are
sensitive to latency and jitter (variations in delay).
information in each packet’s header. The NWA automatically determines the priority to use for an
individual traffic stream. This prevents reductions in data transmission for applications that are
sensitive to latency and jitter (variations in delay).
6.5.2 Spanning Tree Protocol (STP)
STP detects and breaks network loops and provides backup links between switches, bridges or
routers. It allows a bridge to interact with other STP-compliant bridges in your network to ensure
that only one route exists between any two stations on the network.
routers. It allows a bridge to interact with other STP-compliant bridges in your network to ensure
that only one route exists between any two stations on the network.
6.5.2.1 Rapid STP
The NWA uses IEEE 802.1w RSTP (Rapid Spanning Tree Protocol) that allow faster convergence of
the spanning tree (while also being backwards compatible with STP-only aware bridges). Using
RSTP topology change information does not have to propagate to the root bridge and unwanted
learned addresses are flushed from the filtering database. In RSTP, the port states are Discarding,
Learning, and Forwarding.
the spanning tree (while also being backwards compatible with STP-only aware bridges). Using
RSTP topology change information does not have to propagate to the root bridge and unwanted
learned addresses are flushed from the filtering database. In RSTP, the port states are Discarding,
Learning, and Forwarding.
6.5.2.2 STP Terminology
The root bridge is the base of the spanning tree; it is the bridge with the lowest identifier value
(MAC address).
(MAC address).
Path cost is the cost of transmitting a frame onto a LAN through that port. It is assigned according
to the speed of the link to which a port is attached. The slower the media, the higher the cost - see
the following table.
to the speed of the link to which a port is attached. The slower the media, the higher the cost - see
the following table.
On each bridge, the root port is the port through which this bridge communicates with the root. It is
the port on this switch with the lowest path cost to the root (the root path cost). If there is no root
port, then this bridge has been accepted as the root bridge of the spanning tree network.
the port on this switch with the lowest path cost to the root (the root path cost). If there is no root
port, then this bridge has been accepted as the root bridge of the spanning tree network.
For each LAN segment, a designated bridge is selected. This bridge has the lowest cost to the root
among the bridges connected to the LAN.
among the bridges connected to the LAN.
Table 15
STP Path Costs
LINK SPEED
RECOMMENDED
VALUE
VALUE
RECOMMENDED
RANGE
RANGE
ALLOWED
RANGE
RANGE
Path Cost
4Mbps
250
100 to 1000
1 to 65535
Path Cost
10Mbps
100
50 to 600
1 to 65535
Path Cost
16Mbps
62
40 to 400
1 to 65535
Path Cost
100Mbps
19
10 to 60
1 to 65535
Path Cost
1Gbps
4
3 to 10
1 to 65535
Path Cost
10Gbps
2
1 to 5
1 to 65535