Zte ZXR10 8900E series, Product Description

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ZXR10 8900E series Core Switch Product Description
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including node and connection node has one spanning tree which has good destination
connectivity and can avoid network cycling. Therefore, spanning tree algorithm and
protocol can avoid network loop in any dynamic topology and clear the loop between any
two stations.
As IEEE802.1s-defined MSTP is compatible with existing IEEE802.1w-defined RSTP
and IEEE802.1D-defined ordinary STP, STP software module is only required to support
MSTP. When started, MSTP can forcedly work as RSTP or STP to support STP and
RSTP mixed networking. And it can start STP in aggregation link and support port-based
enabling STP protocol.
ZXR10 8900E supports STP, RSTP and MSTP, and their mixed networking.
3.1.4.2 RSTP
RSTP (Rapid Spanning Tree Protocol), the STP upgrade version, follows IEEE 802.1w.
RSTP provide the fast port switching mechanism and shorten network convergence time.
RSTP has the following defects:

The entire switching network has only one spanning tree. Large network has slow
convergence and network topology change will have a great effect.

IEEE 802.1q is the switch connection standard protocol. In symmetrical connection
(in VLAN, the connected ports between switches has the same trunk), one spanning
tree has no influence on data forwarding between switches. However, in the
asymmetrical connection, the connected ports between switches are blocked by
RSTP, which will affect the connectivity and waste the bandwidth.
3.1.4.3 MSTP
MSTP (Multiple-instance Spanning Tree Protocol), developed based on STP/RSTP,
follows IEEE 802.1s. MSTP divides switching networks into several zones, and several
STP instances run in one zone. VLAN is translated to instance in M: 1 mode (bind several
VLANs to one instance), thus each VLAN is transformed into a tree network to avoid the
loop.
MSTP has the following advantages:

In single VLAN, STP supports rapid convergence.

As MSTP structure spanning tree through VLAN and does not block inter-switch
connection port, the load will be shared.

M: 1 mapping reduces switch resource utilization rate.

MSTP is compatible with STP/RSTP to make network deployment simpler.