Zte ZXR10 8900 Product Description page 58

ZXR10 8900 Product Description
4.3.7.6 Super VLAN Module
The Super VLAN can locate the hosts attached to same physical equipment but subject
to different virtual broadcast domains in the Ipv4 subnet with the same default gateway.
In a large-scale switching LAN, this mechanism has many advantages compared with
the traditional Ipv4 addressing system. Most of all, it still adopts the address space
utilization of the Ipv4 system.
The Super VLAN enables re-partition of the VLAN with the concepts of Super VLAN and
sub-virtual network. One or multiple sub-virtual networks can belong to one Super VLAN
with the default gateway IP address of the Super VLAN.
Super VLAN is purely software function. It is transparent to the ASIC chip and data are
switched according to the VLAN configuration in the software module. The PVLAN does
not need the support of the protocol packet. Static configuration on the ZXR10 8900
series switches settles all.
4.3.7.7 Spanning Tree Protocol (STP) Functional Module
STP is to detect loops between L2 switching functional units and remove them as well
as provide a redundancy link to improve the performance and reliability of LANs.
The STP module provides the following two functions of
•
Preventing the broadcast storm of LAN caused by the network loop, and providing a
backup redundancy path.
•
Detecting the change of the topology structure and configuring a new spanning tree
topology according to this change.
The STP algorithm executed on the switch in a subnet will help to form a dynamic
topology of a spanning tree, which can ensure that no loop exists between any two
workstations within an LAN to prevent the broadcast storm from occurring. This
algorithm can monitor the change of the topology structure and help to establish a new
spanning tree according to its change. It can offer the switch a certain error tolerance
capability to reconfigure the topology structure of the spanning tree. Then the switch will
monitor and update the MAC route table according to the status of the dynamic topology
structure of the spanning tree to finally implement the routing on the MAC layer.
The purpose of spanning tree algorithm is to let the switch dynamically find a loop-free
subset (tree) with the topological structure and ensure an adequate connectivity. In this
way, if two LANs have the physical connection, the corresponding spanning tree path is
generated. Every line patterns including nodes or connecting nodes has one spanning
tree, which guarantees the destination connectivity and that no cycling is generated.
Therefore, the spanning tree algorithm and protocol can prevent the network cycling
issues occurring in any dynamic topology structure and remove the loop between two
working stations.
The multiple spanning tree protocol (MSTP) defined by IEEE802.1s is compatible with
the RSTP protocol defined in IEEE802.1w and the common STP protocol defined in
IEEE802.1D, therefore only the multiple spanning tree protocol (MSTP) needs to be
implemented by the STP software module. The RSTP or STP can be enabled forcibly
when enabling the MSTP protocol, so the combination using of STP and RSTP can be
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