Abbreviations

• BS - Base station
• CPE - Customer Premises Equipment
• MO - Mobile object
• LOS - Line of Sight (the first Fresnel zone is not overlapped)
  
• nLOS - Near Line of Sight (the first Fresnel zone is slightly overlapped)
• NLOS - Non-Line of Sight (the first Fresnel zone is significantly overlapped)

  ACL – Access Control List

• ARP – Address Resolution Protocol 

• CLI – Command Line Interface

• DSCP –  Differentiated Services Code Point

• HTTP – Hyper Text Transfer Protocol
• IGMP – Internet Group Management Protocol 
  
• IP – Internet Protocol
  
• MAC – Media Access Control
  

• MINT – Mesh Interconnection Networking Technology

• NAT – Network Address Translation
• OSPF – Open Shortest Path First
• PHY – Physical layer

• QoS – Quality of Service

• RIP – Routing Information Protocol
• RSH – Remote Shell
• RSTP – Rapid Spanning Tree Protocol
• SNMP – Simple Network Management Protocol
• STP – Spanning Tree Protocol
  

• TDMA – Time Division Multiple Access

• VLAN – Virtual Local Area Network

Introduction

Complex wireless network topologies require enhanced mechanisms to ensure fast packet transfer constantly adapting to the status of the radio connections, especially in cases with mobile objects. The radio link quality changes may lead to different transmission rates from couple of Mbps to hundreds of Mbps for the same link in different conditions. Thus, InfiNet’s proprietary MINT protocols offer an alternative routing method, by taking into account the network topology changes in real time and evaluating the quality of the radio links in real time. In addition to the routing capabilities, MINT includes a set of features that were designed for ensuring an efficient functionality of the InfiNet Wireless units.
This document describes main features of the MINT protocol to ensure deep understanding and, as a result, correct and effective configuration of the MINT network.

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A Switch Group is a special container that filters data according to specific rules and acts like the transition point between MINT and Ethernet, an Ingressingress/Egress egress point between Ethernet and MINT. Traffic can be switched ONLY only between at least TWO two Ingress/Egress points. Although the main purpose of a Switch Group is to be a container for transporting VLANs, it is possible to use them to transport also other types of traffic using additional filters.

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Even if MINT will not create loops inside the MINT network, the external network can still cause loops if the switch group configuration is not taken into account.
The picture below illustrates a typical scenario that can cause loops. Several units are connected to the same switch as part of an Ethernet segment. The PRF over ETH interfaces Ethernet interfaces are used to unify the MINT area in order to offer alternative paths (redundancy) between the MINT nodes.

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• Only Unit 1 receives the broadcast from SW1, sends a copy of the external broadcast to all the nodes including Unit 2 as they are all in the same switch group. Unit 2 will drop both the external broadcast from SW1 and the MINT copy from Unit 1 since it does not communicate with the external network (ETH Ethernet is not included in the switch group).

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• If N units are connected to the same switch, add the ETH Ethernet interface to the switch groups only for one of the units. This way, only one ETH interface Ethernet interface will communicate with the external network, the other ETH interfaces Ethernet interfaces will use the PRF protocol to communicate with the adjacent unit and will not participate in the L2 switching process;

• MINT offers an additional feature for avoiding loops. STP has a specific design for the InfiNet units, by blocking switch groups instead of physical ports like in the classical implementation. The advantage of this solution over removing the Ethernet ports from the switch group is that all units connected to the Ethernet switch are allowed to communicate with the external network, avoiding single points of failure.

  Warning
  title CAUTION
  There are risks in implementing this solution and InfiNet Wireless should be contacted for the practical aspect considerations.

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