Abbreviations

The following abbreviations are used in this document:

• IW – Infinet Wireless
• MINT - mesh interconnection networking technology
• MINT area – network from MINT units interconnected by MINT protocol as one and only transport protocol
• PRF – Pseudo Radio interface
• OSPF – Open Shortest Path First
• InfiMUX – Switch with MINT protocol
• MINT RCMD – MINT remote command execution

Purpose of this document

Infinet Wireless is one of the leading manufacturers of Broadband Wireless Access equipment for carrier grade fixed installations. Infinet Wireless uses its own proprietary transport protocol – MINT – which interconnects units by wireless and wired (MINT-over-Ethernet technology provides MINT connectivity over wired Ethernet) links. Within MINT areas, it is possible to send ANY command via the MINT protocol to a specified unit for execution (MAC address can be used for specific unit selection or broadcast MAC addresses can also be used)

This document shows how management of the units can be organized by means of MINT protocol. MINT protocol operates on both Layer 2 and Layer 3. However, in case incorrect or missing IP settings on the units, the management configuration on IW unit can be restored by issue of MINT RCMD (remote commands) from another IW unit. MINT management only required L2 and MINT connectivity between units.

Introduction to MINT protocol

MINT – Mesh Interconnection Network Technology

MINT main purpose is to provide path selection with best quality for wireless (and wired) traffic on Layer 2 (switched traffic).

MINT highlights

MINT position

MINT link is the link between two units, which use MINT as transport protocol between each other.

MINT encapsulated and transport through MINT link (or links) all traffic and all protocols. Thus, MINT is the only one transport protocol for IW R5000 family products.

MINT operates between DataLink and Network Layers of the OSI Model. Therefore MINT is capable to encapsulate and carry through link traffic of Layer 2 (Ethernet switched data) and traffic of Layer 3 (IP routed data).

MINT technology overview

Where MINT is available

Only adjacent neighbor connectivity is needed to create MINT powered link:

• For radio interfaces MINT is enabled by default, only radio parameters should be configured;
• For Ethernet interfaces MINT-over-Ethernet should be enabled manually (disabled by default) for Ethernet interfaces. It is supported by additional virtual Pseudo-radio interface (PRF). Every BS or CPE supports such interfaces.

MINT path selection

In case of multiple MINT routes the protocol would always choose one route for single data frame and would have possibility to re-select new route for another data frame in case of any change of path characteristics. Path characteristics are described by aggregated parameter MINT cost.

MINT cost is calculated from the following parameters:

• Signal-to-Noise ratio (for connectivity over radio interfaces);
• Throughput or Bitrate (for connectivity over radio interfaces);
• Percentage of retries ;
• Link load and throughput;
• Some other parameters.

Link quality assessment:

• Each MINT unit has full MINT map with all MINT neighbors;
• Each MINT neighbor constantly checks MINT cost between each other;
• Each check is to be done each 1-3 s;
• MINT path can be predictably changed due to change in link quality (cost drop).

Loop free capability:

• The path for data frame is selected by the lowest overall cost;
• The predefined path is set for every packet, unless any changes in network;
• The path for frame or packet can be different;

STP BPDU transmission can be blocked in configuration through any logical interfaces.

MINT path selection capabilities

MINT protocol will quickly adjust to possible changes in critical parameters – re-calculate MINT cost for each path and rebuild the path accordingly. Moreover, due to built-in capability to quickly adopt to changes, even data flow path within MINT network can change rapidly too.

On the picture below shown mesh topology of units. All units run MINT protocol for each interface, hence each connection is handled by MINT protocol. In this case, node J has to send data to node F.

Red path (1^st path) has been chosen by MINT protocol initially.

Blue path (2^nd path) – MINT decides to switch to 2^nd path due to congestion between node H and
node G.

Green path (3^rd path) – MINT decides to abandon 2^nd path too due to excessive traffic load and switch traffic flow to 3^rd path.

Each decision to change active traffic path can take place every 1-3 seconds depends on tuning of MINT protocol settings for every unit.

MINT area

All benefits of MINT protocol mentioned on previous page, would be active ONLY in network from MINT units and with MINT protocol as the only one transport protocol. Such MINT network is called MINT area. Thus it is required to create unified MINT area consisting of IW units interconnected by Wireless Radio interfaces (RF) or by Wired MINT-over-Ethernet (Pseudo Radio - in brief PRF) interfaces. 

Next section contain logical interconnection scheme with RF and PRF links for current physically (wired and wireless) connected units (MINT connections logical scheme).

MINT connections logical scheme

Wireless connection is represented by red link on logical interconnection scheme, wired PRF links are shown in green color.

So, here we have network where almost each unit has at least two connections via MINT protocol. Therefore, it is possible to balance traffic via one or second path (or even load balance using both). In case of one link failure, another connection would be used as transport. Eventually, under certain circumstances the units can always stay connected because both links down situation is very unlikely to happen. It doesn’t really matter what type of physical connection is used (wired or wireless), MINT use any connection. The only thing different is MINT cost value for each link. Let’s see how our scheme would look with the exact MINT cost values. We need such representation to figure out which way the traffic will flow.

MINT RCMD

Within MINT area every MINT node can receive information about another MINT node through its MINT neighbors. Every MINT neighbor exchanges information about its adjacent links, their quality, load, issue and MAC address. MAC address is used as identification label for MINT node.

List of MINT neighbors

Unknown node#2> mint map det
==============================================================================
Interface rf5.0
Node  000435130AD8  "Unknown node", Id 00000, NetId 0, (Master)(pollqos)
Freq 6140, Band 20, Sid 10101010, autoBitrate 130000 (min 13000), Noise -103 
 1 Active neighbors:
---------------------
   Id          Name                Node     Level  Bitrate Retry  Err  Options
 ------- ---------------------  ------------ rx/tx   rx/tx rx/tx  ---  -------
   00000 Unknown node           000435230A25 26/26  130/130 0/0   0/0  /S/
         dist 2, load <5/2>, pps <4/0>, cost 51, IP=10.10.10.1
         txpwr <0/0>, H11v1.90.14
 ------- ---------------------  ------------ -----   ----- -----  ---  -------
Total nodes in area: 2

So, MINT neighbor is designated by MAC address (marked by bold font in the above example).

Unique feature of MINT protocol is possibility to send any command to ANY MINT neighbor for execution at MINT neighbor unit. It is called MINT Remote Command Execution (RCMD). MINT RCMD could really helpful in lots of cases, such as, for example: lost password, ip address settings cleared, no possibility to login to remote MINT neighbor directly, it is required to send some commands to be executed on all MINT neighbors.

Examples

Unknown node#2> mint rf5.0 -rcmd -node all "co sh"

Unknown node#2> mint rf5.0 -rcmd -node 000435130AD8 "restart yes"

Unknown node#2> mint rf5.0 -rcmd -node 000435130AD8 "ifc svi1 172.12.77.2/27; route add 0.0.0.0/0 172.12.77.1;"

MINT area prerequisites

In default configuration MINT protocol is enabled and used only between wireless radio interfaces. However, in order to create interconnected (by MINT protocol) MINT area MINT-over-Ethernet interfaces (PRF) are required.

In order to enable MINT-over-Ethernet it is required to:

• Create virtual Pseudo Radio Interface (PRF). PRF can be created as logical sub-interface for plain Ethernet interface (parent interface) , or as logical sub-interface for another logical interface (for example, VLAN interface can be used as parent interface for PRF);
• Start MINT protocol for PRF interface;
• JOIN command connects internal bonds between MINT areas behind Radio interfaces and PRF interfaces.

Within the same Ethernet broadcast domain (LAN) two (or more) IW units with PRF interfaces created, with MINT protocol started can find and establish communication via MINT protocol by sending and receiving Ethernet broadcasts initially. Thereafter, IW units will use Ethernet unicast data transfer.

VLAN considerations

In case two IW are placed within certain VLAN, then configuration of PRF should be corrected with certain VLAN tag. Please pay attention that default configuration (or template part) should exactly use the relevant VLAN tag number.

MINT-over-Ethernet & VLANs

MINT-over-Ethernet does generate broadcast traffic to detect and find other MINT neighbors. Sometimes, such broadcast traffic could be treated as abnormal for network, especially for enterprise networking with comprehensive network security policy.

Moreover, in vast MINT-over-Ethernet network different MINT-over-Ethernet areas should be isolated from each other in order to provide complex traffic engineering or prevent undesired traffic path selection.  Hence, VLAN separation should be used in such cases.

Configuration part

Steps to configure MINT-over-Ethernet

Only step 1 is different for untagged approach (1a) and for vlan based approach (1b)

CLI based configuration

1a. Create Pseudo Radio (PRF) interface for untagged interconnection