Possibility to link Preventive Maintenance (PM) Meter reading with Discrete Manufacturing Process in Oracle EAM (R12)

There isn't a synchronization between PM Schedule and duration time (or resource usage time) in finished Discrete Jobs

The PM Schedule is based on the entered meter readings (manually in Meter Readings form or by interface).  Usage rate (defined for meters) is used for PM Schedule calculations until the number of entered meter reading is less than "Number of Past Reading". After that, system calculates usage rate based only on entered meter readings

Difference Of Service Request And Work Request In Oracle EAM

You can probably implement your business flow using either way: Service and EAM Work Requests even there are differences between them. The main difference is that agents can view work orders created in Oracle Enterprise Asset Management related to the service request, but the life cycle of the work order is not in any way tied to the service request life cycle. Closing work orders tied to a service request does not close the service request and vice-versa. This is not the same when using work requests

Other differences: Normally, SRs are used when maintaining instances owned by customers while WRs are used when maintaining own asset numbers. we can use approval workflow for WRs and not for SRs. Using SRs you need to create a repair order then to generate work orders while using the WRs, the WOs are generated directly

Google Map in Oracle EAM (GIS Integration)

Geographic Information System (GIS) is an information system for storing, analyzing, managing and presenting digital data such as geographic features present on the Earth's surface using spatial references. Some of the GIS solutions available in the market are ESRI, Google Maps, Oracle Spatial, etc.

A Geocode (Geospatial Entity Object code) is a representation format of a geospatial coordinate measurement used to provide a standard representation of an exact geospatial point location on the earth. For example, the format (41°54'12"N, 87°37'35"W) indicates latitude, longitude of a unique location on earth.

Latitude gives the location of a place on earth north or south of the equator. Lines of Latitude are the horizontal lines shown running east-to-west on maps. Latitude is given as an angular measurement ranging from 0° at Equator to +90° at North Pole and -90° at South Pole. An example of a latitude in DMS (Degrees Minutes Seconds) format is 41°54'12"N

Longitude is the east-west geographic coordinate measurement. Longitude is given as an angular measurement ranging from 0° at the prime meridian to +180° eastward and −180° westward.
An example of a longitude in DMS (Degrees Minutes Seconds) format is 87°37'35"W

Release 12.1.1 enables GIS Integration using web based source map viewer of Google maps and provision is given to allow assets/ instances to be geocoded so that they can be spatially located on the map viewer. All item instances, i.e. EAM Assets and OAT instances are eligible to be geocoded and viewed in the Asset map viewer

Release 12.1.1 provides ability so that item instances can have a provision to capture their geocodes i.e. Latitude and Longitude. This can be done either manually through a mass data entry page or automatically through an API.

In Enterprise Assets Maintenance, users can search for any EAM assets using simple/ advanced search, enter geocodes for the assets using the 'Mass Geocode Entry' form, then locate the resulting asset on the map viewer by invoking the 'Map All' button. Alternatively, users can navigate to the Asset details page and locate the particular asset on the map viewer.

When a user selects any asset icon on the map viewer, details such as Asset Number, Description, Asset Group, Owning Department, Asset Location and Geocodes are displayed in a pop up. Also, hyperlinks are displayed for performing the following actions:
1. View asset details page
2. Create work request
3. Create work order
4. View open work requests
5. View open work orders
6. View Graphical Asset hierarchy.

When user selects any of the above actions, the page control is transferred to the appropriate tab in EAM responsibility with the context of the asset number selected. All other details corresponding to the selected asset number are defaulted when the page is rendered

Setup Steps

To enable the GIS Integration using Google Map feature, follow these instructions:

1. Set the following profile options:

• (R) System Administrator
• (N) Profile > Systems
• 'CSI: Mapviewer Name' = Google

Profile value can be set at any level.

• 'CSI: Google Registration key'

This profile hold the complete registration key (license key) for the Google Maps and can be set at any level

• 'CSI: Google Map Client ID'

This profile hold the client ID for the licensed copy of

"Asset Group" at inside the Oracle eAM

The word “Asset Group” trips out many people and remains a clearly un-answered question for range of Oracle users including technical consultants and business end users. explaining the Asset Group to different user groups is challenge, particularly when it comes to linear assets,For better clarity on the data model of the eAM Asset Group

Objective of this blog is to explain how an Asset Group relates to the key data objects within Oracle Enterprise Asset Management (eAM) module. These relationships are very important to consider while deciding on eAM Asset Groups for an organisation,Please take a look at following diagram that illustrates the direct and indirect links between eAM Asset Groups with other objects

1.  eAM Attribute Groups are assigned to a particular eAM Asset Group. ie, all eAM Assets belonging to that eAM Asset Group inherit the assigned attribute groups.
2. eAM Activities are assigned to a particular eAM Asset Group. ie, all eAM Assets belonging to that eAM Asset Group inherit the assigned activities.

Asset Warranty in Oracle EAM

There is no automatic action/functionality included with Assets warranty in Enterprise Asset Management.
Field Warranty Status is a lookup code with no values seeded

Field Warranty Active can be set when creating work orders via EAM self service page (values
Yes/No). This field also has no validation in the application. Is just a reference field

Field Warranty Expiration Date can be set on the Asset number definition form or self service (OAF) page. It is also not affecting the system in any way. It is also just a reference field

In other words, even you see some fields which point to warranty, in fact none of these fields are affecting the application in any way. They are just reference fields in order for you to take necessary actions (manually),
So there is nothing to turn on based on current application functionality

What I could suggest to you as workaround is to create your own warranty details based on Asset attributes descriptive flexfields(DFF)

At least we can track warranty information for Assets somehow in this way but not for components (Spare parts) used for maintenance, this functionality is currently not available in EAM 
(Version R12.1)

'Asset Route' Cost Will Distribute Equally in Oracle EAM

Reason for the equal distribution of Asset route cost to its associated Asset numbers are explained at here

1. According to the new design costs no longer reside in the route asset...Instead it will get distributed to the member assets, even if you have a work order for the route asset. 
For example : 
You had a work order for the route asset, Costs for this work order will get distributed to the member assets for the route
When you look at Work Order Value Summary form, you look at costs for a particular work order...Hence in the work order value summary form, you are able to see the costs for the work order 

However in Self Service, you see Costs for an asset...According to the new design the route asset would not hold any cost.It will get distributed to its member assets.Hence route asset does not show up any cost

However if you search for costs for each of the member assets, then you will be able to track the cost of the work order, for the route asset

2. For Asset Routes.Asset route is a logical asset and costing of asset route works as below -

During the transaction processing, costs are accumulated to the A/c's in the asset route work order wip accounting class. Till the closure of asset route work order , these costs would be accounted in the WAC of route work order only.After closing the Asset route work order, these costs would then be actually distributed to each of the member asset wip accounting class variance accounts.

To Delete Work Orders in Oracle EAM

The Oracle EAM is based on WIP and Inventory modules, So Period Closing is used on EAM organizations.
EAM Work Orders can be purged by using "Purge Discrete Jobs" feature. But this program will purge only WOs which are closed in already closed periods. (there are some validations which are not allowing purging of active work orders or WOs which are not in closed periods) Also you will have to run Inventory Transactions Purge program before being able to run WIP Purge.

There is no special program to purge only EAM Work Orders nor EAM Work Requests. Also it is not recommended to delete them from header tables (like wip_entities, wip_discrete_jobs or wip_eam_work_requests) as the records are related with records from detail or transaction tables by foreign keys.

In EAM, closing a period or closing an EAM Work Order act in same way: the costs incurred until that time are relieved by variance accounts. In either way, the costs can be pushed to GL. After that, as the WOs and related WRs are not necessary in the system, they could be deleted but at that time, all the material transactions and the resource transactions (and other transactions like capitalization or billing) will remain orphan and they could result in mismatch in reports and errors on user interfaces.

So purging this info from the system is not an easy task and also not recommended by Oracle 
(version 11.5.10)

'Period Close Variance' Entries From Oracle EAM to GL

The term 'Variance' in both 'Job/Period Close Variance' and 'Work Order Cost details screen - Variance' is causing the confusion. While the former is used in an accounting sense the latter is merely a term used in the cost view of the work order.

The Job Close variance and the Period close variance cause the maintenance expenses incurred on the work order to be passed on from the WO Valuation account to the Variance account. If these two accounts were set up to be the same in the WIP Accounting class, (which is the case that you have and also the recommended modelling specially for Average cost type), then the above postings are merely symbolic in the sense that the same account is debited and credited. The debit to the WO Valuation account during the actual EAM material or labor transaction would be the point at which this maintenance expense is first recognized in the P&L. Subsequent variance posting will have no impact.

The Variance observed in the Work Order Cost details page is just a cost view of the difference between the Estimated Cost and Actual Cost of the work orders. This gives an idea to the maintenance planner and execution team as to the extent of costs incurred in actual compared to the estimated cost.

EAM WO Cost Estimation is not impacting the accounting once the period is closed. (In fact, once the period is closed, nothing from EAM can do adjustments into GL)

If you want to schedule the Work Order Cost Estimate Processor then you will have to schedule the Estimation based on your needs. Are the users checking the WO costs daily? then you should schedule daily. 
But, there is no impact on the accounting if the

Reconcile the Oracle EAM and Payroll to avoid duplicate entries in GL

Oracle EAM is not designed to automatically reconcile with payroll entries. Customer needs to setup the accounts used in resource absorption account (resource definition form) and WIP valuation account for resource (WIP Accounting class) appropriately to achieve the desired results. 
A recommendation that we provide to the customer base independent of the topic being discussed here is that the WIP valuation account and WIP variance account in the WIP Accounting class be set the same. In the context of these possibilities/recommendation, please see the below 3 cases

Case-1 :
If the resource absorption accounts are set the same WIP valuation accounts for resource cost element, then debit and credit will be to the same account and there is no net value posted in GL due to resource charging in eAM. However the cost of resources required /actually used in a eAM work order will be displayed as cost views in Estimated cost view and Actual Cost view. In this approach, you are accounting all payroll related expense through the Payroll module only and eAM just provides a view of the resource costs expended on the work order.

Case-2 :
If the resource absorption account is set the same as the payroll debit side account, then this has the net effect of consuming the payroll expense when maintenance expense is incurred due to utilization of the maintenance resources. So your financial statements would then reflect payroll expenses to the extent of non-maintenance related resources(people) and the maintenance expenses bucket would show all maintenance costs – both items used and resources used.

Case-3:
A third practice that customers employ is to have 3 separate accounts involved in the resource transaction process:

No iPhone/Android Application For Oracle eAM, But there is a " Wireless Maintenance Workbench "

There is no "Oracle EAM eBS app for iPhone/Android" software available till version R12.1.3, Oracle has not provided such software to customers.

However, there is application called "Oracle Wireless Maintenance". This responsibility is a html eBS EAM responsibility and it can be used from mobile devices in on-line mode. The only requirement is that the mobile device to have internet browsing capability This is not requiring any software to be installed on client (mobile) device. However, if you have a VPN secured server, the mobile device must have this capacity to connect via VPN.
Note: Oracle features and applications may have been modified and empowered by third party software providers BUT this modified software is not supported by Oracle.

SETUP required for Wireless Maintenance Workbench

A.    Sysadmin Setup:
1.    Go to System Administrator >Security>Responsibility>Define, Set the "Wireless Maintenance User Workbench" as a Self Service Web Application instead of mobile application and Set Data group Application to Enterprise Asset Management instead of Manufacturing.
2.    Go to System Administrator > Application > Function and query for Function = EAM_WL_MUWB_HOME (User Function Name should be defaulted to MUWB Home Page) and Go to properties tab and make sure that type = "SSWA jsp function" 
3.    Go to System Administrator > Security > User > Define,  Query for your user and make sure there is a valid employee is populated in the Person field.

B.    EAM setup:
6.    EAM Organization must be assigned to the Responsibility 'Wireless Maintenance User Workbench' through the Organization Access form in Inventory
7.    The Login User Employee should have some work order operation assignments (the normal MUWB data):
a.    EAM => Setup => Routing =>

PL/SQL Script To Create Asset Numbers In Oracle EAM R12

Sample Script :-

set serveroutput on
declare
g_Return_Status VARCHAR2(1000);
g_Msg_Count NUMBER;
g_Msg_Data VARCHAR2(1000);
g_Object_Id NUMBER;

begin

fnd_global.apps_initialize (user_id => 1318,resp_id => 23118,resp_appl_id => 426);

EAM_ASSETNUMBER_PUB.Insert_Asset_Number
(  p_api_version => 1.0,
   p_init_msg_list => FND_API.G_FALSE,
 p_commit => FND_API.G_FALSE,
 p_validation_level => FND_API.G_VALID_LEVEL_FULL,
 x_return_status => g_Return_Status,
 x_msg_count => g_Msg_Count,
 x_msg_data => g_Msg_Data,
 x_object_id => g_Object_Id,
 p_INVENTORY_ITEM_ID => 7891,
 p_SERIAL_NUMBER => 'VEH99',
 p_INSTANCE_NUMBER => NULL,
 p_CURRENT_STATUS => 4,
 p_DESCRIPTIVE_TEXT => NULL,
 p_CURRENT_ORGANIZATION_ID => 4812,
 p_ATTRIBUTE_CATEGORY => NULL,
    p_WIP_ACCOUNTING_CLASS_CODE => NULL,
    p_MAINTAINABLE_FLAG

Work Order Relationship Types in Oracle eAM

In Oracle Enterprise Management we can define 4 different type of relationships between work orders.

1. Parent Child.
2. End to Start Dependency,
3. Cost
4. Follow-up Work

Relationship between work orders helps to manage complex maintenance jobs.

1. Parent Child: This relationship enables a network of Work Orders, which includes one top level Work Order that defines the time line of all its children Work Orders. The start and end dates of the children Work Orders are within  the start and end dates of the parent Work Order. A child Work Order can be parent to another Work Order. One parent can have multiple children, but one child can have a single parent. There can be an infinite number of parent-child Work Order levels, within the Parent-Child relationship.
2. End to Start Dependency: You can create Work Orders with scheduling dependency relationships (including child sibling Work Orders). For example, one Work Order's scheduled start date is dependent on another Work

Two Step Material Issue Vs One Step material issue

User has two different option to issue the materials for a work order in Oracle eAM, Those are 1.Two step material issue, 2.One step material issue

1.Two Step Material Issue: - System will Perform 

1. Material Allocation and then 
2. Material Issue 

Material Allocation will be performed as soon as eAM Work Order got Released and after that user need to perform the material issue for Self Service Page .. Store > Two Step material issue > Issue

Note: For Allocation to be triggered at the Time of Work Order Release , please make sure that Auto Allocate Flag is ON at the Material Order Line as well as Work Order Header ( In WO header it got defaulted from Parameter - Enable Material issue request ) 

2.One Step Material Issue:- we don't perform Allocation, user can directly issue the Material.

Another Advantage of One Step Material issue is , it let you do Over Issue

Oracle eAM Implementation Tips

The following tips highlight common questions and issues that arise during eAM implementation:

General Setup: An inventory org may be used for inventory, manufacturing, or maintenance. Spare parts are managed and maintenance work orders are executed in “eAM enabled” inventory orgs.

• Set up an org for eAM separate from any manufacturing orgs.

• Use Average Cost for inventory valuation in eAM orgs.

• When setting up WIP Accounting Classes, use the same maintenance expense account code in both the valuation and variance columns. This will cause maintenance expenses to book to the proper GL account and period.

Asset Definition: Assets are the object that work is performed on. Assets are also defined to represent hierarchical groupings for organizing work and rolling up costs. Asset can be used to represent positions for installation of rebuildable inventory items.

• Define a new Asset Group for each Manufacturer and Model Number combination.

• Define Templates for Asset Groups that will be repetitively used to create new Assets.

• Assign a Parent Asset for each new Asset to place it in the Asset Hierarchy.

• Consider setting up Assets that will move in and out of inventory as Rebuildables. Creating a “position asset” in the asset hierarchy will allow the tracking of rebuildables that have been installed and the cost of maintenance for the position.

• Use the Rebuildable Serial Number form to quickly setup rebuildables.

Preventive Maintenance and Activity Definition: Activities are the method for predefining work. Activities are used as templates to create work orders. Preventive maintenance activities may be scheduled based on meter readings and dates. Condition based maintenance may be triggered by absolute meters or collection plans.

• When launching the Activity Workbench and Maintenance Workbench enter a Parent Asset ID and check the “include children” box. Open Results, All Assets to view and use the hierarchy.

• Standard Operations may be useful for creating Activity Routings.

• When defining meters, be sure to check “used in scheduling.”

• When defining meters, set “past readings” to a number greater than

API To Create And Update An ESTIMATE in Oracle EAM

Following API procedure help us to create and update an ESTIMATE.

Here are the details of the specifications  for the create and update procedures:-
PACKAGE EAM_CONSTRUCTION_EST_PUB
File name: EAMPCESS.pls/EAMPCESB.pls

/*
* These procedures are used to create and update construction estimate records
* p_api_version Version of the API
* p_commit Flag to indicate whether API should commit changes
* p_init_msg_list Flag to indicate initialization of message list
* p_validation_level Validation Level of the API
* px_estimate_rec Record for estimation details of type EAM_EST_DATASTRUCTURES_PUB.EAM_CONSTRUCTION_ESTIMATE_REC
* x_return_status Return status of the procedure call
* x_msg_count Count of the return messages that API returns
* x_msg_data The collection of the messages
*/

PROCEDURE CREATE_ESTIMATE(
p_api_version IN NUMBER,
p_commit IN VARCHAR2,
p_init_msg_list IN VARCHAR2,
p_validation_level IN NUMBER,
px_estimate_rec IN OUT NOCOPY EAM_EST_DATASTRUCTURES_PUB.EAM_CONSTRUCTION_ESTIMATE_REC,
x_return_status OUT NOCOPY VARCHAR2,
x_msg_count OUT NOCOPY NUMBER,
x_msg_data OUT NOCOPY VARCHAR2
);

PROCEDURE UPDATE_ESTIMATE(
p_api_version IN NUMBER,
p_commit IN VARCHAR2,

Aims, Objects and Benefits of Oracle Enterprise Asset Management (EAM)

1.An asset is an entity for which users can report problems. Assets can be cooling towers, cranes, buses, buildings, conveyors, or anything that needs work

2. eAM creates and implements maintenance procedures for both assets and rebuildable Inventory items and takes care of comprehensive and routine maintenance requirements of asset intensive organizations. It effectively maintains assets such as vehicles, cranes and HVAC systems and rotable Inventory items such as motors and engines.

3. eAM enables users to optimally plan and schedule maintenance operations /activities with minimal disruptions to an organization’s operations and productions. It measures performance and optimizes maintenance operations. It tracks the performance of the assets and rebuildable inventory items by using meters, quality plans and conditioning systems.

4. By effectively monitoring operational data such as maintenance history, performance trends, meter readings, and operating conditions, organizations can proactively manage available resources such as inventory, equipment and skilled personnel to match them to asset maintenance demand.

5. Optimization of asset utilizations, scheduling and resources improves resource efficiency and enhances maintenance quality, maximizes resource availability including equipment and labor. Maintenance costs and work history are tracked at asset level.

6. Oracle eAM enables organizations to create and implement optimal and effective asset management strategies that can increase revenue and decrease costs. Both Preventive and Predictive Maintenance strategies are

Failure Analysis in Oracle eAM

Failure Analysis enables maintenance users to track an asset failure from the time it is reported until its resolution. Statistics from their collected failure data provide them with information on why an event occurs and causes asset failure. They can then take the necessary steps to eliminate that event. Additionally, they can use the failure statistics, among others, to help them formulate their Reliability-Centered Maintenance (RCM) program. 

Failure hierarchies that support multiple-level failure reporting provide effective root cause and reliability analysis. For specific Asset Groups, each failure (problem) has a defined number of root causes, with each root cause having a defined number of resolutions (remedies). 

1. First step is to define Failure Codes. There are three main Failure Code Types:

1. Failure Code
2. Cause Code and
3. Resolution Code

2. Second step is to define Failure sets. In failure sets user-defined Failure codes, Cause codes and

Enhanced features in R12.1 (+) series at Oracle EAM

This blog will throw light on the important features that exist in Enterprise Asset Management module in Oracle EBS R12.1
Enhanced features in R12.1 (+) series-

• Express Work : It's an integrated way of finishing the emergency work quickly with all the details like labor, charge time, material issued entered in single page.
• Microsoft Project Integration : This will help in integrating the Microsoft project with eAM which in turn used in Work order scheduling in effective manner.
• Google Maps integration : Apart from maintaining an asset, it's becoming important to track them. eAM has come up with solution of integrating the assets with the web-based Google maps. During asset creation or after we need to provide some geo information such as Longitude, Latitude, and Direction for the Assets to locate.
• Construction units : This feature is provided under the Maintenance Super User responsibility in OAF. The activities carried out on repetitive jobs like commissioning of Towers, Electric Lines, Power plant construction etc., can be effectively estimated and planned using Construction units.
• Primavera Integration : One of the products in market dealing with Project management. Integration of Primavera and eAM will help in scheduling eAM work orders for Project based activities.
• Encumbrance : Long living feature with purchasing modules has been introduced in eAM for Acconting encumbrance with eAM Purchase orders/ Purchase requisitions.
• Work Permits : Creating only work order without information about operations, manitenance and safety precautions are of no use. eAM has come up with feature called Work permit where we need to take permission before taking up any work along with above details.

Predictive Maintenance & Reliability Centered Maintenance

Maintenance, in all its essence, is an absolutely indispensable activity for all organizations today. Downtimes or any damage due to malfunctioning of an equipment are most expensive and thus an immense squeeze in the profits. Almost each and every organization across industries have woken up to this fact and employ some or the other maintenance system

Furthermore to just having a system in place to take care of the maintenance activities, organizations today are moving towards most intelligent and sophisticated methods of maintenance viz. Predictive Maintenance and Reliability Centered Maintenance.

The goal of Predictive Maintenance is to perform maintenance exactly when the equipment needs it - neither earlier nor later than necessary. This essentially means tracking key indicators over time to predict when the equipment needs repair. Predictive maintenance programs measure equipment on a regular basis, track these measurements over time, and take preventive action whenever the measurements are about to go outside the operating limits. Repairing equipment as-needed requires fewer man-hours and parts than corrective maintenance.
In a similar fashion, Reliability Centered Maintenance focuses on prioritizing maintenance efforts based on equipment's importance to operations, its downtime cost in revenue and customer loss, its cost of repair, and its impact on safety. It offers extensive analytical data to ensure that the critical equipments are identified and maintained on a priority. Reliability maintenance depends on the same measurements used in predictive maintenance, but saves additional maintenance cost by spending less effort on lesser important equipments

The EAM (Enterprise Asset Management) module in the Oracle E-Business Suite family offers these refined maintenance techniques of Predictive Maintenance as well as Reliability Centered Maintenance

But as they say, just implementing something does not ensure a job been done. It is equally important for people working with these methods to understand them thoroughly and learn how to identify potential problem areas. If an intelligent solution is implemented and work practices change accordingly, phenomenal results become apparent pretty soon.

Most challenges in Linear Asset Management

Maintenance of linear assets (A kind of networks) is completely different from maintaining non linear assets like a fleet, machine. They through lot more challenges in modelling and executing the maintenance work compared to non linear assets. The ability to model and execute the maintenance these assets is what can tap the huge market potential in this segment

Assets can be broadly divided into two categories namely Liner and Non linear. If we underrated non linear assets, it is easy to understand linear assets. Non linear assets are like Plant, equipment, Machine, fleet etc., they are confined to a size and specific location etc., Maintenance of them is relatively easy. Linear assets are not specific to single location. Linear assets can be like roads, runways, gas pipe lines, electrical transmissions, rail tracks, telecom lines etc., where they are not specific one single location. They more or less represent a network. Many linear asset networks cross over with other networks and can also be a place holder of many non linear assets. For e:g one railway track can connect to other railway track and also holds many non linear assets like traffic control systems, stations, power generating equipment and more importantly other parallel linear asset like power cables etc., Maintaining these assets requires much more capability than maintaining non linear assets

There are many challenges that will surface in maintaining these assets. All these challenges need to be addresses adequately by any ERP to realize the benefits. Again the challenges will be different for different industries and this blog lists these challenges a generic manner

1. Modelling of the linear assets: As the linear assets are not confined to a single location but widely spread across some geographies, modelling of these assets is the first most challenge for any ERP. This modelling can be either engineering or visual in nature. For e.g. a metro rail network is spread across a city. Typical asset hierarchy may not work here.
2. Assigning the non linear assets to the linear assets: Every linear asset can be a place holder for many non linear assets. For e.g.  a national highway contains traffic signals, light posts at definite locations also requires maintenance.
3. Parallel networks: There are some networks that work in parallel. A metro rail network requires a parallel power lines. Failure of any of them can result in stoppage of the services. Modelling of such networks is a challenge.
4. Intersecting networks: Networks that cross over. Typically can operate independently but the shutting down of one network can result in