COMP3122 Network Management Richard Henson March 2011

Week 7 – Managing Network Printing n Objectives –Identify all possibilities for allowing a printer to be used by network users –Explain how a print queue and spooler work –Manage user needs in terms of printing priorities

Whole Session on Printers? n Until you come to manage a network, the amount of time spent on printer related problems will not be appreciated: –so much can go wrong… –and frequently does! n Good news for network administrators… –printer control and troubleshooting software is much improved… –and people print less…

Printer Topologies n A printer can be attached to a network in a number of ways: –as a standalone network device »needs its own network card –connected to a user workstation which can allow network access via a share –connected directly to a network server, which provides the print services

Local Printing n A network user may have their own computer and printer –the print device will be connected via a local port e.g. LPT1 or USB –stills need to be configured on that machine for local printing n Installation and configuration is best left to the wizard (if there is one…) –however, even the wizard won’t be able to help if the driver for that printer is not available…

Sharing a Local Printer using UNC names n Once a local printer is working, the user may wish to make it available to other network users –achieved on Microsoft networks by setting up a printer share –the share can be made available to other network users via a Microsoft UNC (Universal Naming Convention) pathname »e.g. \\printserver\printname \\printserver\printname

Limitations on Network Printer Sharing n To send print data, a communications channel needs to be opened between the sending computer and the print controlling computer –channel takes up resources… –and stays open? »in Windows printing, channels generally stay open for the rest of the user session »if many users print it can take a lot of bandwidth

Limitations on Network Printer Sharing n Problem: –usually a limit on channels open simultaneously on a workstation (e.g Professional – 10 users) –only overcome by using server software (e.g Server) to manage the connections –means making the computer connected to the printer a network server »security implications if not managed appropriately…

Microsoft Network Printing n The component that does the printing is referred to as a print device n The software object on the IP address based device that controls the print device is called the printer n There can be several print devices connected to a single printer, through the use of different ports

Mechanism for Printing I n Before a document is even sent for printing: –the required printer driver software needs to be located –the relevant type of printing device needs to be identified –the driver software needs to format the document for printing as a “print job” –the print queue (a folder) needs to be ready to receive the print job

Mechanism for Printing II n Once the formatted document arrives at the IP address of the relevant device for containing the software “printer” –printing priority needs to be identified –the document needs to be put into an appropriate place in the print queue as a print job n A lot of print jobs creates a large queue… –plenty of disk space needs to be available on that hard disk drive/partition

Configuration of a Network Printer I n Hardware requirements: –plenty of RAM »a lot of processes will be running concurrently –plenty of hard disk space »requested print jobs will need to be queued n Software Requirements: –operating system that will support the expected volume of network printing –the appropriate printer driver(s)

Configuration of a Network Printer II n Administrator privileges required… –assuming there are sufficient LPT ports –several printing devices can be configured to work on the same computer »assuming that appropriate device drivers are available n Drivers also need to be installed… –for each type of client operating system (e.g. XP, Vista, 7, apple?) involved in sending print jobs –need to be available to client machines when they first connect to the network printer

Configuration of a Network- Interface Print Device n Avoids tying up a computer as a “printer” n Two possibilities: –EITHER… the device is intelligent (e.g. HPJetDirect) »in which case it should be automatically detectable by the NOS –OR… it is just a printer with network card n In each case, an IP address needs to be allocated –if DHCP is running on the network »printing will be managed by the DHCP server »an IP address lease can be assigned as soon as communication is established

Configuration of a Network- Interface Print Device n As with any other network printer… –server needs to create a logical port to send print jobs to n In this case, the port will point to the IP address of the network connection to the printer –assuming that the network protocol is TCP/IP –if network uses active directory, it will be »within the scope for managing printers with active directory

Connecting to a Network “Printer”/Print Device n Each network print device also has its own UNC name –should be stored in a database on a Domain Controller –database should be accessible to any computer on the network n The local computer can use a configuration wizard to link to the UNC name –any required drivers should be accessed and installed from the print server

SPOOLing n Sequential Processing Operations OnLine n All requests for printing on a particular print device will be stored in a directory on the relevant print server n Generally known as a spooler: –once upon a time (e.g. 1960s, 70s, 80s) the print jobs would be “spooled” onto magnetic tape –would be printed at a later date »e.g. overnight n Nowadays, the “spooler” is the folder that holds print jobs in the print queue

Setting Printing Priorities n Lowest priority = 1 n Highest priority = 99 n Multiple logical printers need to be created for a single print device n The logical printers can then be set to have different priorities: –different groups of users point to different logical printers –users send different priority documents to different logical printers

Print Queue n Simply an ordered list of print jobs n Ordering of jobs to be serviced occurs according to: –time received by the spooler –printing priority of the user sending that print job

Managing Print Queues n Windows Servers have automated Queue Management –print jobs will get processed in order of priority n BUT… if a high priority print job gets stuck for some reason –no other print job will be able to take precedence n Manual queue management therefore needed so the faulty print job can be deleted/bypassed

Printer Hardware Failures n Many printer problems are hardware related: –out of paper –paper jam –printer accidentally switched off n In each case, the print job will: –get through to the print server –be added to the queue –then gets stuck in the queue! n Result: could be a very long queue!

Printer Queue Manager n Need someone who can step in and: –sort out the printer hardware problem –log on to the print server with sufficient status to manage the print queue n Dangerous to give Administrative access to a user! n Windows Servers & Professional have a user group called “Print Operators” –any user can be added to this group n Print Operators: –HAS sufficient access to print server to manage print queues –DOES NOT give sufficient access to change printer settings

Setting up a Printer Pool n Required: –one logical printer interface –connected to two or more print devices n Print devices can local or network-interface n Print jobs go to the first available print device n Advantages: –decreases wait time on the print server –multiple print devices administered from one logical printer

Assigning Logical Printer Permissions n A Server should provide… –a range of printer permissions –a smaller number of permission levels n e.g. Windows printing uses: –nine types of permission (!) –three levels of permission: »Print »Manage Documents »Manage Printers

Managing Printing across the Internet n Print jobs submitted via browser n Can be used for any printer connected to the Internet –all that is needed is the URL –or the IP address n With Windows printing, the web browser can be used to provide the interface to: –view print queues –manage logical printers

Active Directory and Printing n Active Directory uses IP addresses to locate network devices –DNS names also pinpoint network devices –and UNC names can identify print devices linked to a “printer” computer, via its IP address n Printer settings of all relevant devices on the network can be stored in Active Directory –therefore AD is the most convenient way to manage configurations of printing devices…

Group Policies and Printing n Group Policy is one of the best reasons to deploy Active Directory because –it allows management of data objects of both user and computer –and has an infrastructure that allows an administrator to implement specific configurations for users and computers n Group Policy settings are contained in Group Policy objects (GPOs) –these are associated with Active Directory sites, domains, or sub-domain organizational units (OUs) –cumulative settings can be evaluated on a target machine, using the hierarchical nature of Active Directory

Group Policy Architecture

Location of Group Policies n Group policies held in templates (GPT) on domain controller n Stored in the GPC (Group Policy Container) –found in Active Directory on each domain controller in the domain –within the /Sysvol folder »in the /Policies sub-folder n Accessed most easily using GPMC

Group Policy Objects and Printing n All Group Policy settings are contained in Group Policy objects (GPO) n GPOs associated via GPTs with Active Directory containers e.g. –sites –domains –organizational units n Most of Active Directory printer-related settings can be enabled or disabled by using Group Policies –this maximizes Active Directory’s usefulness for controlling printing activities

Active Directory & Printer Locations I n Basic principle: –printer’s location can be associated with a particular IP subnet –“location” is defined by a string separated by / character… n e.g. Europe/London/ParkLane/Accounting n First step: map out the locations… –once defined in this way the location will pre-populate for the printers

Active Directory & Printer Locations II n Three rules for naming locations: –any single level cannot be more than 32 characters –maximum of 256 levels –maximum length of the entire location is 260 characters n Components of location names can occur in any order –city usually at level 2 in the location name but could also be level 3 e.g. NorthAmerica/Ohio/Chicago –allows flexibility of design of location codes

Setting up Printer Locations n Configuration uses “active directory sites and services” –associate name with subnet n And “active directory users and computers” »pre-populate search location

Finding Location of a Printer n Again, using Active Directory… n Just a matter of searching “locations” –achievable directly from the desktop with “Search” facility –Select “printers”then “advanced” option, add search string and click on “find” »the local machine will interrogate active directory directly… n BIGGEST PROBLEM: printer name not appropriate or meaningful enough for the user…

Using Multiple Subnets n For users to still track printers… deployment must include: –directory service including more than one subnet –IP addressing scheme that roughly matches the physical layout of the enterprise –one or many subnet objects for each site »created using Active Directory Sites and Services

Thanks for listening