DICOM Configuration Robert Horn Agfa Corporation Health Car

DICOM Configuration Robert Horn, Agfa Corporation

Health. Car Supplement 67 – Existing Industry Protocols • NTP (Network Time Protocol) • DHCP (Dynamic Host Configuration Protocol) • DNS (Domain Name System) • LDAP (Lightweight Directory Access Protocol) – Existing Configuration Tools – Existing support databases – DICOM specific information model for LDAP databases

Health. Car DICOM Configuration Goals – Support New Functions • Security and Privacy • Synchronized Multi-device Acquisitions – Reduce Operational Costs • Network Administration • AE-Title management • Service location management • Feature location management

Health. Car Time Synchronization • For – Multi-device simultaneous acquisitions • Cardiac Catheterization laboratory – Coordination • Security Logs, Procedure Logs – Convenience

Health. Car Synchronization Specification – Specify error relative to time reference(s) – Acceptable absolute time error (relative to UTC) – o( 1 s ) security logs – o( 100 s ) cardiac catheterization – Acceptable synchronization error within a Time Source (0018, 1801) (relative to local source) – o( 1 s ) security logs – o( 10 ms) cardiac catheterization (a few percent of one cycle of a rapidly beating heart).

Health. Car NTP - Network Time Protocol – Widely available – Suitable for both low precision time and high precision time synchronization – SNTP (Simple NTP) clients for low precision and limited capability systems. – Extensively documented and explained on www. ntp. org

Health. Car Accuracy capability of NTP – o(1 s) Either client (NTP, SNTP), network capable OS, Internet, GPS, or radio connection – o(250 ms) NTP client, interrupt driven OS, NTP clock controls – o(100 ms) local network topology – o(10 ms) OS clock, OS design – o(1 ms) OS/application design, network topology – o(100 us) Hardware assist, OS/application design – o(10 us) Instrumentation clock, custom OS – o(1 us) Atomic clock, extensive hardware assist

Health. Car How NTP works Time Sent (Ta) Response Redundant Servers NTP Server Query Time Query Received (Ti) Time Response Sent (Tj) Current Time Parameters (TP) Client Provides Old Network Parameters Old Time Parameters Response Mathematical Magic happens Client Sets and Fine Tunes System Clock NTP Client SNTP performs only the clock setting NTP includes the network delay estimation, optimal estimation mathematics and fine tuning of the system clock. NTP clients may utilize redundant servers NTP clients may utilize instrumentation grade pulse generators (e. g. Atomic Clocks)

Health. Car Typical NTP configurations Internet NTP Server GPS Receiver Campus Network NTP Clients Switching Hub Local NTP Server

Health. Car Network admin • DHCP (Dynamic Host Configuration Protocol) • Assigns IP address, hostname • Informs DNS of assignment • Provides routing, NTP, DNS, etc. information to client • DNS (Domain Name System) • Provides hostname to IP lookup services • Provides server location lookup services • LDAP (Lightweight Directory Access Protocol) • Provides simple information directory services

Health. Car DHCP – Widely used – Support stable IP allocation (needed for transition and legacy equipment) – Supports dynamic IP allocation – Understood by IT administrators – Documents network IP configuration in file – Devices only need their "name"

Health. Car DNS – Widely used – Provides translation from hostname to IP – DHCP uses DDNS option to maintain coordination with dynamic IP assignments – RR SRV records provide location of LDAP server

Health. Car LDAP – Widely used (known as Active Directory in Windows) – Simple query oriented network database – Simple information model. Schema provided as part of Supplement 67. – Alternatives examined • CIM: very attractive, but a much larger effort to define and implement. Not yet widely used. • SNMP, DMTF: interesting but deal with different aspects of network administration and management.

Health. Car Locate AE-title (internal operation) LDAP Server Where is AE-X is at hostname, port Database Where is hostname? DNS Server Hostname is x. y. z. w DICOM Traffic

Health. Car Beyond Finding AE-Titles – Installation and Network Configuration oriented – AE Configuration • Obtain new unique AE-Title • SOP Classes supported (SCU/SCP, Transfer Syntaxes) • IHE Actor • Vendor extension – Device Configuration • Description • Vendor extension • Hospital extension

Health. Car Pre-configured Installation – Large network addition – Multiple vendors – Reduce coordination and scheduling delays – Reduce configuration errors – Reduce staging requirements

Health. Car Pre-configured Installation Vendor A Preparation LDAP Prepared Configurations LDIF IT Organization A A DHCP Network Planning A LDIF Prepared Configurations A B B B Vendor B preparation

Health. Car Add another machine Get IP, hostname, etc. DHCP Install Hardware Assign Name Find LDAP Server DNS Query Configuration LDAP Configure System Obtain Unique AE Titles Update Configuration