Setting up a secure VPN Connection between SCALANCE M-800 and SSC

Transcription

1 Configuration Example 12/2015 Setting up a secure VPN Connection between SCALANCE M-800 and SSC SCALANCE S615, SCALANCE M-800, SOFTNET Security Client

2 Warranty and Liability Warranty and Liability Note The Application Examples are not binding and do not claim to be complete regarding the circuits shown, equipping and any eventuality. The Application Examples do not represent customer-specific solutions. They are only intended to provide support for typical applications. You are responsible for ensuring that the described products are used correctly. These Application Examples do not relieve you of the responsibility to use safe practices in application, installation, operation and maintenance. When using these Application Examples, you recognize that we cannot be made liable for any damage/claims beyond the liability clause described. We reserve the right to make changes to these Application Examples at any time without prior notice. If there are any deviations between the recommendations provided in this Application Example and other Siemens publications e.g. Catalogs the contents of the other documents shall have priority. We do not accept any liability for the information contained in this document. Any claims against us based on whatever legal reason resulting from the use of the examples, information, programs, engineering and performance data etc., described in this Application Example shall be excluded. Such an exclusion shall not apply in the case of mandatory liability, e.g. under the German Product Liability Act ( Produkthaftungsgesetz ), in case of intent, gross negligence, or injury of life, body or health, guarantee for the quality of a product, fraudulent concealment of a deficiency or breach of fundamental contractual obligations ( wesentliche Vertragspflichten ). The damages for a breach of a substantial contractual obligation are, however, limited to the foreseeable damage, typical for the type of contract, except in the event of intent or gross negligence or injury to life, body or health. The above provisions do not imply a change of the burden of proof to your detriment. Any form of duplication or distribution of these Application Examples or excerpts hereof is prohibited without the expressed consent of Siemens AG. Security information Siemens provides products and solutions with industrial security functions that support the secure operation of plants, solutions, machines, equipment and/or networks. They are important components in a holistic industrial security concept. With this in mind, Siemens products and solutions undergo continuous development. Siemens recommends strongly that you regularly check for product updates. For the secure operation of Siemens products and solutions, it is necessary to take suitable preventive action (e.g. cell protection concept) and integrate each component into a holistic, state-of-the-art industrial security concept. Third-party products that may be in use should also be considered. For more information about industrial security, visit To stay informed about product updates as they occur, sign up for a productspecific newsletter. For more information, visit Entry ID: , V1.0, 12/2015 2

3 Table of Contents Table of Contents Warranty and Liability Task and Solution Task Possible solution Characteristics of the solution Configuration and Project Engineering Setting up the environment Required components and IP address overview SOFTNET Security Client DSL access for SCALANCE S SCALANCE M Setting up the infrastructure Setting up VPN communication Integrating the VPN endpoint SCALANCE M Integrating the VPN endpoint SOFTNET Security Client Configuring the VPN tunnel Transferring the configuration data VPN configuration in the SCALANCE M Establishing the VPN connection Testing the Tunnel Function History Entry ID: , V1.0, 12/2015 3

4 1 Task and Solution 1 Task and Solution 1.1 Task The task is to allow a service employee secure access to automation cells or PCs via the Internet or a company s internal network. The following customer requirements have to be considered: Protection against spying and data manipulation. Prevention of unauthorized access. Provision of secure remote access for remote maintenance and remote control. Flexible access for the service employee (regardless of the user s location). 1.2 Possible solution Complete overview The figure below shows one way of implementing these customer requirements: Service PC with SOFTNET Security Client VPN Tunnel SSC VPN Client Industrial Ethernet Internet Modem/Router Internet Router Static WAN IP Address SCALANCE M-800 VPN Server Automation Cell SIMATIC S7 Stations Remote access of a service employee to the automation cell (nodes such as SIMATIC stations, panels, drives, PCs) is protected by a VPN tunnel. Client access from the PC to the automation cell is established using the SOFTNET Security Client, a VPN client software product. A SCALANCE M-800 (here: VPN server) placed in front of the automation cell is used as the endpoint of the VPN tunnel. WAN access to the SCALANCE M-800 is implemented using a static public IP address. WAN access on the client side is flexible; the IP address of the WAN port is not relevant. When establishing the VPN tunnel, the roles are defined as follows: Table 1-1 Component SOFTNET Security Client SCALANCE M-800 VPN role Initiator (VPN client); starts the VPN connection Responder (VPN server); waits for the VPN connection Entry ID: , V1.0, 12/2015 4

5 1 Task and Solution SOFTNET Security Client The SOFTNET Security Client allows programming devices, PCs and notebook computers access to network nodes or automation systems protected by SCALANCE S, SCALANCE M or CPs. It is characterized by the following features: Secure access of programming devices or notebook computers to entire automation cells via IPSec VPN. Easy to use on PCs due to an intuitive graphical user interface. configuration import. Connection control and management, connection statistics, log files; trace tool for error diagnostics; icons to indicate the connection status. Protection of data transmission against spying and spoofing by means of certified standards. Supports the DNS client function. SCALANCE M-800 The security modules of the SCALANCE M-800 family are designed specifically for use in automation but integrate seamlessly with the security structures of the office and IT world. They provide the following functions: High-quality stateful inspection firewall with filtering of IP-based data traffic. Router functionality. IPSec VPN (data encryption and authentication). Initiation of OpenVPN tunnels for connection to SINEMA Remote Connect. Protection of all devices of an Ethernet network. Flexible, reaction-free and protocol-independent protection. Support of multiple VPN tunnels at a time. Products of the SCALANCE M-800 family: SCALANCE M874/ M876 (3G/4G router) SCALANCE M812/ M816 (ADSL router) SCALANCE M826 (SHDSL router) SCALANCE S615 (LAN router) The basic/security configuration is almost the same for all these products. Only the configuration for the connection to the WAN differs. Note This configuration example uses the SCALANCE S615 as the security module. If you are using a different module, please consult the appropriate manual for the WAN port configuration. Entry ID: , V1.0, 12/2015 5

6 1 Task and Solution 1.3 Characteristics of the solution VPN tunnel for flexible access to the automation cell possible, for example, for a service employee. Controlled, encrypted data traffic between SCALANCE M-800 and SOFTNET Security Client. High degree of security for machines and plants through the implementation of the cell protection concept. Integrated network diagnostics via SNMP or Syslog. Easy integration into existing networks and protection of devices that do not have their own security functions. Entry ID: , V1.0, 12/2015 6

7 2 Configuration and Project Engineering 2.1 Setting up the environment Required components and IP address overview Software packages This solution requires the following software packages: Security Configuration Tool V4.1 (included in the scope of delivery of the SCALANCE S or available as a download under the following entry ID: ) SOFTNET Security Client V5 Install this software on a PC/PG. Required devices/components: Note To set up the environment, use the following components: A SCALANCE S615 (optional: a DIN rail installed accordingly, including fitting accessories). DSL access with a dynamic WAN IP address and a DSL router. DSL access with a static WAN IP address and a DSL router. A 24V power supply with cable connector and terminal block plug. PC on which the Security Configuration Tool and the SOFTNET Security Client are installed. The necessary network cables, TP cables (twisted pair) according to the IE FC RJ45 standard for Industrial Ethernet. You can also use a different SCALANCE M-800 type or Internet access method (e.g., UMTS). The configuration described below refers explicitly to the components listed in Required devices/components. Entry ID: , V1.0, 12/2015 7

8 IP addresses For this example, the IP addresses are assigned as follows: DSL Router1 DSL Router2 M-800 (here: S615) SSC Dynamic WAN IP Static WAN IP Table 2-1 Component Port IP address Router Subnet mask SSC (SOFTNET Security Client) DSL router1 LAN port DSL router1 WAN port Dynamic IP address from provider DSL router2 WAN port Static IP address from provider - Assigned by provider - Assigned by provider DSL router2 LAN port SCALANCE M-800 (here: S615) SCALANCE M-800 (here: S615) WAN port LAN port Entry ID: , V1.0, 12/2015 8

9 2.1.2 SOFTNET Security Client Network The subnet on the local network adapter of the SOFTNET Security Client and the internal subnet on the SCALANCE M must be different. If the PC has multiple network adapters, please note the following: A default gateway must only be entered for a single network adapter. If necessary, remove any other default gateways or replace them with static routes. The other connected networks on the PC where the SOFTNET Security Client is installed and the internal network of the VPN remote end must be different. Even if no cable is plugged in, the routing function is impaired. Change the subnet of the other network adapter or disable it completely. VPN software VPN software from third-party manufacturers may cause incompatibilities and prevent the SOFTNET Security Client from functioning properly. Uninstall this software if disabling is not sufficient. Firewall Time When the SOFTNET Security Client is run on the Windows Vista or Windows 7 operating system, establishing a VPN connection requires that the Windows firewall be enabled. Make sure that the current date and time are always set on the SOFTNET Security Client PC. Otherwise, the certificates used are interpreted as invalid and secure VPN communication is not possible. Entry ID: , V1.0, 12/2015 9

10 2.1.3 DSL access for SCALANCE S615 Static IP address When using the SCALANCE S615, WAN access of the SOFTNET Security Client to the SCALANCE M-800 is implemented using a fixed public IP address. This IP address must be requested from the provider and then stored in DSL router2. Port forwarding on DSL router2 VPN function Due to the use of a DSL router as an Internet gateway, you have to enable the following ports on DSL router2 and forward the data packets to the S612 (WAN port): UDP port 500 (ISAKMP) UDP port 4500 (NAT-T) If your DSL router2 itself is VPN-capable, make sure that this function is disabled. Entry ID: , V1.0, 12/

11 2.1.4 SCALANCE M-800 Factory default To make sure that no old configurations and certificates are stored in the SCALANCE M-800, reset the modules to factory default. Press the SET button for approx. 10 seconds to reset the device to factory default; it can now be accessed via IP address Requirements for Web Based Management The SCALANCE M features an integrated HTTP server for Web Based Management (WBM). In order to use this function without any restrictions, please note the following: Access via HTTPS is enabled. JavaScript is enabled in the Web browser. When the firewall is enabled, TCP port 443 must be enabled for access via HTTPS. Physical connection between PC and SCALANCE M Connect the PC to a LAN port of the SCALANCE M. Use a Web browser to open the Web user interface of the SCALANCE M. When the SCALANCE M is set to factory default, the IP address of the internal interface of the module is In this case, change the network settings on the PC as follows: IP address: Subnet mask: Use address to open Web Based Management. Entry ID: , V1.0, 12/

12 Web Based Management login When you log in for the first time or after setting to factory default, the login data is defined as follows: Name: admin Password: admin 1. Enter the name and password in the appropriate text boxes. 2. Click the Login button or confirm your entries with Enter. 3. When you log in for the first time or after setting to factory default, you are prompted to change the password. Entry ID: , V1.0, 12/

13 4. Enter the old and new password. 5. Click the Set Values button to complete the operation and activate the new password. 6. After successful login, the start page appears. Entry ID: , V1.0, 12/

14 Changing the IP address Note The interfaces in the SCALANCE S615 are handled differently so that the IP configuration differs from the other modules of the SCALANCE M-800 type. The following assignment applies to the SCALANCE S615: Ethernet interface P1 (vlan1): connection to LAN Ethernet interface P5 (vlan 2): connection to WAN For the other SCALANCE M-800 modules, you can use System > Agent IP to change the IP address. To change the IP address of the internal interface of the SCALANCE S615, proceed as follows: 1. In the navigation bar, navigate to Layer 3 > Subnets. This page displays the subnets for the selected interface. A subnet always relates to an interface and is created in the Configuration tab. Go to the Configuration tab. 2. In Interface (Name), select vlan2 (EXT). Uncheck DHCP and change the IP address as shown in Table 2-1. Click the Set Values button. Entry ID: , V1.0, 12/

15 3. In Interface (Name), select vlan1 (INT) and change the IP address as shown in Table 2-1. Click the Set Values button. The Web page refreshes. 4. Change the network settings on the PC as follows: IP address: Subnet mask: Result The IP subnets have been created and are displayed in the Overview tab. Defining routes As a public network is between the station and the control center and the IP subnets differ, you have to create an appropriate route. 1. In the navigation pane, click Layer 3 > Routes and configure the route to the router with the following settings: Destination Network: (all IP addresses) Subnet Mask: Gateway: LAN IP address of the router connected to WAN port Select Create to apply the parameters. Result A new entry has been created in the table. Entry ID: , V1.0, 12/

16 Setting the time To establish secure communication, it is essential that the current date and time are always set on the SCALANCE M. Otherwise, the certificates used are interpreted as invalid and secure VPN communication is not possible. 1. In the navigation bar, navigate to System > System Time. 2. Click the Use PC Time button to apply the time setting of the PC. 3. Click the Set Values button. Result The date and time are applied and Manual is entered in the Last Synchronization Mechanism field. Note When manually setting the time, please note that the time is reset to factory default when the power supply is interrupted. When the power supply has been restored, you have to set the system time once again. Due to this, certificates may lose their validity. Note You also have the option to have the system time automatically synchronized with a time server. A number of time servers from which the exact current time can be retrieved can be found on the Internet. Synchronizing the system time using a public time server causes additional traffic on the connection. Entry ID: , V1.0, 12/

17 2.1.5 Setting up the infrastructure Connect all the components involved in this solution. DSL Router 1 DSL Router 2 M-800 (here: S615) SSC LAN Port LAN Port WAN Port WAN Port LAN Port WAN Port LAN Port Table 2-2 Component Local port Partner Partner port SOFTNET Security Client LAN port DSL router1 LAN port SCALANCE M-800 (here: S615) WAN port DSL router2 LAN port SCALANCE M-800 (here: S615) LAN port e.g., an automation network (does not exist in this solution) Note In all devices in the internal network of the SCALANCE M-800 (e.g., controllers, panels, etc.), please make sure to enter the IP address of the internal port as the default gateway. 2.2 Setting up VPN communication SCT project Component overview The VPN tunnel is configured using the Security Configuration Tool V4.1. Open the tool and select Project > New to create a new project. Define a user name and password. This solution uses the following security components: SCALANCE M-800 SOFTNET Security Client V5 Entry ID: , V1.0, 12/

18 2.2.1 Integrating the VPN endpoint SCALANCE M-800 To integrate the SCALANCE M-800 component into the Security Configuration Tool, proceed as follows: 1. Use Insert > Module or select the appropriate menu icon to open the module selection dialog. Note: If you have created a new project, this dialog opens automatically. Define the following module: Product type: SCALANCE M Module: SCALANCE M Assign a name to the module. Enter the external and internal IP address and the subnet mask as shown in Table 2-1. Click OK to close the dialog. Result Now the SCALANCE M-800 appears as a new module. Entry ID: , V1.0, 12/

19 2.2.2 Integrating the VPN endpoint SOFTNET Security Client To integrate the SOFTNET Security Client component into the Security Configuration Tool, proceed as follows: 3. Use Insert > Module or select the appropriate menu icon to open the module selection dialog. Define the following module: Product type: SOFTNET configuration Module: SOFTNET Security Client Firmware release:v4 4. Assign a name to the module. Click OK to close the dialog. Result Now the SSC appears as an additional module. Entry ID: , V1.0, 12/

20 2.2.3 Configuring the VPN tunnel Creating a VPN group All members of a VPN group are authorized to communicate with each other through a VPN tunnel. To create a VPN group, proceed as follows: 1. In the project tree, select the VPN groups item. Use Insert > Group or select the appropriate menu icon to create a new VPN group. 2. One after the other, select the SCALANCE M-800 and the SOFTNET Security Client from the All modules list and use drag and drop to insert them into the VPN group. Result The SCALANCE M-800 and the SOFTNET Security Client have been assigned to VPN group Group1. Certificates are used for authentication. Entry ID: , V1.0, 12/

21 Defining the VPN parameters To establish the VPN tunnel, you have to enter the following information: WAN IP address of DSL router2 VPN role Parameterize this information as follows: 1. In the All modules project tree, select the SCALANCE M-800 and double-click to open its properties dialog. 2. In the VPN tab, select the Responder VPN role for the product. In the WAN IP address / FQDN field, enter the WAN IP address of your DSL access point. 3. Click OK to close the dialog. 4. Click OK to confirm the message. 5. Save the project. Result The VPN configuration is complete. Entry ID: , V1.0, 12/

22 2.2.4 Transferring the configuration data The Security Configuration Tool creates one configuration guide per security module and exports the required data to a specified location. To transfer the configuration data of the two nodes, proceed as follows: 6. In the All modules project tree, select the SCALANCE M-800 ( S615 ) and select the Transfer > To module(s) menu command. 7. Save the <Project name>.s615.txt configuration guide and the certificates to your project directory. 8. Enter a password for the.p12 certificate. If you do not assign a password, the project name (not the password of the logged in user) is applied as the password. 9. Repeat the steps for the SSC module. 10. Close the Security Configuration Tool. Result The following files are saved to the project directory: For the SCALANCE M-800 For the SOFNET Security Client Entry ID: , V1.0, 12/

23 2.3 VPN configuration in the SCALANCE M-800 Use the Web user interface of the SCALANCE M to configure it with the aid of the saved <Project name>.s615.txt configuration guide. Configuration guide for the VPN server The configuration guide (here: <Project name>.s615.txt ) navigates you to the items in Web Based Management and shows the settings required in WBM: Entry ID: , V1.0, 12/

24 The configuration includes the following steps shown below: Table 2-3 No. Configuration step 1. Enter the certificate password. 2. Load the certificates to the SCALANCE M. 3. Define the VPN remote end. 4. Create the connection. 5. Define the authentication method for the connection. 6. Define the VPN parameters for Phase Define the VPN parameters for Phase Define the VPN role. 9. Enable the VPN function. Physical connection between PC and SCALANCE M Use the PC to connect to the Web user interface of the SCALANCE M (address: Make sure that the PC and the SCALANCE M are in the same IP network. After successful login, the start page appears. Entry ID: , V1.0, 12/

25 Managing the certificate password There are files whose access is password-protected. When saving the configuration files of the SCALANCE M from the Security Configuration Tool, you were prompted to assign a password for the private key of the certificate or use the project name as the password. To successfully download the file to the SCALANCE M, enter the password defined for the file on the WBM page. 1. In the navigation bar, navigate to System > Load&Save > Passwords. 2. In the Password text box, enter the password. In Password Confirmation, reenter the password to confirm it. Check the Enabled option. 3. Click the Set Values button. Result The password for the private key of the certificate has been defined. Entry ID: , V1.0, 12/

26 Loading the certificates The certificates are required to authenticate the VPN user and therefore to establish a secure VPN connection. Load the two required certificates to the SCALANCE M as described in the following section: 1. In the navigation bar, navigate to System > Load&Save > HTTP. 2. In X509Cert, click the Load button to start loading. 3. The dialog for loading a file opens. Navigate to your project directory with the configuration files of the SCALANCE M. 4. Select a certificate. For the exact certificate name, please refer to your configuration guide. 5. In the dialog, click the Open button. The file is loaded. 6. Repeat steps 2 through 5 with the second certificate. Result The required certificates have been loaded to the SCALANCE M. Entry ID: , V1.0, 12/

27 Defining the VPN remote end The VPN tunnel is always established to one or more users. In this example, the only endpoint is the SOFTNET Security Client. Configure the remote end as follows: 1. In the navigation bar, navigate to Security > IPSec VPN > Remote End. 2. In the Remote End Name text box, enter a name for the VPN remote end (e.g., Service). Click Create to create a new remote end. 3. Set the parameters for the VPN remote end as follows: Remote Mode: Roadwarrior Remote Type: any Remote Address: /0 4. Click the Set Values button. Result The access address of the remote end and the subnet reachable through the tunnel have been made known to the SCALANCE M. Entry ID: , V1.0, 12/

28 Creating the VPN connection In this section, you configure the basic settings for the VPN connection. Then you define the security settings. 1. In the navigation bar, navigate to Security > IPSec VPN > Connections. 2. In Connection Name, enter a name for the VPN connection. Click Create to create a new entry. 3. Set the parameters for the VPN connection as described in your configuration guide: Keying Protocol: IKEv1 Remote End: Name of the VPN remote end (here: Service) Local Subnet: /24 4. Click the Set Values button. Result A VPN connection has been created, the remote end for this connection has been selected and the subnet allowed to communicate with the remote end has been defined. Entry ID: , V1.0, 12/

29 Defining the authentication method For secure communication via VPN, all VPN partners must authenticate each other. This example uses the certificate of the remote end as the authentication method. Note For the exact names of your certificates, please refer to your configuration guide. 1. In the navigation bar, navigate to Security > IPSec VPN > Authentication. 2. Configure authentication with the settings described in your configuration guide: Authentication: Remote Cert Local Certificate: <see configuration guide> Remote Certificate: <see configuration guide> 3. Click the Set Values button. Result The SCALANCE M can authenticate for the shared VPN tunnel with the loaded certificates and accept the remote end as the VPN partner. Entry ID: , V1.0, 12/

30 Defining Phase 1 Phase 1 of authentication involves the encryption agreement and authentication between the VPN users via the standardized IKE (Internet Key Exchange) protocol. For IPSec key management, you have to enter defined protocol parameters. 1. In the navigation bar, navigate to Security > IPSec VPN > Phase Set the protocol parameters as described in your configuration guide: Encryption: 3DES Authentication: SHA1 Key Derivation: Group 2 Keying Tries: 0 Lifetime [min]: DPD: yes DPD Delay [sec]: default DPD Timeout [sec]: default Aggressive Mode: No 3. Click the Set Values button. Entry ID: , V1.0, 12/

31 Defining Phase 2 Phase 2 is data exchange via the standardized ESP (Encapsulating Security Payload) security protocol. For IPSec data exchange, you have to enter defined protocol parameters. 1. In the navigation bar, navigate to Security > IPSec VPN > Phase Set the protocol parameters as described in your configuration guide: Encryption: 3DES Authentication: SHA1 Key Derivation: Group 2 Lifetime [min]: 2880 Lifebytes: 0 3. Click the Set Values button. Result You have defined all the necessary parameters for the IKE and ESP protocols. Entry ID: , V1.0, 12/

32 Establishing the VPN connection The SCALANCE M is configured as the responder of the VPN tunnel and waits for the connection from the SOFTNET Security Client. 1. In the navigation bar, navigate to Security > IPSec VPN > Connections. 2. In the Operation column, change the mode to wait. 3. Click the Set Values button. Result The SCALANCE M is the responder of the VPN connection. Entry ID: , V1.0, 12/

33 Activating IPSec For the secure connection between the two nodes, a VPN tunnel is established with IPSec. 1. In the navigation bar, navigate to Security > IPSec VPN > General. 2. Check the Activate IPSec VPN check box to activate IPSec. 3. Click the Set Values button. Result IPSec is active and used for the VPN tunnel. Final steps 1. Connect the PC (SOFTNET Security Client) to the LAN interface of DSL router1. 2. Assign the required network configuration to the network card as shown in Table In all devices on the internal port of the SCALANCE M-800, enter a default gateway (IP address of the LAN port). Entry ID: , V1.0, 12/

34 2.4 Establishing the VPN connection To establish the VPN connection, proceed as follows: 1. Start the SOFTNET Security Client. To load the configuration file, click the Load Configuration button. 2. Navigate to your project folder and open the <Project name>.ssc.dat configuration file. 3. Activate the VPN tunnel for the internal nodes. Click Next. Entry ID: , V1.0, 12/

35 4. Make sure that the IP address of your WAN port is correct and click OK. 5. Enter the password for the private key of the certificate. Click Next. 6. The configuration is loaded and the tunnel to the SCALANCE M-800 is established. For more information on the tunnel status, click the Tunnel Overview button. Entry ID: , V1.0, 12/

36 Result The tunnel between the SCALANCE M-800 and the SOFTNET Security Client has been established. The green circle to the left of the S615 item signals that the remote end is accessible. Entry ID: , V1.0, 12/

37 3 Testing the Tunnel Function 3 Testing the Tunnel Function Chapter 2 completes the commissioning of the configuration and the SCALANCE M-800 and the SOFTNET Security Client have established a VPN tunnel for secure communication. You can test the established tunnel connection using a ping command on an internal node. This is described below. Alternatively, you can also use other methods to test the configuration (for example, by opening the internal Web page when using a SCALANCE X or CPU). 1. On the SOFTNET Security Client PC, select Start > All Programs > Accessories > Command Prompt in the start bar. 2. In the command line of the Command Prompt window that appears, enter the ping <IP address of internal node> command at the cursor position. Result You get a positive response from the internal node. Note In Windows, the default settings of the firewall may prevent ping commands from passing. You may have to enable the ICMP services of the Request and Response type. Note If the MTU size on the SOFTNET Security Client PC is larger than the MTU size in the SCALANCE M-800, it is possible that the VPN tunnel is established and displayed as such but that it prevents a related application (e.g., opening a Web page of a node in the remote network) from functioning. In this case, adjust the MTU size on you PG. An appropriate size is between 1000 and 1400 bytes. Entry ID: , V1.0, 12/

38 4 History 4 History Table 4-1 Version Date Modifications V1.0 12/2015 First version Entry ID: , V1.0, 12/