Network Security Devices

This AD diagram example was redesigned from the picture "Site links" from the book "Active Directory for Dummies".
"Site links represent the Active Directory replication paths between sites.
These paths are manually defined so that the designer has control over which network links the replication traffic occurs on. These site links also control how clients are directed to domain controllers when there’s no DC in the client’s local site. Each site link has the following attributes:
(1) Connected sites: A site link is defined by the sites to which it connects. A site link can connect two or more sites together.
(2) Network transport: Site links support replication communication over IP-based RPCs or with the Simple Mail Transport Protocol (SMTP). You normally want to use RPC whenever possible, but you can use SMTP when the sites you’re linking don’t support RPC.
(3) Cost: Each site link has a cost associated with it. Costs are used to assign preferences to links that determine which link should be followed when multiple link paths are available between sites. The cost represents what it “costs” to use this site link relative to the other site links and affects replication traffic as well as how users are assigned a domain controller. Links with lower cost values have preference over links with higher cost values. Cost values range from 1–32,767; the default being 100.
(4) Frequency: The frequency value defines how often a replication occurs
when using this site link (the replication latency). You can configure the time between replications from a minimum of 15 minutes to a maximum of 10,080 minutes (one week). The default frequency is 180 minutes.
(5) Schedule: The schedule dictates when this link is active and available for replication between the sites. The schedule can also control which days of the week the link is available. Normally, the schedule is set so that the link is available 24 hours a day, but you can set up different schedules on a per-day-of-the-week basis.
By creating a site link, you enable two or more sites to be connected and to share the same site link attributes (transport, cost, frequency, and schedule). By default, site links create transitive connectivity between sites.
If you create a site link between sites A and B and another site link between
sites B and C, an automatic connection (known as a site link bridge) is created between sites A and C..." [Steve Clines and Marcia Loughry, Active Directory® For Dummies®, 2nd Edition. 2008]
The Active Directory diagram example "Site links" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Active Directory Diagrams solution from the Computer and Networks area of ConceptDraw Solution Park.

This computer security diagram example was designed on the base of the Wikimedia Commons file: Firewall.png.
[commons.wikimedia.org/ wiki/ File:Firewall.png]
This file is licensed under the Creative Commons Attribution-Share Alike 3.0 Unported license. [creativecommons.org/ licenses/ by-sa/ 3.0/ deed.en]
"In computing, a firewall is a network security system that monitors and controls the incoming and outgoing network traffic based on predetermined security rules. A firewall typically establishes a barrier between a trusted, secure internal network and another outside network, such as the Internet, that is assumed to not be secure or trusted. Firewalls are often categorized as either network firewalls or host-based firewalls. Network firewalls are a software appliance running on general purpose hardware or hardware-based firewall computer appliances that filter traffic between two or more networks. Host-based firewalls provide a layer of software on one host that controls network traffic in and out of that single machine. Firewall appliances may also offer other functionality to the internal network they protect such as acting as a DHCP or VPN server for that network." [Firewall (computing). Wikipedia]
The cybersecurity diagram example "Firewall between LAN and WAN" was created using the ConceprDraw PRO software extended with the Network Security Diagrams solution from the Computer and Neworks area of ConceptDraw Solution Park.

This vehicular network diagram example was drawn on the base of picture illustrating the post "LED Traffic Signals and Vehicle Lights for Optical Broadband Communications" from the blog "Terranautix".
"Visible Light Communication (VLC) is a rapidly emerging field that focuses on the use of light sources (between 400 THz and 800 THz) for the primary purpose of broadband communications. In order to transmit data over light, the light source (transceiver) is pulsed on and off rapidly to create a data stream, similar to fiber optic communications, but in the wireless form, or “Free-Space Optical Transmission“. By pulsing lights many thousands (and millions) of times per second, data transmission occurs at a rate undetectable by the human eye. Optical receivers convert the light pulses to an electronic signal on the receiver end. The Light Emitting Diode (LED) is the primary form factor currently undergoing extensive research."
[terranautix.com/ tag/ communications]
The vehicular network diagram example "Visible light communication" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Vehicular Networking solution from the Computer and Networks area of ConceptDraw Solution Park.

This vehicular network diagram example was drawn on the base of the picture "Inter-Vehicle Communication (IVC) systems" from the website of the Department of Electrical and Computer Engineering, the Ohio State University.
[www2.ece.ohio-state.edu/ ~ekici/ res_ ivc.html]
"Driver assistance systems are meant to support drivers with driving process in order to avoid traffic accidents, speed up the traffic and have a higher control over the traffic in general. There are a lot of systems which give support to the drivers, such as adaptive cruise control, traffic sign recognition, automatic parking, etc. ... the vehicular communication systems ... use the capacity of the vehicles to communicate, not only between them but also with infrastructures. All the information is collected and processed to offer use
ful services. Wireless Sensor Networks (WSN) are widely used in this area. With the incoming upgrades of these networks, they are becoming an attractive solution to give support with the communication mechanisms between vehicles." [mi.fu-berlin.de/ inf/ groups/ ag-tech/ teaching/ 2011_ SS/ S_ 19510b_ Proseminar_ Technische_ Informatik/ daniel-lopez-report.pdf?1346662267]
The vehicular network diagram example "Inter-vehicle communication systems" was created using the ConceptDraw PRO diagramming and vector drawing software extended with the Vehicular Networking solution from the Computer and Networks area of ConceptDraw Solution Park.