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Joel King is technical leader for IP video surveillance at Cisco. He kicks off our series with a look at IP addressing basics.

"Networking for Video Surveillance" presents core concepts systems integrators need to know before deploying IP video systems on a network.

[Editor's Note: This series of articles will examine basic concepts that systems integrators need to comprehend when deploying video systems over a network. Articles will appear monthly on the CCTV and Integrators sections of SecurityInfoWatch.com and under the "columns" listing of IPSecurityWatch.com.]

Overview
IP addressing is one of the first topics people learning the Internet Protocol (IP) must comprehend and will need to use when deploying IP video surveillance cameras on a LAN switch. Because most IP surveillance cameras have an underlying IP stack based on a Linux implementation, they require an IP address just like a laptop PC or server on the network. IP surveillance cameras typically only have a single Ethernet interface; unlike routers which have multiple interfaces on different IP networks.

IP addressing (IPv4/IPv6)
IP addressing is a general term for assigning a unique address to the network layer (Layer 3 of the OSI model) of the IP camera. IP addresses can be either IP Version 4 or Version 6. IP Version 6, or IPv6, will gradually replace IPv4 networks and many vendors already support IPv6 in their cameras. However, most enterprise networks continue to use IPv4 and will for some time. Before considering IPv6, IPv4 addressing must be well understood. In this article, let's look at IPv4 addressing and unless noted, references to "IP addressing" refers to IPv4 addresses.

IP addresses are four-byte fields in the IP header. There are two IP address fields assigned, a source IP address and a destination address. The source address is where the packet originated and the destination address is where it is going. To transport a video feed across the network for recording, an IP camera places its IP address in the source address field and the IP address of the server or network digital video recorder (NDVR, a.k.a. NVR) is in the destination field.

Displayed below is a screenshot of a packet capture of a media stream from a high-definition IP camera to the server.  This capture was made by using a program called Wireshark.Click on the image to view it in a readable, full-size window.

In this capture the source IP address is 192.0.2.144 and the destination IP address is 192.0.2.137. This H.264 stream is encapsulated in UDP/RTP; User Datagram Protocol/Real-time Transport Protocol.