Xpyda Network Specifications

General | Wireless networks | Power over Ethernet (PoE)

General

Before you embark on building your Xpyda network, ensure your existing or proposed network infrastructure meets the following criteria:

• the network uses or can use the following standards:
  • TCP/IP,
  • UDP,
  • ICMP PING,
  • HTTP,
  • FTP,
  • SMTP;
• the network has at least one Windows XP or equivalent server connected to it onto which will be installed the Xpyda Service (hereafter called the Xpyda Service Server);
• the Xpyda Service Server is on and available twenty-four hours in the day, every day;
• the Xpyda Service Server is physically and software protected from attack or intrusion and is controllable solely by the network administrator(s);
• the Xpyda Service Server has full power backup using a suitably rated UPS;
• the network is composed solely of category 5 cabling between the Xpydas and the Xpyda Service Server (see below regarding the use of wireless networks);
• the network uses either DHCP or fixed IP address ranges controlled by the network administrator(s);
• if external mail or related services (SMS text notification via mobile telephony or paging) is to be used, that the network is permanently connected to the Internet via a protected gateway;
• if remote viewing of the Xpyda network is required using a web browser, that the network's firewall provides the relevant permissions for doing this;
• if remote broadcasting of Xpyda Remote Monitor UDP alert packets is required, that the network's firewall provides the relevant permissions for doing this together with the firewall of all networks on which the receiving computers reside;
• the network has sufficient IP addresses available to ensure that each Xpyda is assigned its own IP address;
• where the network is extremely large, that the administrator(s) can assign IP address ranges for use by the Xpydas alongside the address ranges used by other equipment already present on the network.

Where using wireless communications over any part of the network, or where using PoE to power any IP equipment on your network, refer to the notes below.

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Wireless networks

Because the Xpyda Service is in constant communication with the Xpydas installed on the network using UDP broadcasting, it is very sensitive to very slow networks. This is not an issue on a hard wired network, but a wireless network which is much slower and which is more prone to variable data transfer speeds, can occasionally cause false alerts if the Xpyda network settings are not carefully regulated.

The whole issue is to do with the network's maximum return trip time (MAX RTT): the higher the MAX RTT value on a wireless network, the longer it takes to send a packet of data across the network, and therefore the greater the likelihood that the corresponding device will not respond (not acknowledge, NAK) within a reasonable period of time. The result: occassional false alerts because the Xpyda Service logs NAKs as alerts.

If the Xpyda administrator has set a low alert threshold for any particular device on the system, and there is a wireless link between the Xpyda Service Server and that device, and the MAX RTT is high, then false alerts will occur.

Solution: upgrade or replace the wireless link with a hard wired link or use wireless bridges which provide adjustable Quality of Service (QoS) to favour UDP traffic.

N.B. Alert broadcasts issued by the Xpyda Service to receiving computers using UDP broadcasts or NET Messenger, as well as the Xpyda HTTP Web Server interface, are all unaffected by the network transmission path, and will therefore work correctly and efficiently over hard wired and wireless connections alike.

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Power over Ethernet (PoE)

Equipment such as IP telephone handsets and IP cameras which are powered over an Cat. 5/RJ45 data network cable are all subject to the same restriction: the PoE device must be directly connected to the PoE switch powering the device.

No other network equipment can sit in line between the PoE switch and the device powered using PoE. Similarly, it is not possible to place two or more PoE devices in series on the same network connection.

Also, there is not a standard in place for a non-PoE device sharing the same network connection as the PoE device.

So wherever PoE is used, Xpydas must not be connected to the same network connection as a PoE device, but instead must be allocated their own separate network connections.

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