Connectionless<\/h2>\n\n\n\n
Communications\nbetween the Client and Server are connectionless. This means that the device\nwill continue to display the last session screen until the user provides input\nor the server sends new display information. The Client and Server will not\ncommunicate if there are no transactions for a period of time. This is\naccomplished by operating under the UDP network protocol, with reliability\nadded by the StayLinked Client2Host Protocol. <\/p>\n\n\n\n
After the handshake with the server completes, devices will show the emulation screen presented by the telnet host. The client and server will confirm that they are synchronized after each transaction. As the user provides input, the client will queue these transactions in order and deliver them to the server as fast as the network allows. The client then clears them from the queue once the server has acknowledged receipt of that transaction.<\/p>\n\n\n\n
Radio Power Management<\/h3>\n\n\n\n
Some devices have the option for aggressive radio power management. These PSP and Fast PSP power management protocols can have a direct impact on network performance, especially for small, fast packets like those used by StayLinked. We typically recommend that the device power management settings are used to conserve battery, and not the radio power management features. The device isn\u2019t very useful without the radio, so you might as well suspend the whole device if you want to save power. We have seen great success in reducing network interruptions by setting the radio to CAM mode in the radio profile power save options.<\/p>\n\n\n\n
Quality of Service (QoS)<\/h3>\n\n\n\n
StayLinked clients communicate with the StayLinked server using the UDP network protocol. StayLinked enhances the transactions for reliable delivery. Many network appliances can offer packet prioritization based on the protocols in use. Since UDP is commonly used in streaming media, it can sometimes be the target of these QoS features. Allowing QoS to downgrade or restrict UDP packets used by StayLinked can negatively impact performance and result in a poor user experience. Be sure to disable these QoS services or configure exceptions for your StayLinked transactions for the best performance.<\/p>\n\n\n\n
Asterisk vs. Exclamation<\/h2>\n\n\n\n
Most\ninterruptions in communication should be invisible to the user. These\ninterruptions will occur and resolve between inactivity or within a fast enough\ntime frame that the users are none the wiser. If the interruption persists for\ntwo seconds, a character will appear in the upper right corner of the display.\nThis character is a precursor to the one of the messages below.<\/p>\n\n\n\n
The\nAsterisk is a prelude to the [Linking] screen. This means that there has not\nbeen a successful synchronization between the client and server for at least four\nseconds. If the state persists, the screen is replaced with [Linking] after a\ntotal of 10 seconds.<\/p>\n\n\n\n
The Exclamation mark is a precursor to the [Out of Range] screen. This means that the device operating system is currently reporting that it is not associated to an access point for at least one second. If this state persists, it will be replaced with the [Out of Range] screen after a total of five seconds.<\/p>\n\n\n\n
Linking<\/h2>\n\n\n\n
During the [Linking] screen, the retry counter represents each attempt to synchronize with the server. These requests are two seconds apart, and will continue until the Client and Server are able to successfully synchronize. <\/p>\n\n\n\n
![\"\"](\"https:\/\/portal.staylinked.com\/sl\/kb\/wp-content\/uploads\/2019\/10\/Session-SpecificLogFile_1.1.jpg\")
<\/figure><\/div>\n\n\n\nDevices operating behind a connection using a Network Address Translation (NAT) may display this screen when the NAT entry times out on the network appliance that is performing the NAT. This would affect devices that use a gateway, proxy, or shared network interface similar to what many home networks use for internet access. This message would never recover, requiring the user to press escape and reconnect with a standard handshake. Enabling the Server setting for \u2018Support for Client Dynamic NAT\u2019 will usually resolve this issue. <\/p>\n\n\n\n
Out of Range<\/h2>\n\n\n\n
This message will appear three seconds after the exclamation. If it persists, you can use the StayLinked client\u2019s \u2018radio stats\u2019 option to view the MAC address of the access point reported by the radio. <\/p>\n\n\n\n
![\"\"](\"https:\/\/portal.staylinked.com\/sl\/kb\/wp-content\/uploads\/2019\/10\/Session-SpecificLogFile_1.2.jpg\")
<\/figure><\/div>\n\n\n\nIf this appears on a new device, it could mean that the client installed does not match the hardware, making it unable to properly request the association status. This may also appear if the hardware manufacturer makes changes to the radio hardware during the lifecycle of the device. Devices can be configured to ignore the association status using the client setting always_in_range=1. This setting is best applied using the Scan2Command profile options in the Administrator. <\/p>\n\n\n\n
Log File Records<\/h2>\n\n\n\n
We\ncan break these interruptions into two possible situations. The first is that\nthe server is not receiving transactions from the device and the second is that\nthe server is receiving the transactions, but the replies are not making it\nback to the device. There are a multitude of reasons that packets may not reach\nthe server, but the second scenario is different because you know the device is\nassociated and authenticated with an access point, has a valid network address\nand can probably communicate with other systems on your network. In either\ncase, the ping and tracert commands can be important tools in detecting network\nconnectivity. We typically recommend that these tests are completed from the StayLinked\nServer to the device, in order to confirm routing and other network variables\nfor the StayLinked Server operating system.<\/p>\n\n\n\n
The\nfollowing are sample events recorded in the staylink.log file from a client\ndevice.<\/p>\n\n\n\n
In this event, the client is connecting to the server and logging the server IP and port for this connection:<\/p>\n\n\n\n
In this event, the client is reporting the Exclamation and then [Out of Range], including a confirmation from the device operating system that the MAC of the access point is blank:<\/p>\n\n\n\n In this event, the client is reporting two interruptions, the first displays the [Linking] screen very briefly at the oos_max entry and then another interruption shortly thereafter. These current logs also show a ping of the gateway and server, confirming partial network connectivity:<\/p>\n\n\n\n In this event, the client is reporting an interruption that displays [Linking] in which the user presses the escape key to cancel the retry attempts:<\/p>\n\n\n\n From the Server perspective, the server will not be aware of packets that do not make it from the device. Once the device is displaying the exclamation or asterisk, these synchronization requests will be recorded in the StayLinkedManager log file as a query session status. The date and time are removed from this example for formatting.<\/p>\n\n\n\n \n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\nAll log files are best reviewed with the\nassistance of StayLinked Support.\n\n\n\n<\/p>\n","protected":false},"excerpt":{"rendered":" The StayLinked Server is the key component in the StayLinked Host-based Telnet solution. As a telnet client, the StayLinked Server performs all transactions between itself and the telnet server. It also communicates input (keys, scans and touchscreen) and output (screen updates) to the remote device. StayLinked is designed to provide…<\/p>\n","protected":false},"author":7,"comment_status":"open","ping_status":"closed","template":"","format":"standard","meta":[],"ht-kb-category":[59],"ht-kb-tag":[],"yoast_head":"\n 140401-215131.340:[i] reg_ip=10.162.21.10, reg_port=20050<\/code><\/p>\n\n\n\n100321-011635.599:[i] <- oor_beg
100321-011636.614:[i] <- oor_max - AP=[00:00:00:00:00:00]
100321-011639.979:[i] <- oor_end<\/code><\/p>\n\n\n\n140401-131508.548:[i] <- oos_beg
140401-131510.855:[i] gateway ping: reply from 10.133.1.1: time=3ms
140401-131510.889:[i] server ping: reply from 10.162.21.10: time=31ms
140401-131518.904:[i] <- oos_max - AP=[00:08:A2:01:64:00]
140401-131519.893:[i] <- oos_end
140401-131526.736:[i] <- oos_beg
140401-131528.051:[i] gateway ping: reply from 10.133.1.1: time=2ms
140401-131528.087:[i] server ping: reply from 10.162.21.10: time=31ms
140401-131528.090:[i] <- oos_end<\/code><\/p>\n\n\n\n140130-152938.077:[i] <- oos_end
140130-155357.570:[i] <- oos_beg
140130-155404.035:[i] <- oos_max - AP=[54:78:1A:D1:70:10]
140130-155445.206:[i] <- oos_abt
140130-155445.383:[i] <- oos_end
140130-155445.383:[i] host disconnect, code=120<\/code><\/p>\n\n\n\nProcessing Query Session ID Request from 192.186.83.7: 'A8~05~263EC~'
Results of Query Session ID Request from 192.186.83.7 for 263EC is 'Y'<\/code><\/p>\n\n\n\n