Perle Systems IOLINK-520 manual Iolink Router Feature Definitions, Telnet, Link Compression

Introduction

IOLINK Router Feature Definitions

Telnet

A Telnet LAN station or another IOLINK router has the ability to connect to the Operator Interface of any IOLINK router supporting the Telnet feature. With the Telnet feature, all IOLINK routers on a network may be managed from a single point.

Once a connection is established, all of the menus of the other bridge/router are now available on the bridge/router that initiated the connection. All menu operation on the initiating bridge/router is suspended during the connection. Entering a control-C character <^C> at any time during the connection will cause a disconnection, and you will be back to the menu of the first bridge/router.

To implement the Telnet feature, each bridge/router requires an IP address (see the Internet Set-Up Menu). It is advisable to assign an IP address to each IOLINK router in your network.

The IP address of another bridge/router may be assigned a name to simplify the connection process. Telnet connection to the other IOLINK Router may be established by entering either the name or the IP address of that router. Refer to the Remote Site Set-Up Menu (under Configuration / WAN Set-UP) for more information on adding names to the bridge/router.

If a bridge/router does not have an IP address, Telnet connections cannot be initiated or received.

If a Telnet connected bridge/router receives a second connection attempt from another bridge/router the connection attempt will be ignored.

Connecting to a bridge/router while the remote bridge/router menu system is operating with a different terminal setting may cause unexpected screen errors. Once the connection to the bridge/router has been established, it is recommended that the operator change the terminal setting to be the same as the initiating device.

When a Telnet connection is made to a bridge/router, ensure that the Telnet session is in character mode, and carriage return padding (or translation) is set to NULL (or no translation). The extra character sent when carriage return padding is on will cause some displays to behave erratically.

Link Compression

The IOLINK router’s optional compression feature multiplies the effective data throughput across wide area links operating at speeds from 9600 bps through to 256 Kbps. The exact amount a given transmission can be compressed is dependent upon the type of data being transferred over the wide area network. As an example, because of their repetitive make-up, most graphics and database files can easily be compressed by a ratio of 6:1. In contrast, other types of files (such as binary files), that are not as repetitive, typically yield a compression ratio of 2:1. It should also be noted that compression ratios are entirely dependent upon the make-up of the specific file — while it may be possible to compress a given ASCII file far beyond the 6:1 ratio, a different ASCII file may only compress to a ratio of 4:1 or lower.

At link speeds above 256 Kbps, link compression is not advised as the processing time involved in compressing the data does not yield significant gains over the transmission of raw data.

1.16— IOLINK-PRO & 520 Reference Manual