Technical Manual

Preliminary Release

MAC table are forwarded. The remote radio can also be configured for RTU filtering. This causes

the remote radio to forward only packets back over the RF link when they are sourced by an

authorized source RTU MAC address. This also greatly reduces the probability of system

flooding.

The combined RTU and Host screening mode provides the greatest amount of filtering. Only

authorized traffic has access to the radio address with both source and destination MAC

address complying with the system definition. This makes system flooding nearly impossible to

occur.

6.2.2 Telnet Radio Configuration and Diagnostics

The primary mission of the 2788 is to provide robust RF linkage with total protocol

transparency; however, a Telnet server for local and remote radio configuration is provided in

each 2788. Thus, each 2788 is factory-assigned a unique Alligator MAC address for IP access

using the Telnet protocol. The user is able to program the IP address, gateway address, subnet

mask, and Telnet port address. This gives the radio visibility to the host and/or a separate client

host for radio configuration and diagnostics. Users of RS-232 interfaces also use the Ethernet

interface with a Telnet client program. The Telnet communications over the RF link shares the

bandwidth of the system transparently.

6.2.3 Graphics Heavy Communications

The use of communications carrying a large amount of graphics data is discouraged. Please be

aware that at 9600 bps, the transmission rate is only about 1K bytes per second. Sending large

graphics files can take tens of seconds. This can be done concurrently with the normal polling

traffic along with Telnet diagnostic traffic, but at the cost of system time latency. Nothing

prohibits doing large file transfers, but be aware of the time required to push the data through

a 9600 bps link. IP addresses associated with this type of traffic should not be placed in the QIP

table (see 6.2.4).

6.2.4 High QOS (Quality Of Service) IP Communications

IP packets can be assigned high QOS status. This is performed by storing the IP address in a QIP

table. These tables reside in both the master and remote radios. Up to 16 IP addresses can be

saved in the QIP table. This table normally contains the IP addresses of hosts that are polling

remote RTUs and require low timer latency. RS-232 packets are assigned high QOS by default.