Browse Prior Art Database

Network Monitor

IP.com Disclosure Number: IPCOM000049680D
Original Publication Date: 1982-Jul-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 4 page(s) / 46K

Publishing Venue

IBM

Related People

Borysowich, LH: AUTHOR [+2]

Abstract

This network monitor performs the function of monitoring data y carried by communication lines connecting a CPU with numerous remote units. For purposes of clarity, only a single communication system will be discussed initially.

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Network Monitor

This network monitor performs the function of monitoring data y carried by communication lines connecting a CPU with numerous remote units. For purposes of clarity, only a single communication system will be discussed initially.

Referring to Fig. 1, it may be seen that the network monitor introduces a simple Y connection between the transmission unit and modem of a CPU. Every message traveling along the communication line to or from the CPU is monitored by a hardware register in the IBM Series/1 which performs the monitoring function. The monitor reads the line at the Y connection, recording for each message: 1. the direction of travel,

2. the length of the message (number of bytes),

3. the time of occurrence of each message

(time of occurrence of last character),

4. the time of poll acquiring data, and

5. the time of previous poll.

Referring to Fig. 2, a large number of communication lines may be monitored by the Series/1. Each Y connection with each data line feeds an associated input/output (I/O) adapter within the Series/1. When a data message is propagated through a Y connection, the I/O adapter to that Y connection raises an interrupt signal and places it on a common bus. The Series/1 using a select line polls the I/O adapters to find which are active for monitoring purposes. In the case of multiple I/O activation, the first one polled by the Series/1 is monitored until the end of its message.

Each line is monitored for a long period of time simultaneously with other communication lines.

In monitoring lines the CPU of the Series/1 monitor creates an event block of ten bytes for storage and future analysis of data sent by the I/O adapters. The composition of an event block is as follows: Byte 1 - Series/1 adapter/probe address.

Byte 2 - Series/1 TOD clock = 250 millisecond intervals.

Byte 3 - Series/1 TOD clock = 250 millisecond intervals.

Byte 4 - Series/1 TOD clock = 250 millisecond intervals.

Byte 5 - Address of the remote "PU".

Byte 6 - Address of the remote "LU".

Byte 7 - Length of message (inbound/outbound).

Byte 8 - Length of message (inbound/outbound).

Byte 9 - Flag (inbound, outbound, status, nack, time

outs. etc).

Byte 10 - Last time polled (250 millisecond intervals).

Byte 1.

The Series/1 adapter address is the physical connection or identification of the line being monitored.

1

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Bytes 2-4.

The "time of day" (TOD) field is the actual time of the event that caused the building of the event block. Byte 5.

The address of the remote "PU" is the actual address of the "Physical Unit" that caused the building of the event block. Byte 6.

The address of the remote "LU" is the same as above except it is the address of the "Logical Unit". Bytes 7-8.

This field serves two purposes. (1) If the event that caused the event block to be built was the result of a transmission or a reception of a data block, this field will be used for recording the length of the data block. (2) However, if the event block...