Point-to-Point Statistics

Point-to-Point Statistics shows a point-to-point (PTP) table (from rvtrace -addrinfo -ptp). The text below introduces important concepts. Point-to-Point Statistics—Column Headings describes the columns in detail.

Warning 

In switched Ethernet environments point-to-point packets remain invisible to rvtrace—except for packets addressed specifically to the rvtrace host computer. Since this fact severely limits the usefulness of reporting point-to-point statistics, rvtrace omits them from its output unless you specify the -ptp command line option.

In some switched networks, you can disable switching behavior—for example, by setting one port to diagnostic mode, or by using a diagnostic utility. This tactic can yield the full stream of point-to-point packets in a limited portion of the network; run rvtrace in that portion.

Figure 158: Point-to-Point Statistics

Network Total Row

The first row (immediately after the table and column headings) is a network total row; the word Totals in the Address column is a visual cue. This row shows the grand total of packets related to retransmission detected on the network during the interval.

The remaining rows display more fine-grained information about those packets—grouping them by UDP service, and destination or source IP address.

Port Subtotal Row

The second row in Point-to-Point Statistics is a port subtotal row—its columns subtotal the statistics over the subsequent destination and source rows which it governs (until the next port subtotal row).

A number in the Port column indicates the UDP service for its row, and the group of rows that follow it. A blank in this column means that the row has the same port as the row above, and is part of the same subtotal group. Notice how the pattern of numbers and blanks in the Port column visually indicates the subtotal groups.

Destination and Source Rows

For each IP address with point-to-point data packet activity, this table contains a destination row and a source row—always paired in that order. An * and an IP address (in the Address column) flags a row as a destination row. A blank (space characters) flags a row as a source row. The address in the destination row also applies to the source row that immediately follows it.

Counting Packets

This table displays each packet twice—once in a destination row, and once in a source row.

In each statistical column, the number in the port subtotal row is equal to the sum of the values in the destination rows, which is also equal to the sum of the values in the source rows.

In many networks it is possible to match the numbers in the source row for one IP address against the numbers in the destination row for another IP address. From this information you can deduce which Rendezvous daemons are exchanging point-to-point data packets and requesting retransmissions.

Point-to-Point Statistics—Column Headings

Column

Description

Port

In port subtotal rows, this column contains a UDP port number indicating the Rendezvous service for the group of rows that it begins.

In destination and source rows this column is blank; the service in the nearest preceding port subtotal row governs the destination and source rows below it.

*

Asterisk (*) in this unlabeled column indicates a destination row.

Blank in this column indicates a source row.

Address

In destination rows this column shows the destination IP address of point-to-point data packets.

In source rows this column shows the IP address from which point-to-point data packets originate.

In network total rows, this column contains the word Totals.

SCid

Service communication ID.

In destination rows this column differentiates the destination ID of point-to-point data packets.

In source rows this column is blank.

Data

Point-to-point data packets.

This column shows the number of point-to-point data packets.

Bytes

Point-to-point data bytes.

This column sums the number of payload bytes over the point-to-point data packets (as counted in the Data column).

AckR

Acknowledgement request packets.

Sending Rendezvous daemons explicitly request positive acknowledgment for groups of point-to-point data packets. This column shows the number of packets containing acknowledgment requests for point-to-point data packets.

Ack

Acknowledgement packets.

Receiving Rendezvous daemons explicitly acknowledge groups of point-to-point data packets upon request from sending daemons. This column shows the number of packets containing acknowledgments for point-to-point data packets.

Nak

Negative acknowledgement packets.

Receiving Rendezvous daemons use negative acknowledgments to request retransmission of missing data point-to-point packets. This column displays the number of packets containing retransmission requests for point-to-point data packets.

For more information, see Nak Diagnoses.

Bad

Bad packets.

This column shows the number of packets that lack UDP checksums, or are corrupt in some other way.

Warning 

See Bad Packets.