Method and apparatus for testing a packet-based network
First Claim
1. A method of testing a packet-based network to ascertain characteristics of packet transmission between first and second nodes on the network, said method comprising the steps of transmitting packets between said first and second nodes;
- receiving the packets at one of said nodes; and
correlating packet transmission and reception to derive correlation data indicative of a first of said transmission characteristics;
transmitting said packets as a sequence in which the packets are in a predetermined relationship to each other with at least one parameter of the packets in said sequence varying over the sequence;
deriving said correlation data so as to relate the correlation data to one parameter of said at least one parameter; and
determining a second of said characteristics of transmission by examination of the relation between the correlation data and said parameter over said sequence.
5 Assignments
0 Petitions
Accused Products
Abstract
In packet-based networks (10), it is often desired to test communications between two specific stations (11, 12). This can generally be effected from a first one of the stations (11) by requesting the other station (12) to `loop-back` a test packet sent from the first station. The first station (11), on receiving back the test packet, can thereby ascertain that not only is communication with the other station (12) possible, but it can also measure the round trip time. However, more complex characteristics of the transmission path between the stations (11, 12) are not ascertainable in this manner. The transmission of a predetermined sequence of packets permits such characteristics to be determined by observing the effect of the network (10) on the sequence considered as a whole. Thus by varying packet size in a sequence, characteristics such as bandwidth, propagation delay, queuing delay and the network'"'"'s internal packet size can be derived. The use of bursts of packets enables buffer size and re-sequencing characteristics to be determined.
439 Citations
14 Claims
-
1. A method of testing a packet-based network to ascertain characteristics of packet transmission between first and second nodes on the network, said method comprising the steps of transmitting packets between said first and second nodes;
- receiving the packets at one of said nodes; and
correlating packet transmission and reception to derive correlation data indicative of a first of said transmission characteristics;
transmitting said packets as a sequence in which the packets are in a predetermined relationship to each other with at least one parameter of the packets in said sequence varying over the sequence;
deriving said correlation data so as to relate the correlation data to one parameter of said at least one parameter; and
determining a second of said characteristics of transmission by examination of the relation between the correlation data and said parameter over said sequence. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
- receiving the packets at one of said nodes; and
-
14. Apparatus for testing a packet-based network to ascertain characteristics of packet transmission between first and second nodes on the network, said apparatus comprising transmission means for transmitting packets between said first and second nodes, receiving means for receiving the packets of one of said nodes, and correlation means for correlating packet transmission and reception to derive correlation data indicative of a first of said packet transmission characteristics;
- said transmission means being operative to transmit said packets as a sequence in which the packets are in a predetermined relationship to each other with at least one parameter of the packets in said sequence varying over the sequence;
said correlation means being operative to derive said correlation data so as to relate it to one parameter of said at least one parameter; and
means for determining a second of said packet transmission characteristics of transmission by examination of the relation between the correlation data and said one parameter over said sequence.
- said transmission means being operative to transmit said packets as a sequence in which the packets are in a predetermined relationship to each other with at least one parameter of the packets in said sequence varying over the sequence;
Specification