Electrical computers and digital processing systems: multicomput – Computer network managing – Computer network monitoring
Reexamination Certificate
1997-05-13
2001-03-27
Geckil, Mehmet B. (Department: 2756)
Electrical computers and digital processing systems: multicomput
Computer network managing
Computer network monitoring
C709S223000, C370S232000
Reexamination Certificate
active
06209033
ABSTRACT:
DISCUSSION OF THE RELATED ART
1. Field of the Invention
This invention relates to computer network communications systems, and in particular to techniques for evaluating network traffic capacity and evaluating alternative network configurations.
2. Background of the Invention
Computer networks are widely used to provide increased computing power, sharing of resources and communication between users. Networks may include a number of computer devices within a room, building or site that are connected by a high-speed local data link such as token ring, Ethernet, or the like. Local area networks (LANs) in different locations may be interconnected by for example packet switches, microwave links and satellite links to form a wide area network (WAN). A network may include several hundred or more connected devices, distributed across several geographical locations and belonging to several organizations.
In the operation and maintenance of computer networks a number of issues arise, including traffic overload on parts of the network, optimum placement and interconnection of network resources, security, isolation of network faults, and the like. These issues become increasingly complex and difficult to understand and manage as the network becomes larger and more complex. For example, if a network device is not sending messages, it may be difficult to determine whether the fault is in the device itself, a data communication link, or an intermediate network device between the sending and receiving devices.
Network management systems are intended to resolve such issues. Older management systems typically operated by collecting large volumes of information which then required evaluation by a network administrator, and thus placed a tremendous burden on and required a highly-skilled network administrator.
Newer network management systems systematize the knowledge of the networking expert such that common problems of a single domain (i.e., a portion of the network under common management) can be detected, isolated and repaired, either automatically or with the involvement of less-skilled personnel. Such a system typically includes a graphical representation of that portion of the network being monitored by the system. Alarms are generated to inform an external entity that an event has occurred or requires attention. Since a large network may have many such events occurring simultaneously, some network management systems provide alarm filtering (i.e., only certain events generate an alarm).
Commercially available network management systems and applications for alarm filtering include: (1) SPECTRUM®, Cabletron Systems, Inc., 35 Industrial Way, Rochester, N.H. 03867; (2) HP OpenView, Hewlett Packard Corp., 3000 Hanover Street, Palo Alto, Calif. 94304; (3) LattisNet, Bay Networks, 4401 Great American Pkwy., Santa Clara, Calif. 95054; (4) IBM Netview/6000, IBM Corp., Old Orchard Road, Armonk, N.Y. 10504; (5) SunNet Manager, SunConnect, 2550 Garcia Ave, Mountain View, Calif. 94043; and (6) NerveCenter, NetLabs Inc., 4920 El Camino Real, Los Altos Calif. 94022.
To evaluate the performance of a communications network, both the network configuration and the raw message traffic data may be analyzed. Network configuration, also called network topology, refers to the structure of a network's physical and virtual connections, and may include the structure of the network's nodes as well. Generally, a network is made up of one or more physical or logical subnets (segments), where each subnet includes a plurality of nodes (e.g., servers and host computers). Different subnets in a network may be connected by a network trunk. The performance analysis may include consideration of the network load on various subnets based on number of packets, packet collision rate, packet deferment rate, packet length, and network communication protocols. This information is normally obtained by placing monitors at selected points in the network. These monitors, also called daemons, network monitors, or network analyzers, monitor the traffic that flows through the selected points.
Some current monitors simply report various parameters of network packets in real time. For example, the table of
FIG. 1
shows a few seconds of network activity
10
where the parameters of interest are packet length
11
, protocol
12
, source node
13
, destination node
14
, source port
15
, and destination port
16
. However, an analysis of such raw data is rather cumbersome, particularly if the raw data has been collected for days or months. Thus, tools have been built that can transform the raw data into graphical representations such as bar graphs, X-Y plots, histograms, and scatter plots, shown generally as
20
in FIG.
2
.
Other monitors display a topological view of the network showing the amount of traffic flowing among the various nodes. Over time, the monitor discovers all of the traffic patterns on the subnet, and in some instances also indicates the amount of traffic between the nodes by, for example, line color or line thickness.
However, the prior methods of monitoring network performance as shown for example in
FIGS. 1-2
, provide only the ability to monitor, but do not provide the ability to evaluate alternative network topologies or to perform comparison studies. In addition, the previous methods do not provide an indication of the overall balance of traffic on a network.
It would be desirable for a network management system to have the ability to evaluate the overall capacity of a particular network configuration and analyze alternate configurations.
SUMMARY OF THE INVENTION
In accordance with one aspect of the invention, network capacity evaluation and planning (CEP) is performed based upon the traffic across the links of the network. Once a link's traffic volume has been measured, it is compared with the link's traffic capability, and the resulting parameters may be compared with the traffic and capability of other links of the network to create measures of network capacity and balance. Then, simulated changes to the network configuration may be made by substituting simulated traffic volume amounts and capabilities for selected link traffic measurements and capabilities, and the resulting determinations of network capacity and balance may then be compared to determine whether the simulated changes represent a preferred network configuration.
An embodiment of the invention is directed to a method for evaluating network traffic on a communications network, the network having a present configuration of nodes connected by a plurality of links, the method comprising the steps of determining a traffic capability for an amount of time for each of the plurality of links of the network, measuring a traffic volume for the amount of time across each of the plurality of links, and evaluating a communications capability of the communications network based upon the traffic capability and the traffic volume.
The communications capability may also be evaluated by determining a contribution to an overall bandwidth of the communications network by a first link of the plurality of links based upon the traffic capability of the first link with respect to a traffic capability of all of the plurality of links, and may also include determining a contribution to an overall traffic of the communications network by a first link of the plurality of links based upon the traffic volume across the first link with respect to a traffic volume across all of the plurality of links. The link balance for the first link may then be evaluated based upon a comparison between the contribution to overall bandwidth and the contribution to overall traffic.
The communications capability may also be evaluated by evaluating a link balance for a first link of the plurality of links based upon a comparison between a contribution to overall bandwidth of the communications network by the first link and a contribution to overall traffic of the communications network by the first link. Additionally, an upper bound and a lower bound of link utilization ma
Datta Utpal
Lewis Lundy
Cabletron Systems Inc.
Geckil Mehmet B.
Wolf Greenfield & Sacks P.C.
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