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Network Planning with Cariden Mate
Over the last few weeks, I’ve been spending time evaluating Cariden Mate – a software tool designed to assist the task of capacity planning and traffic engineering on large scale IP networks. As a result I can provide a brief review of its capabilities.
Cariden Mate ships on three major platforms: Windows, Solaris UNIX and Macintosh OS X. In a style consistent with other network management tools but disappointing nonetheless, there seems to be an implicit assumption that the network operator is likely to dedicate a user workstation to running the software since the user interface and network element data collection software all exist wthin the same installable package. In most cases, what is infinitely preferable is a server installaton that communicates with the network elements and client installations that provide the necessary interfaces to the user.
That said, unlike a lot of other network management tools, the separate components of Cariden Mate, such as the GUI, the network collecting agents, the processing tools are actually all available to execute separately in a modular fashion and are documented as such. This allows a skilled systems architect the ability to construct a client/server-style architecture or, indeed, any other customised architecture that might introduce other data or systems in a flexible manner. One requires an amount of development time and effort to do this, of course.
The operation of Cariden Mate is centred around a plan file. A plan file contains various items of data about a network and since it is not always possible to gather this data from one place, the plan file format is flexible enough to be edited by hand, manipulated by user scripts or generated automatically by Cariden Mate’s built-in tools.
For those wanting a quick start, the GUI offers a fairly comprehensive “Get Plan” operation that will probe a router and generate a plan file by collecting a backbone router’s IGP database – both OSPF and IS-IS are supported – and enriching it with interface and bandwidth levels, obtained through SNMP. This allows Cariden Mate to understand which nodes are connected to which other nodes and with what link metrics.
With this data alone, it is possible to generate a plan file that a user can use offline as a planning tool. The plan file is rendered in the GUI and shows how devices are linked in the network topology and allows the user to discover which links would be used for any specified route. The user is also able to define an arbitrary traffic matrix (a simple spreadsheet-like table of input node, output node and traffic level) and see it reflected on the discovered topology in terms of link usage, thus facilitating capacity checks for customer turn-ups.
At this point, the topology can also be manipulated: link metrics can be changed or links can be taken down, and Cariden Mate will show the new routes that will be taken by traffic and the resulting load on the remaining links as a result of the provided traffic matrix.
Assuming the availability of a reasonably accurate traffic matrix – in the right format – using Cariden Mate in this way without further access to the network is a powerfol tool in its own right.
In addition to this, however, Cariden Mate provides tools to enrich the plan file with currently measured interface link utilisation data collected from SNMP. The tools are flexible and can be run in the background in order to constantly poll the network and populate an archive or, alternatively, the GUI’s “Get Plan” function is able to grab a single snapshot of link utilisation for the current time.
In possession of the link utilisation data, Cariden Mate’s powerful Estimation and Deduction functions can be used to compute a candidate traffic matrix that would result in the observed link utilisation. The mathematics and exact algorithm I confess to not understanding at all beyond the premise that the software seems to consider all possible traffic matrices that could be put to the network and how they would effect the links and offers the most likely traffic candidate.
The traffic matrix is very valuable data when one considers the difficulties in acquiring an actual observed matrix (different network platforms, different line cards with different features etc.). It can be based on data collections from a perceived network high-tide and then be made available offline in order to run simulations against in order to determine where new circuits would best be placed and what the likely impact of planned works would be.
Cariden also provides a light HTTP interface into a plan file using its WeatherMap-style interface. This presents a dynamically rendered image which shows the plan file with links coloured according to usage from continuous data stored in archive file. This is a convenient and license-effective way to propagate basic network visualisation to users in the organisation that don’t require the full-blown GUI functionality.
Licensing is typically per-node and per-seat. The per-node licensing is reasonable but it de-values the topology discovery mechanism which happily disovers every node in the IGP database – inferring location from network naming convention as it goes – whether you intend to use the Cariden Mate functionality for it or not. Unless you license the software for all nodes in the IGP, discovery is hampered by the necessary manual “deletion strategy” to remove all the low-end access routers that you don’t care about. Per-seat licensing is enforced through a stubborn adherence to MAC address for client installations which is frustrating.
But in conclusion, Cariden Mate provides a very useful complement to the usual first-generation network performance reporting tools that measure interface usage by offering various levels of user both a topology understanding and visibility, and also a view on end-to-end traffic which cannot be gleaned from SNMP data alone.
原文来自
http://blog.packetsource.net/2008/10/10/cariden-mate/