I would like to pursue the concept of view or model. My primary interest is in terms of how the dynamic circuit path finding and path creation will use a topology description. My thought on how this would work, which may be different than everyone else's, is something like the following. This is very rough - I offer it for discussion. The definitions need work, but I hope it gives the idea of what I think would be good in a "model or view". I may also misunderstand this, so please correct if needed. 1. A "real" topology exists which describes real devices, interfaces, and links. It includes parameters like bw, latency, geographic location, and capabilities like switchint or adaptation (e.g. mapping VLANS or doing GFP conversion between ethernet and SDH). 2. The "real" topology includes information about control of capabilities - the administrative owner(s), the operational owner(s), and any device that can activate the capabilities. 3. The real topology has groups - which might be called networks, or domains or both. It is not clear exactly how this will work. 4. On and from this real topology there are derived "views or models" which are useful to different applications. In my mind this ability to have a common real topology from which different views are created is very powerful. DCN views An Interdomain Controller is the DCN entity that controls circuit establishment over multiple domains. A domain is the set of capabilities that are controlled by an IDC. An internal topological view of a domain will include all the capabilities that are in a domain and the devices that contain the capabilites. In the simple case this is all the nodes and links in the domain. An external topological view of a domain includes the links to external domains and the internal device to which the link is connected. It also includes the capabilities of the domain to act on external links. A DCN internal pathfinding view contains Nodes and links for a domain. The nodes and links may correspond to the real topology or may be virtual links that are created by combining connections between locations into a single link (e.g. 4 GEs between sites are treated as a single link for pathfinding purposes) or by splitting connections into different links (e.g. STS-1-48= link1, STS-49-96 = link2). A DCN external pathfinding view contains domains and links between domains. There is some question as to whether a domain should be abstracted to look like a node. My view is that from a DCN operational view they are different. routes inside domain are calculated between nodes. routes between domains are calculated between edges of domains. A DCN path request view includes resources in the request. It will have parameters for the request (e.g. bw) but will also include specific resources that are available. I am not sure if the elements in a path request need to have a topological name. I have called these route objects - there is probably a better name. A DCN circuit is a path with specific resources at each link and node in the path. Perhaps there is a better name for this - e.g. it is a link. From a DCN perspective it is different than the links that are used to create the circuit, and needs a name in the DCN view. -- I am not sure how different the monitoring view would be. If the intent is to monitor DCN then I am guessing the view would be the same, perhaps with some information about monitoring devices. -- I am wondering how this plays with the idea of showing links to applications - perhaps the network view can be limited to showing where applications connect to the net. On Mar 18, 2008, at 4:22 PM, Freek Dijkstra wrote:
Hi Aaron, Evangelos and Aurélien,
I wrote:
So I, Aaron, and Evangelos (and perhaps Aurélien and John if they have the coureage) now have a moral obligation to summarize our network / domain / view discussion on the wiki, in order to save others the ordeal of reading our entire flood of mails from two weeks ago.
I very much hope you are willing to help with this.
I just made a first attempt at the wiki: https://forge.gridforum.org/sf/wiki/do/viewPage/projects.nml-wg/wiki/ https://forge.gridforum.org/sf/wiki/do/viewPage/projects.nml-wg/ wiki/Grouping https://forge.gridforum.org/sf/wiki/do/viewPage/projects.nml-wg/ wiki/Interfaces
I will try to re-read the rest of the mails, and see if there are things to add (or better: perhaps we can eliminate some of the controversies by reaching a consensus!). Please have a look in the mean time, and add whatever you feel is important feedback you want to give to the NML WG. I'd say this is your chance to enforce your superior model on other mortal souls :-)
Regards, Freek
John Vollbrecht, Senior Network Engineer Internet2 office +1-734-352-4960 | mobile +1-734-395-7890