GISquirrel does the job at a fraction of the cost of SDE. It supports arcgis connection to both MSSQL and PostGIS. Very simple to setup (able to import to postgres from shapefile/featureclass) and simple to maintain. For a small number of users who need multi-user edit capability, its just fine.
arcgis 10 torrent 37
Doyen IT columnist Robert X. Cringely once reported he got best throughput with six torrents underway; more connections, less total speed, as per his experiments. (Wish I could find that blog post....)
Abstract: This paper explores the methodology for compiling the torrent hazard and risk zonation map by means of GIS technique for the Red River basin in Yunnan province of China, where is vulnerable to torrent floods. Based on a 1:250,000 scale digital map, six factors including the number slope angle, rainstorm days, buffer of river channels, maximum runoff discharge of standard area, debris flow distribution density and flood disaster history were analyzed and superimposed to create the torrent hazard risk evaluation map. Population density, farmland percentage, house property, and GDP as indexes accounting for torrent hazards were analyzed in terms of vulnerability mapping. Torrent risk zonation by means of GIS automatically was overlaid on the two data layers of hazard and vulnerability. Then each grid unit with a resolution of 500 m 500 m was divided into four categories of the risk: extremely high, high, medium and low. Finally the same level risk was combined into a confirmed zone, which represents torrent risk of the study area. The risk evaluation result in the upper Red River basin shows that the extremely high risk area takes up 17.9% of the total inundated area of 13 150 km2, the high risk area is 45.9% of 33 783 km2, the medium is 25.2% of 18 563 km2 and the low risk is 11.0% of 8115 km2.
Blocking Bittorrent is challenging, and can't really be done effectively with port blocks. The standard ports are 6881-6889 TCP, but the protocol can be run on any port, and the peer-to-peer nature of the protocol means that discovering peers that use unblocked ports is simple.
If you own the network and bandwidth is your big issue, then you would be best served by a bandwidth monitoring solution. Quality-of-service (QOS) control and bandwidth caps for endpoints could limit the impact the Bittorrent users are having on your overall bandwidth, without the cat-and-mouse game of trying to block a particular protocol.
Another approach would be to block the types of connections that Bittorrent requires. As a peer-to-peer protocol, peers outside your network need to connect in. A firewall could prohibit incoming connections to your user subnet, while permitting them to your intended outward-facing services. An IPS could put a threshold on the number of incoming and outgoing connections, since Bittorrent clients need to connect to multiple peers (and have multiple peers connect to them) in order to function.
Torrent programs can use both TCP and UDP ports.Bad news : you probably don't know torrent proxies that runs on port 80 ? They allow users to redirect their torrent traffic to the regular port 80, so you won't be able to do anything with ports.
Alternative : you could search for a list of popular torrent trackers and ban their IP (eg the most famous French tracker is tracker.t411.me : block it and the problem is solved. Users still can use proxies and VPN, but most of them will be discouraged). Search for torrent proxies too.
There really isn't any "optimal" ratio of seeds/peers. You could max out your download bandwidth from one single seed, regardless of how many peers or leechers there are. In general, the more seeds, the better, as this gives you more places to connect to to download the file. So, yes, a torrent with 100 seeds may be slower than a torrent with 1000 seeds. It really depends on the upload speed of the seeds themselves.
A number of reasons could prevent you from connecting to all available seeds. Note that the numbers in parenthesis are the total number of seeds and peers as reported by the tracker, which may not be correct. Some of these seeds may not have their torrent clients open at the moment, or may have reached their maximum amount of connections, so that they are not able to connect to you.
You must also take into account the number of connections per torrent and the total connections your bit torrent client will allow. This is based on the upload speed you enter when you set up your client. For example I have an upload speed of 20 Megabits per second or 2.5 MB/s (Megabytes per Second).
MY TOTAL number of connections over all active torrents is 1100, so again 5000 seeds can never connect. With the more common much lower UPLOAD speeds of 1.5 to 5 mbps far fewer connections per torrent and overall are allowed.
You have to remember as well that the total of 130 connection per torrent also includes peers who are trying to download the wanted torrent just like myself, they connect to me so we can share bits between each other. So not all 130 connections are seeds, some are fellow peers as well.
As a general rule you will achive faster download & upload speeds to your wanted torrent swarm if you only run ONE ACTIVE downloading torrent and stop all the rest. Most of today's slow download speeds are cause by PEERS and SEEDS running too many active torrents at the same time. 2ff7e9595c
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