Currently, the P2P download software traffic represented by BitTorrent (hereinafter referred to as BT) occupies a large amount of broadband access bandwidth, according to statistics has exceeded 50%. This poses a great challenge to the broadband access mode of shared bandwidth such as Ethernet access. A large number of ports on the access layer switch work in a long-term online state, which seriously affects the user's use of normal Web, E-mail, and video. On-demand services. As a result, operators, enterprise users, and users in industries such as education have requirements to limit such traffic.
This article uses BT as an example to introduce the general and special methods to control P2P download traffic
How to carry out BT?
BT and the biggest difference is that the traditional way to download full play to the characteristics of the Internet host such that each run TCP /IP stack hosts can be equally (end to end) to receive or initiate please visit request. Although with the popularity of technologies such as NAT and firewalls, the end-to-end era of the entire Internet has gone, but there are still many hosts that still have Interenet end-to-end capabilities. In addition, even in campus networks and enterprises isolated by firewalls. In the intranet, hosts also have an end-to-end environment. The traditional way to download
is C /S mode, or centralized mode, i.e., the individual host files are downloaded from the server, the host is not available for download, and the download server is usually only.
while BT download mechanism to download both hosts, and available for download, while the server only provides a host and directory information about the file downloaded, shown in Figure 2. The content selected by each host download has a certain hash feature. Therefore, each host that participates in the download usually has content that has not been downloaded by other hosts, so that the download service can be provided for other hosts. Under this mechanism, each host can be downloaded from multiple locations at the same time, so the download rate can be greatly improved.
BT server what role?
BT server provides unified management of the release, BT client needs to connect to the server to get other host nodes involved in the download. In fact, this also provides a simple and feasible means for us to limit BT traffic.
BT's .torrent file includes the server's address, file name, directory name, file length and other information. After analyzing the .torrent file, the BT client software sends a download request to the server, and the requested URL includes itself. Port information, download progress and status information, etc.
The BT server uses the track program to manage these download requests. After getting the URL, it will look up the list and find the host that provides the corresponding file download. The client can download, at the same time, if the client has the ability to accept the connection request, the track program will also add the host's information to the list, so that other hosts can find the host and download.
As P2P clients can specify their own are generally used to provide the port to download /upload, so the traditional way of blocking ports is difficult to work. How
control P2P traffic?
Using QoS
Objectively speaking, P2P technology is a mechanism that is very suitable for the Internet structure and can maximize the use of network resources. In many cases, P2P can save network basic resources. For example, in a broadband access network, if there are 100 users who want to download the same file on the external network, the traditional way is that the same traffic should be exported 100 times by the operator. Unless the carrier provides caching or distribution services. However, in the BT mode, the traffic passing through the exit will be significantly reduced because the users of the intranet can download each other. P2P applications have become a trend, and it is difficult to block the development of P2P by blocking alone.
However, due to the superiority of the mechanism, P2P this model will inevitably have an impact at this stage traditional applications, affecting normal business traffic. //This article comes from the computer software and hardware application network www.45it.com
Therefore, a reasonable starting point is to use the QoS mechanism to allow users to use P2P applications while ensuring normal service operation. Difficulty
this way is more, first of all is how to define the normal business flow, how to plan bandwidth.
At this stage, voice, video traffic, e-commerce transaction traffic of enterprise users, and web traffic, E-mail traffic and instant communication traffic of broadband access users can be included in the normal business and are divided into different Priority. Thereafter, the operator can modify and optimize the QoS configuration according to the user's usage and application development.
For this embodiment, from the point of view of traffic analysis, existing MRTG and other SNMP-based flow rate detection means has been difficult to meet the requirements. To this end, Jusheng Technology has developed real-time bandwidth control technology, which directly analyzes the communication protocol used in data packet transmission and directly intercepts its protocol signature. Since the protocol signatures of various P2P transmission tools are different, it can be specifically analyzed whether the P2P tools are used for normal service transmission (voice, e-commerce transaction traffic) or for abnormal business needs (such as BT downloads movies and music) to provide real-time traffic reports that are differentiated by business type and controlled.
control P2P download 1
control P2P download 2
port and bandwidth limitations
gateway, firewall
in Port blocking is currently the most common practice, with lower costs, but the results are often unsatisfactory. Because applications such as BT allow users to modify the download and upload ports, it is easy to bypass by relying on the restricted transport port, but as mentioned earlier, it is relatively easier to achieve the goal if you limit the tracker port (usually 6969) that would normally not be modified. .
In the conventional method is difficult to use, you can use the bandwidth limit method to control BT traffic.
host LAN bandwidth is provided in FIG. 1
Figure 2: flow rate setting
LAN hosts the control P2P traffic in the long run by the network QoS and The combination of traffic-aware technologies (such as the identification of P2P protocol codes by Jusheng Network Management) enables intelligent control of business transparency. From the current point of view, both QoS and network traffic awareness have been implemented, but there is still no effective integration mechanism. In addition, using basic methods such as port limitation and bandwidth limitation, BT traffic can be suppressed to some extent.