udp - based data transfer protocol
udt is a reliable udp based application level data transport protocol for distributed data intensive applications over wide area high - speed networks .
this article introduces an open source udp - based data transfer library, namely udt (u dp - based d ata t ransfer) .
i am programming a real - time game in which i need reliable udp, so i' ve chosen to work with udt (udp - based data transfer protocol - urltoken) .
udt is a reliable udp based application level data transport protocol for distributed data intensive applications over wide area high - speed networks. udt uses udp to transfer bulk data with its own reliability control and congestion control mechanisms. the new protocol can transfer data at a much higher speed than tcp does. udt is also a highly configurable framework that can accommodate various congestion control algorithms. . install this package if you wish to develop your own programs using the udp - based data transfer protocol library .
there is no protocol directly modified on udp known to the authors. while, based on udp, several new transfer protocols with reliability are designed, such as reliable
tsunami blends together both tcp and udp. it uses tcp control and udp data transfer to allow for higher speeds .
udt is a reliable udp based application level data transport protocol for distributed data intensive applications over wide area high - speed networks. udt uses udp to transfer bulk data with its own reliability control and congestion control mechanisms. the new protocol can transfer data at a much higher speed than tcp does. udt is also a highly configurable framework that can accommodate various congestion control algorithms .
udt is a reliable udp - based application level data transport protocol for distributed data intensive applications over wide area high - speed networks. udt uses udp to transfer bulk data with its own reliability control and congestion control mechanisms. the new protocol can transfer data at a much higher speed than tcp does. udt is also a highly configurable framework that can accommodate various congestion control algorithms .
is a high - performance data transfer protocol designed for transferring large volumetric datasets over high - speed wide area networks .
blast udp (rbudp) (he et al. , 2002), udp - based data transport (udt) (yunhong et al. , 2004, 2007) and tsunami (mark, 2002) and so on. they are usually above the tcp and udp and use udp to transfer data and tcp to transfer control information. a quick review of these udp - based protocols is given as follows .
in this study, the issue of bulk data transfer over fldnet is investigated. after identifying the shortcoming of tcp and tcp variants, the principle of several udp - based transfer protocols are studied .
the way my system is setup, control messages are sent over udp with data transfer over tcp (so that the data remains ordered) .
udt (udp - based data transfer protocol) was added to touchdesigner as an alternative to udp, which is not reliable because packet loss is not recoverable in udp. udt is fast and recovers from lost packets. it is also faster and more immediate than tcp / ip .
udt is a reliable udp based application level data transport protocol for distributed data intensive applications over wide area high - speed networks. udt uses udp to transfer bulk data with its own reliability control and congestion control mechanisms. the new protocol can transfer data at a much higher speed than tcp does. udt is also a highly configurable framework that can accommodate various congestion control algorithms. (presentation: ppt 450kb / poster: pdf 435kb )
udt is an extension of the udp transfer protocol. it is used to transfer bulk data at much higher speeds than tcp. utd is also more configurable and allows you to set various congestion control algorithms .
udp - based transfer protocols rbudp, tsunami and udt use udp to transfer data and tcp to transfer some control information. currently, throughput is the focus because it is the urgent requirement for transferring bulk data on dedicated link over fldnet. by the analysis of experiment results from the fldnet testbed, it can be concluded that all the three udp - based transfer protocols have mach better performance than tcp. among them, tsunami has the best performance and rbudp also performs well when transfer file which is not too big .
for the design of udt, check the paper udt: udp - based data transfer for high - speed wide area networks and supporting configurable congestion control in data transport services. for more technical details, the internet - draft udt: udp - based data transfer protocol is a good point to start with. and of course, you can read the source code of udt which is opened under bsd license (since udt version 4) .
gu, y. , grossman, r. : udt: udp - based data transfer for high - speed wide area networks. computer networks 51 (7) (2007 )
using authentication for data transfer would also require being able to handle variable length messages .
as aforementioned, udp has its complexities for programming with. for reliable bulk data transfer, udt is a possible good option .
currently, there are two major internet transport protocols, tcp and udp. tcp provides connection oriented reliable data streaming service, whereas udp provides connection - less unreliable messaging service. most applications use tcp to transfer data because they require data reliability .
check the wikipedia article on udp user datagram protocol for a brief overview. rfc 768 defines the standard of the udp. for an introduction to tcp and udp, the wiki book tcp and udp protocols is a good source .
if you’re interested in learning more about udp and making use of it, consider checking out the udp file transfer tools above for more details .
some commercial managed file transfer solutions claiming to have udp acceleration have integrated one of those open source projects into their core file transfer technology. these solutions will inherit the strengths but also the weaknesses of the open source project. filecatalyst has developed its own udp based protocol written from the ground up, and does not include any code from open source udp technology .
i' m talking about udt, which is based on udp, but according to its official website (urltoken )
udt is a reliable udp based application level data transport protocol
, so since it adds reliability to the messages, it' s weird that some of them are being lost ...
one important concept in udp programming is that a udp packet is sent as a whole. the order inside the udp packet is ensured .
in these experiments, high performance servers are used, so, the performance of terminals has little effect on transport protocol. but in practical application, the terminal performance should be considered. however, all the three udp - based protocols have not considered this point. recently, a new kind of udp - based protocol named performance adaptive udp (pa - udp) is proposed by eckart et al. (2008) .
yes. how i handle synchronization might depend on how the system is setup to transfer data .
there are a few differences that exist between the way udp and tcp work. these differences are important components in determining what each protocol is suitable for your use - case in terms of data transfer. a few distinctions between udp vs tcp include :
speed. udt is designed for extremely high speed networks and it has been used to support global data transfer of terabyte sized data sets .
for more details on udp programming including udp sockets and detailed explanation of the data structures used, check this tutorial: programming with udp sockets. this worksheet introduction to user datagram protocol on * nix with c can also be a good learning material .
) achieved high utilization of bandwidth in high bdp networks by radically changing the tcp congestion control algorithm, but the fairness problem still remains. considering the background above, new transport protocol is needed to support the high performance bulk data transfer in high bdp networks. we propose a new application level transport protocol, named udt, or udp based data transfer protocol, together with a new congestion control algorithm. this document presents the two orthogonal parts of the udt protocol and the udt congestion control algorithm. the application level protocol, layering over udp, can use other congestion control algorithms; whereas the algorithm defined in this document can be implemented in other protocols, such as tcp. an example implementation of the protocol can be found at [
although gridftp is not udp based, it can be used to solve the problem of poor tcp performance with ftp .
for beginners to udp programming, i recommend the easy to follow tutorial udp makde simple. this tutorial can help you quickly get started writing udp programs .
udp, which stands for user datagram protocol, is a method used to transfer large files across the internet. tcp, or transmission control protocol, is the more widely known and used protocol for file transmission, however, falls short in comparison when it comes to transferring large files at fast speeds. a few scenarios where udp is commonly preferred over tcp include :
it can. and if you are sending variable - length data over tcp, you have to express that data length in the message data .
uftp is a udp - based file transfer protocol and the name of a tool that implements that protocol. (uftp) is designed for particularly efficient file transfers under scenarios where the file is to be broadcast / multicast or the transfer occurs over a wireless link (such as satellite). however, in low - error, high - bandwidth or high - latency scenarios, it can outperform tcp - based protocols such as ftp by 100% or more. source: wikipedia
gu, y. , grossman, r. l. : udt: udp - based data transfer for high - speed wide area networks, computer networks. the international journal of computer and telecommunications networking 51 (7), 1777–1799 (2007 )
i am using the udp - based data transfer protocol with udt - m / udt v4, ! but sometimes it crashes in some map / vector functions inside the udt. dll! i think it is a conflict with the queue and multithreading. did someone use the udt - m and it works better? - jens schneeweiß urltoken urltoken
in future, these existing udp - based protocols are still needed to be enhanced. first, an ideal protocol which can get stable high throughput for bulk data transferring on dedicated lightpath of fldnet is needed to be designed. then, the issues like fairness and tcp - friendliness when running the protocol on shared internet link are needed to be considered .
we will review 4 open source projects: three which use udp and one which only optimizes tcp parameters to provide fast file transfer .
udt is completely based on udp, which makes it easier to traverse the firewall. in addition, multiple udt flows can share a single udp port, thus a firewall can open only one udp port for all udt connections. udt also supports rendezvous connection setup .
there are many udp file transfer tools and projects that implement udp for both usability purposes as well as performance reasons. below are a list of projects that you can use within your own network to enable the transfer of files over udp. the dependability of each project varies and it will require a certain amount of testing to verify which one works best for your use case. however, each udp file transfer tool below is open source, therefore you can use it for free .
udt is designed for extremely high speed networks and it has been used to support global data transfer of terabyte sized data sets. udt is the core technology in many commercial wan acceleration products .
firewall friendly. udt is completely based on udp, which makes it easier to traverse the firewall. in addition, multiple udt flows can share a single udp port, thus a firewall can open only one udp port for all udt connections. udt also supports rendezvous connection setup .
as massive data generated in large scale e - science projects such as high energy physics (hep) and astronomical observation (e - vlbi) needs to be transported internationally over fast long distance network, high performance transport protocol is needed. based on udp, some reliable transfer protocols are designed. this research mainly studies the principles of these protocols and compares their performance by experiments. it is found that they far outperform tcp, but still have some limitations and cant satisfy the requirement of bulk data transfer perfectly .
in conclusion, the performance of tcp and tcp variants is still not good enough to satisfy the requirement of bulk data transfer over fldnet .
many applications need to transfer bulk data, but their requirements are not completely the same. a basic and general requirement is high speed. most applications require stable and reliable transfer. some applications like e - vlbi and hdtv can tolerate few data loss. and some applications like e - vlbi require real - time transfer, but others like hep dont require .
uftp is an encrypted udp based ftp with multicast. it is used to deliver files securely, reliably, and efficiently to multiple servers at the same time .
fast. udt is designed for extremely high speed networks and it has been used to support global data transfer of terabyte sized data sets. udt is the core technology in many commercial wan acceleration products .
in this post, we’ll go over some of the granular differences between udp and tcp as well as a few udp tools you can use .
udt is a transport protocol with its own reliability control and flow / congestion control built above udp. udt provides both reliable data streaming service quite similar to tcp and partial reliable messaging. the latter allows users to send data as messages with specified delivery order and time - to - live value .
there are other situations where people do not want to use either tcp or udp. for example, an application may require data reliability (so cannot use udp directly) but also wants data to arrive at a user - controlled rate or the message boundaries to be conserved. furthermore, sometimes it is easier to use udp to traverse firewalls than tcp .
bernardo, d. v. , hoang, d. b. : a security framework and its implementation in fast data transfer next generation protocol udt. journal of information assurance and security 4 (354 - 360) (2009) isn 1554 - 1010
a video example of norm in action, helping improve an mpeg - 4 video stream can be found on the noviss webpage. a norm - based socks5 proxy (norp) has also been developed to make it easier to use norm with standard tcp / udp - based applications .
the alternative i was thinking of is having the system listening on a single port and synchronizing threads so the' control' thread knows the data transfer is progressing .
rbudp and udt also provide memory - to - memory transfer mode. all the following experiment results are from practical file transfer in disk - to - disk transfer mode. a high definition tv (hdtv) file with file size of 4. 5 gb is used in experiments by default .
this website will be expanded in the future to contain example norm applications and norm software development toolkits based on the nrl reference implementation. the nrl norm work is heavily based on previous work with mdp which has similar capabilities .
up to now, most researchers focus on modification on tcp. but, there are still some researchers try to design new protocols based on udp. udp is much simpler than tcp. it merely adds ports to identify individual application processes and a checksum to detect erroneous packets and simply discard them. udp has no reliable transfer mechanism like sequence number, ack and retransmission. additionally, udp makes no flow control and congestion control like tcp. so, it runs fast over fldnet. but its unreliable. if reliability is added into udp and the merit of fast is kept, it will satisfy the requirement of many e - science applications .
udt (udp - based data transfer protocol) is one of the most promising network protocols developed for high data speed data transfer. it does not, however, have any inherent security mechanisms, and thus relies on other transport protocols to provide them. towards its implementation in high speed networks, security and privacy are critical factors and important challenges that need to be addressed. there were substantial research efforts we carried out so far to address these challenges. we introduced security mechanisms through the application layer using udt’s api and presented dtls, gss - api, and cga, in transport and ip layers. in this paper, we make the following contributions: we out line security requirements for udt implementation and propose practical encryption methods for securing udt within the network layer .
“a field that specifies the length in bytes of the entire datagram: header and data. the minimum length is 8 bytes since that’s the length of the header. the field size sets a theoretical limit of 65, 535 bytes (8 byte header + 65, 527 bytes of data) for a udp datagram. the practical limit for the data length which is imposed by the underlying ipv4 protocol is 65, 507 bytes (65, 535 − 8 byte udp header − 20 byte ip header). ” — from wikipedia .
for a regular send, a simply copies the data into the protocol buffer and returns, so
send
does not know the error. if you use overlapped send, which wait until the data is actually sent to the peer side, it will detect the error .
kent, s. , atkinson, r. : security architecture for the internet protocol. rfc 2401 (1998 )
there exist a number of open source projects trying to tackle accelerated file transfer via udp. some solutions are more mature than others and also use different technologies to solve the same problem of large data transfer over wan. this article should provide the reader enough information to compare the different solutions and gauge if an open source project could be used instead of purchasing a commercial solution like filecatalyst .
udp certainly provides attractive features when it comes to performance and speeding up the delivery of data sets across the internet. although it still has certain drawbacks that prevent it from being used in all applications, there have been great advancements in improving its stability and reliability. udp is likely the protocol the internet will move towards in order to deliver standard information (such as website data, videos, etc) thus making for a great enhancement in terms of web performance .
in computer networking, the stream control transmission protocol (sctp) is a transport - layer protocol, serving in a similar role to the popular protocols tcp and udp. it is standardized by ietf in rfc 4960. sctp provides some of the same service features of both udp and tcp: it is message - oriented like udp and ensures reliable, in - sequence transport of messages with congestion control like tcp; it differs from these in providing multi - homing and redundant paths to increase resilience and reliabil ...
a streaming video server is sending data to many clients. the server may choose a specific sending rate for each client during any specific period. you may have trouble asking tcp to send data at a fixed rate. and using udp you have to do most of the data reliability control work by yourself. in addition, video frames are time sensitive data, if the frame is delayed too long, it will not be needed any more. that is, complete data reliability is not desired in this situation .
the norm protocol is designed to provide end - to - end reliable transport of bulk data objects or streams over generic ip multicast routing and forwarding services. norm uses a selective, negative acknowledgement (nack) mechanism for transport reliability and offers additional protocol mechanisms to conduct reliable multicast sessions with limited
a priori
coordination among senders and receivers. a congestion control scheme is specified to allow the norm protocol fairly share available network bandwidth with other transport protocols such as transmission control protocol (tcp). it is capable of operating with both reciprocal multicast routing among senders and receivers and with asymmetric connectivity (possibly a unicast return path) from the senders to receivers. the protocol offers a number of features to allow different types of applications or possibly other higher level transport protocols to utilize its service in different ways. the protocol leverages the use of fec - based repair and other ietf reliable multicast transport (rmt) building blocks in its design .
udt is a protocol and library; it does not provide a tool / application for end users directly. if you need a system software to support wide area data storage and distribution, please try sector .
udt is a protocol and library; it does not provide a tool / application for end users directly. if you need a system software to support wide area data storage and distribution, please try sector .
however, udt implementations should check that all arrived packets are from the expected source, since udp is connectionless. this is inherently accomplished because in the socket api a
connected
udp socket only accepts packets from a certain source the udp socket is
connected
to. normative references [
that is what i mean by a unique data channel - probably not the best terminology .
it may be helpful to build an open source user space transport protocol above udp, but with the data reliability control and network flow / congestion control. because it is at user space, it is easy to get installed. because it is open source, it can be easily modified to meet various requirements from applications .
the science dmz will benefit current and future projects including: increasing access to and improving analyses of particle physics data generated at the large hadron collider; accessing large genomic datasets stored on the bionimbus system; connecting communities of scientists to raw data from upcoming ground and space based telescope surveys such as the dark energy survey; using data from the south pole telescope to probe astrophysical processes at new levels of detail and sharing this data with the larger scientific community; assisting computer science researchers to explore future internets at scale and research advanced data - intensive computing infrastructure and tools; providing general public to access high fidelity cosmological simulations and visualizations from the adler planetarium; and enabling community access to a unique database of marketing data from chicago booth and nielsen .
this is the nack - oriented reliable multicast (norm) protocol web site maintained by the naval research laboratory (nrl) protocol engineering advanced networking (protean) research group. the purpose of this site is to provide information on norm and provide access to the norm reference software provided by nrl. the norm protocol is currently under development within the internet engineering task force (ietf) reliable multicast transport (rmt) working group .
hi: i have a question about udt, i see the document in urltoken which says: while udt was originally written for extremely high speed data transfer, there are many other potential benefits from this reliable udp - based library. one particular usage is to setup reliable connections between machines behind firewalls, especially those nat firewall. to meet this requirement, udt has added the rendezvous connection setup support. it seems udt only support punching firewall / nat only in rendezvous mode, is that right ?
checksum – used to verify that the data has not been corrupted by routers of bridges in the network .
as mentioned in the table above, the udp header is quite small (8 bytes in total) and consists of four fields, each one being 2 bytes in length. the purpose and function of each udp header section is described below .
quic, short for quick udp internet connections, is an experimental network protocol design by google. the goal for quic is that it allows for an even faster internet browsing experience and in time, will likely replace http / 2. learn more about quic via this quic faq guide .
to satisfy the high requirement of these applications, high performance network transport is needed. first, high speed network is needed. traditional packet - switched ip network is difficult to satisfy this requirement. new emerged circuit - switched optical network technology is being used to build fast long - distance network (fldnet). there are many optical fldnets and related projects now, such as dynamic resource allocation via gmpls optical network (dragon), hybrid optical and packet infrastructure (hopi), the global ring network for advanced applications development (gloriad) and user controlled light paths (uclp) and so on. end - to - end lighpath can provide high bandwidth and qos guarantee for these special applications (ren, 2008a). second, high performance transfer protocol is needed. traditional tcp protocol performs poorly over fldnet and udp is not reliable. so, research on new transfer protocol has become a hot research topic .
june 14, 2010: a high performance data distribution and sharing solution with sector we invite you to try sector as your data distribution and sharing platform. unlike ftp and most commercial applications, sector can provide a uniform namespace over multiple servers, even 1000s. meanwhile, users can mount the client side as a local file system directory so that it is completely transparent. all data transfer between servers and clients is on top of udt. you can follow this blog to set up the system .
there are many large scale e - science projects such as lhc particle accelerator in high energy physics (hep), iter experiment in fusion energy science and e - vlbi in astronomical observation fields. during these projects, the movement of massive amounts of data between labs, facilities and instruments distributed all over the world are becoming common. these e - science applications have high requirement for network performance on bandwidth, stability and reliability and so on. other emerging applications like hdtv transfer and e - health also require high speed data transfer over long distance .
udt is an efficient and easy to use library to transfer bulk data with its own reliability control and congestion control mechanisms. being fast is one of udt’s key features. besides, concurrent udt flows can share the available bandwidth fairly and udt is also friendly to tcp flows .
auto - optimization for tunneled protocols —many emerging applications for big data and vm mobility rely on non - tcp tunneled protocols such as overlay transport virtualization (otv) developed by cisco systems, udp - based data transfer protocol (udt) for transferring large volumetric datasets over high speed wans (e. g. emc vplex), virtual extensible lan (vxlan) from vmware and cisco, and network virtualization using generic routing encapsulation (nvgre) developed by microsoft and others. silver peak auto - optimization with real - time tunneling helps customer quickly and easily optimize the wan for these types of non - tcp applications “out - of - the - box. ” no special configuration or software is required. silver peak vxoa automatically discovers the applications requiring optimization, sets - up the tunnel, and optimizes application performance by overcoming common wan obstacles, including bandwidth, distance, and quality .
how to cite this article: yongmao ren, haina tang, jun li and hualin qian, 2009. performance comparison of udp - based protocols over fast long distance network. information technology journal, 8: 600 - 604. doi: 10. 3923 / itj. 2009. 600. 604 url: urltoken
i am currently working on a project and i am asked to
break
udt protocol from application, what i mean exactly is to make two different exes (one for protocol and one for application) and make them correspond with each other through pipes or something like that. i am newbie to newtwork programming so any help would be appreciated !
silver peak vxoa is a software - based approach to wan optimization that makes deployment, management, and growth easy and cost - effective. the software optimizes all internet protocol (ip) traffic, runs on any hardware platform or hypervisor, and offers flexible pricing options that align with customer requirements. the new capabilities in silver peak vxoa 5. 2 include :
“the proliferation of ‘big data’ and cloud - based applications is driving change within today’s data centers, including standardizing on larger - capacity networks, virtualization, and the use of non - tcp tunneled protocols like otv, vxlan and nvgre that are required for virtual machine (vm) mobility across data centers, ” said damon ennis, vice president of product management for silver peak. “with silver peak vxoa, enterprises can quickly and easily future - proof the wan for these evolving data center requirements and the inevitable transition to the cloud. customers benefit from the industry’s highest performance virtual and physical wan optimization appliances that can be deployed anywhere, and on nearly any platform or hypervisor. ”
poor performance on high packet loss, low bandwidth links, default configuration is very sensitive to packet loss. in fact a single dropped packet could force a failed transfer
“having evaluated numerous wan optimization solutions, silver peak’s unrivaled performance and unique capabilities for optimizing all ip - based applications makes it best - in - class, ” said peter mayo, director of ecologic systems, a leading cloud - based managed service provider delivering optimization - as - a - service (oaas) to uk enterprises. “silver peak’s virtual architecture maps perfectly with our services platform, offering delivery and deployment flexibility for optimizing remote branches to data centers at a much lower cost than its competitors. ”
i found that you will have a
:: connect
routine under udp. is that in rendzvous mode, the
udt: : connect
will call the
:: connect
? my concern is, since under udp, if you call
:: connect
, it is just for one peer connection. according to the document of unix ,
connect
under udp mode only support one peer .
]. additionally, the unfairness of rtt bias inherent in tcp congestion control also becomes more serious in distributed data intensive applications. concurrent tcp flows with different rtt will tend to unfairly share the available bandwidth. although small bdp networks will share bandwidth relatively fairly using conventional tcp implementations, networks with large bdp tend to suffer severe unfairness issues under conventional tcp. this rtt bias severely limits the effectiveness of distributed computations based on high - speed wide - area networks as, for example, grid - based computations in
the way tcp and udp protocols both work are that they break down a large data set (i. e. a file) into individual packets. these packets are then sent across the internet, hopping from one node to the next until they eventually end up at their destination. once all of the packets have arrived, the data set is reconstructed and the file is back to its original state .
data structures and variables: 1) snd pkt history window: a circular array that records the departure time of each data packet. 2) sender' s loss list: the sender' s loss list is a linked list used to store the sequence numbers of the lost packets fed back by the receiver in nak packets. the numbers are stored in increasing order. data sending algorithm :
while it is not very difficult, there is no simple way to do it. first, you have to write a udp multiplexer that deals with multiple connection sending and receiving. once you have this ready, you can use it to replace the regular udp channel as in channel. h .
udt is duplex. each udt entity has two parts: the sender and the receiver. the sender sends (and retransmits) application data according to flow control and rate control. the receiver receives both data packets and control packets, and sends out control packets according to the received packets as well. both the sender and the receiver share one udp port for packet sending / receiving. the receiver is also responsible for triggering and processing all control events, including congestion control and reliability control, and their related mechanisms such as rtt estimation, bandwidth estimation, acknowledging and retransmission. udt always tries to pack application data into fixed size packets, unless there is not enough data to be sent. similar to tcp, this fixed packet size is named mss (maximum segment size). since udt is supposed to be used to transfer bulk data stream, we assume that there is only a very small portion of irregular sized packets in a udt session. mss can be set up by applications (see
all of the three udp - based protocols get much larger throughput than tcp. among them, rbudp and tsunami have very high throughput up to 660 mbps. note that the throughput of rbudp drops obviously when transferring large file (> 2 gb), thats because rbudp has to use stream to transfer large file (this point has been explained hereinbefore). when using tsunami, the file size has no limit and the throughput is high. but some parameters like block size and buffer size are needed to be adjusted to be optimal value .
the position of udt in the layered architecture of internet reference model is shown in the figure below. applications use udt socket to transfer their data, which is passed to the udp socket. (effort was made to avoid one time memory copy here .) a congestion control (cc) algorithm can be provided by applications; otherwise the default control algorithm is used. if user - defined control algorithm is provided, udt will call the callback functions in cc once a control event occurs :
efficiency and stability: utilization of the available network resource is used to measure the protocol efficiency. for fldnet, the link is not cheap, so the utilization of bandwidth is important. and for most e - science applications, high speed and stable throughput is necessary. a series of experiments are made under typical fldnet configuration (rtt > 300 m sec, loss rate = 0. 1 %). the throughput of tcp is very low (about 1. 05 mbps). figure 2 shows the throughput of these udp - based protocols when transferring different size of payloads .
i would encourage you to think about whether you actually need guaranteed receipt of that data, and, if you do, consider using tcp .
“our environment is highly - centralized with large amounts of live data from many applications traversing our data center wan, ” said jason barrett, it manager for m3 engineering, a full - service global design firm providing clients with architecture, engineering and construction management. “we found silver peak to be the only vendor that could automate the optimization of our applications and data traversing the wan, including all our business - critical applications. ”
an internet2 - based context. as of today, improvements on the standard tcp still fails to satisfy the efficiency and fairness (especially the rtt bias problem) objectives in high bdp environments. such tcp modifications as presented in
the default udt control algorithm is designed for high performance data transfer over wide area high speed networks (e. g. in the case of example a). however, udt' s congestion control algorithm is configurable such that you can add your own control algorithm with ease (e. g. , in the case of example b) .
udp has its advantages over tcp, such as being relatively lightweight and receiving one packet per read call (recvmsg), although the programmers need to handle related issues, such as packet lost and out - of - order packets delivery. this post gives information and references on how to write udp programs in a c / linux environment .
bernardo, d. v. , hoang, d. b. : “network security considerations for a new generation protocol udt. in: proc. ieee the 2nd iccist conference 2009, beijing, china (2009 )
rbudp: based on udp, rbudp adds simple ack and retransmission mechanism to guarantee reliability. but it is different from tcps ack. in tcp, receiver sends an ack to sender for each or every other received segment. this is too frequent. sending ack takes up handling time and the ack packets also take up bandwidth. on other hand, in fldnet, because the rtt is large, after the sender sends out all the packets allowed by window, it may has to wait for a long time to receive the ack. while, rbudp firstly uses udp to continually transfer all the data, the receiver keeps a tally of the packets that are received but gives no ack until it receives the finish signal done. then, the receiver sends an ack consisting of a bitmap tally of the received packets by tcp. the sender resends the missing packets and the process repeats until no more packets need to be retransmitted .
jokela, p. , moskowitz, r. , nikander, p. : using the encapsulating security payload (esp) transport format with the host identity protocol (hip). rfc 5202, ietf (april 2008 )
gazis, v. , patouni, e. , alonistioti, n. , merakos, l. : a survey of dynamically adaptable protocol stacks. ieee communications surveys and tutorials 10 (1), 3–23 (2010 )
this project established a science dmz network at the university of chicago distinct from the general - purpose campus network, engineered specifically to support data - intensive science. the science dmz further enables the university’s participation in activities involving data access, collaborative research, real - time analysis, science education, and citizen science .
kliazovich, d. , granelli, f. : distributed protocol stacks: a framework for balancing interoperability and optimization. in: ieee international conference on communications workshops 2008 (icc workshops 2008), pp. 241–245 (2008 )
the authors thank the designers or developers of the udp - based protocols for their explanation and help in experiments. they are eric he (rbudp), yunhong gu (udt) and jan wagner (tsunami). this research was supported in part by international cooperation and communications project of national ministry of science and technology of china under grant no. 2006dfa1990 and the knowledge innovation program of chinese academy of sciences under grant no. 0814061101 .
] y. gu, x. hong, and r. l. grossman ,
experiences in design and implementation of a high performance transport protocol
. sc 2004, pittsburgh, pa, nov. 6 - 12, 2004. [
i think we are on the same boat my friend, handling udp packets lose, duplication or miss order is a very interesting topic. if you find any results, please let me know
chown, t. , juby, b. : overview of methods for encryption of h. 323 data streams. technical paper, university of southampton (march 2001 )
when data needs to be transferred, the server would start listening on a
new
port, and send the port number to the client via a control message .
however, when using tcp some applications suffer from two problems. first, tcp demonstrates poor performance in long distance links, especially when the bandwidth is high (e. g. , 1gb / s or higher). second, when incorporating multiple concurrent tcp flows with different rtts in the same application, different tcp flows may have different data transfer rates (also known as rtt bias) .
udp is not a guaranteed - transmission protocol. a host will send a message, but if the recipient does not receive it, or if it is not received properly, no error will be raised. therefore, it is commonly used in applications that require speed over perfect delivery, such as games. tcp does guarantee delivery, because it requires that a connection be set up first, and each message is acknowledged by the client .
tsunami: the basic principle of tsunami is the same as rbudp. tsunami mainly makes two points of improvement on rbudp. first, tsunami receiver does not wait for finishing of all the data transfer, but periodically (every 50 blocks) makes a retransmission request and periodically calculates the current error rate and sends it to the sender. second, tsunami adds rate - based congestion control mechanism. the sender control the sending rate by adjusting the inter - packet delay according to the error rate received. additionally, if the number of packets that need to be retransmitted is too large, the sender will restart transmission of the file at the given block number .
]. the packet size information can be used to derive the size of the payload in a data packet and the size of control information field in an nak control packet .
bernardo, d. v. , hoang, d. b. : a conceptual approach against next generation security threats: securing a high speed network protocol – udt. in: proc. ieee the 2nd icfn 2010, shanya, china (2010 )
it can be seen that tcp also performs well if the rtt is very small (< 2 m sec in lan), but performs poorly if the rtt is big (in wan and fldnet). still, udp - based protocols have much higher throughput than tcp (fig. 5). the throughputs of rbudp and udt reduce as the increasing of rtt. the throughput of tsunami is much higher than others and changes little as the increasing of rtt .
alonistioti, n. , patouni, e. , gazis, v. : generic architecture and mechanisms for protocol reconfiguration. special issue on reconfigurable radio technologies in support of ubiquitous seamless computing, mob. netw. appl journal 11 (6), 917–934 (2006 )
for tcp, a kind of tcp variant named bic - tcp (default tcp protocol used in linux 2. 6. 18 kernel) is used and the tcp buffer size is set to be larger than bdp (bandwidth delay product) in order to get optimal performance .
in next generation networks, the introduction of intelligence and flexibility in mobile devices and network nodes appears as a promising solution to the high degree of variability in the telecommunication environment. the materialization of these concepts under the autonomic networking notion paves the way for introduction of awareness and adaptation capabilities in various layers of mobile devices, also including the protocol stack. in this paper we investigate the problem of dynamic protocol stack adaptation and propose enabling mechanisms for the dynamic binding and replacement of their constituent components. our work addresses the challenge of the application feasibility and performance evaluation of these concepts by quantifying the introduced delay. the obtained results show that the introduced protocol adaptation functionalities pose negligible performance impact in the system. our work reveals that although flexibility and performance stand on the opposite sides of the system balance, the introduction of transparent mechanisms leads to great adaptability with minimum performance impact .
about silver peak systems, inc. silver peak is the leader in data center class wan optimization. the company’s virtual acceleration open architecture (vxoa) delivers unprecedented scalability and flexibility, enabling rapid deployment of wan optimization anywhere and on any platform or hypervisor. silver peak’s wan optimization solutions are strategic enablers for large it initiatives, including data center consolidation, data migration, cloud computing, disaster recovery, server centralization, and hosted virtual desktops (vdi). for more information, visit the silver peak infocenter or follow silver peak on twitter, facebook, youtube, linkedin, and the wan speak blog .
niamanesh, m. , jalili, r. : a dynamic - reconfigurable architecture for protocol stacks of networked systems. in: proceedings of the 31st annual international computer software and applications conference (compsac 2007), washington, dc, usa, vol. 1, pp. 609–612 (2007 )
udt seems to be pulling ahead for now. but none of these projects are a viable replacement for the enterprise because they are lacking the functionality and the ease of use of commercial applications. gridftp could be used if the organization plans to use globus and develop a file transfer workflow based on the cli. a commercial solution such as filecatalyst addresses each of the weak points, including flexible congestion control, firewall friendliness, gui client apps and automatic resume / retry which provides a real cost savings and efficiency boost when compared to piecing together a custom solution using a bare bones api .
udt: udt is more complex than rbudp and tsunami and its similar to tcp. based on udp, in addition to add reliability, udt also adds congestion control and flow control mechanisms. for reliability, udt receiver sends selective acknowledgment (sack) at a fixed interval and sends negative acknowledgment (nak) once a loss is detected to explicitly feed back packet loss. for congestion control, udt adopts daimd (aimd with decreasing increase) algorithm to adjust sending rate (not congestion window size like tcp). to differentiate congestion and error, udt does not react to the first packet loss, while decreases the sending rate if there is more than one packet loss in a congestion event. additionally, udt uses receiver - based packet pairs to estimate the link capacity. like tcp, udt also uses a flow control window to limit the number of unacknowledged packets .
patouni, e. , holland, o. , alonistioti, n. : cognitive functionalities for mobile terminal self - recovery and protocol auto - configuration. in: the proceedings of the ieee international symposium on personal, indoor and mobile radio communications 2008 (pimrc 2008), cannes, france (2008 )
. acknowledgments the authors thank dr. xinwei hong for his cooperated work in the sabul protocol, an early prototype of udt protocol. dr. marco mazzucco and dr. sivakumar harinath also contribute to the earlier idea of sabul. we appreciate those researchers, developers, and system administrators inside or outside lac / ncdm for their helpful feedbacks on using udt. we are grateful to starlight, sara, and canarie for providing us the high - speed networking infrastructures. we are also grateful for the feedback and comments from the following individuals: guy almes, cees de laat, freek dijkstra, rajkumar kettimuthu, and johan blom .
common problems with all 4 solutions is lack of graphical user interface. two provide bare bones sender and receiver apis (meaning that the end user has to compile the classes), while the third one only comes with a command line interface (cli). another common problem is poor support for firewall traversal. while this is not an issue for internal transfers, most organizations are interested in sending files over the wan (which will almost certainly have at least one firewall somewhere on the route). none of these solution fare well in the worst network conditions, where packet loss, bandwidth or latency are very high. finally the congestion control in the udp projects is missing the flexibility to adapt to ever changing network conditions during the data transfer .
rbudp needs user to set the sending rate. user has to measure the available bandwidth before transfer. another problem is that because the sender has to keep all the packets that have been sent for retransmission if needed, if the file size is bigger than the memory, it cant be done.
udp-based data transfer protocol ( udt ) , is a high-performance data transfer protocol designed for transferring large volumetric datasets over high-speed wide area networks . such settings are typically disadvantageous for the more common tcp protocol . initial versions were developed and tested on very high-speed networks ( 1 gbit/s , 10 gbit/s , etc. ) ; however , recent versions of the protocol have been updated to support the commodity internet as well . for example , the protocol now supports rendezvous connection setup , which is a desirable feature for traversing nat firewalls using udp . udt has an open source implementation which can be found on sourceforge . it is one of the most popular solutions for supporting high-speed data transfer and is part of many research projects and commercial products . 
udp-based data transfer protocol (udt), is a high-performance data transfer protocol designed for transferring large volumetric datasets over high-speed wide area networks. such settings are typically disadvantageous for the more common tcp protocol. initial versions were developed and tested on very high-speed networks (1 gbit/s, 10 gbit/s, etc.); however, recent versions of the protocol have been updated to support the commodity internet as well. for example, the protocol now supports rendezvous connection setup, which is a desirable feature for traversing nat firewalls using udp. udt has an open source implementation which can be found on sourceforge. it is one of the most popular solutions for supporting high-speed data transfer and is part of many research projects and commercial products.
udp-based data transfer protocol (udt), is a high-performance data transfer protocol designed for transferring large volumetric datasets over high-speed wide area networks. such settings are typically disadvantageous for the more common tcp protocol. initial versions were developed and tested on very high-speed networks (1 gbit/s, 10 gbit/s, etc.); however, recent versions of the protocol have been updated to support the commodity internet as well. for example, the protocol now supports rendezvous connection setup, which is a desirable feature for traversing nat firewalls using udp. udt has an open source implementation which can be found on sourceforge. it is one of the most popular solutions for supporting high-speed data transfer and is part of many research projects and commercial products.