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UDP

The is a connectionless transport-layer protocol within the that enables the transmission of datagrams without establishing a prior connection, guaranteeing neither delivery, ordering, nor duplicate suppression, while providing only a basic for error detection. Defined in RFC 768 and published in August 1980, UDP operates atop the (IP) to multiplex application data into discrete, self-contained packets known as datagrams, each carrying a minimal 8-byte header consisting of source and destination ports, length, and fields. Designed by as a lightweight alternative to more robust protocols, it prioritizes simplicity and minimal overhead, making it suitable for scenarios where speed and efficiency outweigh the need for reliability mechanisms like acknowledgments or retransmissions. UDP's core features include its stateless nature, absence of or , and lack of sequencing, which collectively result in lower and reduced compared to connection-oriented protocols such as , though at the cost of potential or corruption in unreliable networks. This design facilitates applications demanding real-time performance, including (DNS) queries, (DHCP) exchanges, (VoIP), online gaming, and streaming, where occasional data loss is tolerable if overall throughput remains high. Extensions like UDP-Lite have since introduced partial coverage for in contexts, but the base remains unchanged in its fundamental unreliability. While UDP's efficiency has cemented its role in modern networking—evident in protocols like that build reliability atop it—the protocol's inherent vulnerabilities to issues such as amplification attacks in DNS or lack of built-in have prompted supplementary measures, including application-layer and , rather than alterations to its core specification. Its enduring adoption underscores a favoring performance in bandwidth-constrained or latency-sensitive environments over guaranteed fidelity, influencing developments in tunneling and real-time transport without supplanting more assured alternatives.

Science and technology

User Datagram Protocol

The (UDP) is a minimalistic protocol in the , providing a connectionless, mechanism for transmitting datagrams between applications on networked hosts. Defined to enable simple, transaction-oriented communication without the overhead of connection establishment or reliability guarantees, UDP assumes the underlying (IP) for routing and assumes IP version 4 or compatible addressing. It operates by encapsulating user data into datagrams with a short header, appending the protocol number 17 to IP headers, and relying on IP for transmission. UDP was specified in RFC 768, authored by and published on August 28, 1980, as a core component for lightweight messaging in the early environment transitioning to the . Unlike connection-oriented protocols, UDP does not establish virtual circuits, sequence numbers, acknowledgments, or retransmissions, making it unsuitable for applications requiring guaranteed delivery or ordering but ideal for scenarios prioritizing low latency and minimal processing overhead. Datagrams may arrive out of order, be duplicated, lost, or corrupted without protocol-level recovery; applications must implement any needed error handling or reliability atop UDP. The protocol's design minimizes state maintenance at endpoints, supporting and broadcast via while allowing optional checksums for basic integrity checks—set to zero to disable verification. This simplicity contrasts with the , which enforces reliability through handshakes and congestion control, resulting in UDP's lower overhead and faster transmission but higher risk of . UDP's header consists of eight bytes across four 16-bit fields: (identifying the sending application, optional and zero if unused), destination port (specifying the receiving application, context-dependent on the ), length (total octets of header plus data, minimum eight), and (one's complement sum including a pseudo-header with addresses, UDP length, and 17, plus the UDP header and data; covers errors in headers or data but optional). The pseudo-header ensures checksums detect misdelivery across networks. Ports range from 0 to 65,535, with well-known assignments like for DNS queries. Processing involves user interfaces for port creation, reception (including source details), and transmission without flow control. Early applications included the Internet Name Server (precursor to DNS) for query-response transactions and (TFTP) for simple file exchanges, leveraging UDP's efficiency for short, non-critical transfers. Modern guidelines recommend UDP for applications needing low delay, such as media streaming or tunneling, but advise against it for bulk data without application-layer mitigations for loss. Usage has expanded to protocols like DNS (UDP port 53 for queries under 512 bytes), DHCP for address assignment, NTP for time synchronization, and RTP for VoIP or video, where occasional loss is tolerable over retransmission delays. RFC 8085 provides contemporary guidelines, emphasizing path MTU awareness and checksum enablement to avoid amplification risks in tunnels or .

Uridine diphosphate

(UDP) is a ribonucleoside 5'-diphosphate composed of the nucleoside —a linked to a sugar—and two groups connected via a linkage at the 5' position of the ribose. Chemically, it functions as an activated form of in cellular metabolism, with a molecular formula of C₉H₁₄N₂O₁₂P₂ and a molecular weight of 404.18 g/mol. UDP is ubiquitous across kingdoms of life, serving as an intermediate in nucleotide sugar biosynthesis and energy transfer processes. UDP primarily acts as a precursor for UDP-sugars, such as UDP-glucose and , which donate sugar moieties in reactions catalyzed by uridine diphosphate glycosyltransferases (UGTs). These enzymes, part of the GT1 family of glycosyltransferases, facilitate the addition of or other sugars to xenobiotics, hormones, and endogenous substrates, aiding in , metabolic , and stabilization of biomolecules. For instance, UDP-glucuronosyltransferases (UGTs) in the catalyze , a phase II conjugation reaction essential for rendering lipophilic compounds water-soluble for excretion. In plants, UDP-dependent modifies secondary metabolites like , enhancing their solubility and bioactivity. In , UDP is critical for and synthesis through the formation of UDP-glucose, which serves as the glucosyl donor for . Elevated ATP consumption or UDP-glucose utilization, as observed in conditions of high metabolic demand, correlates with increased plasma levels, reflecting UDP's role in linking nucleotide and sugar metabolism. UDP-glucose dehydrogenase further oxidizes UDP-glucose to UDP-glucuronic acid, supporting production and defense in mammals and . Structural studies of UDP-binding enzymes reveal conserved motifs, such as the UDP-binding domain in UGTs, where the diphosphate group coordinates magnesium ions to facilitate nucleophilic attack by the acceptor . Beyond , UDP participates in as an extracellular for P2Y receptors, though this role is secondary to its intracellular metabolic functions. Dysregulation of UDP-related pathways, such as in UGT deficiencies, can lead to metabolic disorders like Crigler-Najjar syndrome, characterized by impaired . In tumor biology, altered UGT expression modulates and hormone metabolism, with UDP-sugar availability influencing patterns on glycoproteins. Experimental evidence from yeast microsomes confirms UDP-glucose transport into the , underscoring its compartmentalized role in and quality control.

Politics

Political parties

The United Democratic Party (UDP) of , established in 1973, functions as one of the nation's two dominant political entities, emphasizing free-market policies and opposition to the ruling . It secured victory in the 1984 general election under leader Manuel Esquivel but alternated power with its rival in subsequent decades; as of 2025, it holds opposition status following electoral defeat. In , the United Democratic Party (UDP), founded on August 23, 1996, by advocate Ousainou Darboe amid bans on predecessor groups under Jammeh's regime, promotes democratic reforms and an inclusive national agenda. It emerged as the largest opposition force, capturing 31 of 53 contested seats in the elections. The United Democratic Party (UDP) in , , formed in 1997 by E.K. Mawlong, operates as a regional entity advocating for and state development, currently under the leadership of following internal shifts. It participates in coalitions within Meghalaya's fragmented assembly politics. Nigeria's United Democratic Party (UDP), registered as a national entity, outlines a non-tribal, non-religious platform in its constitution, though it remains marginal compared to major parties like the and in federal contests.

Public administration and

Unitary Development Plan

A Unitary Development Plan (UDP) is a statutory land use that forms the development plan for certain authorities in , as defined under the Town and Country 1990. It combines strategic policies (Part I) with detailed proposals (Part II), replacing the previous of county plans and district plans in applicable areas. UDPs guide decisions on applications by setting policies for , improvements, , and provision, typically covering a 10-year period. The legal framework for UDPs was established by the Town and Country Planning Act 1990 (sections 12–17 for and equivalent provisions for ), with procedural regulations outlined in the Town and Country Planning (Unitary Development Plans) Regulations 1988. Preparation requires , including a deposit stage for objections and an independent examination by a planning inspector appointed by the Secretary of State. Authorities such as metropolitan districts, , and some unitary councils—totaling around 56 in as of adoption—must ensure the plan aligns with while addressing local needs like housing allocation and site-specific allocations. In , similar requirements applied to National Parks and other unitary areas until phased out. UDPs emphasize , with Part I focusing on broad strategies (e.g., targets and protections) and Part II on granular policies (e.g., for residential or commercial uses and development control standards). For instance, City Council's UDP, adopted in 2001, allocated sites for over 27,000 new homes while safeguarding employment land. renders the UDP presumptively in decisions, subject to material considerations under section 70(2) of the 1990 . Since the Planning and Compulsory Purchase Act 2004, many UDPs have been superseded by Local Development Frameworks (now consolidated into Local Plans), with over 80% of English authorities transitioning by 2015. Remaining UDPs, such as those in (adopted 2005) or Bury, continue as saved policies until full replacement, ensuring continuity in areas without updated plans. This evolution reflects shifts toward more flexible, evidence-based planning, though critics note UDPs' rigidity aided certainty in development control pre-2004.

References

  1. [1]
    RFC 768 - User Datagram Protocol - IETF Datatracker
    RFC 768 defines the User Datagram Protocol (UDP), a datagram mode for packet-switched communication, using IP as the underlying protocol.
  2. [2]
    RFC 5218: What Makes for a Successful Protocol?
    1. Extensible Protocols that are extensible are more likely to be wildly successful in terms of being used for purposes outside their original design. · 2. · 3.<|separator|>
  3. [3]
    RFC 8304 - Transport Features of the User Datagram Protocol (UDP ...
    RFC 8304 describes the transport protocol interface primitives of UDP and UDP-Lite, including how applications can configure and use their features.
  4. [4]
    RFC 6936 - Applicability Statement for the Use of IPv6 UDP ...
    Oct 14, 2015 · This document provides an applicability statement for the use of UDP transport checksums with IPv6. It defines recommendations and requirements.
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    https://datatracker.ietf.org/doc/html/rfc761
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    Uridine Diphosphate | C9H14N2O12P2 | CID 6031 - PubChem
    UDP is a uridine 5'-phosphate and a pyrimidine ribonucleoside 5'-diphosphate. It has a role as an Escherichia coli metabolite and a mouse metabolite.
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    The Uridine diphosphate (UDP)-glycosyltransferases (UGTs ...
    This review summarizes the roles of members of the four UGT enzyme families in tumor function, metabolism, and multiple regulatory mechanisms
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    Structure and function of uridine diphosphate ... - PubMed
    The uridine diphosphate (UDP)-glucuronosyltransferases (UGT) are a family of enzymes that catalyse the covalent addition of glucuronic acid to a wide range of ...
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    Six Uridine-Diphosphate Glycosyltransferases Catalyze the ... - NIH
    In plants, uridine diphosphate (UDP) sugar-dependent glycosyltransferases (UGTs) catalyze the production of small-molecule glycosides by transferring a ...
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    Biochemistry of uridine in plasma - PubMed
    Sep 18, 2011 · Factors associated with an increase in plasma concentration of uridine include enhanced ATP consumption, enhanced uridine diphosphate (UDP)-glucose consumption ...
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    Structure-function relationships for UGDH and proposals for the enzymatic reaction mechanism are reviewed in the present paper, and structure-based sequence ...
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    Structure-function and engineering of plant UDP-glycosyltransferase
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    Uridine Diphosphate - an overview | ScienceDirect Topics
    Uridine, a pyrimidine nucleoside in RNA, exhibits activities in the regulation of insulin action. Uridine regulates glycogen synthesis via uridine diphosphate ( ...
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    Structural and functional studies of UDP-glucuronosyltransferases
    Recent findings with regard to UGT structure and topology are presented, including a dynamic topological model of UGTs in the ER.<|separator|>
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    Uridine Diphosphate–Glucose Transport into the Endoplasmic ...
    Oct 13, 2017 · We have detected transport of this sugar nucleotide into the ER in vivo and into ER–containing microsomes in vitro. Experiments with ER- ...
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    United Democratic Party | political party, Belize | Britannica
    The United Democratic Party (UDP), formed in 1973 and led by Manuel Esquivel, won the general election in 1984, but in 1989 the PUP won the election.
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    About Us - United Democratic Party
    We are the largest political party in The Gambia, founded on the 23 rd August 1996. The UDP won 31 out of 53 contested seats at the National Assembly.
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    UDP – Background History - United Democratic Party
    The United Democratic Party (UDP) is a registered political party in The Gambia, founded in 1996. The leader of the UDP is His Excellency ANM Ousainu Darboe.
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    United Democratic Party - India Today
    The United Democratic Party (UDP) is a regional political party based in Meghalaya, India, founded in 1997 by EK Mawlong.
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    [PDF] UDP-Constitution.pdf - INEC
    29. Page 2. PREAMBLE. We the member of United Democratic Party having actualized our dream of being formed into a virile non-tribal, non-religious, national ...<|separator|>
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    [PDF] 1 Introduction to the Unitary Development Plan
    1 A Unitary Development Plan (UDP) is a 'land use' plan and is the development plan for purposes of Section 54A of the Town and Country Planning Act 1990.
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    [PDF] CONTENTS - Westminster City Council
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    The Town and Country Planning (Unitary Development Plans ...
    6.—(1) A unitary development plan shall be given a title which comprises the name of the area of the local planning authority followed by the words ...
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    The Unitary Development Plan (UDP) is part of Walsall's Local Plan. Find out about the UDP and planning policies.
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    The Bury Unitary Development Plan (UDP) acts as a guide for the future development or protection of land in the Borough.Missing: definition | Show results with:definition