Characteristic of the User Datagram Protocol Udp
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DE-CIX Academy Handout
Networking Basics 04 - User Datagram Protocol (UDP) Wolfgang Tremmel [email protected] DE-CIX Management GmbH | Lindleystr. 12 | 60314 Frankfurt | Germany Phone + 49 69 1730 902 0 | [email protected] | www.de-cix.net Networking Basics DE-CIX Academy 01 - Networks, Packets, and Protocols 02 - Ethernet 02a - VLANs 03 - the Internet Protocol (IP) 03a - IP Addresses, Prefixes, and Routing 03b - Global IP routing 04 - User Datagram Protocol (UDP) 05 - TCP ... Layer Name Internet Model 5 Application IP / Internet Layer 4 Transport • Data units are called "Packets" 3 Internet 2 Link Provides source to destination transport • 1 Physical • For this we need addresses • Examples: • IPv4 • IPv6 Layer Name Internet Model 5 Application Transport Layer 4 Transport 3 Internet 2 Link 1 Physical Layer Name Internet Model 5 Application Transport Layer 4 Transport • May provide flow control, reliability, congestion 3 Internet avoidance 2 Link 1 Physical Layer Name Internet Model 5 Application Transport Layer 4 Transport • May provide flow control, reliability, congestion 3 Internet avoidance 2 Link • Examples: 1 Physical • TCP (flow control, reliability, congestion avoidance) • UDP (none of the above) Layer Name Internet Model 5 Application Transport Layer 4 Transport • May provide flow control, reliability, congestion 3 Internet avoidance 2 Link • Examples: 1 Physical • TCP (flow control, reliability, congestion avoidance) • UDP (none of the above) • Also may contain information about the next layer up Encapsulation Packets inside packets • Encapsulation is like Russian dolls Attribution: Fanghong. derivative work: Greyhood https://commons.wikimedia.org/wiki/File:Matryoshka_transparent.png Encapsulation Packets inside packets • Encapsulation is like Russian dolls • IP Packets have a payload Attribution: Fanghong. -
User Datagram Protocol - Wikipedia, the Free Encyclopedia Página 1 De 6
User Datagram Protocol - Wikipedia, the free encyclopedia Página 1 de 6 User Datagram Protocol From Wikipedia, the free encyclopedia The five-layer TCP/IP model User Datagram Protocol (UDP) is one of the core 5. Application layer protocols of the Internet protocol suite. Using UDP, programs on networked computers can send short DHCP · DNS · FTP · Gopher · HTTP · messages sometimes known as datagrams (using IMAP4 · IRC · NNTP · XMPP · POP3 · Datagram Sockets) to one another. UDP is sometimes SIP · SMTP · SNMP · SSH · TELNET · called the Universal Datagram Protocol. RPC · RTCP · RTSP · TLS · SDP · UDP does not guarantee reliability or ordering in the SOAP · GTP · STUN · NTP · (more) way that TCP does. Datagrams may arrive out of order, 4. Transport layer appear duplicated, or go missing without notice. TCP · UDP · DCCP · SCTP · RTP · Avoiding the overhead of checking whether every RSVP · IGMP · (more) packet actually arrived makes UDP faster and more 3. Network/Internet layer efficient, at least for applications that do not need IP (IPv4 · IPv6) · OSPF · IS-IS · BGP · guaranteed delivery. Time-sensitive applications often IPsec · ARP · RARP · RIP · ICMP · use UDP because dropped packets are preferable to ICMPv6 · (more) delayed packets. UDP's stateless nature is also useful 2. Data link layer for servers that answer small queries from huge 802.11 · 802.16 · Wi-Fi · WiMAX · numbers of clients. Unlike TCP, UDP supports packet ATM · DTM · Token ring · Ethernet · broadcast (sending to all on local network) and FDDI · Frame Relay · GPRS · EVDO · multicasting (send to all subscribers). HSPA · HDLC · PPP · PPTP · L2TP · ISDN · (more) Common network applications that use UDP include 1. -
Routing Loop Attacks Using Ipv6 Tunnels
Routing Loop Attacks using IPv6 Tunnels Gabi Nakibly Michael Arov National EW Research & Simulation Center Rafael – Advanced Defense Systems Haifa, Israel {gabin,marov}@rafael.co.il Abstract—IPv6 is the future network layer protocol for A tunnel in which the end points’ routing tables need the Internet. Since it is not compatible with its prede- to be explicitly configured is called a configured tunnel. cessor, some interoperability mechanisms were designed. Tunnels of this type do not scale well, since every end An important category of these mechanisms is automatic tunnels, which enable IPv6 communication over an IPv4 point must be reconfigured as peers join or leave the tun- network without prior configuration. This category includes nel. To alleviate this scalability problem, another type of ISATAP, 6to4 and Teredo. We present a novel class of tunnels was introduced – automatic tunnels. In automatic attacks that exploit vulnerabilities in these tunnels. These tunnels the egress entity’s IPv4 address is computationally attacks take advantage of inconsistencies between a tunnel’s derived from the destination IPv6 address. This feature overlay IPv6 routing state and the native IPv6 routing state. The attacks form routing loops which can be abused as a eliminates the need to keep an explicit routing table at vehicle for traffic amplification to facilitate DoS attacks. the tunnel’s end points. In particular, the end points do We exhibit five attacks of this class. One of the presented not have to be updated as peers join and leave the tunnel. attacks can DoS a Teredo server using a single packet. The In fact, the end points of an automatic tunnel do not exploited vulnerabilities are embedded in the design of the know which other end points are currently part of the tunnels; hence any implementation of these tunnels may be vulnerable. -
Is QUIC a Better Choice Than TCP in the 5G Core Network Service Based Architecture?
DEGREE PROJECT IN INFORMATION AND COMMUNICATION TECHNOLOGY, SECOND CYCLE, 30 CREDITS STOCKHOLM, SWEDEN 2020 Is QUIC a Better Choice than TCP in the 5G Core Network Service Based Architecture? PETHRUS GÄRDBORN KTH ROYAL INSTITUTE OF TECHNOLOGY SCHOOL OF ELECTRICAL ENGINEERING AND COMPUTER SCIENCE Is QUIC a Better Choice than TCP in the 5G Core Network Service Based Architecture? PETHRUS GÄRDBORN Master in Communication Systems Date: November 22, 2020 Supervisor at KTH: Marco Chiesa Supervisor at Ericsson: Zaheduzzaman Sarker Examiner: Peter Sjödin School of Electrical Engineering and Computer Science Host company: Ericsson AB Swedish title: Är QUIC ett bättre val än TCP i 5G Core Network Service Based Architecture? iii Abstract The development of the 5G Cellular Network required a new 5G Core Network and has put higher requirements on its protocol stack. For decades, TCP has been the transport protocol of choice on the Internet. In recent years, major Internet players such as Google, Facebook and CloudFlare have opted to use the new QUIC transport protocol. The design assumptions of the Internet (best-effort delivery) differs from those of the Core Network. The aim of this study is to investigate whether QUIC’s benefits on the Internet will translate to the 5G Core Network Service Based Architecture. A testbed was set up to emulate traffic patterns between Network Functions. The results show that QUIC reduces average request latency to half of that of TCP, for a majority of cases, and doubles the throughput even under optimal network conditions with no packet loss and low (20 ms) RTT. Additionally, by measuring request start and end times “on the wire”, without taking into account QUIC’s shorter connection establishment, we believe the results indicate QUIC’s suitability also under the long-lived (standing) connection model. -
RFC 5405 Unicast UDP Usage Guidelines November 2008
Network Working Group L. Eggert Request for Comments: 5405 Nokia BCP: 145 G. Fairhurst Category: Best Current Practice University of Aberdeen November 2008 Unicast UDP Usage Guidelines for Application Designers Status of This Memo This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. Distribution of this memo is unlimited. Copyright Notice Copyright (c) 2008 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust’s Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/ license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Abstract The User Datagram Protocol (UDP) provides a minimal message-passing transport that has no inherent congestion control mechanisms. Because congestion control is critical to the stable operation of the Internet, applications and upper-layer protocols that choose to use UDP as an Internet transport must employ mechanisms to prevent congestion collapse and to establish some degree of fairness with concurrent traffic. This document provides guidelines on the use of UDP for the designers of unicast applications and upper-layer protocols. Congestion control guidelines are a primary focus, but the document also provides guidance on other topics, including message sizes, reliability, checksums, and middlebox traversal. Eggert & Fairhurst Best Current Practice [Page 1] RFC 5405 Unicast UDP Usage Guidelines November 2008 Table of Contents 1. Introduction . 3 2. Terminology . 5 3. UDP Usage Guidelines . -
Internet Protocol Suite
InternetInternet ProtocolProtocol SuiteSuite Srinidhi Varadarajan InternetInternet ProtocolProtocol Suite:Suite: TransportTransport • TCP: Transmission Control Protocol • Byte stream transfer • Reliable, connection-oriented service • Point-to-point (one-to-one) service only • UDP: User Datagram Protocol • Unreliable (“best effort”) datagram service • Point-to-point, multicast (one-to-many), and • broadcast (one-to-all) InternetInternet ProtocolProtocol Suite:Suite: NetworkNetwork z IP: Internet Protocol – Unreliable service – Performs routing – Supported by routing protocols, • e.g. RIP, IS-IS, • OSPF, IGP, and BGP z ICMP: Internet Control Message Protocol – Used by IP (primarily) to exchange error and control messages with other nodes z IGMP: Internet Group Management Protocol – Used for controlling multicast (one-to-many transmission) for UDP datagrams InternetInternet ProtocolProtocol Suite:Suite: DataData LinkLink z ARP: Address Resolution Protocol – Translates from an IP (network) address to a network interface (hardware) address, e.g. IP address-to-Ethernet address or IP address-to- FDDI address z RARP: Reverse Address Resolution Protocol – Translates from a network interface (hardware) address to an IP (network) address AddressAddress ResolutionResolution ProtocolProtocol (ARP)(ARP) ARP Query What is the Ethernet Address of 130.245.20.2 Ethernet ARP Response IP Source 0A:03:23:65:09:FB IP Destination IP: 130.245.20.1 IP: 130.245.20.2 Ethernet: 0A:03:21:60:09:FA Ethernet: 0A:03:23:65:09:FB z Maps IP addresses to Ethernet Addresses -
Problems of Ipsec in Combination with NAT and Their Solutions
Problems of IPsec in Combination with NAT and Their Solutions Alexander Heinlein Abstract As the Internet becomes more and more a part of our daily life it also evolves as an at- tractive target for security attacks, often countered by Internet Protocol Security (IPsec) to establish virtual private networks (VPNs), if secure data communication is a primary objective. Then again, to provide Internet access for hosts inside Local Area Networks, a public IP address shared among all peers is often used, achieved by Network Address Translation (NAT) deployment. IPsec, however, is incompatible with NAT, leading to a variety of problems when using both in combination. Connection establishments origi- nating from the outside are blocked and NAT, as it modifies the outer IP header, breaks IPsec’s security mechanisms. In the following we analyze problems of NAT in combination with IPsec and multiple approaches to solve them. 1 Introduction The current TCP/IP protocols originate from a time where security was not a great concern. As the traditional Internet Protocol (IP) does not provide any guarantees on delivery, the receiver cannot detect whether the sender is the same one as recorded in the protocol header or if the packet was modified during transport. Moreover an attacker may also easily replay IP packets or read sensitive information out of them. In contrast, today, as the Internet becomes more and more a part of our everyday life, a more security aware protocol is needed. To fill this gap the Internet Engineering Task Force (IETF) worked on a new standard for securing IP, called Internet Protocol Security (IPsec). -
User Datagram Protocol (UDP)
Overview • User datagram protocol (UDP) • Packet checksums • Reliability: sliding window • TCP connection setup • TCP windows, retransmissions, and acknowledgments Transport Protocol Review FTP HTTP NV TFTP TCP UDP IP … NET1 NET2 NETn • Transport protocols sit on top of the network layer (IP) • Can provide: - Application-level multiplexing (“ports”) - Error detection, reliability, etc. UDP – user datagram protocol 0 16 31 SrcPort DstPort Length Checksum Data • Unreliable and unordered datagram service • Adds multiplexing, checksum on whole packet • No flow control, reliability, or order guarantees • Endpoints identified by ports • Checksum aids in error detection Error detection • Transmission errors definitely happen - Cosmic rays, radio interference, etc. - If error probability is 2−30, that’s 1 error per 128 MB! • Some link-layer protocols provide error detection - But UDP/IP must work over many link layers - Not all links on a path may have error detection - Moreover, recall end-to-end argument! Need end-to-end check • UDP detects errors with a checksum - Compute small checksum value, like a hash of the packet - If packet corrupted in transit, checksum likely to be wrong - Similar checksum on IP header, but doesn’t cover payload Checksum algorithms • Good checksum algorithms - Should detect errors that are likely to happen (E.g., should detect any single bit error) - Should be efficient to compute • IP, UDP, and TCP use 1s complement sum: - Set checksum field to 0 - Sum all 16-bit words in pkt - Add any carry bits back in (So 0x8000 + -
Hybrid ATA with FXS and FXO Ports
Hybrid ATA with FXS and FXO ports HT813 The HT813 is an analog telephone adapter that features 1 analog telephone FXS port and 1 PSTN line FXO port in order to offer backup lifeline support using a PSTN line. The integration of a FXO and FXS port enables this hybrid ATA to support remote calling to and from the PSTN line. For added flexibility, the FXS port extends VoIP service to one analog device. Users can convert their analog technology to VoIP thanks to the HT813’s ultra-compact size, HD voice quality, advanced VoIP functionality, high-end security protection and multiple auto provisioning options. These advanced features also allow service providers to offer high quality IP service to customers looking to upgrade to VoIP. Supports 2 SIP Dual 100Mbps LAN Lifeline support (FXS 3-way voice profiles through 1 and WAN ports port will be hard- conferencing per FXS port and 1 FXO relayed to FXO port) port port in case of power outage Automated & secure Supports T.38 Fax Failover SIP server Strong AES encryption provisioning options for reliable Fax- automatically with security using TR069 over-IP switches to certificate per unit secondary server if main server loses connection www.grandstream.com Telephone Interfaces One (1) RJ11 FXS port, One (1) RJ11 FXO PSTN line port with lifeline support Network Interface Two (2) 10/100Mbps ports (RJ45) with integrated NAT router LED Indicators POWER, LAN, WAN, FXS, FXO Factory Reset Button Yes Voice, Fax, Modem Caller ID display or block, call waiting, flash, blind or attended transfer, forward, -
User Datagram Protocol UDP Is a Connectionless Transport Layer
UDP: User Datagram Protocol UDP is a connectionless transport layer (layer 4) protocol in OSI model, which provides a simple and unreliable message service for transaction-oriented services. UDP is basically an interface between IP and upper-layer processes. UDP protocol ports distinguish multiple applications running on a single device from one another. Since many network applications may be running on the same machine, computers need something to make sure the correct software application on the destination computer gets the data packets from the source machine, and some way to make sure replies get routed to the correct application on the source computer. This is accomplished through the use of the UDP "port numbers". For example, if a station wished to use a Domain Name System (DNS) on the station 128.1.123.1, it would address the packet to station 128.1.123.1 and insert destination port number 53 in the UDP header. The source port number identifies the application on the local station that requested domain name server, and all response packets generated by the destination station should be addressed to that port number on the source station. Details of UDP port numbers could be found in the TCP/UDP Port Number document and in the reference. Unlike the TCP , UDP adds no reliability, flow-control, or error-recovery functions to IP. Because of UDP's simplicity, UDP headers contain fewer bytes and consume less network overhead than TCP. UDP is useful in situations where the reliability mechanisms of TCP are not necessary, such as in cases where a higher-layer protocol might provide error and flow control, or real time data transportation is required. -
Nist Sp 800-77 Rev. 1 Guide to Ipsec Vpns
NIST Special Publication 800-77 Revision 1 Guide to IPsec VPNs Elaine Barker Quynh Dang Sheila Frankel Karen Scarfone Paul Wouters This publication is available free of charge from: https://doi.org/10.6028/NIST.SP.800-77r1 C O M P U T E R S E C U R I T Y NIST Special Publication 800-77 Revision 1 Guide to IPsec VPNs Elaine Barker Quynh Dang Sheila Frankel* Computer Security Division Information Technology Laboratory Karen Scarfone Scarfone Cybersecurity Clifton, VA Paul Wouters Red Hat Toronto, ON, Canada *Former employee; all work for this publication was done while at NIST This publication is available free of charge from: https://doi.org/10.6028/NIST.SP.800-77r1 June 2020 U.S. Department of Commerce Wilbur L. Ross, Jr., Secretary National Institute of Standards and Technology Walter Copan, NIST Director and Under Secretary of Commerce for Standards and Technology Authority This publication has been developed by NIST in accordance with its statutory responsibilities under the Federal Information Security Modernization Act (FISMA) of 2014, 44 U.S.C. § 3551 et seq., Public Law (P.L.) 113-283. NIST is responsible for developing information security standards and guidelines, including minimum requirements for federal information systems, but such standards and guidelines shall not apply to national security systems without the express approval of appropriate federal officials exercising policy authority over such systems. This guideline is consistent with the requirements of the Office of Management and Budget (OMB) Circular A-130. Nothing in this publication should be taken to contradict the standards and guidelines made mandatory and binding on federal agencies by the Secretary of Commerce under statutory authority. -
NAT Tutorial
NAT Tutorial Dan Wing, [email protected] IETF77, Anaheim March 21, 2010 V2.1 1 Agenda • NAT and NAPT – Types of NATs • Application Impact – Application Layer Gateway (ALG) – STUN, ICE, TURN • Large-Scale NATs (LSN, CGN, SP NAT) • IPv6/IPv4 Translation (“NAT64”) • NAT66 2 Agenda • NAT and NAPT – Types of NATs • Application Impact – Application Layer Gateway (ALG) – STUN, ICE, TURN • Large-Scale NATs (LSN, CGN, SP NAT) • IPv6/IPv4 Translation (“NAT64”) • NAT66 3 NAT • First described in 1991 • 1:1 translation – Does not conserve IPv4 addresses • Per-flow stateless • Today’s primary use is inside of enterprise networks – Connect overlapping RFC1918 address space draft-tsuchiya-addrtrans-00 4 NAT Diagram • Hosts seem to have multiple IPv4 addresses – almost like “ghosts” 192.168.0.2 10.1.1.2 192.168.0.1 10.1.1.1 192.168.0.3 10.1.1.3 5 NAPT • Described in 2001 (RFC3022) • 1:N translation – Conserves IPv4 addresses – Allows multiple hosts to share one IPv4 address – Only TCP, UDP, and ICMP – Connection has to be initiated from ‘inside’ • Per-flow stateful • Commonly used in home gateways and enterprise NAT 6 NAPT Diagram • Hosts share an IPv4 address 192.168.0.2 157.55.0.1 Internet 192.168.0.3 192.168.0.1 7 NAPT complications • NAPT requires connections initiated from ‘inside’ • Creates state in the network (in the NAPT) – This is bad – NAPT crashes -> connections break • When to discard state? – TCP RST? Spoofed RSTs? – Timeout? 8 Terminology • “NAT” is spoken/written instead of “NAPT” – Even though NAPT is often more accurate – The more accurate