IP - the Internet Protocol
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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. -
IP Datagram ICMP Message Format ICMP Message Types
ICMP Internet Control Message Protocol ICMP is a protocol used for exchanging control messages. CSCE 515: Two main categories Query message Computer Network Error message Programming Usage of an ICMP message is determined by type and code fields ------ IP, Ping, Traceroute ICMP uses IP to deliver messages. Wenyuan Xu ICMP messages are usually generated and processed by the IP software, not the user process. Department of Computer Science and Engineering University of South Carolina IP header ICMP Message 20 bytes CSCE515 – Computer Network Programming IP Datagram ICMP Message Format 1 byte 1 byte 1 byte 1 byte VERS HL Service Total Length Datagram ID FLAG Fragment Offset 0781516 31 TTL Protocol Header Checksum type code checksum Source Address Destination Address payload Options (if any) Data CSCE515 – Computer Network Programming CSCE515 – Computer Network Programming ICMP Message Types ICMP Address Mask Request and Reply intended for a diskless system to obtain its subnet mask. Echo Request Id and seq can be any values, and these values are Echo Response returned in the reply. Destination Unreachable Match replies with request Redirect 0781516 31 Time Exceeded type(17 or 18) code(0) checksum there are more ... identifier sequence number subnet mask CSCE515 – Computer Network Programming CSCE515 – Computer Network Programming ping Program ICMP Echo Request and Reply Available at /usr/sbin/ping Test whether another host is reachable Send ICMP echo_request to a network host -n option to set number of echo request to send -
Lesson 1 Key-Terms Meanings: Internet Connectivity Principles
Lesson 1 Key-Terms Meanings: Internet Connectivity Principles Chapter-4 L01: "Internet of Things " , Raj Kamal, 2017 1 Publs.: McGraw-Hill Education Header Words • Header words are placed as per the actions required at succeeding stages during communication from Application layer • Each header word at a layer consists of one or more header fields • The header fields specify the actions as per the protocol used Chapter-4 L01: "Internet of Things " , Raj Kamal, 2017 2 Publs.: McGraw-Hill Education Header fields • Fields specify a set of parameters encoded in a header • Parameters and their encoding as per the protocol used at that layer • For example, fourth word header field for 32-bit Source IP address in network layer using IP Chapter-4 L01: "Internet of Things " , Raj Kamal, 2017 3 Publs.: McGraw-Hill Education Protocol Header Field Example • Header field means bits in a header word placed at appropriate bit place, for example, place between bit 0 and bit 31 when a word has 32-bits. • First word fields b31-b16 for IP packet length in bytes, b15-b4 Service type and precedence and b3-b0 for IP version • Chapter-4 L01: "Internet of Things " , Raj Kamal, 2017 4 Publs.: McGraw-Hill Education IP Header • Header fields consist of parameters and their encodings which are as per the IP protocol • An internet layer protocol at a source or destination in TCP/IP suite of protocols Chapter-4 L01: "Internet of Things " , Raj Kamal, 2017 5 Publs.: McGraw-Hill Education TCP Header • Header fields consist of parameters and their encoding which are as -
TCP Over Wireless Multi-Hop Protocols: Simulation and Experiments
TCP over Wireless Multi-hop Protocols: Simulation and Experiments Mario Gerla, Rajive Bagrodia, Lixia Zhang, Ken Tang, Lan Wang {gerla, rajive, lixia, ktang, lanw}@cs.ucla.edu Wireless Adaptive Mobility Laboratory Computer Science Department University of California, Los Angeles Los Angeles, CA 90095 http://www.cs.ucla.edu/NRL/wireless Abstract include mobility, unpredictable wireless channel such as fading, interference and obstacles, broadcast medium shared In this study we investigate the interaction between TCP and by multiple users and very large number of heterogeneous MAC layer in a wireless multi-hop network. This type of nodes (e.g., thousands of sensors). network has traditionally found applications in the military To these challenging physical characteristics of the ad-hoc (automated battlefield), law enforcement (search and rescue) network, we must add the extremely demanding requirements and disaster recovery (flood, earthquake), where there is no posed on the network by the typical applications. These fixed wired infrastructure. More recently, wireless "ad-hoc" include multimedia support, multicast and multi-hop multi-hop networks have been proposed for nomadic computing communications. Multimedia (voice, video and image) is a applications. Key requirements in all the above applications are reliable data transfer and congestion control, features that are must when several individuals are collaborating in critical generally supported by TCP. Unfortunately, TCP performs on applications with real time constraints. Multicasting is a wireless in a much less predictable way than on wired protocols. natural extension of the multimedia requirement. Multi- Using simulation, we provide new insight into two critical hopping is justified (among other things) by the limited problems of TCP over wireless multi-hop. -
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. -
Configuring Ipv6 First Hop Security
Configuring IPv6 First Hop Security This chapter describes how to configure First Hop Security (FHS) features on Cisco NX-OS devices. This chapter includes the following sections: • About First-Hop Security, on page 1 • About vPC First-Hop Security Configuration, on page 3 • RA Guard, on page 6 • DHCPv6 Guard, on page 7 • IPv6 Snooping, on page 8 • How to Configure IPv6 FHS, on page 9 • Configuration Examples, on page 17 • Additional References for IPv6 First-Hop Security, on page 18 About First-Hop Security The Layer 2 and Layer 3 switches operate in the Layer 2 domains with technologies such as server virtualization, Overlay Transport Virtualization (OTV), and Layer 2 mobility. These devices are sometimes referred to as "first hops", specifically when they are facing end nodes. The First-Hop Security feature provides end node protection and optimizes link operations on IPv6 or dual-stack networks. First-Hop Security (FHS) is a set of features to optimize IPv6 link operation, and help with scale in large L2 domains. These features provide protection from a wide host of rogue or mis-configured users. You can use extended FHS features for different deployment scenarios, or attack vectors. The following FHS features are supported: • IPv6 RA Guard • DHCPv6 Guard • IPv6 Snooping Note See Guidelines and Limitations of First-Hop Security, on page 2 for information about enabling this feature. Configuring IPv6 First Hop Security 1 Configuring IPv6 First Hop Security IPv6 Global Policies Note Use the feature dhcp command to enable the FHS features on a switch. IPv6 Global Policies IPv6 global policies provide storage and access policy database services. -
Junos® OS Protocol-Independent Routing Properties User Guide Copyright © 2021 Juniper Networks, Inc
Junos® OS Protocol-Independent Routing Properties User Guide Published 2021-09-22 ii Juniper Networks, Inc. 1133 Innovation Way Sunnyvale, California 94089 USA 408-745-2000 www.juniper.net Juniper Networks, the Juniper Networks logo, Juniper, and Junos are registered trademarks of Juniper Networks, Inc. in the United States and other countries. All other trademarks, service marks, registered marks, or registered service marks are the property of their respective owners. Juniper Networks assumes no responsibility for any inaccuracies in this document. Juniper Networks reserves the right to change, modify, transfer, or otherwise revise this publication without notice. Junos® OS Protocol-Independent Routing Properties User Guide Copyright © 2021 Juniper Networks, Inc. All rights reserved. The information in this document is current as of the date on the title page. YEAR 2000 NOTICE Juniper Networks hardware and software products are Year 2000 compliant. Junos OS has no known time-related limitations through the year 2038. However, the NTP application is known to have some difficulty in the year 2036. END USER LICENSE AGREEMENT The Juniper Networks product that is the subject of this technical documentation consists of (or is intended for use with) Juniper Networks software. Use of such software is subject to the terms and conditions of the End User License Agreement ("EULA") posted at https://support.juniper.net/support/eula/. By downloading, installing or using such software, you agree to the terms and conditions of that EULA. iii Table -
Network Connectivity and Transport – Transport
Idaho Technology Authority (ITA) ENTERPRISE STANDARDS – S3000 NETWORK AND TELECOMMUNICATIONS Category: S3510 – NETWORK CONNECTIVITY AND TRANSPORT – TRANSPORT CONTENTS: I. Definition II. Rationale III. Approved Standard(s) IV. Approved Product(s) V. Justification VI. Technical and Implementation Considerations VII. Emerging Trends and Architectural Directions VIII. Procedure Reference IX. Review Cycle X. Contact Information Revision History I. DEFINITION Transport provides for the transparent transfer of data between different hosts and systems. The two (2) primary transport protocols in the Transmission Control Protocol/Internet Protocol (TCP/IP) suite are the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP). II. RATIONALE Idaho State government must be able to easily, reliably, and economically communicate data and information to conduct State business. TCP/IP is the protocol standard used throughout the global Internet and endorsed by ITA Policy 3020 – Connectivity and Transport Protocols, for use in State government networks (LAN and WAN). III. APPROVED STANDARD(S) TCP/IP Transport: 1. Transmission Control Protocol (TCP); and 2. User Datagram Protocol (UDP). IV. APPROVED PRODUCT(S) Standards-based products and architecture S3510 – Network Connectivity and Transport – Transport Page 1 of 2 V. JUSTIFICATION TCP and UDP are the transport standards for critical State applications like electronic mail and World Wide Web services. VI. TECHNICAL AND IMPLEMENTATION CONSIDERATIONS It is also important to carefully consider the security implications of the deployment, administration, and operation of a TCP/IP network. VII. EMERGING TRENDS AND ARCHITECTURAL DIRECTIONS The use of TCP/IP (Internet) protocols and applications continues to increase. Agencies purchasing new systems may want to consider compatibility with the emerging Internet Protocol Version 6 (IPv6), which was designed by the Internet Engineering Task Force to replace IPv4 and will dramatically expand available IP addresses. -
Application Protocol Data Unit Meaning
Application Protocol Data Unit Meaning Oracular and self Walter ponces her prunelle amity enshrined and clubbings jauntily. Uniformed and flattering Wait often uniting some instinct up-country or allows injuriously. Pixilated and trichitic Stanleigh always strum hurtlessly and unstepping his extensity. NXP SE05x T1 Over I2C Specification NXP Semiconductors. The session layer provides the mechanism for opening closing and managing a session between end-user application processes ie a semi-permanent dialogue. Uses MAC addresses to connect devices and define permissions to leather and commit data 1. What are Layer 7 in networking? What eating the application protocols? Application Level Protocols Department of Computer Science. The present invention pertains to the convert of Protocol Data Unit PDU session. Network protocols often stay to transport large chunks of physician which are layer in. The term packet denotes an information unit whose box and tranquil is remote network-layer entity. What is application level security? What does APDU stand or Hop sound to rot the meaning of APDU The Acronym AbbreviationSlang APDU means application-layer protocol data system by. In the context of smart cards an application protocol data unit APDU is the communication unit or a bin card reader and a smart all The structure of the APDU is defined by ISOIEC 716-4 Organization. Application level security is also known target end-to-end security or message level security. PDU Protocol Data Unit Definition TechTerms. TCPIP vs OSI What's the Difference Between his Two Models. The OSI Model Cengage. As an APDU Application Protocol Data Unit which omit the communication unit advance a. -
Don't Trust Traceroute (Completely)
Don’t Trust Traceroute (Completely) Pietro Marchetta, Valerio Persico, Ethan Katz-Bassett Antonio Pescapé University of Southern California, CA, USA University of Napoli Federico II, Italy [email protected] {pietro.marchetta,valerio.persico,pescape}@unina.it ABSTRACT In this work, we propose a methodology based on the alias resolu- tion process to demonstrate that the IP level view of the route pro- vided by traceroute may be a poor representation of the real router- level route followed by the traffic. More precisely, we show how the traceroute output can lead one to (i) inaccurately reconstruct the route by overestimating the load balancers along the paths toward the destination and (ii) erroneously infer routing changes. Categories and Subject Descriptors C.2.1 [Computer-communication networks]: Network Architec- ture and Design—Network topology (a) Traceroute reports two addresses at the 8-th hop. The common interpretation is that the 7-th hop is splitting the traffic along two Keywords different forwarding paths (case 1); another explanation is that the 8- th hop is an RFC compliant router using multiple interfaces to reply Internet topology; Traceroute; IP alias resolution; IP to Router to the source (case 2). mapping 1 1. INTRODUCTION 0.8 Operators and researchers rely on traceroute to measure routes and they assume that, if traceroute returns different IPs at a given 0.6 hop, it indicates different paths. However, this is not always the case. Although state-of-the-art implementations of traceroute al- 0.4 low to trace all the paths -
Ip Fragmentation
NETWORKING CASE STUDY IN STEM EDUCATION - IP FRAGMENTATION M. Mikac1, M. Horvatić2, V. Mikac2 1Inter-biz, Informatic Services (CROATIA) 2University North (CROATIA) Abstract In the last decade, or even longer, computer networking has been a field that cannot be overseen in technical and STEM education. While technological development and affordable prices brought powerful network devices to the end-user, all the networking principles are still based (and probably will remain so) on old protocols developed back in the ‘60s and the ‘70s of the twentieth century. Therefore, it can be expected that understanding the basics of networking principles is something that future engineers should be familiar with. The global network of today, the Internet, is based on a TCP/IP stack of protocols. That is the fact that is not to be changed - the most important change that seems to be predictable will be wider acceptance and usage of a newer version of Internet Protocol (IP) - IPv6 increases its adoption in the global network but it is still under 30%. Even though different modifications of certain transport (TCP, UDP) and network (IP) protocols appeared, essentially the basics are still based on old protocols and most of the network traffic is still using the good old TCP/IP stack. In order to explain the basic functional principles of today’s networks, different kinds of case studies in real-networks or emulated environments can be introduced to students. Among those, one of the case studies we use in our education is related to explaining, the so-called, IP fragmentation - the process that sometimes "automagically" appears in IP network protocol-based networks when certain constraints are met. -
Transport Layer Chapter 6
Transport Layer Chapter 6 • Transport Service • Elements of Transport Protocols • Congestion Control • Internet Protocols – UDP • Internet Protocols – TCP • Performance Issues • Delay-Tolerant Networking Revised: August 2011 CN5E by Tanenbaum & Wetherall, © Pearson Education-Prentice Hall and D. Wetherall, 2011 The Transport Layer Responsible for delivering data across networks with the desired Application reliability or quality Transport Network Link Physical CN5E by Tanenbaum & Wetherall, © Pearson Education-Prentice Hall and D. Wetherall, 2011 Transport Service • Services Provided to the Upper Layer » • Transport Service Primitives » • Berkeley Sockets » • Socket Example: Internet File Server » CN5E by Tanenbaum & Wetherall, © Pearson Education-Prentice Hall and D. Wetherall, 2011 Services Provided to the Upper Layers (1) Transport layer adds reliability to the network layer • Offers connectionless (e.g., UDP) and connection- oriented (e.g, TCP) service to applications CN5E by Tanenbaum & Wetherall, © Pearson Education-Prentice Hall and D. Wetherall, 2011 Services Provided to the Upper Layers (2) Transport layer sends segments in packets (in frames) Segment Segment CN5E by Tanenbaum & Wetherall, © Pearson Education-Prentice Hall and D. Wetherall, 2011 Transport Service Primitives (1) Primitives that applications might call to transport data for a simple connection-oriented service: • Client calls CONNECT, SEND, RECEIVE, DISCONNECT • Server calls LISTEN, RECEIVE, SEND, DISCONNECT Segment CN5E by Tanenbaum & Wetherall, © Pearson Education-Prentice