DOCSLIB.ORG

Spanning Tree Protocol and Ethernet PAUSE Frames Ddos Attacks: Their Efficient Mitigation

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Spanning Tree Protocol and Ethernet PAUSE Frames Ddos Attacks: Their Efficient Mitigation Spanning Tree Protocol and Ethernet PAUSE Frames DDoS Attacks: Their Efficient Mitigation Luis A. Trejo1, Ra´ul Monroy1, and Rafael L´opez Monsalvo2 1 Department of Computer Science, Tecnol´ogico de Monterrey, Campus Estado de M´exico Carr. Lago de Guadalupe, Km. 3.5, Estado de M´exico, 52926, Mexico [email protected], [email protected] 2 Forˆet Network Consulting Carlos Bustamante 9B, Estado de M´exico, 53100, Mexico 159 E. 33rd Street Suite 3, New York, NY 10016, U.S.A. [email protected] Abstract. Making protocols at layer 2 of the OSI model less vulnerable against computational attacks has become essential. They represent a great percentage of attacks being originated within the organization. Recently, several attacks using Ethernet PAUSE frames in combina- tion with well known Spanning Tree Protocol (STP) attacks have been reported. We believe that STP can be properly configured and continuously monitored so as to avoid any network degradation due to an undetected intrusion and misuse of Ethernet PAUSE frames (802.3x). In this paper, the main STP security threats that an intruder can exploit are presented: becoming root, modifying the STP active topology, changing STP timers, and generating persistent Topology Change Notification (TCN) messages. Also, a switched network can be brought down completely, hence achieving a Distributed Denial of Service Attack, by sending malicious Ethernet PAUSE frames. These threats were fully implemented in laboratory and general recommendations to attain a better level of security through best STP and network management practices were derived. Furthermore, some recommendations can be translated into security policies and incorporated as part of an existing Intrusion Detection/Prevention System. Keywords: Spanning Tree Protocol, Distributed DoS, 802.1D, 802.1w, 802.3x, Network Man- agement, Ethernet Flow Control, Layer 2 Attacks, Intrusion Detection Systems 1 Introduction Many information security attacks performed over the communications infrastructure of an organization are known to have their source within the organization. Special attention to information security attacks arising at layer 2 of the OSI model has increased in a very important manner [6]. This is the case of layer 2 attacks that take advantage of publicly known vulnerabilities at this layer. A computer’s system security is considered to be as strong as its weakest link. Considering that OSI layer 2 is the foundation of upper layers, verifying security at this point becomes essential. One of the main goals of this research is the study of protocols that operate at layer 2 (such as the Spanning Tree Protocol (STP), and the 802.3x standard) in order to under- stand their full operation and to discover possible security flaws. In this manner, general recommendations and best administrative practices can be derived, hence increasing the level of security of the network. STP is a protocol used in switched networks to obtain a logical topology free of loops from a physical topology containing loops [1, 14]. It offers the administrator the benefits of a redundant topology without the risk caused by physical loops. The main known STP threats that an intruder can take advantage of are: becoming root, modifying the STP active topology, changing STP timers, and generating persistent Topology Change Notification (TCN) messages [13]. Another important threat that can be exploited by an intruder consists of the frequent triggering of the active topology reconfig- uration, forcing some ports to go to the blocking, listening, learning, and forwarding states. Given that ports in a state different than the forwarding state do not forward user frames, a degradation of the network service becomes evident. On the other hand, 802.3x is a pause-based flow control mechanism basically used to reduce the receiving packet rate coming from a peer device in order to avoid packet loss. Recently, several attacks using 802.3x frames in combination with well known Spanning Tree Protocol (STP) attacks have been reported [8]. We fully implemented in our networking laboratory the above STP threats and 802.3x attacks. Our results are detailed in the following sections. We proved that replicating the attack scenarios on a production environment is a very simple task, which is a result of great concern, since in some cases the network service had been brought completely down. Therefore, recommendations in order to attain a better level of security through best man- agement practices become essential. Furthermore, some recommendations can be translated into security policies and incorporated as part of an existing Intrusion Detection System [7, 10]. Many of the aspects discussed in this paper also apply to 802.1w [2, 5, 11] networks, which is the standard that describes the Rapid Spanning Tree Protocol (RSTP). Marro in [9] describes a very detailed study on R/STP (RSTP and STP) vulnerabilities and proposes efficient countermeasures to be included as part of any new R/STP implementation. He built SToP, a tool that allows modifying any field in the BPDU message and is capable of generating BPDU packets at a high rate thus very quickly flooding a network. The tool was mainly used to validate on a controlled environment the assumptions made about R/STP security flaws and their mitigation. Howard [6] gives an overview of layer 2 protocols, including R/STP, that are susceptible to attacks and thus compromise upper layers of an organization’s IT infrastructure. Paper overview This paper is organized as follows. In the previous section, a valid jus- tification for studying layer 2 attacks was presented, choosing as a starting point for our research, the STP protocol and 802.3x. Then main threats were introduced pointing out the need of general recommendations aiming at improving security at layer 2. In Section 2, the pause-based flow control mechanism for Ethernet implementations, as specified by 802.3x, is explained. In Section 3, a quick review of the STP protocol is introduced. In Section 4, the STP attack scenarios we implemented in laboratory are described and in Section 5, DDoS attacks using 802.3x frames on a STP active topology are presented. In Section 6 general recommendations for improving security at layer 2 are given. Finally, Sections 7 and 8 present our conclusions and ongoing research along with a brief description of the laboratory equipment used to implement the different attack scenarios. 2 Ethernet Flow Control The standard 802.3x [3] is a supplement to the ANSI/IEEE 802.3 standard, where a mech- anism for pause-based flow control is added. The main purpose of flow control is to reduce the receiving packet rate at some point in the network in order to avoid packet loss. Flow control is achieved by means of special MAC Control frames, known as PAUSE frames. MAC Control frames are distinguished from other MAC frames, i.e. data frames, only by their Length/Type field; in this case, the Length/Type field value is set to 0x88-08. Therefore, a PAUSE frame is defined as a MAC Control frame and an Opcode value of 0x00-01 (see Fig. 1). A device is capable of supporting multiple flow control modes. These modes are sym- metric flow control (SFC), asymmetric flow control (AFC), and no flow control at all. In SFC mode, PAUSE frames may flow in either direction. In AFC mode, they may flow only in one direction, whether that direction is towards the local device or away from the local device. Destination Address (6) Source Address (6) Length/Type (2) MAC Control Opcode (2) MAC Control Parameters (variable) Reserved [Zeroes padding] (variable) Fig. 1. MAC Control frame format. The number in parenthesis represents the number of octets used. The last two fields together add to 44 octets. 2.1 Transmission of a PAUSE frame A device wishing to reduce the receiving packet rate, sends a PAUSE frame to its peer device indicating the period of time the transmitting device should stop sending data frames. This time is specified in the MAC Control Parameters field. The generated PAUSE frame will contain the following values: 1. A globally-assigned 48 bit multicast address 01-80-C2-00-00-013 , as the destination ad- dress, or the unicast address of the peer device. 2. The MAC Control Opcode = 0x00-01, indicating a PAUSE frame. 3. A two-octet MAC Control Parameter, known as pause time, indicating the length of time for which the peer device is requested to inhibit data frame transmission. The pause time is measured in units of pause quanta, which is equal to 512 bit times of the particular Ethernet implementation. The range of possible pause time values is 0 to 65,535 pause quanta. For example, if pause time is set to 0x00-0A, then the time requested to inhibit transmission would be equal to 5,120 bit times. For a 10-Gigabit Ethernet im- plementation, this corresponds to 0.512 µs. Table 1 shows different inhibition times for a pause time of 0xFF-FF. 3 The multicast address is reserved for use of MAC Control PAUSE frames. IEEE 802.1D-conformant bridges will not forward frames sent to this multicast destination address, regardless of the state of the bridges ports. Table 1. Total time a device stops sending using a maximum pause time value for different Ethernet implementations. Ethernet pause time pause quanta Total inhibition time 10 Gbps 0xFF-FF 0.0512 µs 3.35 ms. 1 Gbps 0xFF-FF 0.512 µs 33.55 ms. 100 Mbps 0xFF-FF 5.12 µs 333.53 ms. 2.2 Reception of a PAUSE frame Upon reception of a valid PAUSE frame, the device will start a timer called pause timer, and will set the timer to the time specified by the received pause time parameter multiplied by pause quanta of the particular Ethernet implementation.
Load more

Recommended publications
  • Ciena 5305 Service Aggregation Switch Datasheet
    5305 SERVICE AGGREGATION SWITCH Features and Benefits The 5305 Ethernet/MPLS service aggregation > Features advanced Ethernet and MPLS to support demanding business, mobile switch is purpose-built for Carrier Ethernet backhaul, transport, and residential applications including L2VPN service to deliver cost-effective capacity, scalability, delivery and aggregation, 3G/4G wireless backhaul, FTTx and IP DSLAM and resiliency. With this switch, service Aggregation and L2 backhaul of L3VPNs > Delivers optimal density and service providers can keep pace with the constantly flexibility with a compact modular chassis, supporting incremental increasing demand for bandwidth and next- expansion of service and bandwidth capacity with linear CAPEX outlay generation services that support business, > Supports tens of thousands of services mobile backhaul, transport, and residential on a single system with robust scalability of up to 30,000+ VLANs and applications in metro networks. two million MAC addresses per chassis > Delivers high reliability, five-9s The 5305 is a modular, chassis-based system optimized for metro-edge deployments availability, and 50 ms protection in a wide variety of network topologies, including fiber and microwave rings, point-to- switching resiliency using state-of- the-art hardware and software design point fiber, microwave mesh, and fiber or copper to the subscriber. The switch coupled with advanced control plane supports high-density Gigabit Ethernet (GbE) connectivity to the subscriber edge and and Ethernet OAM capabilities
    [Show full text]
  • Data Center Ethernet 2
    DataData CenterCenter EthernetEthernet Raj Jain Washington University in Saint Louis Saint Louis, MO 63130 [email protected] These slides and audio/video recordings of this class lecture are at: http://www.cse.wustl.edu/~jain/cse570-15/ Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse570-15/ ©2015 Raj Jain 4-1 OverviewOverview 1. Residential vs. Data Center Ethernet 2. Review of Ethernet Addresses, devices, speeds, algorithms 3. Enhancements to Spanning Tree Protocol 4. Virtual LANs 5. Data Center Bridging Extensions Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse570-15/ ©2015 Raj Jain 4-2 Quiz:Quiz: TrueTrue oror False?False? Which of the following statements are generally true? T F p p Ethernet is a local area network (Local < 2km) p p Token ring, Token Bus, and CSMA/CD are the three most common LAN access methods. p p Ethernet uses CSMA/CD. p p Ethernet bridges use spanning tree for packet forwarding. p p Ethernet frames are 1518 bytes. p p Ethernet does not provide any delay guarantees. p p Ethernet has no congestion control. p p Ethernet has strict priorities. Washington University in St. Louis http://www.cse.wustl.edu/~jain/cse570-15/ ©2015 Raj Jain 4-3 ResidentialResidential vs.vs. DataData CenterCenter EthernetEthernet Residential Data Center Distance: up to 200m r No limit Scale: Few MAC addresses r Millions of MAC Addresses 4096 VLANs r Millions of VLANs Q-in-Q Protection: Spanning tree r Rapid spanning tree, … (Gives 1s, need 50ms) Path determined by r Traffic engineered path spanning tree Simple service r Service Level Agreement.
    [Show full text]
  • Converged Networking in the Data Center
    Converged Networking in the Data Center Peter P. Waskiewicz Jr. LAN Access Division, Intel Corp. [email protected] Abstract data center as a whole. In addition to the general power and cooling costs, other areas of focus are the physical The networking world in Linux has undergone some sig- amount of servers and their associated cabling that re- nificant changes in the past two years. With the expan- side in a typical data center. Servers very often have sion of multiqueue networking, coupled with the grow- multiple network connections to various network seg- ing abundance of multi-core computers with 10 Gigabit ments, plus they’re usually connected to a SAN: ei- Ethernet, the concept of efficiently converging different ther a Fiber Channel fabric or an iSCSI infrastructure. network flows becomes a real possibility. These multiple network and SAN connections mean large amounts of cabling being laid down to attach a This paper presents the concepts behind network con- server. Converged Networking takes a 10GbE device vergence. Using the IEEE 802.1Qaz Priority Group- that is capable of Data Center Bridging in hardware, ing and Data Center Bridging concepts to group mul- and consolidates all of those network connections and tiple traffic flows, this paper will demonstrate how dif- SAN connections into a single, physical device and ca- ferent types of traffic, such as storage and LAN traf- ble. The rest of this paper will illustrate the different fic, can efficiently coexist on the same physical connec- aspects of Data Center Bridging, which is the network- tion.
    [Show full text]
  • Interactions Between TCP and Ethernet Flow Control Over Netgear
    Interactions between TCP and Ethernet flow control over Netgear XAVB2001 HomePlug AV links Radika Veera Valli, Grenville Armitage, Jason But, Thuy Nguyen Centre for Advanced Internet Architectures, Technical Report 130121A Swinburne University of Technology Melbourne, Australia [email protected], [email protected], [email protected], [email protected] Abstract—HomePlug AV links are usually slower than buffers along network paths. A side-effect of such loss- the surrounding wired LAN links, creating a bottleneck based CC behaviour is that all traffic sharing the bottle- where traffic may be buffered and delayed. To investigate neck will experience additional latency due to increased the interactions between TCP congestion control and average queueing delays [5]. This is particularly prob- Ethernet flow control we trialled four TCP variants over a lematic for real-time application flows (such as VoIP and HomePlug AV link using two Netgear XAVB2001 devices. We observed that the XAVB2001’s use of Ethernet flow online games) given the growth of arguably-gratuitous control effectively concatenates the buffers in both the buffering (“buffer bloat”) in network devices, interface XAVB2001 and the directly attached sending host. This led cards and network software stacks [6]. to multi-second RTTs when using NewReno and CUBIC In this report we borrow from, and extend, previous (loss-based) TCPs, which is significantly troublesome for work by one of the current authors [7]. Our new work multimedia traffic on home LANs. In contrast, Vegas explores in greater detail the latency and flow control and CDG (delay-based) TCPs kept buffer utilisation low, issues that emerge when end-to-end TCP is allowed to and induced five to ten milliseconds RTT.
    [Show full text]
  • Chapter 2 Link Layer Verilog Hardware Implementation, and One Wireless Broadcast Link, I.E
    Modern Computer Networks: An open source approach Chapter 2 Modern Computer Networks: An open source approach Chapter 2 package, one wired broadcast link, i.e. Ethernet in Section 2.4 along with its Chapter 2 Link Layer Verilog hardware implementation, and one wireless broadcast link, i.e. wireless LAN (WLAN) in Section 2.5 plus a brief on Bluetooth and WiMAX. PPP is Problem Statement popularly used in the last-mile dial-up services or routers carrying various network protocols over point-to-point links. Ethernet has occupied more than 95 percent of To effectively and efficiently transmit data over physical links from one node wired LANs. It is also poised to be ubiquitous in MANs and WANs. In contrast to to one or more nodes, there is much more to do than simply modulating or desktop PCs, which usually use wired links, many devices such as laptop PCs encoding bit stream into signal. Transmission impairments, such as crosstalk and cellular phones are mobile and prefer wireless links such as WLAN, Bluetooth, between two adjacent pairs, can unexpectedly change transmission signal and and WiMAX. thus result in errors. The transmitter might transmit faster than the receiver can Table 2.1 Link protocols. handle. The transmitter has to somehow indicate the destination(s), if on a PAN/LAN MAN/WAN broadcast link, i.e. LAN, and usually needs to name itself to let the receiver know Token Bus (802.4) DQDB (802.6) Token Ring (802.5) HDLC where the source is. If multiple stations share a LAN, an arbitration mechanism is HIPPI X.25 required to determine who can transmit next.
    [Show full text]
  • Understanding Ethernet
    Chapter 1 Understanding Ethernet In This Chapter ▶ Exploring carrier sensing and collision detection methods ▶ Understanding directional traffic and simultaneous transmissions ▶ Examining Ethernet speed limits and wire-rated standards ▶ Exploring Gigabit Ethernet ▶ Distinguishing between local and backbone Ethernet ▶ Recognizing Ethernet interfaces ▶ Understanding Ethernet’s simplicity n today’s connected business world, ubiquitous access to Idigitized information and data is critical. Networking has not only reshaped the information landscape, but it has also vastly increased speeds at which information moves and is consumed. In fact, networking is the key to accessing the com- plex services and applications within which information plays a starring role. Although access to the Internet is essential, all networking begins at the local level. For modern networks, Ethernet is the standard infrastructure upon which local net- works rest. Ethernet comprises a family of frame-based protocols and tech- nologies designed to connect local area networks (LANs) — computersCOPYRIGHTED and devices situated in MATERIAL close proximity and able to communicate with one another. Ethernet draws its name from the fanciful Latin terminology luminiferous aether, which trans- lates to a light-bearing medium once thought to fill space and propagate magnetic waves. As such, Ethernet is a metaphorical reference for the physical transmission medium in the work- place (and at home) that propagates digitized information in electronic form. The term “Ethernet” was originally coined by 4 Carrier Ethernet For Dummies Bob Metcalfe while jointly developing basic Ethernet network computing with David Boggs at Xerox Palo Alto Research Center (PARC). Sensing a Carrier and Handling Collisions Two people on opposite ends of a phone conversation can sense carrier presence (either a dial-tone or a connected call) and handle collisions (overlapping conversations).
    [Show full text]
  • Storage and Network Convergence Using Fcoe and Iscsi
    Front cover Storage and Network Convergence Using FCoE and iSCSI Learn how to improve IT service performance and availability Simplify your storage and network infrastructure See how to reduce data center network costs Sangam Racherla Silvio Erdenberger Harish Rajagopal Kai Ruth ibm.com/redbooks International Technical Support Organization Storage and Network Convergence Using FCoE and iSCSI January 2014 SG24-7986-01 Note: Before using this information and the product it supports, read the information in “Notices” on page xi. Second Edition (January 2014) This edition applies to the latest supported Converged Network Adapters and Switches in the IBM System Networking Portfolio of products. © Copyright International Business Machines Corporation 2012, 2014. All rights reserved. Note to U.S. Government Users Restricted Rights -- Use, duplication or disclosure restricted by GSA ADP Schedule Contract with IBM Corp. Contents Notices . xi Trademarks . xii Preface . xiii Authors. xiii Now you can become a published author, too! . .xv Comments welcome. .xv Stay connected to IBM Redbooks . xvi Part 1. Overview of storage and network convergence . 1 Chapter 1. Introduction to convergence . 3 1.1 What convergence is. 4 1.1.1 Calling it what it is . 4 1.2 Vision of convergence in data centers . 4 1.3 The interest in convergence now . 5 1.4 Fibre Channel SANs today . 5 1.5 Ethernet-based storage today. 6 1.6 Benefits of convergence in storage and network . 7 1.7 Challenge of convergence . 8 1.8 Conclusion . 10 Chapter 2. Fibre Channel over Ethernet . 11 2.1 Background: Data Center Bridging . 12 2.1.1 Priority-based Flow Control: IEEE 802.1Qbb .
    [Show full text]
  • TROUBLESHOOTING FEATURES for Media Conversion Products Table of Contents
    WHITE PAPER : TROUBLESHOOTING FEATURES for Media Conversion Products Table of Contents Introduction ......................................................................................................... 3 Link Integrity ....................................................................................................... 4 Ethernet Troubleshooting Features ................................................................... 4 1. Auto Negotiation (AN) ....................................................................................... 4 a. Full Duplex ................................................................................................ 4 b. 100 Mbps Speed ..................................................................................... 4 c. Selective Advertising ................................................................................... 5 d. Rate Converters ....................................................................................... 5 e. FX Auto Negotiation (FX AN) ..................................................................... 5 2. FX LinkLoss (FXLL) ........................................................................................... 6 3. TX LinkLoss (TXLL) ........................................................................................... 6 4. FiberAlert (FA) ................................................................................................... 7 5. LinkLoss & FiberAlert ........................................................................................ 7
    [Show full text]
  • Fairness in a Data Center
    University of New Hampshire University of New Hampshire Scholars' Repository Doctoral Dissertations Student Scholarship Winter 2012 Fairness in a data center MIkkel Hagen University of New Hampshire, Durham Follow this and additional works at: https://scholars.unh.edu/dissertation Recommended Citation Hagen, MIkkel, "Fairness in a data center" (2012). Doctoral Dissertations. 694. https://scholars.unh.edu/dissertation/694 This Dissertation is brought to you for free and open access by the Student Scholarship at University of New Hampshire Scholars' Repository. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of University of New Hampshire Scholars' Repository. For more information, please contact [email protected]. Fairness in a data center BY Mikkel Hagen M.S. Computer Science, University of New Hampshire (2008) B.S. Computer Science/Biology/Psychology, St. Bonaventure University (2004) DISSERTATION Submitted to the University of New Hampshire in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Computer Science December 2012 UMI Number: 3537816 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. Dissertation Publishing UMI 3537816 Published by ProQuest LLC 2013. Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code. uest ProQuest LLC 789 East Eisenhower Parkway P.O.
    [Show full text]
  • 19540 - Telematics 7Th Tutorial - Media Access, Ethernet & Wireshark
    19540 - Telematics 7th Tutorial - Media Access, Ethernet & Wireshark Bastian Blywis Department of Mathematics and Computer Science Institute of Computer Science 26. November, 2009 Institute of Computer Science – Telematics Tutorial – 26. November, 2009 1 Outline 1. Frame Size 2. Packets and Cells 3. FDDI Performance 4. ATM 5. Tunneling 6. Bridge Classification 7. Virtual LANs 8. IEEE 802.1Q and IEEE 802.2 9. Features of Layer 2 Protocols 10. Security Considerations 11. IEEE 802.1D Institute of Computer Science – Telematics Tutorial – 26. November, 2009 2 Frame Size Consider a 10 MBit/s CSMA/CD LAN with a bus of 50m length. The speed of the signal within the transmission medium is 2 ∗ 108m=s. 1. Calculate the upper bound of the collision detection time. 2. Specify the minimum frame length. Institute of Computer Science – Telematics Tutorial – 26. November, 2009 3 Frame Size Maximum time depends on maximum distance: AB 50m 5*10^-7s – Worst case: station A senses a free medium and starts to transmit – Station B senses a free medium and starts to transmit just at the time the signal from A arrives at B – Signal from B has to travel through the whole network until A detects the collision – Maximum time until collision detection, is twice the time of the signal propagation time for the whole network buslength 50m t = 2 ∗ = 2 ∗ = 5 ∗ 10−7s 8 m signalspeed 2 ∗ 10 s Institute of Computer Science – Telematics Tutorial – 26. November, 2009 4 Frame Size To ensure the stations are able to detect a collision, the frame has be take at least t to send: framelength min > t capacity 10MBit framelength > ∗ 5 ∗ 10−7s = 5Bit min s Institute of Computer Science – Telematics Tutorial – 26.
    [Show full text]
  • Network Transport for Data Centers
    X_405082 Advanced Computer Networks Data Center Transport Lin Wang ([email protected]) Period 2, Fall 2020 Course outline Warm-up Video ■ Fundamentals ■ Video streaming ■ Forwarding and routing ■ Video stream analytics ■ Network transport Networking and ML Data centers ■ Networking for ML ■ Data center networking ■ ML for networking ■ Data center transport � Mobile computing Programmability ■ Wireless and mobile ■ Sofware defined networking ■ Programmable forwarding 2 Learning objectives What are the new challenges in data center transport? What design choices do we have for data centers transport design? 3 What is special about data center transport Network ■ Extremely high speed (100+ Gbps) ■ Extremely low latency (10-100s of us) Diverse applications and workloads ■ Large variety in performance requirements Traffic patterns ■ Large long-lived flows vs small short-lived flows ■ Scatter-gather, broadcast, multicast Built out of commodity components: no expensive/customized hardware 4 Congestion control recall Network Do you still remember the goal of congestion control? 5 Congestion control recall Network Congestion control aims to determine the rate to send data on a connection, such that (1) the sender does not overrun the network capability and (2) the network is efficiently utilized 6 TCP Sender Receiver Network ACK ACK ACK Application The transport layer in the network model: Reliable TCP ■ Reliable, in-order delivery using acknowledges ■ Make sure not to overrun the receiver (receiving window, IP rwnd) and the network (congestion window,
    [Show full text]
  • NC-SI Over MCTP Binding Specification 6
    1 2 Document Number: DSP0261 3 Date: 2013-08-22 4 Version: 1.0.0 5 NC-SI over MCTP Binding Specification 6 7 Document Type: Specification 8 Document Status: DMTF Standard 9 Document Language: en-US 10 11 NC-SI over MCTP Binding Specification DSP0261 12 Copyright notice 13 Copyright © 2013 Distributed Management Task Force, Inc. (DMTF). All rights reserved. 14 DMTF is a not-for-profit association of industry members dedicated to promoting enterprise and systems 15 management and interoperability. Members and non-members may reproduce DMTF specifications and 16 documents for uses consistent with this purpose, provided that correct attribution is given. As DMTF 17 specifications may be revised from time to time, the particular version and release date should always be 18 noted. 19 Implementation of certain elements of this standard or proposed standard may be subject to third party 20 patent rights, including provisional patent rights (herein "patent rights"). DMTF makes no representations 21 to users of the standard as to the existence of such rights, and is not responsible to recognize, disclose, 22 or identify any or all such third party patent right, owners or claimants, nor for any incomplete or 23 inaccurate identification or disclosure of such rights, owners or claimants. DMTF shall have no liability to 24 any party, in any manner or circumstance, under any legal theory whatsoever, for failure to recognize, 25 disclose, or identify any such third party patent rights, or for such party’s reliance on the standard or 26 incorporation thereof in its product, protocols or testing procedures.
    [Show full text]