Source routing

Last updated

In computer networking, source routing, also called path addressing, allows a sender of a data packet to partially or completely specify the route the packet takes through the network. [1] In contrast, in conventional routing, routers in the network determine the path incrementally based on the packet's destination. Another routing alternative, label switching, is used in connection-oriented networks such as X.25, Frame Relay, Asynchronous Transfer Mode and Multiprotocol Label Switching.

Contents

Source routing allows easier troubleshooting, improved traceroute, and enables a node to discover all the possible routes to a host. It does not allow a source to directly manage network performance by forcing packets to travel over one path to prevent congestion on another.

Many high-performance interconnects including Myrinet, Quadrics, [2] IEEE 1355, and SpaceWire support source routing.

Internet Protocol

In the Internet Protocol, two header options are available which are rarely used: "strict source and record route" (SSRR) and "loose source and record route" (LSRR). [3] Because of security concerns, packets marked LSRR are frequently blocked on the Internet. If not blocked, LSRR can allow an attacker to spoof an address but still successfully receive response packets by forcing return traffic for spoofed packets to return through the attacker's device. [4]

In IPv6, two forms of source routing have been developed. The first approach was the Type 0 Routing header. [5] This routing header was designed to support the same use cases as the IPv4 header options. As there were several significant attacks against this routing header, its utilisation was deprecated. [6] A more secure form of source routing was being developed within the IETF as of 2017 to support the IPv6 version of segment routing. [7]

Software-defined networking

Software-defined networking can also be enhanced when source routing is used in the forwarding plane. Studies have shown significant improvements in convergence times as a result of the reduced state that must be distributed by the controller into the network. [8] [9]

Myrinet

When using source routing with Myrinet, the sender of the packet prepends the complete route, one byte for every crossbar, to each packet header. Each crossbar examines the first routing byte of the packet. When using source routing, that byte indicates a particular port of that crossbar; when that port becomes available, the router discards that routing byte and sends the rest of the packet out that port. [2]

SpaceWire

Each packet traveling through a SpaceWire network can use path addressing (source routing) or logical addressing or some combination. The router examines the first data character of the packet; when it indicates some specific port of the router, the router discards that routing character and sends the rest of the packet out that port. [10] [11] [12]

See also

Related Research Articles

The Internet Control Message Protocol (ICMP) is a supporting protocol in the Internet protocol suite. It is used by network devices, including routers, to send error messages and operational information indicating success or failure when communicating with another IP address, for example, an error is indicated when a requested service is not available or that a host or router could not be reached. ICMP differs from transport protocols such as TCP and UDP in that it is not typically used to exchange data between systems, nor is it regularly employed by end-user network applications.

<span class="mw-page-title-main">Internet Protocol version 4</span> Fourth version of the Internet Protocol

Internet Protocol version 4 (IPv4) is the fourth version of the Internet Protocol (IP). It is one of the core protocols of standards-based internetworking methods in the Internet and other packet-switched networks. IPv4 was the first version deployed for production on SATNET in 1982 and on the ARPANET in January 1983. It is still used to route most Internet traffic today, even with the ongoing deployment of Internet Protocol version 6 (IPv6), its successor.

<span class="mw-page-title-main">IPv6</span> Version 6 of the Internet Protocol

Internet Protocol version 6 (IPv6) is the most recent version of the Internet Protocol (IP), the communications protocol that provides an identification and location system for computers on networks and routes traffic across the Internet. IPv6 was developed by the Internet Engineering Task Force (IETF) to deal with the long-anticipated problem of IPv4 address exhaustion, and was intended to replace IPv4. In December 1998, IPv6 became a Draft Standard for the IETF, which subsequently ratified it as an Internet Standard on 14 July 2017.

The Internet Protocol (IP) is the network layer communications protocol in the Internet protocol suite for relaying datagrams across network boundaries. Its routing function enables internetworking, and essentially establishes the Internet.

In computer networking, the maximum transmission unit (MTU) is the size of the largest protocol data unit (PDU) that can be communicated in a single network layer transaction. The MTU relates to, but is not identical to the maximum frame size that can be transported on the data link layer, e.g., Ethernet frame.

The Transmission Control Protocol (TCP) is one of the main protocols of the Internet protocol suite. It originated in the initial network implementation in which it complemented the Internet Protocol (IP). Therefore, the entire suite is commonly referred to as TCP/IP. TCP provides reliable, ordered, and error-checked delivery of a stream of octets (bytes) between applications running on hosts communicating via an IP network. Major internet applications such as the World Wide Web, email, remote administration, and file transfer rely on TCP, which is part of the Transport Layer of the TCP/IP suite. SSL/TLS often runs on top of TCP.

In computer networking, the User Datagram Protocol (UDP) is one of the core communication protocols of the Internet protocol suite used to send messages to other hosts on an Internet Protocol (IP) network. Within an IP network, UDP does not require prior communication to set up communication channels or data paths.

In computing, Internet Protocol Security (IPsec) is a secure network protocol suite that authenticates and encrypts packets of data to provide secure encrypted communication between two computers over an Internet Protocol network. It is used in virtual private networks (VPNs).

<span class="mw-page-title-main">Network address translation</span> Protocol facilitating connection of one IP address space to another

Network address translation (NAT) is a method of mapping an IP address space into another by modifying network address information in the IP header of packets while they are in transit across a traffic routing device. The technique was originally used to bypass the need to assign a new address to every host when a network was moved, or when the upstream Internet service provider was replaced, but could not route the network's address space. It has become a popular and essential tool in conserving global address space in the face of IPv4 address exhaustion. One Internet-routable IP address of a NAT gateway can be used for an entire private network.

The Virtual Router Redundancy Protocol (VRRP) is a computer networking protocol that provides for automatic assignment of available Internet Protocol (IP) routers to participating hosts. This increases the availability and reliability of routing paths via automatic default gateway selections on an IP subnetwork.

In computer networking, the multicast DNS (mDNS) protocol resolves hostnames to IP addresses within small networks that do not include a local name server. It is a zero-configuration service, using essentially the same programming interfaces, packet formats and operating semantics as unicast Domain Name System (DNS). It was designed to work as either a stand-alone protocol or compatibly with standard DNS servers. It uses IP multicast User Datagram Protocol (UDP) packets and is implemented by the Apple Bonjour and open-source Avahi software packages, included in most Linux distributions. Although the Windows 10 implementation was limited to discovering networked printers, subsequent releases resolved hostnames as well. mDNS can work in conjunction with DNS Service Discovery (DNS-SD), a companion zero-configuration networking technique specified separately in RFC 6763.

Anything In Anything (AYIYA) is a computer networking protocol for managing IP tunneling protocols in use between separated Internet Protocol networks. It is most often used to provide IPv6 transit over an IPv4 network link when network address translation masquerades a private network with a single IP address that may change frequently because of DHCP provisioning by Internet service providers.

Internet Control Message Protocol version 6 (ICMPv6) is the implementation of the Internet Control Message Protocol (ICMP) for Internet Protocol version 6 (IPv6). ICMPv6 is an integral part of IPv6 and performs error reporting and diagnostic functions.

6LoWPAN was a working group of the Internet Engineering Task Force (IETF). It was created with the intention of applying the Internet Protocol (IP) even to the smallest devices, enabling low-power devices with limited processing capabilities to participate in the Internet of Things.

Path MTU Discovery (PMTUD) is a standardized technique in computer networking for determining the maximum transmission unit (MTU) size on the network path between two Internet Protocol (IP) hosts, usually with the goal of avoiding IP fragmentation. PMTUD was originally intended for routers in Internet Protocol Version 4 (IPv4). However, all modern operating systems use it on endpoints. In IPv6, this function has been explicitly delegated to the end points of a communications session. As an extension to the standard path MTU discovery, a technique called Packetization Layer Path MTU Discovery works without support from ICMP.

The internet layer is a group of internetworking methods, protocols, and specifications in the Internet protocol suite that are used to transport network packets from the originating host across network boundaries; if necessary, to the destination host specified by an IP address. The internet layer derives its name from its function facilitating internetworking, which is the concept of connecting multiple networks with each other through gateways.

An IPv6 transition mechanism is a technology that facilitates the transitioning of the Internet from the Internet Protocol version 4 (IPv4) infrastructure in use since 1983 to the successor addressing and routing system of Internet Protocol Version 6 (IPv6). As IPv4 and IPv6 networks are not directly interoperable, transition technologies are designed to permit hosts on either network type to communicate with any other host.

<span class="mw-page-title-main">IPv6 address</span> Label to identify a network interface of a computer or other network node

An Internet Protocol Version 6 address is a numeric label that is used to identify and locate a network interface of a computer or a network node participating in a computer network using IPv6. IP addresses are included in the packet header to indicate the source and the destination of each packet. The IP address of the destination is used to make decisions about routing IP packets to other networks.

An IPv6 packet is the smallest message entity exchanged using Internet Protocol version 6 (IPv6). Packets consist of control information for addressing and routing and a payload of user data. The control information in IPv6 packets is subdivided into a mandatory fixed header and optional extension headers. The payload of an IPv6 packet is typically a datagram or segment of the higher-level transport layer protocol, but may be data for an internet layer or link layer instead.

The Stream Control Transmission Protocol (SCTP) is a computer networking communications protocol in the transport layer of the Internet protocol suite. Originally intended for Signaling System 7 (SS7) message transport in telecommunication, the protocol provides the message-oriented feature of the User Datagram Protocol (UDP), while ensuring reliable, in-sequence transport of messages with congestion control like the Transmission Control Protocol (TCP). Unlike UDP and TCP, the protocol supports multihoming and redundant paths to increase resilience and reliability.

References

  1. ↑ Carl A. Sunshine (1977), "Source routing in computer networks", ACM SIGCOMM Computer Communication Review, 7: 29, doi:10.1145/1024853.1024855, S2CID   31169173
  2. 1 2 Patrick Geoffray; Torsten Hoefler (26–28 August 2008). Adaptive Routing Strategies for Modern High Performance Networks (PDF). 16th IEEE Symposium on High Performance Interconnects. IEEE. p. 2. doi:10.1109/HOTI.2008.21. ISBN   978-0-7695-3380-3.
  3. ↑ Internet Protocol. IETF. September 1981. doi: 10.17487/RFC0791 . RFC 791.
  4. ↑ Rik Farrow (August 2007). "Source Address Spoofing".
  5. ↑ Deering, S.; Hinden, R. (December 1998). Internet Protocol, Version 6 (IPv6) Specification. IETF. doi: 10.17487/RFC2460 . RFC 2460.
  6. ↑ Abley, J. (December 2007). Deprecation of Type 0 Routing Headers in IPv6. IETF. doi: 10.17487/RFC5095 . RFC 5095.
  7. ↑ Previdi, S., ed. (July 2017). IPv6 Segment Routing Header (SRH). IETF. I-D draft-ietf-6man-segment-routing-header-07.
  8. ↑ Soliman, Mourad; Nandy, Biswajit; Lambadaris, Ioannis; Ashwood-Smith, Peter (2012-12-10). Source routed forwarding with software defined control, considerations and implications. Proceedings of the 2012 ACM conference on CoNEXT student workshop. ACM. p. 43–44. doi:10.1145/2413247.2413274. ISBN   978-1-4503-1779-5.
  9. ↑ Peter Ashwood-Smith. "SDN State Reduction" (PDF). IETF.
  10. ↑ Steve Parkes. "SpaceWire User’s Guide". 2012. p. 20.
  11. ↑ Paul Walker, Barry Cook. "SpaceWire: Key principles brought out from 40 year history". 2006. p. 5.
  12. ↑ S.M. Parkes and C. McClements. "SpaceWire Networks". 2002. page 61.4.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.