Core router
Encyclopedia
A core router is a router designed to operate in the Internet backbone
Internet backbone
The Internet backbone refers to the principal data routes between large, strategically interconnected networks and core routers in the Internet...

, or core. To fulfill this role, a router must be able to support multiple telecommunications interfaces of the highest speed in use in the core Internet and must be able to forward IP packets at full speed on all of them. It must also support the routing protocols being used in the core. A core router is distinct from an edge router: edge routers sit at the edge of a backbone network and connect to core routers.

History

Like the term "supercomputer
Supercomputer
A supercomputer is a computer at the frontline of current processing capacity, particularly speed of calculation.Supercomputers are used for highly calculation-intensive tasks such as problems including quantum physics, weather forecasting, climate research, molecular modeling A supercomputer is a...

", the term "core router" refers to the largest and most capable routers of the then-current generation. A router that was a core router when introduced will not be a core router ten years later. At the inception of the ARPANET
ARPANET
The Advanced Research Projects Agency Network , was the world's first operational packet switching network and the core network of a set that came to compose the global Internet...

 (the Internet's predecessor) in 1969, the fastest links were 56 kbit/s and a given routing node had at most six links. The "core router" was a dedicated minicomputer called an IMP Interface Message Processor
Interface Message Processor
The Interface Message Processor was the packet-switching node used to interconnect participant networks to the ARPANET from the late 1960s to 1989. It was the first generation of gateways, which are known today as routers. An IMP was a ruggedized Honeywell DDP-516 minicomputer with...

. Link speeds increased steadily, requiring progressively more powerful routers until the mid-1990s, when the typical core link speed reached 155 Mbit/s. At that time, several breakthroughs in fiber optic telecommunications (notably DWDM
Wavelength-division multiplexing
In fiber-optic communications, wavelength-division multiplexing is a technology which multiplexes a number of optical carrier signals onto a single optical fiber by using different wavelengths of laser light...

 and EDFA
Optical amplifier
An optical amplifier is a device that amplifies an optical signal directly, without the need to first convert it to an electrical signal. An optical amplifier may be thought of as a laser without an optical cavity, or one in which feedback from the cavity is suppressed...

) technologies combined to permit a sudden dramatic increase in core link speeds: by 2000, a core link operated at 2.5 Gbit/s and core internet companies were planning for 10 Gbit/s speeds.

The largest provider of core routers in the 1980s and 1990s was Cisco Systems
Cisco Systems
Cisco Systems, Inc. is an American multinational corporation headquartered in San Jose, California, United States, that designs and sells consumer electronics, networking, voice, and communications technology and services. Cisco has more than 70,000 employees and annual revenue of US$...

, who provided core routers as part of a broad product line. This was despite the presence of faster and more capable routers from Wellfleet Communications
Wellfleet communications
Wellfleet Communications was an Internet router company founded in 1986 by Paul Severino, Bill Seifert, Steven Willis and David Rowe based in Bedford, Massachusetts, and later Billerica, Massachusetts...

, which existed as an independent company until it merged with SynOptics Communications in 1994, to become Bay Networks
Bay Networks
Bay Networks was a network hardware vendor formed through the merger of Santa Clara, California based SynOptics Communications and Billerica, Massachusetts based Wellfleet Communications on July 6, 1994...

. Juniper Networks
Juniper Networks
Juniper Networks is an information technology and computer networking products multinational company, founded in 1996. It is head quartered in Sunnyvale, California, USA. The company designs and sells high-performance Internet Protocol network products and services...

 entered the business in 1996, focusing primarily on core routers. Both companies addressed the need for a radical increase in routing capability that was driven by the increased link speed. In addition, several new companies attempted to develop new core routers in the late 1990s. It was during this period that the term "core router" came into wide use. The required forwarding rate of these routers became so high that it could not be met with a single processor or a single memory, so these systems all employed some form of a distributed architecture based on an internal switching fabric.

The Internet was historically supply-limited, and core Internet providers historically struggled to expand the Internet to meet the demand. During the late 1990s, they expected a radical increase in demand, driven by the Dot-com bubble
Dot-com bubble
The dot-com bubble was a speculative bubble covering roughly 1995–2000 during which stock markets in industrialized nations saw their equity value rise rapidly from growth in the more...

. By 2001, it became apparent that the sudden expansion in core link capacity had outstripped the actual demand for internet services in the core. The core internet providers were able to defer purchases of new core routers for a time, and most of the new companies went out of business.

As of 2007, the internet core link speed is 10 Gbit/s, with a few links at 40 Gbit/s.

Current core router manufacturers

(core router model between parenthesis)
  • Brocade Communications Systems
    Brocade Communications Systems
    Brocade Communications Systems, Inc. , based in Silicon Valley , is a vendor of storage area network hardware and software. The company also designs, manufactures, and sells networking products and management applications for local, metro, and wide area networks...

     (NetIron XMR Series)
  • Cisco Systems
    Cisco Systems
    Cisco Systems, Inc. is an American multinational corporation headquartered in San Jose, California, United States, that designs and sells consumer electronics, networking, voice, and communications technology and services. Cisco has more than 70,000 employees and annual revenue of US$...

     (CRS
    Carrier Routing System
    Carrier Routing System is a large-scale core router, developed by Cisco Systems, Inc. It runs IOS XR which is a train of IOS built upon the QNX microkernel. A single chassis holds a maximum of 16 line cards, and can run an OC-768 SONET interface...

     series)
  • Extreme Networks
    Extreme Networks
    Extreme Networks, founded in 1996, is a publicly listed company that designs, builds, and installs Ethernet network solutions for enterprise and Carrier Class networks.-Corporate History:Extreme Networks is located in Santa Clara, California...

     (Black Diamond 20808), high-end core switch
  • Huawei
    Huawei
    Huawei is a Chinese multinational networking and telecommunications equipment and services company headquartered in Shenzhen, Guangdong, China...

     Technologies Ltd. (NetEngine 5000E, NetEngine 80E, NetEngine 80)
  • Juniper Networks
    Juniper Networks
    Juniper Networks is an information technology and computer networking products multinational company, founded in 1996. It is head quartered in Sunnyvale, California, USA. The company designs and sells high-performance Internet Protocol network products and services...

     (T-series
    Juniper T-Series
    Juniper T-Series is a series of core routers designed and manufactured by Juniper Networks. The T-Series core router family comprises the T320, T640, T1600, TX Matrix, and TX Matrix Plus, designed for high-end and core networks with throughput from 320 Gbit/s to 25.6 Tbit/s with a maximum...

    )
  • ZTE
    ZTE
    ZTE Corporation formerly Zhongxing Telecommunication Equipment Corporation is a Chinese multinational telecommunications equipment and systems company headquartered in Shenzhen, China...

     (ZXR10 Series
    ZTE ZXR10-Series
    ZTE ZXR10 series is a series of Network Routers designed and manufactured by ZTE. The ZXR10 Series router family comprises the T8000, M6000, T1200, and T600....

     : T8000,M6000)

Previous core router manufacturers

  • Axiowave Networks
  • Allegro Networks
  • Avici Systems (changed name to Soapstone Networks in 2008 and no longer making core routers)
  • Caspian Networks
  • Charlotte's Web Networks
  • Foundry Networks
    Foundry Networks
    Foundry Networks, Inc. was a networking hardware vendor selling high-end Ethernet switches and routers. The company was founded in 1996 by Bobby R. Johnson, Jr. and was headquartered in Santa Clara, California, USA...

     (acquired by Brocade in 2008)
  • Hyperchip
  • IPOptical
  • Ironbridge
  • Marconi
    Marconi Company
    The Marconi Company Ltd. was founded by Guglielmo Marconi in 1897 as The Wireless Telegraph & Signal Company...

     (still in business, not making core routers)
  • Nortel Networks (bankrupt)
  • Osphere Net Systems
  • Pluris
  • Procket Networks
    Procket Networks
    Procket Networks was a startup founded in 1999 by Dr. Sharad Mehrotra, Dr. Bill Lynch, and Dr. Tony Li to build network processors but was later redirected to build core routers. The company produced two systems, the 8801, a one slot 40Gb/s router and the 8812, a half-rack 480Gb/s router...

    (acquired by Cisco Systems in 2004)
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