The Hierarchical internetworking model is a three-layer model for
network design first proposed by
Cisco
Cisco Systems, Inc., commonly known as Cisco, is an American-based multinational corporation, multinational digital communications technology conglomerate (company), conglomerate corporation headquartered in San Jose, California. Cisco develo ...
. It divides
enterprise networks into three layers: core, distribution, and access layer.
Access layer
End-stations and servers connect to the enterprise at the ''access layer''. Access layer devices are usually commodity switching platforms, and may or may not provide
layer 3
In the seven-layer OSI model of computer networking, the network layer is layer 3. The network layer is responsible for packet forwarding including routing through intermediate routers.
Functions
The network layer provides the means of transf ...
switching services. The traditional focus at the access layer is minimizing "cost-per-port": the amount of investment the enterprise must make for each provisioned
Ethernet
Ethernet () is a family of wired computer networking technologies commonly used in local area networks (LAN), metropolitan area networks (MAN) and wide area networks (WAN). It was commercially introduced in 1980 and first standardized in ...
port. This layer is also called the desktop layer because it focuses on connecting client nodes, such as workstations to the network.
Distribution layer
The distribution layer is the ''smart'' layer in the three-layer model. Routing, filtering, and
QoS policies are managed at the distribution layer. Distribution layer devices also often manage individual branch-office
WAN connections. This layer is also called the Workgroup layer.
Core layer
The core is the backbone of a network, where the internet(internetwork) gateway are located. The core network provides high-speed, highly redundant forwarding services to move packets between distribution-layer devices in different regions of the network. Core switches and routers are usually the most powerful, in terms of raw forwarding power, in the enterprise; core network devices manage the highest-speed connections, such as
10 Gigabit Ethernet
10 Gigabit Ethernet (10GE, 10GbE, or 10 GigE) is a group of computer networking technologies for transmitting Ethernet frames at a rate of 10 gigabits per second. It was first defined by the IEEE 802.3ae-2002 standard. Unlike previous Et ...
or
100 Gigabit Ethernet
40 Gigabit Ethernet (40GbE) and 100 Gigabit Ethernet (100GbE) are groups of computer networking technologies for transmitting Ethernet frames at rates of 40 and 100 gigabits per second (Gbit/s), respectively. These technologies offer significantly ...
.
See also
*
Multi-tier architecture
*
Service layer
In intelligent networks (IN) and cellular networks, service layer is a conceptual layer within a network service provider architecture. It aims at providing middleware that serves third-party value-added services and applications at a higher a ...
References
*
* {{citation , url=http://www.cisco.com/c/en/us/td/docs/solutions/Enterprise/Campus/HA_campus_DG/hacampusdg.html , title=High Availability Campus Network Design , accessdate=2022-04-05
Computer_networking
Reference models