Edge devices are switches, routers, routing switches, IADs and a variety of MAN/WAN devices which are installed in the edge network to pass packets between the access devices and core/backbone network devices. It is a physical device using Data Link layer (layer 2) and Network layer (layer 3) technologies.
Edge devices may translate between one type of network protocol and another. For example, ATM networks send data in cells and use connection-oriented virtual circuits. An IP network is packet oriented; so if ATM is used as a core, packets must be encapsulated in cells and the destination address must be converted to a virtual circuit identifier. Edge devices are responsible for handling this conversion. There is an ingress (input) and egress (output) edge device for all connections. The edge device aggregates ingress traffic for high speed transmission in the core/backbone network and then distribute egress traffic to end user through access devices.
An edge switch for a WAN may be a multiservice unit, meaning that it supports a wide variety of communication technologies, including voice and IP over dial-up connections, ISDN, T1 circuits, frame relay, and ATM. An edge device may provide enhanced services, such as VPN support, voice over IP, and QoS services.
Edge devices provide entry points into enterprise or carrier/service provider core/backbone networks. On an enterprise network, edge devices may connect LANs (Ethernet or Token Ring) to an ATM backbone.
Edge devices also provide connections of users into service provider networks. In a service provide network, an edge device are typically installed at the Service Provide side, verses the access device which is typically installed at the customer premises.
Related Terms: Edge Network, Access Network, Core/Backbone Network, Access Device, IAD, Router, Switch