Interconnection Technologies

Technology Use

Fast Ethernet CO

Fast Ethernet CO

Gigabit Ethernet

10-Gigabit High-speed I Ethernet switch linkS

EtherChannel High-speed I

©2006 Cisco Systems, Inc. All rights reserved.

A number of technologies are available to interconnect devices in the campus network. Some of the more common technologies are listed here. The interconnection technology selected will depend on the amount of traffic the link must carry. A mixture of copper and fiber-optic cabling will likely be used, based on distances, noise immunity requirements, security, and other business requirements.

■ Fast Ethernet (100-Mbps Ethernet): This LAN specification (IEEE 802.3u) operates at 100 Mbps over twisted-pair cable. The Fast Ethernet standard raises the speed of Ethernet from 10 Mbps to 100 Mbps with only minimal changes to the existing cable structure. A switch with port functioning at both 10 and 100 Mbps can move frames between ports without Layer 2 protocol translation.

■ Gigabit Ethernet: An extension of the IEEE 802.3 Ethernet standard, Gigabit Ethernet increases speed tenfold over that of Fast Ethernet, to 1000 Mbps, or 1 Gbps. IEEE 802.3z specifies operations over fiber optics, and IEEE 802.3ab specifies operations over twistedpair cable.

■ 10-Gigabit Ethernet: 10-Gigabit Ethernet was formally ratified as an IEEE 802.3 Ethernet standard in June 2002. This technology is the next step for scaling the performance and functionality of an enterprise. With the deployment of Gigabit Ethernet becoming more common, 10-Gigabit will become the norm for uplinks.

© 2006 Cisco Systems, Inc. Defining VLANs 2-9

■ EtherChannel: This feature provides link aggregation of bandwidth over Layer 2 links between two switches. EtherChannel bundles individual Ethernet ports into a single logical port or link, providing aggregate bandwidth of up to 1600 Mbps (8-100Mbps links, full duplex) or up to 16 Gbps (8-Gigabit links, full duplex) between two Cisco Catalyst switches. All interfaces in each EtherChannel bundle must be configured with similar speed, duplex, and VLAN membership.

Interconnection Technologies

The table discusses the use of each technology in the Campus Infrastructure module.


Use in Campus Infrastructure Module

Fast Ethernet

Often used to connect end-user devices to the access layer switch. If user connections are running at 10 Mbps, Fast Ethernet links between access and distribution switches may be adequate.

It is adequate for servers in small- to medium-sized networks if full duplex is invoked.

Gigabit Ethernet

High-speed LAN backbones connecting building distribution switches to campus backbone switches. Widely used internal or Internet-accessible servers might be connected via gigabit Layer 2 technology.

10-Gigabit Ethernet

Very high-speed LAN backbone and link aggregation. As gigabit links become more common, 10-Gigabit will be necessary to scale the uplinks.


Any connection between switches with multiple physical links that requires high bandwidth and redundancy. Links between Building Distribution and Campus Backbone might be Gigabit EtherChannel. Links between access and distribution layer devices might be Fast Ethernet EtherChannel.

2-10 Building Cisco Multilayer Switched Networks (BCMSN) v3.0 © 2006 Cisco Systems, Inc.

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