Expanding Networks

CS 363

DePaul University

Network Connectivity

• Deals with connecting pieces of one network

• Hubs, bridges, repeaters, and multiplexers are used to accomplish connectivity

Problem

• You need to run cabling from your network to some new offices that were recently built on the other side of the building. Since you plan to use 10BaseT on this Ethernet network segment, your maximum cabling length is only 330 feet. This is 50 feet short of the new office. Which network connectivity device would you consider adding to ensure proper signal strength?

Problem

• You have a very busy network that is becoming bogged down with traffic. You decide that the layout of the network is conveniently organized in a way such that you could simply divide the network into two segments and most traffic would stay on the side of the segment on which it originated. Which network connectivity device might you use to connect the two segments?

Problem

• You are reorganizing a 10Base2 Ethernet network and need to install a device to bring everything together. Because of the size of the network, you are concerned about signal strength diminishing. Which kind of device would you want to choose, making sure that signal strength is not compromised?

Network Connectivity

• Hubs– Provide mechanisms for adding more

computers to network– Number used limited by networking technology– Also called concentrators and multiport

repeaters

Passive Hubs

• combines the signals of network segments

• no amplification or regeneration

• halves the max cable length

• hubs broadcast signals to all attached equipment

Active Hubs

• include repeaters/regenerators

• can sustain greater distances between hubs

• amplify noise as well as signal

• often called multiport repeaters

Intelligent Hubs

• also called managed hubs

• switching hubs route signal to addressed destination

• all intelligent hubs route signal only to proper segment, not to the entire network

Bridges

• connect network segments of the same network technology (ethernet to ethernet)

• increases the maximum possible size of the network

• routes signals across network segments only as needed

• transparent bridges=>• source-routing bridges=>

Multiplexers

• Allows multiple signals to share a baseband or broadband medium

• FDM=>

• TDM=>

• StatTDM=>

Network Interconnectivity

• Why interconnect?– Reduction in network traffic– Optimizes performance of network– Simplifies management of network– Efficiently spans geographical distances

Creating and Managing Subnetworks

Interconnectivity Equipment

• Routers=>devices that connect two or more networks

• Brouters=>router with bridging capabilities

• Gateways=>interprets and translates different network protocols used in two distinct networks

• CSU/DSU=>interconnection point for LANs and public data/voice networks

Problem

• Your network frequently experiences network storms. Which type of internetwork device would you use to prevent a storm from spreading and why?

Problem

• You are going to hook up your LAN to a mainframe. You will need an internetwork connectivity device. What would this device be? Why would you need it?

Problem

• You are connecting your network to the PSTN in your area. A representative from the local telephone company explains that you’ll need to use a specific internetwork device that will change your network signal to another strength and format. What will you need?

Routers

• hardware and software (though all software possible)

• connect two or more subnets (logically separate networks)

• make use of physical and logical addressing

• more intelligent than bridges, but also slower

Routing Costs

• cost to transmit=>time, distance, money

• Hop count=>

• Tick count=>

• Relative expense=>

Route Discovery

• Distance-vector routing

• Link-state routing– open shortest path first (OSPF)– Dynamic route selection

– Static route selection

Broadcast Storms

Gateways

CSUs/DSUs