1.2 Devices required to meet a network specification

As mentioned in section 1.1, we already knows something about router, switch, and hub, also bridge as addition in internetwork. Figure below shows how network look with all of those internetwork devices in place. Please note that left and right part of this figure are not commonly use this day (we can say that bridge and hub are old technology). Typical network this day can be found in middle part (switch 1, 2, and 3).

Figure 1

Remember that a router will not only break up broadcast domain in every LAN interfaces, but also it will break up collision domain as well.

Notice that we use bridge, it break up collision domain, operate similary with switch. Hub does not break up collision domain, we can say that every devices connected to hub belong to the same collision domain.

The best network connected to the router is the LAN switch network in the middle. Why ? Because each port on switch has its own collision domain. Well, we still can enhance this LAN switch in the middle. Since its still belong to the same broadcast domain, it can turn into bad thing. Imagine if the broadcast domain too large, so all devices must listen to all broadcast transmitted, the users then have less bandwidth and require to proccess more broadcast, as result network response time will slow. We can do enhancement by using separate VLAN (Vitual LAN) for each switches to meet bussiness requirement. For example Switch 2 using VLAN 100 to serve users in IT Departement, Switch 3 using VLAN 200 to server Accounting Departement. This will separate or break up broadcast domain, router still need for interVLAN communication.

Ok, let’s back to Figure 1 above ..
How many broadcast and collision domains are in this internetwork ?
Leave your answer in comment box below .. C U..