Frequently Asked Questions (FAQ)

1:	Does the LAN topology affect the WAN?
A1:	No, the LAN topology is independent of the WAN. LAN applications can affect the WAN, however, especially in multicast and broadcast environments. It is not uncommon to find LAN broadcasts unnecessarily traversing the WAN, impacting WAN traffic and possibly costing more money in WAN costs supporting this unnecessary LAN traffic.
2:	Can unicast, multicast, and broadcast applications be mixed?
A2:	Yes, because the traffic type is associated with the application. For example, a LAN could support video (multicast), e-mail and print (unicast), and DHCP (broadcast) applications. As long as there is sufficient LAN bandwidth to support user applications, there is no issue.
3:	Which is better of the following topologies: star, bus, ring, or tree topology?
A3:	The answer to this question is the same answer to any design question: "It depends." The LAN topology depends on several variables, such as applications in use, traffic load and patterns, geographic location of the LAN hosts (within a single room or spread across a campus), and redundancy requirements, to name a few.
4:	Can LAN topologies be mixed?
A4:	Yes.
5:	Can routers run multiple routing protocols simultaneously?
A5:	Yes, dependant upon the router's Internetwork Operating System (IOS). For example, with the proper IOS a router can simultaneously maintain and update routes and connections to IP, IPX, and AppleTalk networks.