The three major characteristics of a Wide Area Network are:
1) hierarchical model
2) Spans over large geographical area
3) Holds Many LANs
A regional Bell Operation Company (RBOC) is (also state what it is used for)... A local or regional telephone company that owns and operates telephone lines and switches in one of seven U.S. regions.
OSI Model
The two layers of the OSI model WAN standard typically address are:
Layer 1 (physical) Layer 2 (Data Link)
A WAN data link protocol is (also describe its purpose)...
used to carry data over a network, such as PPP which contains a protocol field to identiy the network-layer protocol.
The purpose of DTE and DCE devices is...(Also state which layer of the OSI model they apply to.) The DCE is typically used to provide clocking signals and to forward traffic..The DCE provides a physical connection to a network.The DTE is typically connected to a data network through a DCE device (for example, a modem) and typically uses clocking signals generated by the DCE.
The four common Data Link layer WAN protocols are -
1)HDLC
2)Frame Relay
3)PPP
4)ISDN
Point Of Presence (POP) is... (also describe where it is located and what its function/purpose is) - the point of interconnection between the communication facilities provided by the telephone company and the building's main distribution facility.
The Central Office (CO) is... (also describe where it is located and what its function/purpose is) - the local telephone company office to which all local loops in a given area connect and in which circuit switching of subscriber lines occurs.
Time Division Multiplexing (TDM) is... (also describe how it works and what WAN technology uses it) - Technique in which information from multiple channels can be allocated bandwidth on a single wire based on preassigned time slots. Bandwidth is allocated to each channel regardless of whether the station has data to transmit.
Customer Premise Equipment is... Terminating equipment, and is typically terminals, telephones and modems, supplied by the telephone company, installed at customer sites, and connected to the telephone company network.
The data encapsulation process across a WAN link is...a hierarchical model.
Connection oriented WAN services across a WAN refers to... A straight established path with a virtual circuit between a source and a destination. One example would be Frame Relay.
Connection less a WAN when there is no... established path between the source and the destination.
WAN signaling standards effect the throughput of WAN services by... establishing sets of standards for communication across a network.
A dedicated leased line is... the line reserved by the communiations carrier for the private use of the customer. These line types are ideal for high volume environments with a steady rate of traffic.
Packet switched connections are...(also state what WAN services use this technology) - a WAN switching method in which network devices share a permanent virtual circuit (PVC). Examples include Frame Relay, X.25 and SMDS.
WAN Design
A hierachical WAN design model is...(also describe the major benefits of) - A model to help design networks. Some major benefits are: Scalability, ease of implementation, ease of troubleshooting, Predictability and protocol support.
The three layers that make up the hierarchical model are (also briefly describe the functions typically performed at each layer)
1) The Core Layer - It provides optimal transport between sites.
2) The Distribution Layer - It provides policy based connectivity.
3)The Access Layer - It provides workgroup and user access to the network.
A One layer hierarchical WAN model is ...able to function best in smaller networks.
A two layer hierarchical WAN design model is... used to interconnect seperate sites.
Other WAN technologies such as ISDN and Frame Relay normally are connected to the WAN at the Core layer because....core services are typically leased from a telecom service provider.
Server placement and associated traffic patterns are important to understand when designing a WAN because...Server placement determines the overall traffic pattern. Servers can consume great amounts of bandwidth if placed incorrectly.
Reflection - In this lesson I learned all about WAN design. I now undertand why the correct placement of servers is so important in the WAN design process.