WAN Connections Based on your understanding of network security, in continuation

ID: 3674297 • Letter: W

Question

WAN Connections

Based on your understanding of network security, in continuation with the course project, prepare a 4- to 5-page report in Microsoft Word responding to the following questions:

Design a WAN between offices including the math calculations of how to meet the bandwidth.

Describe the general type of WAN connections and network hardware that will be used to interconnect the offices. Consider the following while responding:

Ways you will monitor and manage the WANs and the LANs

Define the subnet for each of the five locations and explain the devices at each subnet; also, define the subnet masks and gateway, as well as the number of IP addresses that are used by the users stations and devices

Kind of multiprotocol label switching (MPLS) and the routing protocol you would recommend within the acceptable budget constraint

Security and data center requirements

Below are the specifications for the business

Locations: Five metropolitan geographic urban location; each location has 120 users over three floors; each Floor dimensions are as follows: Length = 210 feet ft), Height = 8 Ft, and Width = 80 ft

Platforms: Multiple (Windows, Mac, Linux, and Mobile Os)

Topology: Ethernet (Copper, Fiber, and Wi-Fi)

Bandwidth: To be determine by you, the network designer, for inbound and outbound

Servers: To be determined by you, the network designer

Intranet access: IP addresses are 172.17. y.x/24, where y is each location IP segment (use any octet that you wish for each location) and x = 1 to 254

Internet access: One access using T1 Link at each location; the public IP address is 96.68.111.x, where x = 1 to 5

Remote virtual private network access for users to telecommute

Explanation / Answer

Wide Area Networks (WAN)

The size of a network is limited due to size and distance constraints. However networks may be connected over a high speed communications link (called a WAN link) to link them together and thus become a WAN. WAN links are usually:

WAN Connection Technologies

Signal

System

Total Kbps

Channels

Number of equivalent T1 lines

DS-1

1544

DS-2

6312

DS-3

44736

672

DS-4

274760

4032

3668

A device resembling a modem (called an ISDN modem) is used to connect to ISDN. The computer and telephone line are plugged into it.

ATM can be embedded in other protocols such as ATM-25, T1, T3, OC-1, OC-3, OC-12, and OC-48. Some ATM technologies include:

WAN Technology comparisons

Technology

Speed

Characteristics

Switched 56

56Kbps

Switched line, not dedicated

X.25

64Kbps

Packet switching, error correction, store and foreward, with round trip delay

Frame Relay

56Kbps to 1.544Mbps

Varying length frames with permanent virtual circuit

SMDS

1.533 to 45Mbps

Fixed cell length with no error checking

1.544Mbps

24 Multiplexed channels

44.736Mbps

672 Multiplexed channels

SONET

51.8Mbps (OC-1)

OC2 is 2X OC1, OC3 is 3X OC1

ATM

155Mbps to 622 Mbps

Fixed length packets. works on SONET and T carrier lines. Uses virtual circuits

Terms

Multi-Protocol Label Switching (MPLS)

Multi-Protocol Label Switching (MPLS) was originally presented as a way of improving the forwarding speed of routers but is now emerging as a crucial standard technology that offers new capabilities for large scale IP networks. Traffic engineering, the ability of network operators to dictate the path that traffic takes through their network, and Virtual Private Network support are examples of two key applications where MPLS is superior to any currently available IP technology.

Although MPLS was conceived as being independent of Layer 2, much of the excitement generated by MPLS revolves around its promise to provide a more effective means of deploying IP networks across ATM-based WAN backbones. The Internet Engineering Task Force is developing MPLS with draft standards expected by the end of 1998. MPLS is viewed by some as one of the most important network developments of the 1990's. This article will explain why MPLS is generating such interest.

The essence of MPLS is the generation of a short fixed-length label that acts as a shorthand representation of an IP packet's header. This is much the same way as a ZIP code is shorthand for the house, street and city in a postal address, and the use of that label to make forwarding decisions about the packet. IP packets have a field in their 'header' that contains the address to which the packet is to be routed. Traditional routed networks process this information at every router in a packet's path through the network (hop by hop routing).

In MPLS, the IP packets are encapsulated with these labels by the first MPLS device they encounter as they enter the network. The MPLS edge router analyses the contents of the IP header and selects an appropriate label with which to encapsulate the packet. Part of the great power of MPLS comes from the fact that, in contrast to conventional IP routing, this analysis can be based on more than just the destination address carried in the IP header. At all the subsequent nodes within the network the MPLS label, and not the IP header, is used to make the forwarding decision for the packet. Finally, as MPLS labeled packets leave the network, another edge router removes the labels.

In MPLS terminology, the packet handling nodes or routers are called Label Switched Routers (LSRs). The derivation of the term should be obvious; MPLS routers forward packets by making switching decisions based on the MPLS label. This illustrates another of the key concepts in MPLS. Conventional IP routers contain routing tables which are looked up using the IP header from a packet to decide how to forward that packet. These tables are built by IP routing protocols (e.g., RIP or OSPF) which carry around IP reachability information in the form of IP addresses. In practice, we find that forwarding (IP header lookup) and control planes (generation of the routing tables) are tightly coupled. Since MPLS forwarding is based on labels it is possible to cleanly separate the (label-based) forwarding plane from the routing protocol control plane. By separating the two, each can be modified independently. With such a separation, we don't need to change the forwarding machinery, for example, to migrate a new routing strategy into the network.

There are two broad categories of LSR. At the edge of the network, we require high performance packet classifiers that can apply (and remove) the requisite labels: we call these MPLS edge routers. Core LSRs need to be capable of processing the labeled packets at extremely high bandwidths.

This is an abstract of the MPLS article contained in techguide.com. The complete article examines MPLS and the opportunities it offers to users and also to the service providers who are designing and engineering the next generation of IP networks. It also describes why new carrier-class edge devices will become a key component in the provisioning of future network services.