* There are three virtual circuit design strategies for a frame relay cloud. Explain what these are and the advantages and disadvantages associated with them.
Star Topology:
Advantages
1) Easy to connect new nodes or devices. In star topology new nodes can be added easily without affecting rest of the network. Similarly components can also be removed easily.
2) Centralized management. It helps in monitoring the network.
3) Failure of one node or link doesn’t affect the rest of network. At the same time its easy to detect the failure and troubleshoot it
Disadvantages
1) Too much dependency on central device has its own drawbacks. If it fails whole network goes down.
2) The use of hub, a router or a switch as central device increases the overall cost of the network.
3) Performance and as well number of nodes which can be added in such topology is depended on capacity of central device.

Fully Meshed Topology:
Advantages
1) Data can be transmitted from different devices simultaneously. This topology can withstand high traffic.
2) Even if one of the components fails there is always an alternative present. So data transfer doesn’t get affected.
3) Expansion and modification in topology can be done without disrupting other nodes.
Disadvantages
1) There are high chances of redundancy in many of the network connections
2) Overall cost of this network is extremely high
3) The set-up and maintenance is very difficult

Partially Meshed Topology:

* What are the pros and cons of using multiprotocols in a network? Explain in detail.
Some pros are that it can:
Improve Uptime – by sending data over an alternative path in less than 50 milliseconds (if one exists). MPLS also reduces the amount of manual intervention your network provider has to do to create a WAN, reducing the likelihood of human error bringing down your circuit.
Create Scalable IP VPNs – with MPLS it’s easy to add an additional site to the VPN. There is no need to configure a complex mesh of tunnels, as is common with some traditional approaches.
Improve User Experience – by prioritizing time-sensitive traffic such as VoIP. Multi-Protocol Label Switching offers multiple Classes of Service, enabling you to apply separate settings to different types of traffic.
Improve Bandwidth Utilization – by putting multiple types of traffic on the same link, you can let high priority traffic borrow capacity from lower priority traffic streams whenever required. Conversely, when the lower priority traffic needs to burst beyond its usual amount of bandwidth, it can use any capacity that’s not being used by higher priority services.
Reduce Network Congestion – Sometimes the shortest path between two locations isn’t the best one to take, as congestion has made it less attractive (at least for the time being). MPLS offers sophisticated traffic engineering options that enable traffic to be sent over non-standard paths. This can reduce latency (the delay in sending/receiving data). It also reduces congestion on the paths that have just been avoided as a result of traffic engineering.
Some cons are that it can:
Although MPLS may be replacing the increasingly antiquated Frame Relay and ATM models for packet routing, there are already issues with network security. MPLS segregates traffic among companies using the same service provider, which gives an assumed level of privacy. The possibility exists that malicious intrusion may affect a company’s data while in transit, either through the service provider eavesdropping or a hacker getting in through one of the internet gateways on the MPLS backbone. Accidents are also possible by a service provider incorrectly configuring an edge router, permitting one company accessing another company’s VPN. Simply deploying MPLS does not ensure a company’s security. For extra security and at a cost company’s can implement IPSec tunnels to encrypt data and further protect packets.