TCS Papers: Sample Questions 330 - 331 of 502

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Question number: 330

» Basic CS » Networks

Essay Question▾

Describe in Detail

What are the improvements made in CAS in. NET 4.0?

Explanation

  • CAS mechanism controls and configures the ability of managed code.

  • Earlier policy was applicable for only native applications and hence security guarantee was limited.

  • Developers thus used alternating solutions, such as operating system-level solutions.

  • . NET Framework 4 turned on the machine-wide security.

  • The shared and hosted Web applications can now run more securely without concerning about the CAS policies.

  • In. NET Framework 4.0, compilation warnings and runtime exceptions warn about obsolete CAS policy types and members either implicitly or explicitly.

  • However, warnings and errors are avoided by using < NetFx40_LegacySecurityPolicy > configuration element.

Question number: 331

» Basic CS » Networks

Essay Question▾

Describe in Detail

What is multicast routing?

Explanation

  • Sending a message to a group is called multicasting, and routing algorithm is called multicast routing.

  • Multicast communications are one-to-many or many-to-many- router forwards the received packets through several of its interfaces copying the data as necessary, and forward it to the receivers through several interfaces

  • Multicasting does not support reliable transport layer protocol such as TCP- source does not care about how many downstream receivers are receiving the data.

  • Multicast group identifies recipients interested in particular data stream represented by an IP address from a well-defined range.

  • Data sent to this IP address is forwarded to all members of the multicast group.

  • Routers between the source and recipients duplicate data packets and forward multiple copies wherever the path diverges.

  • Group membership information is used to calculate the best routers to duplicate the packets in the data stream.

  • Source sends data to a multicast group by setting the destination IP address of the datagram to be the multicast group address.

  • Any host can become a source and send data to a multicast group.

  • There are many different multicast protocols and modes of operation based on following principles:

    • A Multicast Group Membership Discovery protocol is used by receiving hosts to advertise their group membership to a local multicast router, For example, Internet Group Management Protocol (IGMP) for IPv4 and Multicast Listener Discovery (MLD) for IPv6.

    • Multicast Routing Protocol then enables routers to calculate the multicast distribution tree of receiving hosts. Protocol Independent Multicast (PIM) is the most important Multicast Routing Protocol.

Image of multicast routing

Image of Multicast Routing

Image of multicast routing