G1 g2 and g3 are members of multicast group and can

Info icon This preview shows pages 7–10. Sign up to view the full content.

G1, G2 and G3 are members of multicast group and can receive datagram with corresponding destination multicast address. Two hosts S1 and S2, transmit data to this multicast address. The heavy black lines indicates the routing tree for source S1 and this multicast group, and the heavy gray lines indicates the routing tree for source S2 and this multicast group. The arrowed line indicates packet transmission from S1 (black) and S2 (gray). RSVP Protocol Mechanisms RSVP uses two basic message types: Resv and Path. Resv messages originate at multicast group receivers and propagate upstream through the distribution tree being merged and packed when appropriate at each node along the way. Path message is used to provide upstream routing information. In all of the multicast routing protocols currently in use, only a downstream route, in front of the distributing tree, is maintained. Resv messages must propagate upstream through all intermediate routers and to all sending host. In the absence of reserve routing information for routing protocol,RSVP provides this with Path message. Each host wishes to participate as a sender in a multicast group issues a path message that is transmitted through out the distribution tree to or multicast destination. Each router and each destination host creates a path state that indicates the reverse hop to be used for this source. The operation of protocol can be described as:
Image of page 7

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

(a) A receiver joins a multicast group by sending an IGMP join message to a neighboring routers (b) A potential sender issues a Path message to the multicast group address (c) A receiver receives a Path message identifying a sender (d) The receiver has reverse path information; it may become sending Resv messages, specifying the desired flow descriptors. (e) Resv message propagates through the internetwork and it delivered to the sender (f) The sender starts sending data packets (g) The receiver starts receiving data packet Events a and b may happen in either order. (a)Data distribution to a multicast group (b) Merged Resv messages Figure 16.11 RSVP Operation
Image of page 8
7. The discussion of flow control with a reliable network service referred to a back pressure mechanism utilizing a lower level flow control protocol. Discuss the disadvantages of this strategy. (20 marks) Solution Reliable Sequencing Network Service The assumption of a reliable sequencing networking services allows the use of a quite simple transport protocol. Four issues need to be addressed: Addressing Multiplexing Flow control Connection establishment / termination Flow Control Whereas flow control is a relatively simple mechanism at the link layer, it is a rather complex mechanism at the transport layer, for two main reasons: The transmission delay between transport entities is generally long compared to actual transmission time. This means that there is a considerable delay in the communication of flow control information.
Image of page 9

Info icon This preview has intentionally blurred sections. Sign up to view the full version.

Image of page 10
This is the end of the preview. Sign up to access the rest of the document.
  • Winter '09
  • a7a
  • Flow control, Transmission Control Protocol, transport entity, supplier numbers

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern