S. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, and L. Wei. Protocol independent multicast (PIM), sparse mode protocol : Specification. Internet Draft, March 1994. 110  Home/Search   Document Not in Database   Summary   Related Articles   Check

....rtu Figure 3. Mercury software architecture Mercury is a soft state system, in that any writeable state is constantly refreshed by messages, and state which is not refreshed eventually expires [85] Soft state and announce listen protocols have been extensively used at the network level [107, 35] as well as the application level [38] Announce listen makes the default assumption that a component is unavailable unless it says otherwise; soft state can provide information that will carry a system through a transient failure of the authoritative data source for that state. The use of ....

S. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, L. Wei, P. Sharma, and A. Helmy. Protocol independent multicast (PIM), sparse mode protocol: Specification, March 1996. Internet Draft.

....make their interface guarantees sufficiently weak, so they can occasionally restart with no advance warning, yet not cause their callers to hang crash. Using reconstructable soft state with announce listen protocols. Soft state and announce listen have been extensively used at the network level [37, 9] as well as the application level [12] Announce listen makes the default assumption that a component is unavailable unless it says otherwise; soft state can provide information that will carry a system through a transient failure of the authoritative data source for that state. The use of ....

S. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, L. Wei, P. Sharma, and A. Helmy. Protocol independent multicast (PIM), sparse mode protocol: Specification, March 1996. Internet Draft.

....consistency precision measures and a consistency precision utility function (e.g. absolute consistency is twice as good as missing the last two updates ) Use soft state with announce listen. Soft state and announce listen have long been the favorites of wide area network protocols [21, 4, 5, 15]. Announce listen makes the default assumption that a component is unavailable unless it says otherwise; soft state can provide information that will carry a system through a transient failure of the state s authoritative data source. Keeping most shared state soft will therefore increase the ....

S. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, L. Wei, P. Sharma, and A. Helmy. Protocol independent multicast (PIM), sparse mode protocol: Specification, March 1996. Internet Draft.

....in spirit to our iRoom. Their current efforts focus more on the facilities a lower level programming model such as One.world [19] should provide. Finally, we have stolen from well known previous work the principles of loose coupling for robustness, soft state, and announce listen protocols [8, 16]; the case for infrastructurecentric approach to adapting to client and network heterogeneity [15] and the case for a systems of systems approach [18] in which we connect legacy building blocks consisting of complete systems with OS s and applications. 10 Conclusions We have focused on one ....

S. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, L. Wei, P. Sharma, and A. Helmy. Protocol independent multicast (PIM), sparse mode protocol: Specification, March 1996. Internet Draft.

....techniques to be more pervasively applied. The examples presented here draw heavily on prior use of soft stale state as a substitute for hard state when application semantics permit; soft state has been successfully exploited in the context of wide area Internet routing and reservation protocols [3, 12] and load balancing and resource location in clusterbased Internet servers [7, 2] Bounding staleness or inconsistency of distributed state is the basis of both Web caching in HTTP 1.1 and prior work on failure tolerant expiration based consistency [9] Most of this prior work is ....

S. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, L. Wei, P. Sharma, and A. Helmy. Protocol independent multicast (PIM), sparse mode protocol: Specification, March 1996. Internet Draft.

....message delivery. The extension is backward compatible and is easy to be adapted to the current implementation. In the paper, we will address several design issues extensively. Keywords RSVP, soft state. I. INTRODUCTION After years of design and development, RSVP [1] 2] along with PIM[4] [5] and several other new technologies will be gradually deployed to the Internet in the next few years. Continuous media applications such as teleconferencing and interactive multimedia games can interface RSVP to demand QOS from the network. Inside network, routers and switches will have traffic ....

S. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, L. Wei, P. Sharma, and A. Helmy. Protocol Independent Multicast (PIM), sparse mode protocol: Specification. INTERNET DRAFT, March 1996 Work in progress.

....refreshable soft state and a negative acknowledgment repair strategy to provide recoverable session state for a group of clients. A lower level example that is similar in spirit (and in fact inspired the SRM mechanisms) is the mechanism by which IP multicast routing trees are built and maintained [40]; it was explicitly designed to assume no special mechanisms in routers for state recovery. 2 Architecture of SNS, A Cluster Based TACC Server We now describe the system architecture of a cluster based server that supports the TACC model using clusters of PC s. The architecture attempts to ....

....is partitioned from the rest of the cluster (in particular, from the subset of the cluster containing the Manager) the idle processes will eventually die rather than 91 consuming node resources indefinitely. The idea of passive fail out is also used, for example, in IP multicast tree pruning [40]. Worker death. If a worker fails unexpectedly while processing a task, the Manager will either detect this (because the long lived TCP connection to the worker is broken) or infer it (because it stops receiving periodic status reports from the worker on that connection) In either case, the ....

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S. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, L. Wei, P. Sharma, and A. Helmy. Protocol independent multicast (PIM), sparse mode protocol: Specification, March 1996. Internet Draft.

....and 6 bits for the county that gives 22 bits which is 1 64 of the total IP v4 multicast addressing space. With IPv6 we will have, of course, much more addressing space which we can use for the GPS multicast routing. 4.3. 4 PIM solution The receiver driven Protocol Independent Multicast (PIM) 6] [7] [8] comes in two flavors: Sparse Mode (PIM SM) and Dense Mode (PIM DM) PIMDM is essentially the same data driven model currently in use now except with a little extra PIM overhead. It is meant to be used in a local environment which is bandwidth rich and which has a large number of receivers. ....

S. Deering and D. Estrin and D. Farinacci and V. Jacobson and C. Liu and L. Wei, Protocol Independent Multicast (PIM), Sparse Mode Protocol : Specification, Internet Draft, March 1994.

....and 6 bits for the county that gives 22 bits which is 1 64 of the total IP v4 multicast addressing space. With IPv6 we will have, of course, much more addressing space which we can use for the GPS multicast routing. 5.4. 4 PIM solution The receiver driven Protocol Independent Multicast (PIM) 7] [8] [9] comes in two flavors: Sparse Mode (PIM SM) and Dense Mode (PIM DM) PIM DM is essentially the same data driven model currently in use now except with a little extra PIM overhead. It is meant to be used in a local environment which is bandwidth rich and which has a large number of receivers. ....

S. Deering and D. Estrin and D. Farinacci and V. Jacobson and C. Liu and L. Wei, Protocol Independent Multicast (PIM), Sparse Mode Protocol : Specification, Internet Draft, March 1994.

....the number of concurrent senders in an interaction increased. The topologies varied from 10 100 nodes distributed over 1 to 10 clusters. Link cost was defined as a uniform random variable between 1 100 for intra cluster links and 1 1000 for inter cluster links. Node degree was kept in the interval [3,5] by manipulating a and b for each topology. The simulations allowed multiple interactions to be constructed on top of each other. As one interaction was built (each interaction is referred to as an iteration of the approach) the network resources required by that interaction were consumed in the ....

.... hopes that the paths are symmetric 21 Use of a priori information Automatic location of distribution centers Choice between SST and CST Tree formation based on resource availability Support of multiple routing protocols Minimal tree state information Minimal router processing Goal CBT [1] PIM [2,3,4] DVMRP [5, 8] MOSPF [7, 8] N N N N N N Y Y N N Y N Y Y N N N N N N N N Y N Y Y Table 3: Existing Approaches vs. Design Goals Support for asymmetric topologies N N N Y Proposed Approach Y Y Y Y Y Y Y Note 1 Note 2 Note 3 Note 1: Y for sparse mode, N for dense mode Note 2: N for sparse mode, Y for ....

Stephen Deering, Deborah Estrin, Dino Farinacci, Van Jacobson, Ching-Gung Liu, and Liming Wei, Protocol Independent Multicast (PIM), Sparse Mode Protocol Specification, Internet Draft, draft-ietf-idmr-pim-sparse-spec-00.ps, March 1994.

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S. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, and L. Wei. Protocol independent multicast (pim) : Sparse mode protocol specification. Working Draft, Mar 1994. (draft-ietf-idmr-pim-sparse-spec-00.ps).

....a teleconference application might run on top of multiple protocols. Internet Group Management Protocol (IGMP) 1] in a host stores information about the groups that host is participating in. Based on the membership information the multicast routing protocols such as DVMRP [2] MOSPF [3] PIM [4, 5, 6] or CBT [7] create multicast forwarding state in the routers. A reservation protocol such as RSVP [8] or ST II [9, 10] may reserve network resources for the teleconferencing session along the multicast tree. The state has to be modified to reflect the changes in network conditions. The network ....

....routing protocol Core Based Tree (CBT) 7] establishes hard state. On the other hand, Resource Reservation Protocol (RSVP) 8] uses a datagram messaging protocol with periodic refreshes to maintain soft state in network nodes. Protocol Independent Multicast(PIM) another multicast routing protocol [4, 5, 6], also has control messages that are exchanged periodically to keep the multicast forwarding entries; a forwarding entry that is not refreshed is discarded. In hard state architectures, control messages are exchanged among the nodes for installing as well as removing the state and no periodic ....

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S. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, L. Wei, P. Sharma, and A. Helmy. Protocol independent multicast (pim), sparse mode protocol : Specification. Internet Draft, March 1996.

....and group dynamics. The robustness, flexibility, and scaling properties of this architecture make it well suited to large heterogeneous internetworks. This document motivates and describes the PIM architecture. Companion documents describe the protocol mechanisms for both sparse and dense mode PIM[1, 2]. Status of This Memo This document is an Internet Draft. Internet Drafts are working documents of the Internet Engineering Task Force (IETF) its Areas, and its Working Groups. Note that other groups may also distribute working documents as Internet Drafts) Internet Drafts are draft documents ....

....control message processing, and data packet processing required across the entire network in order to deliver data packets to the members of the group. This document motivates and describes the PIM architecture. Companion documents describe the protocol mechanisms for both sparse and dense mode PIM[1, 2]. 1.1 Background In the traditional IP multicast model, established by Deering[4] a multicast address is assigned to the collection of receivers for a multicast group. Senders simply use that address as the destination address of a packet to reach all members of the group. The separation of ....

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S. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, and L. Wei. Protocol independent multicast (pim), sparse mode protocol : Specification. Internet Draft, March 1994.

....a high degree of locality. We also conclude that core choice can be used to control traffic concentration, in fact traffic concentration effects can be ameliorated by appropriate core choice policies. 1 Introduction Given the prominence of center based trees in emerging multicast routing schemes [1, 3, 4], it is important to better understand the relationship between the choice of core router and the performance of the routing scheme. Specifically, our objective is to determine how complex the core choice method must be to ensure reasonable performance. We begin by assessing the circumstances in ....

S. E. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, and L. Wei. Protocol independent multicast (PIM), sparse mode protocol specification. Working Draft, March 1994.

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S. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, and L. Wei. Protocol independent multicast (pim) : Sparse mode protocol specification. INTERNET DRAFT, Mar 1994. (draft-ietf-idmr-pim-sparse-spec-00.ps).

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S. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, and L. Wei. Protocol independent multicast (pim) : Sparse mode protocol specification. Working Draft, Mar 1994. (draft-ietf-idmr-pim-sparse-spec-00.ps).

....discard stale state and we motivate our approach of scalable timers that makes soft state protocols more scalable. Mechanisms required for the proposed approach of regulating control traffic are discussed in Section 4 and Section 5. We look at the application of the scalable timers approach to PIM [2, 3] in Section 6, followed by the simulation results in Section 7. Section 8 compares the traditional and the proposed approaches. We conclude with a summary and a few comments on future directions in Section 9. 2 State Management in Networks State in network nodes refers to information stored by ....

....a teleconference application might run on top of multiple protocols. Internet Group Management Protocol (IGMP) 4] in a host stores information about the multicast groups in which that host is participating. Based on the membership information multicast routing protocols such as DVMRP [5] PIM [2, 3] or CBT [6] create multicast forwarding state in the routers. A reservation protocol such as RSVP [7] or ST II [8] may reserve network resources for the teleconferencing session along the multicast tree. The state has to be modified to reflect the changes in network conditions. The network nodes ....

[Article contains additional citation context not shown here]

S. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, L. Wei, P. Sharma, and A. Helmy. Protocol Independent Multicast (PIM), Sparse Mode Protocol : Specification. Internet Draft, March 1996.

....that are periodically initiated by endpoints. When the endpoints stop initiating refreshes the state automatically times out. Similarly, if the intermediate state disappears, it is re established by the end point initiated refreshes [1] Many soft state designs, such as RSVP [2] RTP [3] and PIM [4, 5, 6], use best effort messages to carry the refreshes. These traditional periodic refreshes generated at fixed periods scale poorly with the increase in the amount of state. Some designers have suggested using explicitly acknowledged, reliable, messages in place of these periodic refreshes [7] The ....

....and various protocols. For instance a teleconference application might run on top of multiple protocols. Internet Group Management Protocol (IGMP) 8] stores information about the hosts participating in the conference. Based on the membership information the multicast routing protocols such as PIM [4, 5, 6] or CBT [9] create multicast forwarding state in the routers. A reservation protocol such as RSVP [2] or ST II [10, 7] may reserve network resources for the teleconferencing session along the multicast tree. The state has to be modified to reflect the changes in network conditions. The network ....

[Article contains additional citation context not shown here]

S. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, L. Wei, P. Sharma, and A. Helmy. Protocol independent multicast (pim), sparse mode protocol : Specification. Internet Draft, March 1996.

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S. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, and L. Wei. Protocol independent multicast (pim), sparse mode protocol : Specification. Working Draft, September 1995.

.... relatively easily in a distributed fashion, using information that is available for shortest path, unicast routing [4, 6] Why, then, are other methods for constructing routes being considered in recent multicast routing schemes such as Core Based Trees [1] and Protocol Independent Multicast [2, 3] Among the reasons are reduction in router storage and control message overhead; both of these issues are addressed by the use of center (or core) based trees, in which the choice of a designated router determines the shape of the multicast routing tree. Shortest path trees have an additional ....

S. E. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, and L. Wei. Protocol independent multicast (PIM), sparse mode protocol specification. Working Draft, March 1994.

....Section 3 describes the network topology and random network model we used in our study; and Section 3.2 presents and analyzes our simulation results. 2 Polynomial Time Algorithms for Group Shared Trees Group shared trees are used in two proposed mechanisms for scalable multicast routing[4, 13]. Here we briefly discuss related work in polynomial time shared tree computation algorithms. We will present comparisons based on simulations of the relevant schemes in section 3.2. We divide these algorithms into two major categories: Pseudo Steiner Tree algorithms, and Center Based Tree ....

....algorithms. The simplicity of this class of algorithms makes it desirable for the design of practical protocols and was used as the basis for the Core Based Tree interdomain multicast routing protocol [4] as well as for the shared tree mode of another inter domain multicast proposal called PIM [13]. Center Based Tree, as the name indicates, uses a shortest path tree rooted at a node in the center of the network [16] Wall proposed two major strategies for locating centers: 1) Choose the optimal network node so that the resulting center tree can have minimal maximum delay or average delay ....

S. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, and L. Wei. Protocol independent multicast (pim), sparse mode protocol: Specification. Working Draft, March 1994.

.... trees can be constructed 1 relatively easily in a distributed fashion, given information used by the underlying unicast mechanism [6, 12] Why, then, are center based methods being considered in recent multicast routing schemes such as Core Based Trees [3] and Protocol Independent Multicast [7, 8] Among the reasons are reduction in router storage and control message overhead; both of these issues are addressed by the use of center based trees, which require amounts of router storage proportional to the number of receiver groups rather than the number of source receiver group pairs. ....

S. E. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, and L. Wei. Protocol independent multicast (PIM), sparse mode protocol specification. Working Draft, March 1994.

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S. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, and L. Wei. Protocol independent multicast (PIM), sparse mode protocol : Specification. Internet Draft, March 1994. 110

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Deering, S., Estrin, D., Farinacci, D., Jacobson, V., Liu, C., and L. Wei, "Protocol Independent Multicast (PIM) : Sparse Mode Protocol Specification, Work in Progress.

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S. E. Deering, D. Estrin, D. Farinacci, V. Jacobson, C. Liu, and L. Wei. Protocol independent multicast (PIM), sparse mode protocol specification. Working Draft, March 1994.

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