A. Ballardie, "Core Based Trees (CBT) Multicast Routing Architecture", Internet RFC 2201 (Experimental), September 1997.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....is known to be NP Hard. Thus, the multicast IP routing algorithms proposed in literature can be cataloged as heuristic procedures that obtain a solution of the minimal Steiner Tree at a limited computational cost. In IP networks, many algorithms were proposed to route multicast traffic [20] 21] [22], some of which have been standardized, but are not yet widely adopted. They can be roughly grouped into two classes: the first is based on distributed algorithms, where shortest paths are used to build the distribution tree. The second class is instead based on centralized algorithms, where a ....

A.Ballardie, "Core Based Trees (CBT) Multicast Routing Architecture", RFC 2201, September 1997.

....number of hops (lightpaths) traversed by each unicast flow. Note however that other routing algorithms can be taken into account during the optimization process, and the final topology becomes optimal for that choice. Many algorithms were instead proposed to route multicast IP traffic [10] 11] [12], some of which have been standardized, but are not yet widely adopted. The existing IP multicast routing algorithms can be roughly grouped into two classes: the first is based on distributed algorithms, where shortest paths are used to build the distribution tree. The second class is instead ....

A.Ballardie, "Core Based Trees (CBT) Multicast Routing Architecture", RFC 2201, September 1997.

....calculated only on demand and cached for later use. It constructs source based multicast trees. It can also be considered as a QoS routing algorithm that minimizes delay. It is one of the dense mode protocols that requires explicit join from the receivers [8] 4.1. 3 Core Based Tree (CBT) CBT [26, 27] builds a single bidirectional shared tree for the data transmission from the source(s) in the group to the receivers. When an intermediate node receives a packet meant for the group, it forwards it to the remaining members of the group that are downstream to the node. It does not need to forward ....

A. Ballardie, "Core Based Trees (CBT) Multicast Routing Architecture", Internet Request for Comment 2201, September 1997.

....observation suggested us to carry out the LTD optimization adopting a shortest path routing for unicast flows, i.e. a routing strategy that minimizes the number of hops (lightpaths) traversed by each unicast flow. Many algorithms were instead proposed to route multicast IP traffic [9] 10] [11], some of which have been standardized, but are not yet widely adopted. The existing IP multicast routing algorithms can be roughly grouped into two classes: the first is based on distributed algorithms, where shortest paths are used to build the distribution tree. The second class is instead ....

A.Ballardie, "Core Based Trees (CBT) Multicast Routing Architecture", RFC 2201, September 1997.

....and in particular of radio and TV broadcasting, into IP networks is the need for efficient multicast support. While the multicast problem already received considerable attention at the algorithmic (or network) level, e.g. with the development of multicast protocols for IP networks [1] 2] [3], the techniques to support multicast traffic within IP routers have not received much attention yet; this is instead a crucial problem, especially when considering IP routers with input queued (IQ) architectures. In this paper we consider techniques to support multicast traffic in IQ cell based ....

A.Ballardie, "Core Based Trees (CBT) Multicast Routing Architecture", RFC 2201, Sept. 1997

....to be NP Hard. Thus, the multicast IP routing algorithms proposed in literature can be cataloged as heuristic procedures that obtain a solution of the minimal Steiner Tree at a limited computational cost. Thus, in IP networks, many algorithms were proposed to route multicast traffic [20] 21] [22], some of which have been standardized, but are not yet widely adopted. They can be roughly grouped into two classes: the first is based on distributed algorithms, where shortest paths are used to build the distribution tree. The second class is instead based on DESIGN OF LOGICAL TOPOLOGIES . ....

A.Ballardie, "Core Based Trees (CBT) Multicast Routing Architecture", RFC 2201, September 1997.

....to the time to live (TTL) or hop count, decrement mechanism currently supported in IP. As discussed in the sequel, the proposed scheme achieves all of the desirable characteristics posed above but only for the case where multicast service is based on shared tree, e.g. Core Based Trees(CBT) 17] [18], versus source tree routing. The paper is organized as follows. In Section II, we discuss the advantages and shortcomings of previous work on this problem. Section III introduces the proposed fan out decrement mechanism, briefly indicating some of its uses for resource and topology discovery. In ....

A. Ballardie, "Core Based Trees(CBT) Multicast Routing Architecture," RFC 2201, Sep., 1997.

....with different QoS requirements for multiple point applications has become increasingly demanding. The main intent of this paper is thus to present a set of QoS enhancements in the member join leave and state update refresh procedures, to allow QoS deployment in the Core Based Tree (CBT) protocol [1, 2], with the minimal impact to the existing infrastructure. The construction of multicast trees can be classified into source based tree approaches and core based tree approaches [3] For example, Distance Vector Multicast Routing Protocol (DVMRP) 11] Multicast extensions to Open Shortest Path ....

.... For example, Distance Vector Multicast Routing Protocol (DVMRP) 11] Multicast extensions to Open Shortest Path First Protocol (MOSPF) 12] and Protocol Independent Multicast Dense Mode (PIM DM) 13] fall in the category of source based tree approaches, while the Core Based Tree (CBT) protocol [1, 2], the Protocol Independent Multicast Sparse Mode (PIM SM) 1 [13, 14] and very recently, Simple Multicast (SM) 10] are representatives of core based tree approaches. From the viewpoint of network management, core based trees offer The work reported in this paper was supported in part by DARPA ....

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A. Ballardie, "Core based trees (CBT) multicast routing architecture," RFC 2201, ftp://ds.internic.net /rfc/rfc2201.txt.

....and in particular of radio and TV broadcasting, into IP networks is the need for efficient multicast support. While the multicast problem already received considerable attention at the algorithmic (or network) level, e.g. with the development of multicast protocols for IP networks [1] 2] [3], the techniques to support multicast traffic within IP routers have not received much attention yet; this is instead a crucial problem, especially when considering IP routers with input queued (IQ) architectures. In this paper we consider techniques to support multicast traffic in IQ cell based ....

A.Ballardie, "Core Based Trees (CBT) Multicast Routing Architecture ", RFC 2201, Sept. 1997

.... Services for multicast and the combination of the various routing protocols such as Distance Vector Multicast Routing Protocol (DVMRP, 17] Multicast extension for OSPF (open shortest path first, 18] Protocol Independent Multicast Sparse Mode (PIM SM, 19] and Core Based Trees (CBT, [20]) Independent of the routing protocol, it can be decided whether or not a host node is allowed to receive or send in a given service class and how much it is permitted to send. When a host sends multicast data and requires a specific service class for its multicast session, it must communicate ....

A. Ballardie, "Core Based Tree (CBT) Multicast Routing Architecture," Sept. 1997. Internet RFC 2201.

....folks associated with this effort. I.F. LAM Scott Corson from the University of Maryland presented a draft on a Lightweight Adaptive Multicast (LAM) protocol [10] LAM creates and maintains a group shared forwarding tree for the group. Conceptually, the protocol can be viewed as a fusion of CBT [11] and TORA. The design of the protocol follows the concept of vertically coupled design to achieve efficiency (low overhead, fast reaction) which is desired in a MANET environment. LAM is specifically built upon TORA, and serves as an integrated component of an IMEP TORA LAM manet routing suite. ....

A. Ballardie. "Core Based Trees (CBT) Multicast Routing Architecture ". Internet RFC 2201, 9/97.

....deliver packets from a sender to all the receivers in a group. Despite a decade of research and development, there are still open technical issues that make it difficult to deploy IP multicast in the global Internet. From the point of view of routing, existing IP multicast routing protocols [1] [2], 3] 4] 5] 6] scale poorly with large number of groups. In particular, with current routing protocols, each router needs to maintain a multicast forwarding table entry for every group whose distribution tree passes through the router. Therefore, the size of the multicast forwarding table ....

....also sends a copy to R3, which is the only receiver in its list. Finally, when the copy traverses N4, N4 makes another copy and sends it to R2. Using unicast addresses instead of class D addresses for data delivery is a key difference between REUNITE and all existing IP multicast protocols [1] [2], 3] 4] 5] 6] As a result, while in these protocols each router in the multicast tree has to maintain multicast forwarding state, in REUNITE multicast packets can be simply forwarded based on a router s unicast forwarding table in any of the following cases: a) the router is ....

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Ballardie A, "Core based trees (CBT) multicast routing architecture," Sept. 1997, RFC-2201.

....established, the tunnel states on the end points are soft. They have to be refreshed periodically, otherwise they will timeout and be deleted. We assume there exists some form of underlying multicast mechanism such as Protocol Independent Multicast Sparse Mode(PIM SM) 4] or Core Based Tree(CBT) [1] on all the routers that want to support dynamic tunnels. In this section, we will first define some new terminologies, then we will present the tunnel operations for establishing, tearing down and adjusting dynamic tunnels. B. Concepts Native Multicast Distribution Tree (Native Tree) We define ....

A. Ballardie. "Core Based Tree(CBT) Multicast Routing Architecture ". draft-ietf-idmr-cbt-arch-**.txt, 1997.

.... shall refer to this tuple of multicast address and aggregation parameters as an aggregated multicast address (AMA (i) Thus, it is intended that AMAs are used in future versions of Internet Group Management Protocol (IGMP) 3, 4] and the various multicast routing protocols (DVMRP [5, 6] CBT [7, 8, 9] PIM [10, 11, 12] to replace 3 of 22 27 11 97 10:16 End to End Aggregation of Multicast Addresses multicast addresses wherever they are used. It would also be highly advantageous for session directory, invitation and announcement protocols (e.g. SDP [13] SAP [14] SIP [15] to evolve to use ....

A. Ballardie, "Core Based Trees (CBT) Multicast Routing Architecture", IETF RFC, Sep 1997, <rfc2201.txt>

....on the practicality of the common source assumption for large numbers of destination sets. Instead of an end system, the source could very well be a core node inside the network from which core based trees are established for multicast routing, an architecture being proposed for the Internet [1,2]. A multicast route would consist of a VPC or SVC from the source to the core node followed by the established VP tree. Also, the destinations may be gateway nodes instead of end systems, in which case the VP trees would be entirely contained within the backbone of the network. M. Montgomery, G. ....

A. Ballardie, "Core based trees (CBT) multicast routing architecture," RFC 2201, Sept. 1997.

....Multicast communication, the delivery of a message from a single source to multiple destinations, is important to many group based network applications, such as computer supported cooperative work, telegaming, and distributed parallel processing. A common multicast technique, found in the CBT [1] and PIM [2] protocols, is core based forwarding (CBF) A CBF multicast protocol associates a core node with each multicast group; the multicast tree of the group is defined to be the union of core to members shortest paths. Messages destined for the group are first sent to the core node, which ....

A. Ballardie, "Core based trees (CBT) multicast routing architecture. " Internet working draft draft-ietf-idmr-cbt-arch06. txt, March 1997.

....group addresses and member addresses [4] and the mapping between network addresses and link layer addresses [5] use a central server approach; a solution to the server assignment problem selects a leader to undertake the server responsibilities. Third, some IP multicast protocols, such as CBT [6] and PIM [7] identify a network node, called a core node, as the traffic transit center for each multicast group; a solution to this multicast core management problem supports multicast services provided by the network. A common requirement of solutions to the above problems is fault tolerance: ....

....5.2 Multicast Core Management The Internet supports multicast communication, the delivery of a message from a single source to multiple destinations, and group addressing, whereby a set of hosts can be referred to by a multicast group address. Some prominent IP multicast protocols, such as CBT [6] and PIM [7] associate a multicast traffic transit center, or core node, with each multicast group. In such approaches, datagrams destined to a multicast group are first forwarded to the core node, from which they are distributed along a multicast tree to reach group members. A new member joins ....

A. Ballardie, "Core based trees (CBT) multicast routing architecture." Internet draft, March 1997.

....network is usually more efficient. A multicast protocol typically constructs a tree of communication links; routers within the tree handle replication and forwarding of messages to group members. The type of multicast tree varies among multicast protocols. A common technique, found in the CBT [1] and PIM [2] protocols, is core based forwarding (CBF) A CBF multicast protocol associates a core node with each multicast group; the multicast tree of the group is defined to be the union of core to members shortest paths. Messages destined for the group are first sent to the core node, which ....

A. Ballardie, "Core based trees (CBT) multicast routing architecture." Internet working draft draft-ietf-idmr-cbt-arch-06.txt, March 1997.

....the SMC continue functioning individually, and eventually will merge with one another. As we will show in Section 5, even while the SMC is fragmented, the ER SAF protocol can still achieve significant performance gain over conventional flooding. The SMC protocol is a variation of the CBT protocol [7], a general MC protocol in which the topology of the MC is the union of shortest paths from the members to a specific node, called the core. In this work, we assume the use of the leader switch in a network, elected by the ATM leader election protocol, as the core node. Given the mutual consensus ....

A. Ballardie, "Core based trees (CBT) multicast routing architecture. " Internet working draft draft-ietf-idmr-cbt-arch06. txt, March 1997.

....maintained at switching elements in the network, are used to forward traffic destined for the group along MC branches. An MC protocol defines how the MC is established and maintained. A number of MC protocols have been proposed for use in the Internet, including the DVMRP [3] MOSPF [4] CBT [5], and PIM [6] For ATM networks, a relatively simple form of MC is described in [2] although other protocols are under consideration [7, 8] Not all applications require the same MC functionality. Three major types of MC topologies have been studied: 1. Source rooted trees (SRT) The MC topology ....

....and the sender to tree paths are represented by dashed lines. An example application of ROSTs is a group of replicated file servers, connected together with a ROST, such that clients perceive the server group as a single entity. ROSTs are supported by the core based tree (CBT) multicast protocol [5] and the PIM protocol [6] An MC is dynamic if its member list changes over time; otherwise, it is static. Dynamic MCs are more difficult to construct and manage than static MCs, but find more application. For example, conferencing applications, video distribution, and replicated file services, ....

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A. Ballardie, "Core based trees (CBT) multicast routing architecture." Internet draft, March 1997.

....group addresses and member addresses [7] and the mapping between network addresses and link layer addresses [8] use a central server approach; a solution to the server assignment problem selects a leader to undertake the server responsibilities. Third, some IP multicast protocols, such as CBT [9] and PIM [10] identify a network node, called a core node, as the traffic transit center for each multicast group; a solution to this multicast core management problem supports multicast services provided by the network. A common requirement of solutions to the above problems 1 We will not ....

....of a datagram is not required to be a member of the group) and are identified by unique multicast addresses. Further, IP multicast groups are dynamic: a group is created when the first member joins and is destroyed when the last member leaves. Some prominent IP multicast protocols, such as CBT [9] and PIM [10] associate a multicast traffic transit center, or core node, with each multicast group. In such approaches, datagrams destined to a multicast group are first forwarded to the core node, from which they are distributed along a multicast tree to reach group members. A new member ....

A. Ballardie, "Core based trees (CBT) multicast routing architecture." Internet draft, March 1997.

....the SMC continue functioning individually, and eventually will merge with one another. As we will show in Section 5, even while the SMC is fragmented, the ER SAF protocol can still achieve significant performance gain over conventional flooding. The SMC protocol is a variation of the CBT protocol [7], a general MC protocol in which the topology of the MC is the union of shortest paths from the members to a specific node, called the core. In this work, we assume the use of the leader switch in a network, elected by the ATM leader election protocol, as the core node. Given the mutual consensus ....

A. Ballardie, "Core based trees (CBT) multicast routing architecture. " Internet working draft draft-ietf-idmr-cbt-arch06. txt, March 1997.

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A. Ballardie, "Core Based Trees (CBT) Multicast Routing Architecture", Internet RFC 2201 (Experimental), September 1997.

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Ballardie, A., "Core Based Trees (CBT) Multicast Routing Architecture", RFC 2201, September 1997.

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A. Ballardie, "Core Based Trees (CBT) Multicast Routing Architecture," RFC 2201, September 1997.

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Ballardie, A., "Core Based Trees (CBT) Multicast Routing Architecture", RFC 2201, September 1997.

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A. Ballardie, "Core Based Trees (CBT) Multicast Routing Architecture" . IETF RFC 2201, Sep. 1997.

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A. Ballardie, "Core Based Trees (CBT) Multicast Routing Architecture", RFC 2201, September 1997.

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