Multicast Routing in Java

Printer QR Code in Java Multicast Routing
Multicast Routing
QR Generator In Java
Using Barcode drawer for Java Control to generate, create QR-Code image in Java applications.
Before examining other multicast routing algorithms, let us consider how multicast routing can be deployed in the Internet The crux of the problem is that only a small fraction of the Internet routers are multicast capable If one router is multicast capable but all of its immediate neighbors are not, is this lone island of multicast routing lost in a sea of unicast routers Most decidedly not! Tunneling, a technique we examined earlier in the context of IP version 6 (section 47), can be used to create a virtual network of multicast capabale routers on top of a physical network that contains a mix of unicast and multicast routers This is the approach taken in the Internet MBone
Bar Code Generation In Java
Using Barcode encoder for Java Control to generate, create barcode image in Java applications.
Figure 48-13: Multicast tunnels Multicast tunnels are illustrated in Figure 48-13 Suppose that multicast router A wants to forward a multicast datagram to multicast router B Suppose that A and B are not physical connected to each other and that the intervening routers between A and B are not multicast capable To implement tunneling, router A takes the multicast datagram and "encapsulates" it [RFC 2003]t inside a standard unicast datagram That is, the entire multicast datagram (including source and multicast address fields) is carried as the payload of an IP unicast datagram - a complete multicast IP dagram inside of a unicast IP datagram! The unicast datagram is then addressed to the unicast address of router B and forwarded towards B by router A The unicast routers between A and B dutifully forward the unicast packet to B, blissfully unaware that the unicast datagram itself contains a multicast datagram When the unicast datagram arrives at B, B then extracts the multicast datagram B may then forward the multicast datagram on to one of its attached hosts, forward the packet to a directly attached neighboring router that is multicast capable, or forward the multicast datagram to another logical multicast neighbor via another tunnel MOSPF The Multicast Open Shortest Path First protocol (MOSPF) [RFC 1584] operates in an autonomous system (AS) that uses the OSPF protocol (see section 44) for unicast routing MOSPF extends OSPF by having routers add their multicast group membership to the link state advertisements that are broadcast by routers as part of the OSPF protocol With this extension, all routers have not only complete topology information, but also know which edge routers have attached hosts belonging to various multicast groups With this information, the routers within the AS can build source-specific, pre-pruned,
Bar Code Scanner In Java
Using Barcode decoder for Java Control to read, scan read, scan image in Java applications.
file:///D|/Downloads/Livros/computa o/Computer%20Newn%20Approach%20Featuring%20the%20Internet/mcasthtm (15 of 20)20/11/2004 15:52:28
QR Code 2d Barcode Drawer In C#
Using Barcode maker for .NET framework Control to generate, create QR Code image in .NET framework applications.
Multicast Routing
Print QR Code ISO/IEC18004 In .NET Framework
Using Barcode maker for ASP.NET Control to generate, create QR Code image in ASP.NET applications.
shortest path trees for each multicast group CBT: Core-Based Trees The core-based tree (CBT) multicast routing protocol [RFC 2201, RFC2189] builds a bi-directional, group-shared tree with a single "core" (center) A CBT edge router unicasts sends a JOIN_REQUEST message towards the tree core The core, or the first router that receives this JOIN_REQUEST and itself has already successfully joined the tree, will respond with a JOIN_ACK message to the edge router Once a multicast routing tree has been built, it is maintained by having a downstream router send keepalive messages (ECHO_REQUEST) messages to its immediate upstream router The immediate upstream router responds with an ECHO_REPLY message These messages are exchanged at a time granularity of minutes If a downstream router receives no reply to its ECHO_REQUEST, it will retry sending the ECHO_REQUEST for a small number of times If no ECHO_REPLY is received, the router will dissolve the downstream tree by sending a FLUSH_TREE message downstream PIM: Protocol Independent Multicast The Protocol Independent Multicast (PIM) routing protocol [Deering 1996, RFC 2362, Estrin 1998b] explicitly envisions two different multicast distribution scenarios In so-called dense mode, multicast group members are densely located, that is, many or most of the routers in the area need to be involved in routing multicast datagrams In sparse mode, the number of routers with attached group members is small with respect to the total number of routers; group members are widely dispersed The PIM designers noted several consequences of the sparse-dense dichotomy In dense mode, since most routers will be involved in multicast (eg, have attached group members), it is reasonable to assume that each and every router should be involved in multicast Thus, an approach like RPF, which floods datagrams to every multicast router (unless a router explicitly prunes itself) is well-suited to this scenario On the other hand, in sparse mode, the routers that need to be involved in multicast forwarding are few and far between In this case, a data-driven multicast technique like RPF, which forces a router to constantly do work (prune) simply to avoid receiving multicast traffic is much less satisfactory In sparse mode, the default assumption should be that a router is not involved in a multicast distribution; the router should not have to do any work unless it wants to join a multicast group This argues for a center-based approach, where routers send explicit join messages, but are otherwise uninvolved in multicast forwarding One can think of the sparse mode approach as being receiver-driven (ie, nothing happens until a receiver explicitly joins a group) versus the dense mode approach as being data-driven (i e, that datagrams are multicast everywhere, unless explicitly pruned) PIM accommodates this dense versus sparse dichotomy by offering two explicit modes of operation: dense mode and sparse mode PIM Dense Mode is a flood-and-prune reverse path forwarding technique similar in spirit to DVMRP Recall that PIM is "protocol independent," ie, independent of the underlying unicast routing protocol A better description might be that it can interoperate with any underlying unicast routing protocol Because PIM makes no assumptions about the underlying routing
Generating QR Code 2d Barcode In .NET Framework
Using Barcode creator for Visual Studio .NET Control to generate, create QR Code image in Visual Studio .NET applications.
file:///D|/Downloads/Livros/computa o/Computer%20Newn%20Approach%20Featuring%20the%20Internet/mcasthtm (16 of 20)20/11/2004 15:52:28
Print QR Code 2d Barcode In Visual Basic .NET
Using Barcode maker for Visual Studio .NET Control to generate, create QR-Code image in .NET applications.
Printing Bar Code In Java
Using Barcode maker for Java Control to generate, create barcode image in Java applications.
UPCA Creation In Java
Using Barcode maker for Java Control to generate, create UPC-A Supplement 5 image in Java applications.
Generate Bar Code In Java
Using Barcode printer for Java Control to generate, create barcode image in Java applications.
UPC - 13 Generator In .NET Framework
Using Barcode printer for .NET Control to generate, create EAN13 image in .NET framework applications.
EAN128 Creation In Visual Studio .NET
Using Barcode generator for ASP.NET Control to generate, create EAN 128 image in ASP.NET applications.
Generating Barcode In .NET
Using Barcode creation for ASP.NET Control to generate, create barcode image in ASP.NET applications.
UPC A Printer In .NET
Using Barcode generation for ASP.NET Control to generate, create UPC-A Supplement 2 image in ASP.NET applications.