CCNP CCIE Complete

PIM DM grafting FIGURE 19.20 CBT data distribution Host A Host F Host B Host C Host D Host E Source for 224.2.125.125 Member Member Member New member of 224.2.125.125 [full story]

Core-Based Trees When we discussed shared trees, you learned that there were two types: unidirectional and bidirectional. CBT utilizes the bidirectional method for its multicast data distribution. Because CBT uses a shared tree system, it designates a core router that ... [full story]

Sparse Mode Routing Protocols Sparse mode protocols use shared tree distribution as their forwarding methods. This is done to create a more efficient method of multicast distribution. Two sparse mode protocols are discussed in this section:  Core-based trees (CBT) ... [full story]

PIM DM pruning Grafting PIM DM is also ready to forward multicast data after a previously inactive interface becomes active. This is done through the process of grafting. When a host sends an IGMP group membership report to the router, ... [full story]

PIM DM flooding Host A Host F Host B Host C Host D Host E Source for 224.2.125.125 Member 224.2.125.125 Member 224.2.125.125 Member 224.2.125.125 Router 1 Router 2 Router 3 Host G Router 5 [full story]

PIM DM There are three types of Protocol Independent Multicast (PIM): sparse mode, dense mode, and a combination of the two. Although PIM dense mode (PIM DM) maintains several functions, the ones that are discussed here are flooding, pruning, and ... [full story]

Intra-Area and Inter-Area MOSPF When discussing the difference between intra-area and inter-area MOSPF, you must remember that all areas connect through Area 0, the backbone. In large networks, having full multicast tables in addition to all the unicast tables flow ... [full story]

Intra-Area MOSPF OSPF route information is shared via different link-state advertisement (LSA) types. LSAs are flooded throughout an area to give all OSPF-enabled routers a logical image of the network topology. When changes are made to the topology, new LSAs ... [full story]

Multicast Open Shortest Path First (MOSPF) Multicast Open Shortest Path First (MOSPF) is a link-state protocol. OSPFv2 includes some changes that allow multicast to be enabled on OSPF-enabled routers. This eliminates the need for tunnels such as those used for ... [full story]

DVMRP tunnels Host A Host B Host C Host D Host E Source for 224.2.125.125 Members of group 224.2.125.125 [full story]

Distance Vector Multicast Routing Protocol (DVMRP) Distance Vector Multicast Routing Protocol (DVMRP) has achieved widespread use in the multicast world. A few years ago, you might have often heard the term “DVMRP tunnel” used when discussing the implementation of multicast ... [full story]

Routing Protocols Unicast has several routing protocols that build route tables enabling layer 3 devices such as routers and some switches to forward unicast data to the next hop toward its final destination. We have also discussed some of the ... [full story]

TTL threshold utilization The multicast source initially sets the TTL value for the multicast packet and then forwards it on throughout the network. In this scenario, the TTL threshold values have been set to 200 on both of the exiting ... [full story]

Time to Live (TTL) You can also control the delivery of IP multicast packets through the TTL counter and TTL thresholds. The TTL counter is decremented by one every time the packet hops a router. After the TTL counter is ... [full story]

Reverse Path Forwarding (RPF) RPF works in tandem with the routing protocols, but it is described briefly here. As you have seen in Figures 19.13 and 19.14, the traffic goes only to the multicast group receivers. We also indicated that ... [full story]

Managing Multicast Delivery The tree distributions explain how source information is managed; now we must discuss how the actual data delivery is managed. There are several methods of making sure that delivery is as efficient as possible. The following techniques ... [full story]

Bidirectional shared tree Host A Host B Host E Host D Router 3 Router 4 Router 1 Router 2 Router 6 Router 7 Router 5 RP (shared root) Source for 224.2.127.254 10.10.2.5 Host C Source for 224.2.127.254 172.16.1.51 Member 224.2.127.254 ... [full story]

Bidirectional Shared Tree Distribution Bidirectional shared tree distribution operates somewhat differently. If a receiver lives upstream from the RP, it can receive data directly from the upstream source. Figure 19.14 depicts how this works. As you can see, Host A ... [full story]

Unidirectional Shared Tree Distribution Unidirectional shared tree distribution operates as shown in Figure 19.13. All recipients of a multicast group receive the data from an RP no matter where they are located in the network. This is very inefficient if ... [full story]

Shared tree forwarding Host A Host D Host C RP (shared root) Source for 225.3.1.100 10.10.2.5 Host B Source for 224.2.127.254 172.16.1.51 Member 225.3.1.100 Member 224.2.127.254 [full story]

Shared Trees There are two types of shared tree distribution:  Unidirectional  Bidirectional Both of them work a little differently from source tree distribution. Shared tree architecture lies in the possibility that there might be multiple sources for one ... [full story]

Source tree forwarding Corporate intranet Host A Host B Host D Host C Router 1 Router 3 Router 2 Router 4 Switch 1 Switch 2 Switch 3 Switch 4 Source 172.16.1.51 for group 225.3.1.100 Member 224.2.127.254 Member 225.3.1.100 Also notice ... [full story]

Source Trees Source trees use special notation. This notation is used in what becomes a multicast route table. Unicast route tables use the destination address and next-hop information to establish a topology for forwarding information. Here is a sample from ... [full story]

Distribution Trees Two types of trees exist in multicast: Source trees Source trees use the architecture of the source of the multicast traffic as the root of the tree. Shared trees Shared trees use an architecture in which multiple sources ... [full story]

Routing Multicast Traffic Up to this point, we have been discussing the host side of multicast. You have learned how hosts interact with switches and routers to join multicast groups and receive the traffic. It is now time to move ... [full story]

Multicast and Spanning Tree It might seem that CGMP and IGMP Snooping are the way to go. That is true—if you have a very stable network. Remember that STP is used to allow for redundancy but that it disables the ... [full story]

IGMP Snooping While CGMP is a Cisco proprietary protocol to enable switches and routers to communicate regarding multicast traffic patterns, IGMP Snooping is referenced in IGMPv3 and does that same thing. Several vendors have created implementations of IGMP Snooping that ... [full story]

Host Management Host management is performed by the router. The router continues to receive IGMP messages from the host. Then the router converts the message into a CGMP message and forwards it to the switch. The switch then performs the ... [full story]

CGMP Join Hosts do not use CGMP; only the switches and routers that the host connects to use it. When a host sends an IGMP report (Membership Report) advertising membership of a multicast group, the message is forwarded to the ... [full story]

Multicast Design If the router interface is connected to a hub or a switch that doesn’t understand multicasting, when the router forwards the multicast, the stream acts like a broadcast. In other words, every device gets a copy. In IGMPv1, ... [full story]

Cisco Group Management Protocol (CGMP) We have discussed IGMPv1, IGMPv2, and IGMPv3, which are open standard protocols for host membership of multicast groups. When running multicast at layer 2, things get a little complicated for the switch. It doesn’t know ... [full story]

Membership Report IGMPv3 receivers signal their membership to a multicast host group in one of two possible modes: Include and Exclude. Include When operating in Include mode, the receiver announces its membership to a host group and provides a list ... [full story]