47
PIM C
ONFIGURATION
PIM Overview
Protocol independent multicast (PIM) means that the unicast routing protocols
providing routes for the multicast could be static routes, RIP, OSPF, IS-IS, or BGP.
The multicast routing protocol is independent of unicast routing protocols only if
unicast routing protocols can generate route entries.
With the help of the reverse path forwarding, PIM can transmit multicast
information in the network. For the convenience of description, the network
consisted of PIM-enabled multicast routers is called PIM multicast domain.
Introduction to PIM-DM
Protocol independent multicast dense mode (PIM-DM) is a dense mode multicast
protocol. It is suitable for small networks.
The features of such network are:
■
Members in a multicast group are dense.
■
PIM-DM assumes that in each subnet of the network there is at least one
receiver interested in the multicast source.
■
Multicast packets are flooded to all the points in the network, and the related
resources (bandwidth and the CPU of the router) are consumed at the same
time.
In order to reduce the network resource consumption, PIM-DM prunes the
branches which do not forward multicast data and keeps only the branches
including receivers. In order that the pruned branches which are demanded to
forward multicast data can receive multicast data flows again, the pruned
branches can be restored to the forwarding status periodically.
In order to reduce the delay time for a pruned branch to be restored to the
forwarding status, PIM-DM uses the graft mechanism to restore the multicast
packet forwarding automatically. Such periodical floods and prunes are the
features of PIM-DM, which is suitable for small LANs only. The flood-prune”
technology adopted in PIM-DM is unacceptable in WAN.
Generally, the packet forwarding path in PIM-DM is a shortest path tree (SPT) with
the multicast source as the root and multicast members as the leaves. The SPT uses
the shortest path from the multicast source to the receiver.
Work Mechanism of
PIM-DM
The working procedure of PIM-DM is summarized as follows:
■
Neighbor discovery
■
SPT establishing
■
Graft
Summary of Contents for Switch 7754
Page 32: ...32 CHAPTER 1 CLI OVERVIEW ...
Page 70: ...70 CHAPTER 5 LOGGING IN USING MODEM ...
Page 76: ...76 CHAPTER 7 LOGGING IN THROUGH NMS ...
Page 86: ...86 CHAPTER 9 CONFIGURATION FILE MANAGEMENT ...
Page 120: ...120 CHAPTER 13 ISOLATE USER VLAN CONFIGURATION ...
Page 126: ...126 CHAPTER 14 SUPER VLAN ...
Page 136: ...136 CHAPTER 16 IP PERFORMANCE CONFIGURATION ...
Page 152: ...152 CHAPTER 17 IPX CONFIGURATION ...
Page 164: ...164 CHAPTER 19 QINQ CONFIGURATION ...
Page 172: ...172 CHAPTER 21 SHARED VLAN CONFIGURATION ...
Page 182: ...182 CHAPTER 22 PORT BASIC CONFIGURATION ...
Page 198: ...198 CHAPTER 24 PORT ISOLATION CONFIGURATION ...
Page 208: ...208 CHAPTER 25 PORT SECURITY CONFIGURATION ...
Page 224: ...224 CHAPTER 27 DLDP CONFIGURATION ...
Page 232: ...232 CHAPTER 28 MAC ADDRESS TABLE MANAGEMENT ...
Page 240: ...240 CHAPTER 29 CENTRALIZED MAC ADDRESS AUTHENTICATION CONFIGURATION ...
Page 280: ...280 CHAPTER 30 MSTP CONFIGURATION ...
Page 348: ...348 CHAPTER 35 IS IS CONFIGURATION ...
Page 408: ...408 CHAPTER 39 802 1X CONFIGURATION ...
Page 412: ...412 CHAPTER 40 HABP CONFIGURATION ...
Page 422: ...422 CHAPTER 41 MULTICAST OVERVIEW ...
Page 426: ...426 CHAPTER 42 GMRP CONFIGURATION ...
Page 480: ...480 CHAPTER 47 PIM CONFIGURATION ...
Page 506: ...506 CHAPTER 48 MSDP CONFIGURATION ...
Page 552: ...552 CHAPTER 51 TRAFFIC ACCOUNTING CONFIGURATION ...
Page 570: ...570 CHAPTER 53 HA CONFIGURATION ...
Page 582: ...582 CHAPTER 54 ARP CONFIGURATION SwitchA arp protective down recover interval 200 ...
Page 622: ...622 CHAPTER 58 DHCP RELAY AGENT CONFIGURATION ...
Page 684: ...684 CHAPTER 61 QOS CONFIGURATION ...
Page 718: ...718 CHAPTER 63 CLUSTER ...
Page 738: ...738 CHAPTER 67 UDP HELPER CONFIGURATION ...
Page 752: ...752 CHAPTER 69 RMON CONFIGURATION ...
Page 772: ...772 CHAPTER 70 NTP CONFIGURATION ...
Page 796: ...796 CHAPTER 72 FILE SYSTEM MANAGEMENT ...
Page 802: ...802 CHAPTER 73 BIMS CONFIGURATION ...
Page 814: ...814 CHAPTER 74 FTP AND TFTP CONFIGURATION ...
Page 830: ...830 CHAPTER 75 INFORMATION CENTER ...
Page 836: ...836 CHAPTER 76 DNS CONFIGURATION ...
Page 852: ...852 CHAPTER 77 BOOTROM AND HOST SOFTWARE LOADING ...
Page 858: ...858 CHAPTER 78 BASIC SYSTEM CONFIGURATION DEBUGGING ...