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tech:network:cisco:multicast:routing:pim:introduction:introduction

Multicast Routing PIM Introduction

PIM (Protocol-Independent Multicast)

  1. PIM has two version
    1. PIMv1
    2. PIMv2 (typical)

PIM Snooping

  1. PIM Snooping prevent flooding to unnecessary port.
  2. PIM Snooping snoop PIM related messages
    1. PIM Hello Message
    2. PIM Join Message
    3. PIM Prune Message
    4. Bidir-PIM designated forwarder(DF)-election Message
    5. etc.
  3. On the other hand, IGMP Snooping only limit Receiver connected port forwarding.
  4. Requirements
    1. IGMP snooping must be enabled

Configuration

  • Enable PIM Snooping Globally
ip pim snooping
  • Enable PIM Snooping specific VLAN
interface Vlan <vlan-id>
 ip pim snooping

no need to set IP address or IP PIM VLAN interface.

  • Verify operation
show ip pim snooping

Configuration(Optional)

  1. PIM Snooping enabled L2 switch will flood multicast traffic to PIM DR by default.
  2. This behavior potential unnecessary multicast packet flooding to PIM DR.(in case of PIM-DM?)
  • Decrease unnecessary traffic to PIM DR.

By This configuration, PIM Snooping will send only explicit Join Message multicast group traffic.???

no ip pim snooping dr-flood
do not disable DR flooding L2 broadcast domain supports multicast sources???

Routing Table

R2#show ip mroute         
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
       L - Local, P - Pruned, R - RP-bit set, F - Register flag,
       T - SPT-bit set, J - Join SPT, M - MSDP created entry, E - Extranet,
       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
       U - URD, I - Received Source Specific Host Report, 
       Z - Multicast Tunnel, z - MDT-data group sender, 
       Y - Joined MDT-data group, y - Sending to MDT-data group, 
       G - Received BGP C-Mroute, g - Sent BGP C-Mroute, 
       N - Received BGP Shared-Tree Prune, n - BGP C-Mroute suppressed, 
       Q - Received BGP S-A Route, q - Sent BGP S-A Route, 
       V - RD & Vector, v - Vector, p - PIM Joins on route, 
       x - VxLAN group
Outgoing interface flags: H - Hardware switched, A - Assert winner, p - PIM Join
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 224.0.1.40), 03:31:52/00:02:28, RP 0.0.0.0, flags: DCL
  Incoming interface: Null, RPF nbr 0.0.0.0
  Outgoing interface list:
    GigabitEthernet0/1, Forward/Sparse, 03:30:59/00:02:28
R2#show ip mroute summary 
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
       L - Local, P - Pruned, R - RP-bit set, F - Register flag,
       T - SPT-bit set, J - Join SPT, M - MSDP created entry, E - Extranet,
       X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
       U - URD, I - Received Source Specific Host Report, 
       Z - Multicast Tunnel, z - MDT-data group sender, 
       Y - Joined MDT-data group, y - Sending to MDT-data group, 
       G - Received BGP C-Mroute, g - Sent BGP C-Mroute, 
       N - Received BGP Shared-Tree Prune, n - BGP C-Mroute suppressed, 
       Q - Received BGP S-A Route, q - Sent BGP S-A Route, 
       V - RD & Vector, v - Vector, p - PIM Joins on route, 
       x - VxLAN group
Outgoing interface flags: H - Hardware switched, A - Assert winner, p - PIM Join
 Timers: Uptime/Expires
 Interface state: Interface, Next-Hop or VCD, State/Mode

(*, 224.0.1.40), 02:20:58/00:02:23, RP 0.0.0.0, OIF count: 1, flags: DCL

References

tech/network/cisco/multicast/routing/pim/introduction/introduction.txt · Last modified: 2021/08/28 14:53 by wnoguchi