IP Multicast Survival Guide Part 2 Second Edition Beau Williamson CCIE 1356 R/S Emeritus CiscoLive Distinguished Speaker aka Multicast Survivorman Twitter: @Mr_Multicast
Rules of Engagement Silence... I kill you! I mean your Cell Phones and Laptops that is. Violators must buy Beer for everyone in the room! Ask questions at any time. 10,000 Bonus Points awarded for Good Questions 20,000 Bonus Points awarded for Great Questions 30,000 Bonus Point deduction for intentionally stumping presenter Remember: I haven t touched this stuff in years so I m a bit rusty. 2
Survival Guide Goal To provide a deep dive into PIM ASM Protocol mechanics in order to provide you with a master IP Multicast survival toolkit that will help you to go alone and unafraid into the CCIE Lab Wilderness of IP Multicast1. 1 You still may be asked to perform unnatural network acts in your CCIE lab. 3
Agenda PIM ASM Review PIM Neighbor Discovery PIM State & State Rules PIM SSM Joining PIM SSM Pruning PIM ASM Joining PIM ASM Registering PIM ASM SPT Switchover PIM ASM Pruning PIM Bidir Joining PIM Bidir Senders Geekometer 4
PIM ASM Review 5
PIM-SM Shared Tree Join RP (*, G) Join Shared Tree (*, G) State Created Only Along the Shared Tree Receiver 6
PIM-SM Sender Registration Source RP Traffic Flow Shared Tree Source Tree (S, G) Register (S, G) Join (unicast) Receiver (S, G) State Created Only Along the Source Tree 7
PIM-SM Sender Registration Source RP Traffic Flow Shared Tree Source Tree (S, G) Register (S, G) Register-Stop (unicast) (unicast) Receiver (S, G) Traffic Begins Arriving at the RP via the Source Tree RP Sends a Register-Stop Back to the First-Hop Router to Stop the Register Process 8
PIM-SM Sender Registration Source RP Traffic Flow Shared Tree Source Tree Receiver Source Traffic Flows Natively Along SPT to RP From RP, Traffic Flows Down the Shared Tree to Receivers 9
PIM-SM SPT Switchover Source RP Traffic Flow Shared Tree Source Tree (S, G) Join Receiver Last-Hop Router Joins the Source Tree Additional (S, G) State Is Created Along New Part of the Source Tree 10
PIM-SM SPT Switchover Source RP Traffic Flow Shared Tree Source Tree (S, G)RP-bit Prune Receiver Traffic Begins Flowing Down the New Branch of the Source Tree Additional (S, G) State Is Created Along the Shared Tree to Prune Off (S, G) Traffic 11
PIM-SM SPT Switchover Source RP Traffic Flow Shared Tree Source Tree Receiver (S, G) Traffic Flow Is Now Pruned Off of the Shared Tree and Is Flowing to the Receiver via the Source Tree 12
PIM-SM SPT Switchover Source RP Traffic Flow Shared Tree Source Tree (S, G) Prune Receiver (S, G) Traffic Flow Is No Longer Needed by the RP so It Prunes the Flow of (S, G) Traffic 13
PIM-SM SPT Switchover Source RP Traffic Flow Shared Tree Source Tree Receiver (S, G) Traffic Flow Is Now Only Flowing to the Receiver via a Single Branch of the Source Tree 14
PIM Packets 15
PIM Packet Header PIMv2 is assigned protocol number 103 Ver 3 7 15 Type Reserved Checksum Ver: PIM Version = 2 Type: 0 = Hello 1 = Register (SM only) 2 = Register-Stop (SM only) 3 = Join/Prune 4 = Bootstrap (SM BSR only) 5 = Assert 6 = Graft (DM only) 7 = Graft-Ack (DM only) 8 = C-RP-Announcement (SM BSR only) 31 For Your Reference PIMv2 messages are multicast to the ALL-PIM-Routers (224.0.0.13) group with a TTL of 1. 16
PIM Hello Messages For Your Reference Ver 3 7 15 Type Reserved Checksum Option Type Option Length Option Value 31... Option Type Option Value Option Length Option Types: 1 = Holdtime (Period of time in seconds before this PIM neighbor times out.) 19 = DR Priority 20 = Generation ID 17
PIM Join/Prune Packets 3 7 15 Ver Type Reserved Checksum Upstream Neighbor Address (Encoded-Unicast) Reserved Num. Groups Holdtime Group List 31 Upstream Neighbor Address: IP address of RPF of upstream neighbor Holdtime: Period of time in seconds before this join/prune times out. Num. Grps # of Groups in Group list For Your Reference Group List: List (by group) of sources to Join and/or Prune. 18
PIM Group Lists 15 Group-1 (Encoded-Group) Num. Join Sources Num. Prune Sources Join Source-1 (Encoded-Source) Join Source-n (Encoded-Source) Prune Source-1 (Encoded-Source) 31 Group-x Group IP address Num. Join Sources # of Joins for Group-x Num. Prune Sources # of Prunes for Group-x For Your Reference Prune Source-n (Encoded-Source) Num. Join Sources Group-2 (Encoded-Group)...... Num. Prune Sources Join/Prune Source-y Encoded Source address to be Joined/Pruned. Group Lists are used in Join/Prune and Graft/Graft-Ack messages. 19
PIM Assert Packets R Ver 3 7 15 Type Reserved Checksum Group Address (Encoded-Group) Source Address (Encoded-Source) Metric Preference Metric Group Address: Identifies Group of the Assert Source Address: Identifies Source of the Assert R: (Sparse Mode Only) 1 = Assert down RP Tree; 0 = Assert Down SPT Metric Preference: Admin. Distance of unicast routing protocol Metric: Unicast routing protocol metric 31 For Your Reference 20
PIM Register Packets 3 Sparse Mode Only 7 15 Ver Type Reserved Checksum B N Reserved 31 For Your Reference Multicast Data Packet B = Border Bit: Indicates DR is a border router performing a proxy-register N = Null Register Bit: Indicates DR is sending a Null-Register before expiring its register-suppression timer. Multicast Data Packet: The original packet sent by the source. For periodic sending of registers, this part is null. 21
PIM Register-Stop Packets For Your Reference Ver 3 Sparse Mode Only 7 15 Type Reserved Checksum Group Address (Encoded-Group) Source Address (Encoded-Source) 31 Group Address: The Group address from the Register message. Source Address: IP host address of Source from multicast data packet in Register message. 22
Encoded Unicast Addresses For Your Reference 7 15 Addr Family Encoding Unicast Address...... Unicast Address 31 Addr Family: IANA Address Family Identifier (e.g. 1=IPv4) Encoding: Type of encoding within Address Family Unicast Address: Unicast Address of the target device. 23
Encoded Source Addresses For Your Reference 3 7 15 Addr Family Encoding Rsvd SWR Source Address... Mask Len 31 Addr Family: IANA Address Family Identifier (e.g. 1=IPv4) Encoding: Type of encoding within Address Family S = Sparse Mode bit Indicates Sparse Mode Group. W = Wildcard bit Indicates Join/Prune is a (*,G) Join/Prune. R = RP bit Indicates this Join/Prune should be sent up Shared Tree toward RP. Mask Len Number of bits in the prefix of the Group Address. Source Address Address of Multicast Source 24
Encoded Group Addresses For Your Reference 3 Addr Family 7 15 Encoding Reserved Group Address... Addr Family: IANA Address Family Identifier (e.g. 1=IPv4) Encoding: Type of encoding within Address Family Mask Len Number of bits in the prefix of the Group Address. Group Address Multicast Group Address Mask Len 31 25
PIM Neighbor Discovery 26
PIM Neighbor Discovery 171.68.37.2 PIM Router 2 Highest IP Address Elected as DR (Designated Router) PIM Hello PIM Hello PIM Router 1 171.68.37.1 PIMv2 Hellos are periodically multicast to the All-PIM-Routers (224.0.0.13) group address (default = 30 seconds) If the DR times-out, a new DR is elected The DR is responsible for sending all Joins and Register messages for any receivers or senders on the network 27
PIM Neighbor Discovery - IOS wan-gw8>show ip pim neighbor PIM Neighbor Table Neighbor Interface Uptime/Expires Ver Mode Address Prio/Mode 171.68.0.70 FastEthernet0/0 2w1d/00:01:24 v2 1 / B S 171.68.0.91 FastEthernet0/0 2w6d/00:01:01 v2 1 / B S 171.68.0.82 FastEthernet0/0 7w0d/00:01:14 v2 5 / DR B S 171.68.0.86 FastEthernet0/0 7w0d/00:01:13 v2 1 / B S 171.68.0.80 FastEthernet0/0 7w0d/00:01:02 v2 1 / B S 171.68.28.70 Serial2.31 22:47:11/00:01:16 v2 1 / B S 171.68.28.50 Serial2.33 22:47:22/00:01:08 v2 1 / B S 171.68.27.74 Serial2.36 22:47:07/00:01:21 v2 N / 171.68.28.170 Serial0.70 1d4h/00:01:06 v2 N / 171.68.27.2 Serial1.51 1w4d/00:01:25 v2 1 / B S 171.68.28.110 Serial3.56 1d4h/00:01:20 v2 1 / B S 171.68.28.58 Serial3.102 12:53:25/00:01:03 v2 1 / B S 28
DR Failover A.2 (DR) 192.168.1.0/24.1 B Rtr-B>show ip pim neighbor PIM Neighbor Table Neighbor Address Interface Uptime Expires Mode 192.168.1.2 Ethernet0 4d22h 00:01:18 Sparse-Dense (DR) Depends on neighbor expiration time Expiration time sent in PIM query messages Expiration time = 3 x <query-interval> Default <query-interval> = 30 seconds DR failover ~ 90 seconds (worst case) by default 29
PIM State & State Rules 30
PIM State Describes the state of the multicast distribution trees As understood by the router at that point in the network Represented by multicast routing (mroute) table entries Used to make multicast traffic forwarding decisions Composed of (*, G) and (S, G) entries Each entry contains RPF information Incoming (i.e. RPF) interface RPF Neighbor (upstream) Each entry contains an Outgoing Interface List (OIL) OIL may be NULL 31
PIM-SM State Example - IOS sj-mbone> show ip mroute 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, X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement, U - URD, I - Received Source Specific Host Report Outgoing interface flags: H - Hardware switched Timers: Uptime/Expires Interface state: Interface, Next-Hop or VCD, State/Mode (*, 224.1.1.1), 2w1d/00:00:00, RP 172.16.25.1, flags: SJC Incoming interface: Serial0/1, RPF nbr 172.16.4.1 Ethernet0/1, Forward/Sparse-Dense, 2w1d/00:01:40 Serial0/0, Forward/Sparse-Dense, 00:4:52/00:02:08 (172.16.8.2, 224.1.1.1), 00:04:52/00:02:59, flags: CJT Incoming interface: Serial0/1, RPF nbr 172.16.4.1 Ethernet0/1, Forward/Sparse-Dense, 00:00:10/00:02:49 Serial0/0, Forward/Sparse-Dense, 00:4:52/00:02:08 32
PIM-SM (*,G) State Rules in IOS (*,G) creation Receipt of a (*,G) Join or IGMP Report Automatically if (S,G) must be created Not applicable to SSM (*,G) reflects default group forwarding IIF = RPF interface toward RP OIL = interfaces That received a (*,G) Join or With directly connected members or Manually configured (*,G) deletion When OIL = NULL and No child (S,G) state exists 33
PIM-SM (S,G) State Rules in IOS (S,G) creation By receipt of (S,G) Join or Prune or By Register process Parent (*,G) created (if doesn t exist) Not applicable to SSM (S,G) reflects forwarding of S to G IIF = RPF Interface normally toward source RPF toward RP if RP-bit set Not applicable to SSM OIL = Initially, copy of (*,G) OIL minus IIF Not applicable to SSM (S,G) deletion By normal (S,G) entry timeout 34
PIM-SM OIL Rules in IOS Interfaces in OIL added By receipt of Join message Interfaces added to (*,G) are added to all (S,G) s Not applicable to SSM Interfaces in OIL removed By receipt of Prune message Interfaces removed from (*,G) are removed from all (S,G) s Not applicable to SSM Interface expire timer counts down to zero Timer reset (to 3 min.) by receipt of periodic Join or By IGMP membership report 35
PIM-SM Triggered Join/Prune Rules Triggering Join/Prune Messages (*,G) Joins are triggered when: The (*,G) OIL transitions from Null to non-null (*,G) Prunes are triggered when: The (*,G) OIL transitions from non-null to Null (S,G) Joins are triggered when: The (S,G) OIL transitions from Null to non-null The (S,G) RP bit is reset (S,G) Prunes are triggered when: The (S,G) OIL transitions from non-null to Null (S,G) RP-bit Prunes are triggered when: The (S,G) RPF info!= the (*,G) RPF info Not applicable to SSM 36
PIM-SM IOS State Flags S C I L P T = Sparse = Router has Directly Connected Host = Router Received Source Specific Host Report (SSM) = Local (Router is member) = Pruned (All interfaces in OIL = Prune) = Indicates at least one packet was forwarded via (S,G) entry Not applicable to SSM. T bit always set. 37
PIM-SM IOS State Flags J = Join SPT Not applicable to SSM In (*, G) entry Indicates SPT-Threshold is being exceeded Next (S,G) received will trigger join of SPT In (S, G) entry Indicates SPT joined due to SPT-Threshold If rate < SPT-Threshold, switch back to Shared Tree F = Register/First-Hop Not applicable to SSM In (S,G) entry S is a directly connected source Triggers the Register Process In (*, G) entry Set when F set in at least one child (S,G) 38
PIM-SM IOS State Flags R = RP bit Not applicable to SSM (S, G) entries only Set by (S,G)RP-bit Prune Indicates info is applicable to Shared Tree Used to prune (S,G) traffic from Shared Tree Initiated by Last-hop router after switch to SPT Modifies (S,G) forwarding behavior IIF = RPF toward RP (I.e. up the Shared Tree) OIL = Pruned accordingly 39
PIM Source-Specific Multicast (SSM) 40
Source Specific Multicast (SSM) Uses Source Trees only Assumes one-to-many model Most Internet multicast fits this model IP/TV also fits this model Hosts responsible for source discovery Typically via some out-of-band mechanism Web page, Content Server, etc. Eliminates need for RP RP discovery (BSR, AutoRP, Static) RP redundancy (BSR, AutoRP, MSDP, PIM-Anycast) RP placement and nurturing Eliminates need for shared trees SPT/RPT switchover complexity Eliminates need for interdomain PIM-SM complexity (MSDP) 41
SSM Overview Hosts join a specific source within a group Content identified by specific (S,G) instead of (*,G) Hosts responsible for learning (S,G) information Last-hop router sends (S,G) join toward source Shared Tree is never Joined or used Eliminates possibility of content Jammers Only specified (S,G) flow is delivered to host Eliminates Networked-Based Source Discovery No RPs for SSM groups Simplifies address allocation Dissimilar content sources can use same group without fear of interfering with each other 42
PIM SSM Joining 43
PIM SSM Joining - IOS 172.16.8.1 /2 Source Data Src 172.16.8.2 /0 10.1.2.1 A /1 10.1.3.1 Source Tree Rcvr1 10.1.2.2 /0 /1 B 10.1.3.2 /0 C /1 Rcvr2 (172.16.8.2, 232.1.1.1), 00:00:09/00:02:51, flags: spt Incoming interface: Ethernet0/2, RPF nbr 0.0.0.0 Null 44
PIM SSM Joining - IOS 172.16.8.1 /2 Source Data Src 172.16.8.2 /0 10.1.2.1 A /1 10.1.3.1 Source Tree 1 IGMPv3 Join Rcvr1 10.1.2.2 /0 /1 B 10.1.3.2 /0 C /1 Rcvr2 1 Rcvr1 wishes to receive SSM S,G traffic. Sends IGMPv3 Join for S,G. 45
PIM SSM Joining - IOS 172.16.8.1 /2 Source Data Src 172.16.8.2 /0 10.1.2.1 A /1 10.1.3.1 Source Tree Rcvr1 10.1.2.2 /0 /1 B 10.1.3.2 /0 C /1 Rcvr2 (172.16.8.2, 232.1.1.1), 00:00:14/00:02:45, flags: sti Incoming interface: Ethernet0/0, RPF nbr 10.1.2.1 Ethernet0/1, Forward/Sparse, 00:00:14/00:02:45 B Creates (172.16.8.2, 224.1.1.1) State 46
PIM SSM Joining - IOS 172.16.8.1 /2 Source Data Source Tree Src 172.16.8.2 Rcvr1 /0 10.1.2.1 (S,G) Join 2 10.1.2.2 /0 /1 B A /1 10.1.3.1 10.1.3.2 /0 C /1 Rcvr2 2 B sends (S,G) Join towards Source. 47
PIM SSM Joining - IOS 172.16.8.1 /2 Source Data Src 172.16.8.2 /0 10.1.2.1 A /1 10.1.3.1 Source Tree Rcvr1 10.1.2.2 /0 /1 B 10.1.3.2 /0 C /1 Rcvr2 (172.16.8.2, 232.1.1.1), 00:00:15/00:02:49, flags: st Incoming interface: Ethernet0/2, RPF nbr 0.0.0.0 Null Ethernet0/0, Forward/Sparse, 00:28:03/00:02:43 A Updates (172.16.8.2, 224.1.1.1) State 48
PIM SSM Joining - IOS 172.16.8.1 /2 Source Data Src 172.16.8.2 /0 10.1.2.1 A /1 10.1.3.1 Source Tree Rcvr1 10.1.2.2 /0 /1 B 10.1.3.2 /0 C /1 Rcvr2 49
PIM SSM Joining - IOS 172.16.8.1 /2 Source Data Src 172.16.8.2 /0 10.1.2.1 A /1 10.1.3.1 Source Tree Rcvr1 10.1.2.2 /0 /1 B 10.1.3.2 /0 C /1 IGMPv3 Join 3 Rcvr2 3 Rcvr2 wishes to receive SSM S,G traffic. Sends IGMPv3 Join for S,G. 50
PIM SSM Joining - IOS 172.16.8.1 /2 Source Data Src 172.16.8.2 /0 10.1.2.1 A /1 10.1.3.1 Source Tree Rcvr1 10.1.2.2 /0 /1 B 10.1.3.2 /0 C /1 Rcvr2 (172.16.8.2, 232.1.1.1), 00:00:02/00:02:49, flags: sti Incoming interface: Ethernet0/0, RPF nbr 10.1.3.1 Ethernet0/1, Forward/Sparse, 00:00:02/00:02:49 C Creates (172.16.8.2, 224.1.1.1) State 51
PIM SSM Joining - IOS 172.16.8.1 /2 Source Data Source Tree Src 172.16.8.2 Rcvr1 /0 10.1.2.1 10.1.2.2 /0 /1 B A /1 10.1.3.1 4 (S,G) Join 10.1.3.2 /0 C /1 Rcvr2 4 C sends (S,G) Join towards Source. 52
PIM SSM Joining - IOS 172.16.8.1 /2 Source Data Src 172.16.8.2 /0 10.1.2.1 A /1 10.1.3.1 Source Tree Rcvr1 10.1.2.2 /0 /1 B 10.1.3.2 /0 C /1 Rcvr2 (172.16.8.2, 232.1.1.1), 00:00:15/00:02:49, flags: st Incoming interface: Ethernet0/2, RPF nbr 0.0.0.0 Ethernet0/0, Forward/Sparse, 00:28:03/00:02:43 Ethernet0/1, Forward/Sparse, 00:00:03/00:02:48 A Updates (172.16.8.2, 224.1.1.1) State 53
PIM SSM Joining - IOS 172.16.8.1 /2 Source Data Src 172.16.8.2 /0 10.1.2.1 A /1 10.1.3.1 Source Tree Rcvr1 10.1.2.2 /0 /1 B 10.1.3.2 /0 C /1 Rcvr2 54
PIM SSM Pruning 55
PIM SSM Pruning - IOS 172.16.8.1 /2 Source Data Src 172.16.8.2 /0 10.1.2.1 A /1 10.1.3.1 Source Tree Rcvr1 10.1.2.2 /0 /1 B 10.1.3.2 /0 C /1 Rcvr2 (172.16.8.2, 232.1.1.1), 00:43:15/00:02:49, flags: st Incoming interface: Ethernet0/2, RPF nbr 0.0.0.0 Ethernet0/0, Forward/Sparse, 00:43:15/00:02:44 Ethernet0/1, Forward/Sparse, 00:40:03/00:02:55 State in A Before Pruning 56
PIM SSM Pruning - IOS 172.16.8.1 /2 Source Data Src 172.16.8.2 /0 10.1.2.1 A /1 10.1.3.1 Source Tree Rcvr1 10.1.2.2 /0 /1 B 10.1.3.2 /0 C /1 Rcvr2 (172.16.8.2, 232.1.1.1), 00:43:15/00:02:49, flags: sti Incoming interface: Ethernet0/0, RPF nbr 10.1.2.1 Ethernet0/1, Forward/Sparse, 00:43:15/00:02:44 State in B Before Pruning 57
PIM SSM Pruning - IOS 172.16.8.1 /2 Source Data Src 172.16.8.2 /0 10.1.2.1 A /1 10.1.3.1 Source Tree Rcvr1 10.1.2.2 /0 /1 B 10.1.3.2 /0 C /1 Rcvr2 (172.16.8.2, 232.1.1.1), 00:40:16/00:02:49, flags: sti Incoming interface: Ethernet0/0, RPF nbr 10.1.3.1 Ethernet0/1, Forward/Sparse, 00:40:16/00:02:42 State in C Before Pruning 58
PIM SSM Pruning - IOS 172.16.8.1 /2 Source Data Src 172.16.8.2 /0 10.1.2.1 A /1 10.1.3.1 Source Tree Rcvr1 1 IGMP Leave 10.1.2.2 /0 /1 B 10.1.3.2 /0 C /1 Rcvr2 1 B is a Leaf router. Last Rcvr, leaves (S,G). 59
PIM SSM Pruning - IOS 172.16.8.1 /2 Source Data Src 172.16.8.2 /0 10.1.2.1 A /1 10.1.3.1 Source Tree Rcvr1 2 10.1.2.2 /0 /1 B 10.1.3.2 /0 C /1 Rcvr2 (172.16.8.2, 232.1.1.1), 00:43:25/00:02:49, flags: sti stp Incoming interface: Ethernet0/0, RPF nbr 10.1.2.1 Ethernet0/1, Forward/Sparse, 00:00:14/00:02:45 2 B removes /1 from (S,G) oilist. 60
PIM SSM Pruning - IOS 172.16.8.1 /2 Source Data Source Tree Src 172.16.8.2 /0 10.1.2.1 (S,G) Prune 3 Rcvr1 10.1.2.2 /0 /1 B A /1 10.1.3.1 10.1.3.2 /0 C /1 Rcvr2 (172.16.8.2, 232.1.1.1), 00:43:26/00:02:49, flags: sti stp Incoming interface: Ethernet0/0, RPF nbr 10.1.2.1 Ethernet0/1, Forward/Sparse, 00:00:14/00:02:45 3 B s (S,G) oilist now empty; triggers (S,G) Prune toward source. 61
PIM SSM Pruning - IOS 172.16.8.1 /2 Source Data Source Tree Src 172.16.8.2 Rcvr1 /0 10.1.2.1 10.1.2.2 /0 /1 4 B A /1 10.1.3.1 10.1.3.2 /0 C /1 Rcvr2 (172.16.8.2, 232.1.1.1), 00:43:44/00:02:49, 00:00:15/00:02:49, flags: st Incoming interface: Ethernet0/2, RPF nbr 0.0.0.0 Ethernet0/1, Ethernet0/0, Forward/Sparse, 00:00:03/00:02:48 00:28:03/00:02:43 Ethernet0/1, Forward/Sparse, 00:00:03/00:02:48 4 A removes /0 from (S,G) oilist. 62
PIM SSM Pruning - IOS 172.16.8.1 /2 Source Data Src 172.16.8.2 /0 10.1.2.1 A /1 10.1.3.1 Source Tree Rcvr1 10.1.2.2 /0 /1 B 10.1.3.2 /0 C /1 IGMP Leave 5 Rcvr2 5 C is a Leaf router. Last Rcvr, leaves (S,G). 63
PIM SSM Pruning - IOS 172.16.8.1 /2 Source Data Src 172.16.8.2 /0 10.1.2.1 A /1 10.1.3.1 Source Tree Rcvr1 10.1.2.2 /0 /1 B 10.1.3.2 /0 C 6 /1 Rcvr2 (172.16.8.2, 232.1.1.1), 00:43:45/00:02:49, flags: stp sti Incoming interface: Ethernet0/0, RPF nbr 10.1.3.1 Ethernet0/1, Forward/Sparse, 00:00:02/00:02:49 6 C removes /1 from (S,G) oilist. 64
PIM SSM Pruning - IOS 172.16.8.1 /2 Source Data Source Tree Src 172.16.8.2 Rcvr1 /0 10.1.2.1 10.1.2.2 /0 /1 B A /1 10.1.3.1 7 (S,G) Prune 10.1.3.2 /0 C /1 Rcvr2 7 C s (S,G) oilist now empty; triggers (S,G) Prune toward source. 65
PIM SSM Pruning - IOS 172.16.8.1 /2 Source Data Source Tree Src 172.16.8.2 Rcvr1 /0 10.1.2.1 10.1.2.2 /0 /1 B A /1 10.1.3.1 8 10.1.3.2 /0 C /1 Rcvr2 (172.16.8.2, 232.1.1.1), 00:43:46/00:02:49, flags: stp Incoming interface: Ethernet0/2, RPF nbr 0.0.0.0 Ethernet0/1, Forward/Sparse, 00:00:03/00:02:48 8 A removes /1 from (S,G) oilist. 66
PIM SSM Pruning - IOS 172.16.8.1 /2 Source Data Src 172.16.8.2 /0 10.1.2.1 A /1 10.1.3.1 Source Tree Rcvr1 10.1.2.2 /0 /1 B 10.1.3.2 /0 C /1 Rcvr2 (172.16.8.2, 232.1.1.1), 00:43:48/00:00:00, 00:43:48/00:00:04, 00:43:48/00:00:02, 00:43:48/00:00:03, 00:43:48/00:00:01, flags: stp Incoming interface: Ethernet0/0, RPF nbr 10.1.2.1 After about 3 minutes... 67
PIM SSM Pruning - IOS 172.16.8.1 /2 Source Data Src 172.16.8.2 /0 10.1.2.1 A /1 10.1.3.1 Source Tree Rcvr1 10.1.2.2 /0 /1 B 10.1.3.2 /0 C /1 Rcvr2 (172.16.8.2, 232.1.1.1), 00:43:48/00:00:00, flags: stp Incoming interface: Ethernet0/0, RPF nbr 10.1.2.1 After about 3 minutes... Same for routers C and A (S, G) State times out 68
PIM Any-Source Multicast (ASM) 69
PIM ASM Joining 70
PIM ASM Joining - IOS Shared Tree To RP (10.1.5.1) 10.1.4.2 A 10.1.2.1 1 IGMP Join Rcvr 10.1.2.2 E1 B 1 Rcvr wishes to receive group G traffic. Sends IGMP Join for G. 71
PIM ASM Joining - IOS Shared Tree To RP (10.1.5.1) Rcvr 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 (*, 224.1.1.1), 00:00:05/00:00:00, RP 10.1.5.1, flags: SC Incoming interface: Ethernet0, RPF nbr 10.1.2.1 Ethernet1, Forward/Sparse-Dense, 00:00:05/00:02:54 B Creates (*, 224.1.1.1) State 72
PIM ASM Joining - IOS Shared Tree To RP (10.1.5.1) 10.1.4.2 A 10.1.2.1 Rcvr 10.1.2.2 E1 B 2 (*,G) Join 1 Rcvr wishes to receive group G traffic. Sends IGMP Join for G. 2 B sends (*,G) Join towards RP. 73
PIM ASM Joining - IOS Shared Tree To RP (10.1.5.1) Rcvr 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 (*, 224.1.1.1), 00:00:05/00:00:00, RP 10.1.5.1, flags: S Incoming interface: Serial0, RPF nbr 10.1.4.1 Ethernet0, Forward/Sparse-Dense, 00:00:05/00:02:54 A Creates (*, 224.1.1.1) State 74
PIM ASM Joining - IOS To RP (10.1.5.1) 4 Shared Tree Shared Tree 3 (*,G) Join 10.1.4.2 A 10.1.2.1 Rcvr 10.1.2.2 E1 B 1 Rcvr wishes to receive group G traffic. Sends IGMP Join for G. 2 B sends (*,G) Join towards RP. 3 A sends (*,G) Join towards RP. 4 Shared tree is built all the way back to the RP. 75
PIM ASM Registering 76
PIM ASM Register Scenarios Receivers Join Group First Source Registers First Receivers along the SPT 77
PIM ASM Registering Receiver Joins First 78
PIM ASM Registering - IOS Receiver Joins Group First RP A B S3 C Shared Tree (*, 224.1.1.1), 00:03:14/00:00:00, RP 171.68.28.140, flags:s Incoming interface: Null, RPF nbr 0.0.0.0, Serial0, Forward/Sparse-Dense, 00:03:14/00:03:15 Serial1, Forward/Sparse-Dense, 00:03:14/00:03:15 State in RP Before Any Source Registers (With Receivers on Shared Tree) 79
PIM ASM Registering - IOS Receiver Joins Group First RP A B C S3 Shared Tree rtr-b>sh ip mroute 224.1.1.1 No such group State in B Before Any Source Registers (With Receivers on Shared Tree) 80
PIM ASM Registering - IOS Receiver Joins Group First RP A B C S3 Shared Tree rtr-a>sh ip mroute 224.1.1.1 No such group. State in A Before Any Source Registers (With Receivers on Shared Tree) 81
PIM ASM Registering - IOS Receiver Joins Group First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 1 RP A B C S3 Shared Tree 1 Source begins sending group G traffic. 82
PIM ASM Registering - IOS Receiver Joins Group First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 2 Register Msgs A B C S3 RP (*, 224.1.1.1), 00:00:03/00:00:00, RP 171.68.28.140, flags: SP Incoming interface: Serial0, RPF nbr 171.68.28.191, Null (171.68.37.121, 224.1.1.1), 00:00:03/00:02:56, flags: FPT Incoming interface: Ethernet0, RPF nbr 0.0.0.0, Registering Null A Creates (S, G) State for Source (After Automatically Creating a (*, G) entry) 1 Source begins sending group G traffic. Shared Tree 2 A encapsulates packets in Registers; unicasts to RP. 83
PIM ASM Registering - IOS Receiver Joins Group First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 Register Msgs A B C 171.68.28.139 (*, 224.1.1.1), 00:09:21/00:00:00, RP 171.68.28.140, flags: S Incoming interface: Null, RPF nbr 0.0.0.0, Serial0, Forward/Sparse-Dense, 00:09:21/00:02:38 Serial1, Forward/Sparse-Dense, 00:03:14/00:02:46 (171.68.37.121, 224.1.1.1, 00:01:15/00:02:46, flags: Incoming interface: Serial3, RPF nbr 171.68.28.139, Serial0, Forward/Sparse-Dense, 00:00:49/00:02:11 Serial1, Forward/Sparse-Dense, 00:00:49/00:02:11 S3 RP 3 (*, 224.1.1.1) Mcast Traffic Shared Tree RP Processes Register; Creates (S, G) State 3 RP (C) de-encapsulates packets; forwards down Shared tree. 84
PIM ASM Registering Receiver Joins Group First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 Register Msgs (S,G) Join 4 A B C 171.68.28.139 S3 Shared Tree RP (*, 224.1.1.1) Mcast Traffic 4 RP sends (S,G) Join toward Source to build SPT. 85
PIM ASM Registering - IOS Receiver Joins Group First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 (S,G) Join 5 Register Msgs A B C 171.68.28.190 S3 Shared Tree RP (*, 224.1.1.1) Mcast Traffic (*, 224.1.1.1), 00:04:28/00:00:00, RP 171.68.28.140, flags: SP Incoming interface: Serial1, RPF nbr 171.68.28.140, Null (171.68.37.121, 224.1.1.1), 00:04:28/00:01:32, flags: Incoming interface: Serial0, RPF nbr 171.68.28.190 Serial1, Forward/Sparse-Dense, 00:04:28/00:01:32 B Processes Join, Creates (S, G) State (After Automatically Creating the (*, G) Entry) 5 B sends (S,G) Join toward Source to continue building SPT. 86
PIM ASM Registering - IOS Receiver Joins Group First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 Register Msgs A B C S3 Shared Tree RP (*, 224.1.1.1) Mcast Traffic (*, 224.1.1.1), 00:04:28/00:00:00, RP 171.68.28.140, flags: SP Incoming interface: Serial0, RPF nbr 171.68.28.191, Null (171.68.37.121, 224.1.1.1), 00:04:28/00:01:32, flags: FT Incoming interface: Ethernet0, RPF nbr 0.0.0.0, Registering Serial0, Forward/Sparse-Dense, 00:04:28/00:01:32 A Processes the (S, G) Join; Adds Serial0 to OIL 87
PIM ASM Registering Receiver Joins Group First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 6 Register Msgs A B C S3 Shared Tree RP (*, 224.1.1.1) Mcast Traffic 6 RP begins receiving (S,G) traffic down SPT. 88
PIM ASM Registering - IOS Receiver Joins Group First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 Register Msgs A B C S3 Shared Tree (*, 224.1.1.1), 00:09:21/00:00:00, RP 171.68.28.140, flags: S Incoming interface: Null, RPF nbr 0.0.0.0, Serial0, Forward/Sparse-Dense, 00:09:21/00:02:38 Serial1, Forward/Sparse-Dense, 00:03:14/00:02:46 RP (*, 224.1.1.1) Mcast Traffic (171.68.37.121, 224.1.1.1, 00:01:15/00:02:46, flags:t Incoming interface: Serial3, RPF nbr 171.68.28.139, Serial0, Forward/Sparse-Dense, 00:00:49/00:02:11 Serial1, Forward/Sparse-Dense, 00:00:49/00:02:11 Note T Flag Is Now Set Traffic Arriving via SPT Is Forwarded Down Shared Tree (This Causes the T Flag to Be Set) 89
PIM ASM Registering - IOS Receiver Joins Group First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 Register Msgs A B C Register-Stop S3 Shared Tree RP (*, 224.1.1.1) Mcast Traffic 7 Once T Flag is set, next Register causes RP to send back a Register-Stop to A 90
PIM ASM Registering - IOS Receiver Joins Group First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 8 Register Msgs A B C Register-Stop S3 (*, 224.1.1.1), 00:04:28/00:00:00, RP 171.68.28.140, flags: SP Incoming interface: Serial0, RPF nbr 171.68.28.191, Null (171.68.37.121, 224.1.1.1), 00:04:28/00:01:32, flags: FT Incoming interface: Ethernet0, RPF nbr 0.0.0.0, Registering Serial0, Forward/Sparse-Dense, 00:04:28/00:01:32 A Stops Sending Register Messages (Final State in A) Shared Tree 8 (S,G) Traffic now flowing down a single path (SPT) to RP. RP (*, 224.1.1.1) Mcast Traffic 91
PIM ASM Registering - IOS Receiver Joins Group First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 A B C S3 Shared Tree RP (*, 224.1.1.1) Mcast Traffic (*, 224.1.1.1), 00:04:28/00:00:00, RP 171.68.28.140, flags: SP Incoming interface: Serial1, RPF nbr 171.68.28.140, Null (171.68.37.121, 224.1.1.1), 00:04:28/00:01:32, flags: T Incoming interface: Serial0, RPF nbr 171.68.28.190 Serial1, Forward/Sparse-Dense, 00:04:28/00:01:32 Final State in B 92
PIM ASM Registering - IOS Receiver Joins Group First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 A B C (*, 224.1.1.1), 00:09:21/00:00:00, RP 171.68.28.140, flags: S Incoming interface: Null, RPF nbr 0.0.0.0, Serial0, Forward/Sparse-Dense, 00:09:21/00:02:38 Serial1, Forward/Sparse-Dense, 00:03:14/00:02:46 (171.68.37.121, 224.1.1.1, 00:01:15/00:02:46, flags: T Incoming interface: Serial3, RPF nbr 171.68.28.139, Serial0, Forward/Sparse-Dense, 00:00:49/00:02:11 Serial1, Forward/Sparse-Dense, 00:00:49/00:02:11 Final State in the RP (With Receivers on Shared Tree) S3 Shared Tree RP (*, 224.1.1.1) Mcast Traffic 93
PIM ASM Registering Source Registers First 94
PIM ASM Registering - IOS Source Registers First RP A B S3 C rtr-c>show ip mroute 224.1.1.1 Group 224.1.1.1 not found. State in RP before Registering (Without Receivers on Shared Tree) 95
PIM ASM Registering - IOS Source Registers First RP A B S3 C rtr-b>show ip mroute 224.1.1.1 Group 224.1.1.1 not found. State in B Before Any Source Registers (With Receivers on Shared Tree) 96
PIM ASM Registering - IOS Source Registers First RP A B S3 C rtr-a>show ip mroute 224.1.1.1 Group 224.1.1.1 not found. State in A Before Any Source Registers (With Receivers on Shared Tree) 97
PIM ASM Registering - IOS Source Registers First (171.68.37.121, 224.1.1.1) Mcast Packets 1 Source 171.68.37.121 A B S3 C RP 1 Source begins sending group G traffic. 98
PIM ASM Registering - IOS Source Registers First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 2 Register Msgs A B S3 C RP (*, 224.1.1.1), 00:00:03/00:00:00, RP 171.68.28.140, flags: SP Incoming interface: Serial0, RPF nbr 171.68.28.191, Null (171.68.37.121, 224.1.1.1), 00:00:03/00:02:56, flags: FPT Incoming interface: Ethernet0, RPF nbr 0.0.0.0, Registering Null A Creates (S, G) State for Source (After Automatically Creating a (*, G) Entry) 1 Source begins sending group G traffic. 2 A encapsulates packets in Registers; unicasts to RP. 99
PIM ASM Registering - IOS Source Registers First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 Register Msgs A B S3 C RP 3 (*, 224.1.1.1), 00:01:15/00:00:00, RP 171.68.28.140, flags: SP Incoming interface: Null, RPF nbr 0.0.0.0, Null (171.68.37.121, 224.1.1.1), 00:01:15/00:01:45, flags: P Incoming interface: Serial3, RPF nbr 171.68.28.139, Null RP Processes Register; Creates (S, G) State (After Automatically Creating the (*, G) Entry) 3 RP (C) has no receivers on Shared Tree; discards packet. 100
PIM ASM Registering - IOS Source Registers First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 Register Msgs A B S3 C RP 4 Register-Stop 4 RP sends Register-Stop to A. 101
PIM ASM Registering - IOS Source Registers First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 A B S3 C 5 RP 5 A stops encapsulating traffic in Register Messages; drops packets from Source. 102
PIM ASM Registering - IOS Source Registers First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 A B S3 C RP (*, 224.1.1.1), 00:01:28/00:00:00, RP 171.68.28.140, flags: SP Incoming interface: Serial0, RPF nbr 171.68.28.191, Null (171.68.37.121, 224.1.1.1), 00:01:28/00:01:32, flags: FPT Incoming interface: Ethernet0, RPF nbr 0.0.0.0 Null State in A After Registering (Without Receivers on Shared Tree) 103
PIM ASM Registering - IOS Source Registers First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 A B S3 C RP rtr-b>show ip mroute 224.1.1.1 Group 224.1.1.1 not found. State in B after A Registers (Without Receivers on Shared Tree) 104
PIM ASM Registering - IOS Source Registers First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 171.68.28.139 A B S3 C RP (*, 224.1.1.1), 00:01:15/00:00:00, RP 171.68.28.140, flags: SP Incoming interface: Null, RPF nbr 0.0.0.0, Null (171.68.37.121, 224.1.1.1), 00:01:15/00:01:45, flags: P Incoming interface: Serial3, RPF nbr 171.68.28.139, Null State in RP After A Registers (Without Receivers on Shared Tree) 105
PIM ASM Registering - IOS Source Registers First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 A B S3 C RP 6 (*, G) Join 6 RP (C) receives (*, G) Join from a receiver on Shared Tree. 106
PIM ASM Registering - IOS Source Registers First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 7 (S, G) Join A B S3 C RP (*, 224.1.1.1), 00:09:21/00:00:00, RP 171.68.28.140, flags: S Incoming interface: Null, RPF nbr 0.0.0.0, Serial1, Forward/Sparse-Dense, 00:00:14/00:02:46 (171.68.37.121, 224.1.1.1, 00:01:15/00:02:46, flags: T Incoming interface: Serial3, RPF nbr 171.68.28.139, Serial1, Forward/Sparse-Dense, 00:00:14/00:02:46 RP Processes (*,G) Join (Adds Serial1 to Outgoing Interface Lists) 7 RP sends (S,G) Joins for all known Sources in Group. 107
PIM ASM Registering - IOS Source Registers First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 8 (S, G) Join A B S3 C 171.68.28.190 RP (*, 224.1.1.1), 00:04:28/00:00:00, RP 171.68.28.140, flags: SP Incoming interface: Serial1, RPF nbr 171.68.28.140, Null (171.68.37.121, 224.1.1.1), 00:04:28/00:01:32, flags: Incoming interface: Serial0, RPF nbr 171.68.28.190 Serial1, Forward/Sparse-Dense, 00:04:28/00:01:32 B Processes Join, Creates (S, G) State (After Automatically Creating the (*, G) Entry) 8 B sends (S,G) Join toward Source to continue building SPT. 108
PIM ASM Registering - IOS Source Registers First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 9 A B S3 C (*, 224.1.1.1), 00:04:28/00:00:00, RP 171.68.28.140, flags: SP Incoming interface: Serial0, RPF nbr 171.68.28.191, Null (171.68.37.121, 224.1.1.1), 00:04:28/00:01:32, flags: FT Incoming interface: Ethernet0, RPF nbr 0.0.0.0, Serial0, Forward/Sparse-Dense, 00:04:28/00:01:32 RP 10 (*, 224.1.1.1) Mcast Traffic A Processes the (S, G) Join; Adds Serial0 to OIL 9 RP begins receiving (S,G) traffic down SPT. 10 RP forwards (S,G) traffic down Shared Tree to receivers. 109
PIM ASM Registering - IOS Source Registers First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 A B S3 C RP (*, 224.1.1.1) Mcast Traffic (*, 224.1.1.1), 00:04:28/00:00:00, RP 171.68.28.140, flags: SP Incoming interface: Serial0, RPF nbr 171.68.28.191, Null (171.68.37.121, 224.1.1.1), 00:04:28/00:01:32, flags: FT Incoming interface: Ethernet0, RPF nbr 0.0.0.0, Serial1, Forward/Sparse-Dense, 00:04:28/00:01:32 Final state in Router A 110
PIM ASM Registering - IOS Source Registers First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 A B S3 C 171.68.28.190 RP (*, 224.1.1.1) Mcast Traffic (*, 224.1.1.1), 00:04:28/00:00:00, RP 171.68.28.140, flags: SP Incoming interface: Serial1, RPF nbr 171.68.28.140, Null (171.68.37.121, 224.1.1.1), 00:04:28/00:01:32, flags: T Incoming interface: Serial0, RPF nbr 171.68.28.190 Serial1, Forward/Sparse-Dense, 00:04:28/00:01:32 Final State in B After Receivers Join 111
PIM ASM Registering - IOS Source Registers First (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 171.68.28.139 A B S3 C (*, 224.1.1.1), 00:09:21/00:00:00, RP 171.68.28.140, flags: S Incoming interface: Null, RPF nbr 0.0.0.0, Serial1, Forward/Sparse-Dense, 00:03:14/00:02:46 RP (*, 224.1.1.1) Mcast Traffic (171.68.37.121, 224.1.1.1, 00:01:15/00:02:46, flags: T Incoming interface: Serial3, RPF nbr 171.68.28.139, Serial1, Forward/Sparse-Dense, 00:00:49/00:02:11 Final State in RP After Receivers Join 112
PIM ASM Registering Receiver Along the SPT 113
PIM ASM Registering - IOS Receivers Along the SPT (171.68.37.121, 224.1.1.1) Mcast Packets Shared Tree RP Source 171.68.37.121 A B S3 C (*, 224.1.1.1) Mcast Traffic (*, 224.1.1.1), 00:04:28/00:00:00, RP 171.68.28.140, flags: SP Incoming interface: Serial0, RPF nbr 171.68.28.191, Null (171.68.37.121, 224.1.1.1), 00:04:28/00:01:32, flags: FT Incoming interface: Ethernet0, RPF nbr 0.0.0.0, Serial1, Forward/Sparse-Dense, 00:04:28/00:01:32 Current state in Router A 114
PIM ASM Registering - IOS Receivers Along the SPT (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 A (*, 224.1.1.1), 00:04:28/00:00:00, RP 171.68.28.140, flags: SP Incoming interface: Serial1, RPF nbr 171.68.28.140, Null B S3 C RP Shared Tree (*, 224.1.1.1) Mcast Traffic (171.68.37.121, 224.1.1.1), 00:04:28/00:01:32, flags: T Incoming interface: Serial0, RPF nbr 171.68.28.190 Serial1, Forward/Sparse-Dense, 00:04:28/00:01:32 Current State in B 115
PIM ASM Registering - IOS Receivers Along the SPT (171.68.37.121, 224.1.1.1) Mcast Packets Shared Tree RP Source 171.68.37.121 A B S3 C (*, 224.1.1.1) Mcast Traffic (*, 224.1.1.1), 00:09:21/00:00:00, RP 171.68.28.140, flags: S Incoming interface: Null, RPF nbr 0.0.0.0, Serial1, Forward/Sparse-Dense, 00:03:14/00:02:46 (171.68.37.121, 224.1.1.1, 00:01:15/00:02:46, flags: T Incoming interface: Serial3, RPF nbr 171.68.28.139, Serial1, Forward/Sparse-Dense, 00:00:49/00:02:11 Current State in the RP 116
PIM ASM Registering - IOS Receivers Along the SPT (171.68.37.121, 224.1.1.1) Mcast Packets Shared Tree RP Source 171.68.37.121 A 1 IGMP Join B S3 C (*, 224.1.1.1) Mcast Traffic Rcvr 1 Rcvr wishes to receive group G traffic. Sends IGMP Join for G. 117
PIM ASM Registering - IOS Receivers Along the SPT (171.68.37.121, 224.1.1.1) Mcast Packets Shared Tree RP Source 171.68.37.121 A B S3 2 C (*, 224.1.1.1) Mcast Traffic Rcvr (*, 224.1.1.1), 00:04:28/00:00:00, RP 171.68.28.140, flags: SC Incoming interface: Serial1, RPF nbr 171.68.28.140, Ethernet0, Forward/Sparse-Dense, 00:00:30/00:02:30 (171.68.37.121, 224.1.1.1), 00:04:28/00:01:32, flags: CT Incoming interface: Serial0, RPF nbr 171.68.28.190 Serial1, Forward/Sparse-Dense, 00:04:28/00:01:32 Ethernet0, Forward/Sparse-Dense, 00:00:30/00:02:30 B adds Ethernet0 to (*,G) and (S,G) OIL s 2 Traffic begins flowing to Rcvr via (S,G) 118
PIM ASM Registering - IOS Receivers Along the SPT (171.68.37.121, 224.1.1.1) Mcast Packets Shared Tree RP Source 171.68.37.121 A B S3 2 (*, G) Join C (*, 224.1.1.1) Mcast Traffic Rcvr 3 B triggers a (*,G) Join to join the Shared Tree 119
PIM ASM Registering - IOS Receivers Along the SPT (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 S3 A B C RP Shared Tree (*, 224.1.1.1) Mcast Traffic Rcvr (*, 224.1.1.1), 00:09:21/00:00:00, RP 171.68.28.140, flags: S Incoming interface: Null, RPF nbr 0.0.0.0, Serial1, Forward/Sparse-Dense, 00:03:14/00:02:46 Serial3, Forward/Sparse-Dense, 00:00:10/00:02:50 (171.68.37.121, 224.1.1.1, 00:01:15/00:02:46, flags: T Incoming interface: Serial3, RPF nbr 171.68.28.139, Serial1, Forward/Sparse-Dense, 00:00:49/00:02:11 Pop Quiz: Why didn t it copy Serial3 to the OIL of the (S,G) entry? RP adds Serial3 to (*,G) OIL 120
PIM ASM Registering - IOS Receivers Along the SPT (171.68.37.121, 224.1.1.1) Mcast Packets Source 171.68.37.121 S3 A B C RP Shared Tree (*, 224.1.1.1) Mcast Traffic Rcvr 4 Other Group G traffic can now flow to Rcvr via Shared Tree. (Note: 171.68.37.121 traffic doesn t flow to RP then back down to B) 121
PIM ASM SPT Switchover 122
PIM ASM SPT-Switchover - IOS SPT Thresholds may be set for any Group Access Lists may be used to specify which Groups Default Threshold = 0kbps (I.e. immediately join SPT) Threshold = infinity means never join SPT Don t use values in between 0 and infinity (In IOS XR, 0 and infinity are the only options) Threshold triggers Join of Source Tree Sends an (S,G) Join up SPT for next S in G packet received 123
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D Rcvr B S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 B 10.1.2.1 (*, 224.1.1.1), 00:01:43/00:02:13, RP 10.1.5.1, flags: S Incoming interface: Serial0, RPF nbr 10.1.5.1, Serial1, Forward/Sparse-Dense, 00:01:43/00:02:11 Serial2, Forward/Sparse-Dense, 00:00:32/00:02:28 A State in C Before Switch Shared Tree 124
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 Shared Tree Rcvr B (*, 224.1.1.1), 00:01:43/00:02:13, RP 10.1.5.1, flags: SC Incoming interface: Serial0, RPF nbr 10.1.4.9, Ethernet0, Forward/Sparse-Dense, 00:01:43/00:02:11 State in D Before Switch 125
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D Rcvr B S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 Shared Tree (*, 224.1.1.1), 00:01:43/00:02:13, RP 10.1.5.1, flags: S Incoming interface: Serial0, RPF nbr 10.1.4.1, Ethernet0, Forward/Sparse-Dense, 00:01:43/00:02:11 State in A Before Switch 126
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D Rcvr B S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 (*, 224.1.1.1), 00:01:43/00:02:13, RP 10.1.5.1, flags: SCJJ Incoming interface: Ethernet0, RPF nbr 10.1.2.1, Ethernet1, Forward/Sparse-Dense, 00:01:43/00:02:11 State in B Before Switch Shared Tree Note J Flag is set 127
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D Rcvr B S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 (*, 224.1.1.1), 00:01:43/00:02:13, RP 10.1.5.1, flags: SCJ Incoming interface: Ethernet0, RPF nbr 10.1.2.1, Ethernet1, Forward/Sparse-Dense, 00:01:43/00:02:11 1 (S i, G) Traffic Flow Shared Tree Flow 1 New source (S i,g) packet arrives down Shared tree. 128
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D Rcvr B S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 (*, 224.1.1.1), 00:01:43/00:02:13, 00:01:43/00:00:00, RP 10.1.5.1, flags: SCJ Incoming interface: Ethernet0, RPF nbr 10.1.2.1, Ethernet1, Forward/Sparse-Dense, 00:01:43/00:02:11 (S i, G) Traffic Flow Shared Tree Flow (171.68.37.121, 224.1.1.1), 00:00:28/00:02:51, flags: CJ Incoming interface: Ethernet0, RPF nbr 10.1.2.1 Ethernet1, Forward/Sparse-Dense, 00:00:28/00:02:32 2 2 Because of C bit, B creates (S i,g) state to cut over to SPT. 129
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 3 (S i,g) Join (S i, G) Traffic Flow Shared Tree Flow Rcvr B 3 B sends (S i,g) Join towards S i. 130
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D Rcvr B S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 10.1.2.1 (*, 224.1.1.1), 00:01:43/00:00:00, RP 10.1.5.1, flags: S Incoming interface: Serial0, RPF nbr 10.1.4.1, Ethernet0, Forward/Sparse-Dense, 00:01:43/00:02:11 (171.68.37.121, 224.1.1.1), 00:13:28/00:02:53, flags: Incoming interface: Serial1, RPF nbr 10.1.9.2 Ethernet0, Forward/Sparse-Dense, 00:13:25/00:02:30 B A A creates (S i,g) state (S i, G) Traffic Flow Shared Tree Flow 131
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 4 (Si,G) Join (S i, G) Traffic Flow Shared Tree Flow SPT Tree Flow Rcvr B 4 A triggers (S i,g) Join toward S i. 132
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 (S i, G) Traffic Flow Shared Tree Flow SPT Tree Flow Rcvr B 4 A triggers (S i,g) Join toward S i. 5 (S i, G) traffic begins flowing down SPT tree instead of Shared Tree. 133
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 (S i, G) Traffic Flow Shared Tree Flow SPT Tree Flow Rcvr B (*, 224.1.1.1), 00:01:43/00:00:00, RP 10.1.5.1, flags: S Incoming interface: Serial0, RPF nbr 10.1.4.1, Ethernet0, Forward/Sparse-Dense, 00:01:43/00:02:11 (171.68.37.121, 224.1.1.1), 00:13:28/00:02:53, flags: T Incoming interface: Serial1, RPF nbr 10.1.9.2 Ethernet0, Forward/Sparse-Dense, 00:13:25/00:02:30 T Flag Set by Arriving Traffic on SPT 134
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D S2 C Rcvr A 6 (S i,g)rp-bit 10.1.4.1 To Source S Prune i 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 (S i, G) Traffic Flow Shared Tree Flow SPT Tree Flow Rcvr B (*, 224.1.1.1), 00:01:43/00:00:00, RP 10.1.5.1, flags: S Incoming interface: Serial0, RPF nbr 10.1.4.1, Ethernet0, Forward/Sparse-Dense, 00:01:43/00:02:11 (171.68.37.121, 224.1.1.1), 00:13:28/00:02:53, flags: Incoming interface: Serial1, RPF nbr 10.1.9.2 Ethernet0, Forward/Sparse-Dense, 00:13:25/00:02:30 Note RPF Info Does Not Match. This Indicates SPT and RPT Diverge. 6 Once T Flag is set, A triggers (S i,g)rp-bit Prunes toward RP. 135
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D Rcvr B S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 B 10.1.2.1 (*, 224.1.1.1), 00:01:43/00:00:00, RP 10.1.5.1, flags: S Incoming interface: Serial0, RPF nbr 10.1.5.1, Serial1, Forward/Sparse-Dense, 00:01:43/00:02:11 Serial2, Forward/Sparse-Dense, 00:00:32/00:02:28 (171.68.37.121, 224.1.1.1), 00:13:28/00:02:53, flags: R Incoming interface: Serial0, RPF nbr 10.1.5.1 Serial2, Forward/Sparse-Dense, 00:00:32/00:02:28 C creates (S i, G) RP-bit State and removes Serial1 from (S i, G) A (S i, G) Traffic Flow Shared Tree Flow SPT Tree Flow Note: Because R bit is set, Incoming interface points to RP not Source. 136
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D S2 C Rcvr A 10.1.4.1 To Source S i 7 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 (S i, G) Traffic Flow Shared Tree Flow SPT Tree Flow Rcvr B 7 Unnecessary (S i, G) traffic is pruned from the Shared tree. 137
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 (S i, G) Traffic Flow Shared Tree Flow SPT Tree Flow Rcvr B (*, 224.1.1.1), 00:01:43/00:00:00, RP 10.1.5.1, flags: SCJ Incoming interface: Serial0, RPF nbr 10.1.4.9, Ethernet0, Forward/Sparse-Dense, 00:01:43/00:02:11 (171.68.37.121, 224.1.1.1), 00:00:28/00:02:51, flags: CJ Incoming interface: Serial0, RPF nbr 10.1.3.1 Ethernet0, Forward/Sparse-Dense, 00:00:28/00:02:32 8 Because of C bit, D also creates (S i,g) state to cut over to SPT. 138
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D Rcvr B 9 S2 C (Si,G) Join Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 (S i, G) Traffic Flow Shared Tree Flow SPT Tree Flow 9 D triggers (S i,g) Join toward S i. 139
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D Rcvr B S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 B 10.1.2.1 (*, 224.1.1.1), 00:01:43/00:00:00, RP 10.1.5.1, flags: S Incoming interface: Serial0, RPF nbr 10.1.5.1, Serial1, Forward/Sparse-Dense, 00:01:43/00:02:11 Serial2, Forward/Sparse-Dense, 00:00:32/00:02:28 (171.68.37.121, 224.1.1.1), 00:13:28/00:02:53, flags: R Incoming interface: Serial1, Serial0, RPF nbr 10.1.4.2 10.1.5.1 Serial2, Forward/Sparse-Dense, 00:00:32/00:02:28 C resets (S i, G) RP-bit State and RPF s (S i, G) toward Source. A (S i, G) Traffic Flow Shared Tree Flow SPT Tree Flow 140
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D S2 C Rcvr A 10.1.4.1 To Source S i 10 (Si,G) Join 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 (S i, G) Traffic Flow Shared Tree Flow SPT Tree Flow Rcvr B 10 C triggers (S i,g) Join toward S i. 141
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D Rcvr B S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 10.1.2.1 (*, 224.1.1.1), 00:01:43/00:00:00, RP 10.1.5.1, flags: S Incoming interface: Serial0, RPF nbr 10.1.4.1, Ethernet0, Forward/Sparse-Dense, 00:01:43/00:02:11 (171.68.37.121, 224.1.1.1), 00:13:28/00:02:53, flags: Incoming interface: Serial1, RPF nbr 10.1.9.2 Ethernet0, Forward/Sparse-Dense, 00:13:25/00:02:30 Serial0, Forward/Sparse-Dense, 00:13:25/00:02:30 A adds Serial0 to (S i,g) OIL B A (S i, G) Traffic Flow Shared Tree Flow SPT Tree Flow 142
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 (S i, G) Traffic Flow Shared Tree Flow SPT Tree Flow Rcvr B Traffic flows to Rcvr B via SPT. 143
PIM ASM SPT-Switchover - IOS 11 (S i,g)rp-bit Prune To RP (10.1.5.1) D S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 (S i, G) Traffic Flow Shared Tree Flow SPT Tree Flow Rcvr B (*, 224.1.1.1), 00:01:43/00:00:00, RP 10.1.5.1, flags: S Incoming interface: Serial0, RPF nbr 10.1.5.1, Serial1, Forward/Sparse-Dense, 00:01:43/00:02:11 Serial2, Forward/Sparse-Dense, 00:00:32/00:02:28 (171.68.37.121, 224.1.1.1), 00:13:28/00:02:53, flags:t Incoming interface: Serial1, RPF nbr 10.1.4.2 Serial2, Forward/Sparse-Dense, 00:00:32/00:02:28 Note RPF Info Does Not Match. This Indicates SPT and RPT Diverge. 11 Once T Flag is set, C triggers (S i,g)rp-bit Prunes toward RP. 144
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 (S i, G) Traffic Flow Shared Tree Flow SPT Tree Flow Rcvr B All (S i,g) Traffic pruned from Shared Tree. 145
PIM ASM SPT-Switchover - IOS To RP (10.1.5.1) D S2 C Rcvr A 10.1.4.1 To Source S i 10.1.4.2 10.1.2.2 E1 B A 10.1.2.1 Shared Tree (S i, G) Traffic Flow Shared Tree Flow SPT Tree Flow Rcvr B But what does the Shared Tree look like now? Don t confuse Forwarding State with Tree Topology! 146
PIM ASM Pruning 147
PIM ASM Pruning - IOS Shared Tree Case To RP (10.1.5.1) (S i, G) Traffic Flow Shared Tree SPT Tree Rcvr A 10.1.4.2 E1 B A 10.1.2.1 10.1.2.2 (*, 224.1.1.1), 00:01:43/00:02:13, RP 10.1.5.1, flags: SC Incoming interface: Ethernet0, RPF nbr 10.1.2.1, Ethernet1, Forward/Sparse-Dense, 00:01:43/00:02:11 State in B Before Pruning 148
PIM ASM Pruning - IOS Shared Tree Case To RP (10.1.5.1) (S i, G) Traffic Flow Shared Tree SPT Tree Rcvr A 10.1.4.2 E1 B A 10.1.2.1 10.1.2.2 (*, 224.1.1.1), 00:01:43/00:02:13, RP 10.1.5.1, flags: S Incoming interface: Serial0, RPF nbr 10.1.4.1, Ethernet0, Forward/Sparse-Dense, 00:01:43/00:02:11 State in A Before Pruning 149
PIM ASM Pruning - IOS Shared Tree Case To RP (10.1.5.1) (S i, G) Traffic Flow Shared Tree SPT Tree 1 IGMP Leave Rcvr A 10.1.4.2 E1 B A 10.1.2.1 10.1.2.2 1 B is a Leaf router. Last Rcvr, leaves group G. 150
PIM ASM Pruning - IOS Shared Tree Case To RP (10.1.5.1) (S i, G) Traffic Flow Shared Tree SPT Tree 10.1.4.2 E1 2 B A 10.1.2.1 10.1.2.2 (*, 224.1.1.1), 00:01:43/00:02:13, RP 10.1.5.1, flags: SP Incoming interface: Ethernet0, RPF nbr 10.1.2.1, Ethernet1, Forward/Sparse-Dense, 00:01:43/00:02:11 2 B removes Ethernet1 from (*,G) and any (S i,g) oilists. 151
PIM ASM Pruning - IOS Shared Tree Case To RP (10.1.5.1) (S i, G) Traffic Flow Shared Tree SPT Tree 10.1.4.2 E1 B A 10.1.2.1 3 (*,G) Prune 10.1.2.2 (*, 224.1.1.1), 00:01:43/00:02:13, RP 10.1.5.1, flags: SP Incoming interface: Ethernet0, RPF nbr 10.1.2.1, 2 B removes Ethernet1 from (*,G) and any (S i,g) oilists. 3 B s (*,G) oilist now empty; triggers (*,G) Prune toward RP. 152
PIM ASM Pruning - IOS Shared Tree Case To RP (10.1.5.1) (S i, G) Traffic Flow Shared Tree SPT Tree 10.1.4.2 E1 B A 10.1.2.1 10.1.2.2 (*, 224.1.1.1), 00:01:43/00:02:13, RP 10.1.5.1, flags: S P Incoming interface: Serial0, RPF nbr 10.1.4.1, Ethernet0, Forward/Sparse-Dense, 00:01:43/00:02:11 4 A receives Prune; removes from (*,G) oilist. (After the 3 second Multi-access Network Prune delay.) 153
PIM ASM Pruning - IOS Shared Tree Case To RP (10.1.5.1) (*,G) Prune 10.1.4.2 (S 5 i, G) Traffic Flow Shared Tree SPT Tree E1 B A 10.1.2.1 10.1.2.2 (*, 224.1.1.1), 00:01:43/00:02:13, RP 10.1.5.1, flags: SP Incoming interface: Serial0, RPF nbr 10.1.4.1, 4 A receives Prune; removes from (*,G) oilist. (After the 3 second Multi-access Network Prune delay.) 5 A s (*,G) oilist now empty; triggers (*,G) Prune toward RP. 154
PIM ASM Pruning - IOS Shared Tree Case To RP (10.1.5.1) (S i, G) Traffic Flow Shared Tree 6 10.1.4.2 A 10.1.2.1 SPT Tree E1 B 10.1.2.2 6 Pruning continues back toward RP. 155
PIM ASM Pruning - IOS Source (SPT) Case To RP (10.1.5.1) To Source S i Shared Tree (S i, G) Traffic Flow SPT Tree 10.1.4.2 A 10.1.2.1 Rcvr E1 B 10.1.2.2 (*, 224.1.1.1), 00:01:43/00:00:00, RP 10.1.5.1, flags: S Incoming interface: Serial0, RPF nbr 10.1.4.1, Ethernet0, Forward/Sparse-Dense, 00:01:43/00:02:11 (171.68.37.121, 224.1.1.1), 00:01:05/00:01:55, flags: T Incoming interface: Serial1, RPF nbr 10.1.9.2 Ethernet0, Forward/Sparse-Dense, 00:01:05/00:02:55 State in A Before Pruning 156
PIM ASM Pruning - IOS Source (SPT) Case To RP (10.1.5.1) To Source S i Shared Tree (S i, G) Traffic Flow SPT Tree 10.1.4.2 A 10.1.2.1 Rcvr E1 B 10.1.2.2 (*, 224.1.1.1), 00:01:43/00:00:00, RP 10.1.5.1, flags: SC Incoming interface: Ethernet0, RPF nbr 10.1.2.1, Ethernet1, Forward/Sparse-Dense, 00:01:43/00:02:11 (171.68.37.121, 224.1.1.1), 00:01:05/00:01:55, flags: CJT Incoming interface: Ethernet0, RPF nbr 10.1.2.1 Ethernet1, Forward/Sparse-Dense, 00:01:05/00:02:55 State in B Before Pruning 157
PIM ASM Pruning - IOS Source (SPT) Case To RP (10.1.5.1) To Source S i Shared Tree (S i, G) Traffic Flow SPT Tree 10.1.4.2 A 10.1.2.1 1 IGMP Leave Rcvr E1 B 10.1.2.2 (*, 224.1.1.1), 00:01:43/00:00:00, RP 10.1.5.1, flags: SC Incoming interface: Ethernet0, RPF nbr 10.1.2.1, Ethernet1, Forward/Sparse-Dense, 00:01:43/00:02:11 (171.68.37.121, 224.1.1.1), 00:01:05/00:01:55, flags: CJT Incoming interface: Ethernet0, RPF nbr 10.1.2.1 Ethernet1, Forward/Sparse-Dense, 00:01:05/00:02:55 1 B is a Leaf router. Last Rcvr leaves group G. 158
PIM ASM Pruning - IOS Source (SPT) Case To RP (10.1.5.1) To Source S i Shared Tree (S i, G) Traffic Flow SPT Tree 10.1.4.2 A 10.1.2.1 E1 2 B 10.1.2.2 (*, 224.1.1.1), 00:01:43/00:00:00, RP 10.1.5.1, flags: SCP Incoming interface: Ethernet0, RPF nbr 10.1.2.1, Ethernet1, Forward/Sparse-Dense, 00:01:43/00:02:11 (171.68.37.121, 224.1.1.1), 00:01:05/00:01:55, flags: CJT Incoming interface: Ethernet0, RPF nbr 10.1.2.1 Ethernet1, Forward/Sparse-Dense, 00:01:05/00:02:55 2 B removes Ethernet1 from (*,G) and all (S,G) OIL s. 159
PIM ASM Pruning - IOS Source (SPT) Case To RP (10.1.5.1) To Source S i Shared Tree (S i, G) Traffic Flow SPT Tree 10.1.4.2 (*,G) Prune 3 A 10.1.2.1 E1 B 10.1.2.2 (*, 224.1.1.1), 00:01:43/00:00:00, RP 10.1.5.1, flags: SCP Incoming interface: Ethernet0, RPF nbr 10.1.2.1, (171.68.37.121, 224.1.1.1), 00:01:05/00:01:55, flags: CJPT Incoming interface: Ethernet0, RPF nbr 10.1.2.1 3 B s (*,G) OIL now empty; triggers (*,G) Prune toward RP. 160
PIM ASM Pruning - IOS Source (SPT) Case To RP (10.1.5.1) To Source S i Shared Tree (S i, G) Traffic Flow SPT Tree 10.1.4.2 (S,G) Prune 4 A 10.1.2.1 E1 B 10.1.2.2 (*, 224.1.1.1), 00:01:43/00:00:00, RP 10.1.5.1, flags: SCP Incoming interface: Ethernet0, RPF nbr 10.1.2.1, (171.68.37.121, 224.1.1.1), 00:01:05/00:01:55, flags: CJPT Incoming interface: Ethernet0, RPF nbr 10.1.2.1 4 B s (S,G) OIL also now empty; triggers (S, G) Prune towards Si. 161
PIM ASM Pruning - IOS Source (SPT) Case To RP (10.1.5.1) To Source S i Shared Tree (S i, G) Traffic Flow SPT Tree 10.1.4.2 5 A 10.1.2.1 E1 B 10.1.2.2 (*, 224.1.1.1), 00:01:43/00:00:00, RP 10.1.5.1, flags: S P Incoming interface: Serial0, RPF nbr 10.1.4.1, Ethernet0, Forward/Sparse-Dense, 00:01:43/00:02:11 (171.68.37.121, 224.1.1.1), 00:01:05/00:01:55, flags: PT T Incoming interface: Serial1, RPF nbr 10.1.9.2 Ethernet0, Forward/Sparse-Dense, 00:01:05/00:02:55 5 After A receives (*, G) Prune; removes from (*,G) & (S,G) OIL s (After the 3 second Multi-access Network Prune delay.) 162
PIM ASM Pruning - IOS Source (SPT) Case To RP (10.1.5.1) To Source S i Shared Tree (S i, G) Traffic Flow SPT Tree (*,G) Prune 10.1.4.2 6 A 10.1.2.1 E1 B 10.1.2.2 (*, 224.1.1.1), 00:02:32/00:00:00, RP 10.1.5.1, flags: SP Incoming interface: Serial0, RPF nbr 10.1.4.1, (171.68.37.121, 224.1.1.1), 00:01:56/00:00:53, flags: PT Incoming interface: Serial1, RPF nbr 10.1.9.2 6 A s (*,G) OIL now empty; triggers (*,G) Prune toward RP. 163
PIM ASM Pruning - IOS Source (SPT) Case To RP (10.1.5.1) To Source S i (S i, G) Traffic Flow SPT Tree 10.1.4.2 A 10.1.2.1 7 (S i,g) Prune E1 B 10.1.2.2 (*, 224.1.1.1), 00:02:32/00:00:00, RP 10.1.5.1, flags: SP Incoming interface: Serial0, RPF nbr 10.1.4.1, (171.68.37.121, 224.1.1.1), 00:01:56/00:00:53, flags: PT Incoming interface: Serial1, RPF nbr 10.1.9.2 7 A s (S,G) OIL also now empty; triggers (S,G) Prune towards S i. 164
PIM ASM Pruning - IOS Source (SPT) Case To RP (10.1.5.1) 8 To Source S i 10.1.4.2 A 10.1.2.1 E1 B 10.1.2.2 (*, 224.1.1.1), 00:02:32/00:00:00, RP 10.1.5.1, flags: SP Incoming interface: Serial0, RPF nbr 10.1.4.1, (171.68.37.121, 224.1.1.1), 00:01:56/00:00:53, flags: PT Incoming interface: Serial1, RPF nbr 10.1.9.2 8 (S i,g) traffic ceases flowing down SPT. 165
PIM ASM Pruning - IOS Source (SPT) Case To RP (10.1.5.1) To Source S i 10.1.4.2 A 10.1.2.1 E1 B 10.1.2.2 (*, 224.1.1.1), 00:02:32/00:00:00, RP 10.1.5.1, flags: SP Incoming interface: Serial0, RPF nbr 10.1.4.1, (171.68.37.121, (171.68.37.121, 224.1.1.1), 224.1.1.1), 00:01:56/00:00:02, 00:01:56/00:00:01, 00:01:56/00:00:03, flags: flags: PT PT Incoming Incoming interface: interface: Serial1, Serial1, RPF RPF nbr nbr 10.1.9.2 10.1.9.2 Outgoing Outgoing interface interface list: list: Not seeing any traffic, (S i,g) entry times out. 166
PIM ASM Pruning - IOS Source (SPT) Case To RP (10.1.5.1) To Source S i 10.1.4.2 A 10.1.2.1 E1 B 10.1.2.2 (*, 224.1.1.1), 00:02:32/00:02:59, RP 10.1.5.1, flags: SP Incoming interface: Serial0, RPF nbr 10.1.4.1, Now (*,G) starts its timer. 167
PIM ASM Pruning - IOS Source (SPT) Case To RP (10.1.5.1) To Source S i 10.1.4.2 A 10.1.2.1 E1 B 10.1.2.2 (*, 224.1.1.1), 00:03:33/00:00:02, 00:03:32/00:00:04, 00:03:32/00:00:03, 00:03:34/00:00:01, RP 10.1.5.1, flags: SP Incoming interface: Serial0, RPF nbr 10.1.4.1, After about 3 minutes... 168
PIM ASM Pruning - IOS Source (SPT) Case To RP (10.1.5.1) To Source S i 10.1.4.2 A 10.1.2.1 E1 B 10.1.2.2 After about 3 minutes... the (*,G) entry times out. 169
PIM Bidir 170
Bidirectional (BiDir) PIM Idea: Use the same tree for traffic from sources towards RP and from RP to receivers Benefits: Less state in routers Only (*, G) state is used Source traffic follows the Shared Tree Flows up the Shared Tree to reach the RP Flows down the Shared Tree to reach all other receivers 171
PIM Modifications for BiDir Operation All trees rooted at the RP Data traveling from source toward RP is moving UPSTREAM Data traveling from RP toward receivers is moving DOWNSTREAM Designated Forwarders (DF) One DF per link Router with best path to the RP is elected DF BiDir (*,G) forwarding rules: DF is the only router that forwards packets traveling downstream onto the link DF is the only router that picks-up upstream traveling packets off the link to forward towards the RP 172
PIM Bidir Joining RP (DF) E E1 (DF) F E1 (DF) A B C E1 (DF) E1 (DF) E1 (DF) D E1 (DF) (*, 224.1.1.1), 00:00:04/00:00:00, RP 172.16.21.1, flags: BC Bidir-Upstream: Ethernet0, RPF nbr 172.16.9.1 Ethernet0, Bidir-Upstream/Sparse-Dense, 00:00:04/00:00:00 Ethernet1, Forward/Sparse-Dense, 00:00:04/00:02:55 IGMP Join Receiver 1 Receiver 1 Joins Group Causing Router D to Create (*, G) State 173
PIM Bidir Joining RP (DF) E E1 (DF) F E1 (DF) PIM (*,G) Join to DF A B C E1 (DF) E1 (DF) E1 (DF) D E1 (DF) (*, 224.1.1.1), 00:00:49/00:02:41, RP 172.16.21.1, flags: B Bidir-Upstream: Ethernet0, RPF nbr 172.16.1.1 Ethernet0, Bidir-Upstream/Sparse-Dense, 00:00:49/00:00:00 Ethernet1, Forward/Sparse-Dense, 00:00:49/00:02:41 Receiver 1 Router D Sends (*, G) Join to Router F (DF) Causing It to Create (*, G) State 174
PIM Bidir Joining RP (DF) PIM (*,G) Join to DF E E1 (DF) F E1 (DF) A B C E1 (DF) E1 (DF) E1 (DF) D E1 (DF) (*, 224.1.1.1), 00:13:49/00:03:29, RP 172.16.21.1, flags: B Bidir-Upstream: Null, RPF nbr 0.0.0.0 Ethernet0, Forward/Sparse-Dense, 00:13:49/00:02:35 Receiver 1 Router F Sends (*, G) Join to RP Causing It to Create (*, G) State 175
PIM Bidir Joining RP (DF) E E1 (DF) F E1 (DF) A B C E1 (DF) E1 (DF) E1 (DF) D E1 (DF) Receiver 1 Branch of Shared Tree Is Now Built Down to Receiver 1 176
PIM Bidir Joining RP (DF) E E1 (DF) F E1 (DF) A B C E1 (DF) E1 (DF) E1 (DF) D E1 (DF) IGMP Join Receiver 2 Receiver 1 Receiver 2 Also Joins Group 177
PIM Bidir Joining (*, 224.1.1.1), 00:00:04/00:00:00, RP 172.16.21.1, flags: BC Bidir-Upstream: Ethernet0, RPF nbr 172.16.9.1 RP (DF) Ethernet0, Bidir-Upstream/Sparse-Dense, 00:00:04/00:00:00 Ethernet1, Forward/Sparse-Dense, 00:00:04/00:02:55 E E1 (DF) F E1 (DF) A E1 (DF) B E1 (DF) C E1 (DF) D E1 (DF) Receiver 2 Receiver 1 Router B Creates (*, G) State 178
PIM Bidir Joining RP (DF) E E1 (DF) (*, 224.1.1.1), 00:00:49/00:02:41, RP 172.16.21.1, flags: B Bidir-Upstream: Ethernet0, RPF nbr 172.16.1.1 Outgoing Finterface list: PIM (*,G) Join to Ethernet0, DF E1 (DF) Bidir-Upstream/Sparse-Dense, 00:00:49/00:00:00 Ethernet1, Forward/Sparse-Dense, 00:00:49/00:02:41 A B C E1 (DF) E1 (DF) E1 (DF) D E1 (DF) Receiver 2 Receiver 1 Router B Sends (*, G) Join to E (DF) Causing It to Create (*, G) State 179
PIM Bidir Joining PIM (*,G) Join to DF RP (DF) E E1 (DF) (*, 224.1.1.1), 00:13:49/00:03:29, RP 172.16.21.1, flags: B Bidir-Upstream: F Null, RPF nbr 0.0.0.0 Outgoing E1 interface (DF) list: Ethernet0, Forward/Sparse-Dense, 00:13:49/00:02:35 A B C E1 (DF) E1 (DF) E1 (DF) D E1 (DF) Receiver 2 Receiver 1 Router E Sends (*, G) Join to RP (State on RP Remains Unchanged) 180
PIM Bidir Joining RP (DF) E E1 (DF) F E1 (DF) A E1 (DF) B E1 (DF) C E1 (DF) D E1 (DF) Receiver 2 Receiver 1 New Branch of Shared Tree Is Built to Receiver 2 181
PIM Bidir Sending RP (DF) E E1 (DF) F E1 (DF) A E1 (DF) B E1 (DF) C E1 (DF) D E1 (DF) Source Receiver 2 (*, 224.1.1.1), 00:32:20/00:02:59, RP 172.16.21.1, flags: BP Bidir-Upstream: Ethernet0, RPF nbr 172.16.7.1 Receiver 1 Ethernet0, Bidir-Upstream/Sparse-Dense, 00:32:20/00:00:00 Arriving Traffic from Source Causes Router A to Create (*, G) State 182
PIM Bidir Sending RP (DF) E E1 (DF) F E1 (DF) A E1 (DF) B E1 (DF) C E1 (DF) D E1 (DF) Source Receiver 2 Receiver 1 Traffic Is Forwarded Toward Router E and Also Arrives at IIF of Router B 183
PIM Bidir Sending E E1 (DF) RP (*, 224.1.1.1), 00:00:04/00:00:00, RP 172.16.21.1, flags: BC (DF) Bidir-Upstream: Ethernet0, RPF nbr 172.16.9.1 Ethernet0, Bidir-Upstream/Sparse-Dense, 00:00:04/00:00:00 Ethernet1, Forward/Sparse-Dense, 00:00:04/00:02:55 F E1 (DF) A E1 (DF) B E1 (DF) C E1 (DF) D E1 (DF) Source Receiver 2 Receiver 1 Router B Forwards Traffic Back Down Shared Tree ala Normal PIM-SM 184
PIM Bidir Sending RP (DF) E E1 (DF) F E1 (DF) A E1 (DF) B E1 (DF) C E1 (DF) D E1 (DF) Source Receiver 2 (*, 224.1.1.1), 00:32:20/00:02:59, RP 172.16.21.1, flags: BP Bidir-Upstream: Ethernet0, RPF nbr 172.16.7.1 Receiver 1 Ethernet0, Bidir-Upstream/Sparse-Dense, 00:32:20/00:00:00 Ethernet1, Forward/Sparse-Dense, 00:00:04/00:02:55 Router E Forwards Traffic on Toward RP 185
PIM Bidir Sending RP (DF) E E1 (DF) F E1 (DF) A E1 (DF) B E1 (DF) C E1 (DF) D E1 (DF) Source Receiver 2 Receiver 1 Traffic Forwarded Toward RP also flows down existing branch to Rcvr 1 186
PIM Bidir Sending RP (DF) E E1 (DF) F E1 (DF) A E1 (DF) B E1 (DF) C E1 (DF) D E1 (DF) Source Receiver 2 Receiver 1 Question: Does the RP even have to physically exist? 187
PIM Bidir RP RP (DF) E E1 (DF) F E1 (DF) A E1 (DF) B E1 (DF) C E1 (DF) D E1 (DF) Source Receiver 2 Receiver 1 Question: Does the RP even have to physically exist? Answer: No. It can just be a phantom address. 188
Recap: Common Multicast Flags - IOS S: s: B: F: P: J: T: Sparse Mode (in contrast to D for Dense Mode) SSM; only seen on (S,G) entries Bidir Register; set on First-Hop router Prune; entry has an empty OIL Join-SPT; (*,G) traffic exceeds SPT Threshold SPT; set on (S,G) entries after first (S,G) packet seen. Not applicable to SSM. L: Local; router should receive and process this traffic C: I: Connected; the router has a directly connected receiver. Router Received Source Specific Host Report (SSM) For Your Reference 189
For Your Reference New PIM Model 190
PIM Old Model IOS IPv4 For Your Reference (Simplified) show ip mroute show ip mroute count show ip igmp groups show ip msdp sa-cache STP IGMP PIM MSDP Route Processor L2 Forwarding Table Mroute Table SA Cache URIB L2 Forwarding IP FIB Various hardware dependent show commands. Hardware Drivers FIB TCAM ADJ Table MAC Table MET Other HW I/O Module 191
PIM New Model IOS-XR example For Your Reference show pim group-map show pim topology [sh ip mroute] show igmp groups show igmp snooping <xxx> show msdp sa-cache STP IGMP MSDP PIM Supervisor Engine PIM Topology show mrib route [sh ip mroute] MRIB URIB show mfib route show mfib connections show mfib counter [sh ip mroute] L2FIB MFIB Hardware Dependent show mfib hardware route olist loc <> show mfib hardware connection loc <> show mfib hardware ltrace loc <> show mfib hardware interface loc <> L2FIB MFIB PI MFIB PD Line Card show controller np counters all show controller np struct <id> all show controller np summary all NETIO NP PRM/uIDB MGID Server Fabric 192
PIM New Model NX-OS example For Your Reference show ip pim topology [sh ip mroute] show ip pim route [sh ip mroute] show ip igmp route show ip igmp snooping groups show ip msdp route STP IGMP MSDP PIM Supervisor Engine PIM Topology show routing ip multicast [sh ip mroute] MRIB URIB show forwarding distribution ip multicast route show forwarding distribution ip igmp snooping MFDM PIXM Hardware Dependent show forwarding ip multicast route IP FIB L2MCAST PIXMC Hardware Drivers show system internal forwarding ip multicast route show system internal ip igmp snooping FIB TCAM ADJ Table MAC Table MET Other HW I/O Module 193
PIM Topology Table Example XR For Your Reference RP/0/5/CPU0:rtr#sh pim topology 225.1.1.1 Fri Sep 16 12:49:18.533 CEST IP PIM Multicast Topology Table Entry state: (*/S,G)[RPT/SPT] Protocol Uptime Info Entry flags: KAT - Keep Alive Timer, AA - Assume Alive, PA - Probe Alive RA - Really Alive, IA - Inherit Alive, LH - Last Hop DSS - Don't Signal Sources, RR - Register Received SR - Sending Registers, E - MSDP External, EX - Extranet DCC - Don't Check Connected, ME - MDT Encap, MD - MDT Decap MT - Crossed Data MDT threshold, MA - Data MDT group assigned Interface state: Name, Uptime, Fwd, Info Interface flags: LI - Local Interest, LD - Local Dissinterest, II - Internal Interest, ID - Internal Dissinterest, LH - Last Hop, AS - Assert, AB - Admin Boundary, EX Extranet (*,225.1.1.1) SM Up: 5w2d RP: 192.168.0.3* JP: Join(never) RPF: Decapstunnel1,192.168.0.3 Flags: GigabitEthernet0/0/0/0 5w2d fwd Join(00:03:20) (192.168.1.18,225.1.1.1)RPT SM Up: 00:00:09 RP: 192.168.0.3* JP: Prune(never) RPF: Decapstunnel1,192.168.0.3 Flags: KAT(00:03:21) RA DCC RR (00:04:22) GigabitEthernet0/0/0/0 00:00:09 off Prune(00:03:20) (192.168.1.18,225.1.1.1) SM Up: 00:07:51 JP: Null(never) RPF: GigabitEthernet0/0/0/1,192.168.1.5 Flags: KAT(00:03:21) RA DCC RR (00:04:22) No interfaces in immediate olist 194
PIM Topology Table Entry Flags/Timers For Your Reference Entry Flags Flag/Timer Name Description KAT() Keep-Alive Timer Countdown timer. If goes to zero, entry is removed. Join() Join Timer Countdown timer. Time until a PIM Join is sent upstream. Prune() Prune Timer Countdown timer. Time until a PIM Prune is sent upstream. AA Assume Alive Only set after the route has been alive once. PA Probe Alive Check to see if any traffic is flowing for this route. RA Really Alive PIM sets this flag when it has been signaled that the route has seen traffic. IA Inherit Alive Inherit Alive Interfaces from Parent route LH Last Hop Last Hop Router. A directly connected host has joined via IGMP/MLD on one of the Entry's Interfaces. DSS Don't Signal Sources PIM doesn't want to be signaled when MFIB hears new sources on Shared Tree. RR Register Received PIM Register Messages are being Received SR Sending Registers PIM Register Messages are being Sent E MSDP External (S,G) learned from MSDP Peer DCC Don't Check Connected Don't check for directly connected Sources Interface Flags Flag/Timer Name Description Join() Join Timer Countdown timer. Time until Interface Join Times Out Prune() Prune Timer Countdown timer. Time until Interface Prune Times Out LI Local Interest Received IGMP/MLD report/join for group ("C" flag in IOS) LD Local Disinterest Received IGMP/MLD exclude (S,G) II Internal Interest Router CPU IGMP/MLD include join ("L" flag in IOS) ID Internal Disinterest Router CPU IGMP/MLD exclude (S,G) LH Last Hop Last Hop Router. A directly connected host has joined via IGMP/MLD on this Interface. AS Assert A PIM Assert has been seen on this Interface AB Admin Boundary Interface would be in olist but it is blocked by Admin Boundary. 195
PIM MRIB State Example XR For Your Reference RP/0/5/CPU0:rtr#show mrib route IP Multicast Routing Information Base Entry flags: L - Domain-Local Source, E - External Source to the Domain, C - Directly-Connected Check, S - Signal, IA - Inherit Accept, IF - Inherit From, D - Drop, MA - MDT Address, ME - MDT Encap, MD - MDT Decap, MT - MDT Threshold Crossed, MH - MDT interface handle CD - Conditional Decap, MPLS - MPLS Decap, MF - MPLS Encap, EX - Extranet Interface flags: F - Forward, A - Accept, IC - Internal Copy, NS - Negate Signal, DP - Don't Preserve, SP - Signal Present, II - Internal Interest, ID - Internal Disinterest, LI - Local Interest, LD - Local Disinterest, DI - Decapsulation Interface EI - Encapsulation Interface, MI - MDT Interface, LVIF - MPLS Encap, EX - Extranet (*,225.0.0.0) RPF nbr: 0.0.0.0 Flags: C Up: 00:02:13 Outgoing Interface List GigabitEthernet0/2/1/0.102 Flags: F NS, Up: 00:02:13 (192.2.1.2,225.0.0.0) RPF nbr: 192.2.1.2 Flags: Up: 00:00:07 Incoming Interface List GigabitEthernet0/2/1/1 Flags: A, Up: 00:00:07 Outgoing Interface List GigabitEthernet0/2/1/0.102 Flags: F NS, Up: 00:00:07 196
MRIB Entry Flags Entry Flags Flag/Timers Name Description UP Entry Up Timer Time Entry has existed C Directly-Connected Check Perform check on incoming packets applicable to this Entry. S Signal Signal PIM. IA Inherit Alive Inherit Alive Interfaces from Parent route IF Inherit From D Drop MA MDT Address MVPN MDT Tunnel Address (Multicast Address) ME MDT Encapsulate Encapsulate in MDT Tunnel MD MDT Decapsulate Decapsulate from MDT Tunnel MT Crossed Data MDT Threshold (S,G) traffic has crossed Data MDT Threshold. MH MDT interface handle Interface used for MVPN MDT Tunnel Interface Flags Flag/Timers Name Description UP Interface Up Timer Time Interface has existed in Outgoing Interface List F Forward Forward multicast packets on this interface A Accept Accept multicast packets on this interface IC Internal Copy NS Negate Signal Invert Signal status of Entry for this interface. (Often means "Signal".) DP Don't Preserve SP Signal Present MFIB is Signaling PIM. Typically for packet arriving on interface. II Internal Interest Router CPU IGMP/MLD include join ("L" flag in IOS) ID Internal Disinterest Router CPU IGMP/MLD exclude (S,G) LI Local Interest Received IGMP/MLD report/join for group ("C" flag in IOS) LD Local Disinterest Received IGMP/MLD exclude (S,G) DI Decapsulation Interface PIM Registers received on this interface. (Typically the DecapTunnel.) EI Encapsulation Interface PIM Registers sent on this interface. (Typically the EncapTunnel.) For Your Reference 197
More Information White Papers Web and Mailers Cisco Press RTFB = Read the Fine Book 198
Multicast Bedtime Stories 199