Connecting to the IP
Multicast World
David Mitchell
NCNE, NLANR, NCAR, and the
Pittsburgh Supercomputing
Center
ncne@ncne.org
2215
1195_05_2000_c2
© 2000, Cisco Systems, Inc.
1
Agenda
•
•
•
•
•
•
What Is Multicast
Multicast Protocols
Multicast Configurations
Troubleshooting
Futures
Useful Links
2
What Is Multicast
• Unicast is one to one
– traffic is sent from a single source to a single
destination
• Multicast is one to many
– traffic is sent from a single source to a “group”
address
3
Unicast vs. Multicast
Unicast
Server
Router
Multicast
Server
Router
4
Why Multicast
• More efficient method of sending the same
data to lots of hosts
– Distributing a video stream to multiple viewers
• Allows unique distributed protocols
– clients can announce services or perform queries
in a distributed fashion ala Appletalk’s “Chooser”
5
Multicast Disadvantages
Multicast Is UDP Based!!!
• Best Effort Delivery: Drops are to be expected.
Multicast applications should not
expect reliable delivery of data and should be designed accordingly. Reliable Multicast is
still an area for much research. Expect to see more developments in this area.
• No Congestion Avoidance: Lack of TCP windowing and “slow-start” mechanisms
can result in network congestion. If possible, Multicast applications should attempt to
detect and avoid congestion conditions.
• Duplicates: Some multicast protocol mechanisms (e.g. Asserts, Registers and SPT
Transitions) result in the occasional generation of duplicate packets. Multicast
applications should be designed to expect occasional duplicate packets.
• Out of Order Delivery : Some protocol mechanisms may also result in out of order
delivery of packets.
6
Agenda
• What Is Multicast
• Multicast Protocols
• Multicast Configurations
• Troubleshooting
• Futures
• Useful Links
7
Multicast Protocols
• Multicast Addressing Basics
• IGMP
• PIM
• MSDP
• MBGP
8
Multicast Addressing
• IP Multicast Group Addresses
– 224.0.0.0–239.255.255.255
– Class “D” Address Space
• High order bits of 1st Octet = “1110”
• Reserved Link-local Addresses
– 224.0.0.0–224.0.0.255
– Transmitted with TTL = 1
– Examples:
•
•
•
•
•
224.0.0.1
224.0.0.2
224.0.0.4
224.0.0.5
224.0.0.13
All systems on this subnet
All routers on this subnet
DVMRP routers
OSPF routers
PIMv2 Routers
9
Multicast Addressing
• Administratively Scoped Addresses
– 239.0.0.0–239.255.255.255
– Private address space
• Similar to RFC1918 unicast addresses
• Not used for global Internet traffic
• Used to limit “scope” of multicast traffic
• Same addresses may be in use at different locations for different
multicast sessions
– Examples
• Site-local scope: 239.253.0.0/16
• Organization-local scope: 239.192.0.0/14
10
Multicast Addressing
IP Multicast MAC Address Mapping
(FDDI and Ethernet)
32 Bits
28 Bits
1110
239.255.0.1
5 Bits
Lost
01-00-5e-7f-00-01
25 Bits
23 Bits
48 Bits
11
Multicast Addressing
IP Multicast MAC Address Mapping
(FDDI & Ethernet)
Be Aware of the 32:1 Address Overlap
32 - IP Multicast Addresses
224.1.1.1
224.129.1.1
225.1.1.1
225.129.1.1
.
.
.
238.1.1.1
238.129.1.1
239.1.1.1
239.129.1.1
1 - Multicast MAC Address
(FDDI and Ethernet)
0x0100.5E01.0101
12
Multicast Addressing
• Dynamic Group Address Assignment
– Historically accomplished using SDR application
• Sessions/groups announced over well-known multicast groups
• Address collisions detected and resolved at session creation
time
• Has problems scaling
– Future dynamic techniques under consideration
• Multicast Address Set-Claim (MASC)
– Hierarchical, dynamic address allocation scheme
– Extremely complex garbage-collection problem.
– Long ways off
• MADCAP
– Similar to DHCP
– Need application and host stack support
13
Multicast Addressing
• Static Group Address Assignment (new)
– Temporary method to meet immediate needs
– Group range: 233.0.0.0 - 233.255.255.255
• Your AS number is inserted in middle two octets
• Remaining low-order octet used for group assignment
– Defined in IETF draft
• “draft-ietf-mboned-glop-addressing-00.txt”
14
Multicast Protocols
• Multicast Addressing Basics
• IGMP
• PIM
• MSDP
• MBGP
15
Host-Router Signaling: IGMP
• How hosts tell routers about group membership
• Routers solicit group membership from directly
connected hosts
• RFC 1112 specifies version 1 of IGMP
Supported on Windows 95
• RFC 2236 specifies version 2 of IGMP
Supported on latest service pack for Windows and most UNIX systems
• IGMP version 3 is specified in IETF draft
draft-ietf-idmr-igmp-v3-03.txt
16
Host-Router Signaling: IGMP
Joining a Group
H1
H2
224.1.1.1
H3
Report
• Host sends IGMP Report to join group
17
Host-Router Signaling: IGMP
Maintaining a Group
224.1.1.1
H1
224.1.1.1
X
Suppressed
H2
224.1.1.1
H3
X
Report
Suppressed
Query
• Router sends periodic Queries to 224.0.0.1
• One member per group per subnet reports
• Other members suppress reports
18
Host-Router Signaling: IGMP
Leaving a Group (IGMPv1)
H1
H2
H3
#1
General Query
#2
•
•
•
•
Host quietly leaves group
Router sends 3 General Queries (60 secs apart)
No IGMP Report for the group is received
Group times out (Worst case delay ~= 3 minutes)
19
Host-Router Signaling: IGMP
Leaving a Group (IGMPv2)
H1
H2
224.1.1.1
H3
Leave to
#1 224.0.0.2
Group Specific
Query to 224.1.1.1
#2
•
•
•
•
Host sends Leave message to 224.0.02
Router sends Group specific query to 224.1.1.1
No IGMP Report is received within ~3 seconds
Group 224.1.1.1 times out
20
IGMPv3
• draft-ietf-idmr-igmp-v3-??.txt
• Early implementations now in beta
– Enables hosts to listen only to a specified
subset of the hosts sending to the group
21
IGMPv3
Source = 1.1.1.1
Group = 224.1.1.1
Source = 2.2.2.2
Group = 224.1.1.1
R2
R1
• H1 wants to receive
from S = 1.1.1.1 but
not from S = 2.2.2.2
• With IGMP, specific
sources can be
pruned back - S =
2.2.2.2 in this case
R3
IGMPv3:
Join 1.1.1.1, 224.1.1.1
Leave 2.2.2.2, 224.1.1.1
H1 - Member of 224.1.1.1
22
Multicast Protocols
• Multicast Addressing Basics
• IGMP
• PIM
• MSDP
• MBGP
23
PIM
• Distribution Trees
• Neighbor Discovery
• PIM-DM
• PIM-SM
24
Multicast Distribution Trees
Shortest Path or Source Distribution Tree
Source 1
Notation: (S, G)
S = Source
G = Group
Source 2
A
B
F
D
C
E
Receiver 1
Receiver 2
25
Multicast Distribution Trees
Shortest Path or Source Distribution Tree
Source 1
Notation: (S, G)
S = Source
G = Group
Source 2
A
B
F
D
C
E
Receiver 1
Receiver 2
26
Multicast Distribution Trees
Shared Distribution Tree
Notation: (*, G)
* = All Sources
G = Group
A
B
C
D (RP)
E
F
(RP)
PIM Rendezvous Point
Shared Tree
Receiver 1
Receiver 2
27
Multicast Distribution Trees
Shared Distribution Tree
Source 1
Notation: (*, G)
* = All Sources
G = Group
Source 2
A
B
C
D (RP)
E
F
(RP)
PIM Rendezvous Point
Shared Tree
Source Tree
Receiver 1
Receiver 2
28
Multicast Distribution Trees
Characteristics of Distribution Trees
• Source or Shortest Path trees
Uses more memory O(S x G) but you get optimal paths from source
to all receivers; minimizes delay
• Shared trees
Uses less memory O(G) but you may get sub-optimal paths from
source to all receivers; may introduce extra delay
29
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)
– Note: PIMv1 multicasts PIM Query messages to the “All-Routers” (224.0.0.2) group
address.
• 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.
30
PIM Neighbor Discovery
wan-gw8>show ip pim neighbor
PIM Neighbor Table
Neighbor Address Interface
171.68.0.70
FastEthernet0
171.68.0.91
FastEthernet0
171.68.0.82
FastEthernet0
171.68.0.86
FastEthernet0
171.68.0.80
FastEthernet0
171.68.28.70
Serial2.31
171.68.28.50
Serial2.33
171.68.27.74
Serial2.36
171.68.28.170
Serial0.70
171.68.27.2
Serial1.51
171.68.28.110
Serial3.56
171.68.28.58
Serial3.102
Uptime
2w1d
2w6d
7w0d
7w0d
7w0d
22:47:11
22:47:22
22:47:07
1d04h
1w4d
1d04h
12:53:25
Expires
00:01:24
00:01:01
00:01:14
00:01:13
00:01:02
00:01:16
00:01:08
00:01:21
00:01:06
00:01:25
00:01:20
00:01:03
Mode
Dense
Dense (DR)
Dense
Dense
Dense
Dense
Dense
Dense
Dense
Dense
Dense
Dense
31
PIM-DM — Evaluation
• Most effective for small pilot networks
• Advantages:
– Easy to configure—two commands
– Simple flood and prune mechanism
• Potential issues...
– Inefficient flood and prune behavior
– Complex Assert mechanism
– Mixed control and data planes
• Results in (S, G) state in every router in the network
• Can result in non-deterministic topological behaviors
– No support for shared trees
32
PIM-SM Overview
• Explicit join model
–Receivers join to the Rendezvous Point (RP)
–Senders register with the RP
–Data flows down the shared tree and goes only to
places that need the data from the sources
–Last hop routers can join source tree if the data
rate warrants by sending joins to the source
• RPF check depends on tree type
–For shared trees, uses RP address
–For source trees, uses Source address
33
PIM-SM Overview
• Only one RP is chosen for a particular group
• RP statically configured or dynamically learned
(Auto-RP, PIM v2 candidate RP advertisements)
• Data forwarded based on the source state (S, G)
if it exists, otherwise use the shared state (*, G)
• RFC 2326 - “PIM Sparse Mode Protocol Spec”
34
PIM-SM Shared Tree Join
RP
(*, G) State created only
along the Shared Tree.
(*, G) Join
Shared Tree
Receiver
35
PIM-SM Sender Registration
RP
Source
(S, G) State created only
along the Source Tree.
Traffic Flow
Shared Tree
Source Tree
(S, G) Register
(unicast)
Receiver
(S, G) Join
36
PIM-SM Sender Registration
RP
Source
(S, G) traffic begins arriving
at the RP via the Source tree.
Traffic Flow
Shared Tree
Source Tree
(S, G) Register
(S, G) Register-Stop
(unicast)
Receiver
RP sends a Register-Stop
back to the first-hop router
to stop the Register process.
(unicast)
37
PIM-SM Sender Registration
RP
Source
Traffic Flow
Source traffic flows natively
along SPT to RP.
Shared Tree
Source Tree
From RP, traffic flows down
the Shared Tree to Receivers.
Receiver
38
PIM-SM SPT Switchover
RP
Source
Last-hop router joins the Source
Tree.
Traffic Flow
Shared Tree
Source Tree
(S, G) Join
Additional (S, G) State is created
along new part of the Source Tree.
Receiver
39
PIM-SM SPT Switchover
RP
Source
Traffic Flow
Shared Tree
Source Tree
(S, G)RP-bit Prune
Traffic begins flowing down the
new branch of the Source Tree.
Receiver
Additional (S, G) State is created
along along the Shared Tree to
prune off (S, G) traffic.
40
PIM-SM SPT Switchover
RP
Source
(S, G) Traffic flow is now
pruned off of the Shared Tree
and is flowing to the Receiver
via the Source Tree.
Traffic Flow
Shared Tree
Source Tree
Receiver
41
PIM-SM SPT Switchover
RP
Source
(S, G) traffic flow is no longer
needed by the RP so it Prunes
the flow of (S, G) traffic.
Traffic Flow
Shared Tree
Source Tree
(S, G) Prune
Receiver
42
PIM-SM SPT Switchover
RP
Source
(S, G) Traffic flow is now only
flowing to the Receiver via a
single branch of the Source
Tree.
Traffic Flow
Shared Tree
Source Tree
Receiver
43
PIM-SM Protocol Mechanics
•
•
•
•
•
•
PIM SM State
PIM SM Forwarding
PIM SM Joining
PIM SM Registering
PIM SM SPT-Switchover
PIM SM Pruning
44
PIM-SM State Example
sj-mbone> show ip mroute
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, 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 - Advertised via MSDP
Timers: Uptime/Expires
Interface state: Interface, Next-Hop or VCD, State/Mode
(*, 224.1.1.1), 00:13:28/00:02:59, RP 10.1.5.1, flags: SCJ
Incoming interface: Ethernet0, RPF nbr 10.1.2.1,
Outgoing interface list:
Ethernet1, Forward/Sparse, 00:13:28/00:02:32
Serial0, Forward/Sparse, 00:4:52/00:02:08
(171.68.37.121/32, 224.1.1.1),
Incoming interface: Serial0,
Outgoing interface list:
Ethernet1, Forward/Sparse,
Ethernet0, forward/Sparse,
00:01:43/00:02:59, flags: CJT
RPF nbr 192.10.2.1
00:01:43/00:02:11
00:01:43/00:02:11
45
PIM-SM (*,G) State Rules
• (*,G) creation
– Upon receipt of a (*,G) Join or
– Automatically if (S,G) must be created
• (*,G) reflects default group forwarding
– IIF = RPF interface toward RP
– OIL = interfaces
• that received a (*,G) Join or
• with directly connected hosts or
• manually configured
• (*,G) deletion
– When OIL = NULL and
– no child (S,G) state exists
46
PIM-SM (S,G) State Rules
• (S,G) creation
– By receipt of (S,G) Join or Prune or
– By “Register” process
– Parent (*,G) created (if doesn’t exist)
• (S,G) reflects forwarding of “S” to “G”
– IIF = RPF Interface normally toward source
• RPF toward RP if “RP-bit” set
– OIL = Initially, copy of (*,G) OIL minus IIF
• (S,G) deletion
– By normal (S,G) entry timeout
47
PIM-SM OIL Rules
• Interfaces in OIL added
– By receipt of Join message
• Intfc’s added to (*,G) are added to all (S,G)’s
• Interfaces in OIL removed
– By receipt of Prune message
• Intfc’s removed from (*,G) are removed from all (S,G)’s
– Interface Expire timer counts down to zero
• Timer reset (to 3 min.) by receipt of periodic Join or
• By IGMP membership report
48
PIM-SM State Flags
• S = Sparse Mode
• C = Directly Connected Host
• L = Local (Router is member)
• P = Pruned (All intfcs in OIL = Prune)
• T = Forwarding via SPT
– Indicates at least one packet was forwarded
49
PIM-SM State Flags (Cont.)
• J = Join SPT
– 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
– In (S,G) entry
•Indicates the router is a first-hop router and there is a
directly connected source or proxy registers are being sent.
– In (*, G) entry
•Set when “F” set in at least one child (S,G)
50
PIM-SM State Flags (Cont.)
• R = RP bit
– (S, G) entries only
– Set by (S,G)RP-bit Prune/Join
– 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
51
PIM-SM Protocol Mechanics
•
•
•
•
•
•
PIM SM State
PIM SM Forwarding
PIM SM Joining
PIM SM Registering
PIM SM SPT-Switchover
PIM SM Pruning
52
PIM-SM Forwarding Rules
• Use longest match entry
– Use (S, G) entry if exists
– Otherwise, use (*, G) entry
• RPF check first
– If Packet didn’t arrive via IIF, drop it.
• Forward Packet (if RPF succeeded)
– Send out all “unpruned” interfaces in OIL
53
PIM SM Forwarding
to RP
(10.1.5.1) S0
Shared Tree
Multicast Packets
(128.9.160.1, 224.1.1.1)
S1
E0
Source Tree (SPT)
Multicast Packets
(128.9.160.43, 224.1.1.1)
rtr-a
E0
E1
Rcvr A
(*, 224.1.1.1)
• Packets are “forwarded” out all interfaces in “oilist”.
• PIM Sparse mode interfaces are placed on the “oilist”
for a Multicast Group IF:
– PIM neighbor Joins the group on this interface
– Host on this interface has joined the group
– Interface has been manually configured to join group.
54
PIM-SM Protocol Mechanics
•
•
•
•
•
•
PIM SM State
PIM SM Forwarding
PIM SM Joining
PIM SM Registering
PIM SM SPT-Switchover
PIM SM Pruning
55
PIM SM Joining
• Leaf routers send a (*,G) Join to toward RP
– Joins sent hop-by-hop via unicast path toward RP
• Each router along path creates (*,G) state
– IF no (*,G) state, create it & send a Join toward RP
– ELSE Join process complete. Reached the (*,G)
tree.
56
PIM SM Joining
S1
To RP (10.1.5.1)
rtr-a
S0
10.1.4.2
E0
10.1.2.1
Shared Tree
10.1.2.2
1 IGMP Join
E1
E0
rtr-b
Rcvr A
1•
“Rcvr A” wishes to receive group G traffic. Sends IGMP Join for G.
57
PIM SM Joining
S1
To RP (10.1.5.1)
rtr-a
S0
10.1.4.2
E0
10.1.2.1
Shared Tree
10.1.2.2
E1
E0
rtr-b
Rcvr A
(*, 224.1.1.1), 00:00:05/00:02:54, RP 10.1.5.1, flags: SC
Incoming interface: Ethernet0, RPF nbr 10.1.2.1
Outgoing interface list:
Ethernet1, Forward/Sparse, 00:00:05/00:02:54
“rtr-b” creates (*, 224.1.1.1) state
58
PIM SM Joining
S1
To RP (10.1.5.1)
rtr-a
S0
10.1.4.2
E0
10.1.2.1
Shared Tree
10.1.2.2
E0
E1
2 PIM Join
rtr-b
Rcvr A
1•
“Rcvr A” wishes to receive group G traffic. Sends IGMP Join for G.
2•
“rtr-b” sends (*,G) Join towards RP.
59
PIM SM Joining
S1
To RP (10.1.5.1)
rtr-a
S0
10.1.4.2
E0
10.1.2.1
Shared Tree
10.1.2.2
E1
E0
rtr-b
Rcvr A
(*, 224.1.1.1), 00:00:05/00:02:54, RP 10.1.5.1, flags: S
Incoming interface: Serial0, RPF nbr 10.1.4.1
Outgoing interface list:
Ethernet0, Forward/Sparse, 00:00:05/00:02:54
“rtr-a” creates (*, 224.1.1.1) state.
60
PIM SM Joining
4 Shared Tree
S1
To RP (10.1.5.1)
3 PIM Join
rtr-a
S0
10.1.4.2
E0
10.1.2.1
Shared Tree
10.1.2.2
E0
E1
rtr-b
Rcvr A
1•
“Rcvr A” wishes to receive group G traffic. Sends IGMP Join for G.
2•
“rtr-b” sends (*,G) Join towards RP.
3•
“rtr-a” sends (*,G) Join towards RP.
4•
Shared tree is built all the way back to the RP.
61
PIM-SM Protocol Mechanics
•
•
•
•
•
•
PIM SM State
PIM SM Forwarding
PIM SM Joining
PIM SM Registering
PIM SM SPT-Switchover
PIM SM Pruning
62
PIM SM Registering
• Senders begin sourcing Multicast Traffic
– Senders don’t necessarily perform IGMP group joins.
• 1st-hop router unicasts “Registers” to RP
– A Mcast packet is encapsulated in each Register msg
– Registers messages follow unicast path to RP
• RP receives “Register” messages
– De-encapsulates the Mcast packet inside Register msg
– Forwards Mcast packet down Shared Tree
– Sends (S,G) Join toward Source / 1st-Hop router
to build an (S,G) SPT between Source and RP
63
PIM SM Registering
• 1st-hop router receives (S,G) Join
– SPT between Source and RP now built.
– Begins forwarding traffic down (S,G) SPT to RP
– (S,G) Traffic temporarily flowing down 2 paths to RP
• RP receives traffic down native (S,G) SPT
– Sends a “Register-Stop” msg to Source / 1st-Hop router.
• 1st-Hop router receives “Register-Stop” msg
– Stops encapsulating traffic in “Register” messages
– (S,G) Traffic now flowing down single SPT to RP
64
PIM SM Register Examples
• Receivers Join Group First
• Source Registers First
65
PIM SM Registering
Receiver Joins Group First
RP
E0
rtr-a
S0
S0
S1
rtr-b
S3
S0
S1
rtr-c
Shared Tree
(*, 224.1.1.1), 00:00:03/00:02:56, RP 171.68.28.140, flags:S
Incoming interface: Null, RPF nbr 0.0.0.0,
Outgoing interface list:
Serial0, Forward/Sparse, 00:03:14/00:02:59
Serial1, Forward/Sparse, 00:03:14/00:02:59
State in “RP” before any source registers
(with receivers on Shared Tree)
66
PIM SM Registering
Receiver Joins Group First
RP
E0
S0
rtr-a
S0
S1
rtr-b
S3
S0
S1
rtr-c
Shared Tree
rtr-b>sh ip mroute 224.1.1.1
No such group
State in “rtr-b” before any source registers
(with receivers on Shared Tree)
67
PIM SM Registering
Receiver Joins Group First
RP
E0
S0
rtr-a
S0
S1
rtr-b
S3
S0
S1
rtr-c
Shared Tree
rtr-a>sh ip mroute 224.1.1.1
No such group.
State in “rtr-a” before any source registers
(with receivers on Shared Tree)
68
PIM SM Registering
Receiver Joins Group First
(171.68.37.121, 224.1.1.1)
Mcast Packets
RP
1
Source
171.68.37.121
E0
rtr-a
S0
S0
S1
rtr-b
S3
S0
S1
rtr-c
Shared Tree
1•
“Source” begins sending group G traffic.
69
PIM SM Registering
Receiver Joins Group First
2
(171.68.37.121, 224.1.1.1)
Mcast Packets
Register Msgs
RP
Source
171.68.37.121
E0
rtr-a
S0
S0
S1
S3
rtr-b
S0
S1
rtr-c
Shared Tree
(*, 224.1.1.1), 00:00:03/00:02:56, RP 171.68.28.140, flags: SP
Incoming interface: Serial0, RPF nbr 171.68.28.191,
Outgoing interface list: Null
(171.68.37.121/32, 224.1.1.1), 00:00:03/00:02:56, flags: FPT
Incoming interface: Ethernet0, RPF nbr 0.0.0.0, Registering
Outgoing interface list: Null
“rtr-a” creates (S, G) state for source
(After automatically creating a (*, G) entry)
1•
“Source” begins sending group G traffic.
2• “rtr-a” encapsulates packets in Registers; unicasts to RP.
70
PIM SM Registering
Receiver Joins Group First
(171.68.37.121, 224.1.1.1)
Mcast Packets
Source
171.68.37.121
E0
rtr-a
Register Msgs
171.68.28.139
S0
S0
S1
rtr-b
RP
S3
S0
S1
rtr-c
3 (*, 224.1.1.1)
Shared Tree
(*, 224.1.1.1), 00:09:21/00:02:38, RP 171.68.28.140, flags: S
Incoming interface: Null, RPF nbr 0.0.0.0,
Outgoing interface list:
Serial0, Forward/Sparse, 00:09:21/00:02:38
Serial1, Forward/Sparse, 00:03:14/00:02:46
Mcast Traffic
(171.68.37.121, 224.1.1.1, 00:01:15/00:02:46, flags:
Incoming interface: Serial3, RPF nbr 171.68.28.139,
Outgoing interface list:
Serial0, Forward/Sparse, 00:00:49/00:02:11
Serial1, Forward/Sparse, 00:00:49/00:02:11
“RP” processes Register; creates (S, G) state
3•
“rtr-c” (RP) de-encapsulates packets; forwards down Shared tree.
71
PIM SM Registering
Receiver Joins Group First
(171.68.37.121, 224.1.1.1)
Mcast Packets
Register Msgs
4
Join S0
Source
171.68.37.121
E0
rtr-a
S0
S0
RP
S1
rtr-b
S0
S1
rtr-c
(*, 224.1.1.1)
Mcast Traffic
Shared Tree
4•
RP sends (S,G) Join toward Source to build SPT.
72
PIM SM Registering
Receiver Joins Group First
(171.68.37.121, 224.1.1.1)
Mcast Packets
Register Msgs
5
Join S0
Source
171.68.37.121
E0
S0
rtr-a
RP
S0
S1
S0
rtr-b
S1
rtr-c
(*, 224.1.1.1)
Mcast Traffic
171.68.28.190
Shared Tree
(*, 224.1.1.1), 00:04:28/00:01:32, RP 171.68.28.140, flags: SP
Incoming interface: Serial1, RPF nbr 171.68.28.140,
Outgoing interface list: Null
(171.68.37.121/32, 224.1.1.1), 00:04:28/00:01:32, flags:
Incoming interface: Serial0, RPF nbr 171.68.28.190
Outgoing interface list:
Serial1, Forward/Sparse, 00:04:28/00:01:32
“rtr-b” processes Join, creates (S, G) state
(After automatically creating the (*, G) entry)
4•
5•
RP sends (S,G) Join toward Source to build SPT.
“rtr-b” sends (S,G) Join toward Source to continue building SPT.
73
PIM SM Registering
Receiver Joins Group First
(171.68.37.121, 224.1.1.1)
Mcast Packets
Register Msgs
RP
Source
171.68.37.121
E0
rtr-a
S0
S0
S1
rtr-b
S0
S1
rtr-c
(*, 224.1.1.1)
Mcast Traffic
Shared Tree
(*, 224.1.1.1), 00:04:28/00:01:32, RP 171.68.28.140, flags: SP
Incoming interface: Serial0, RPF nbr 171.68.28.191,
Outgoing interface list: Null
(171.68.37.121/32, 224.1.1.1), 00:04:28/00:01:32, flags: FT
Incoming interface: Ethernet0, RPF nbr 0.0.0.0, Registering
Outgoing interface list:
Serial0, Forward/Sparse, 00:04:28/00:01:32
“rtr-a” processes the (S, G) Join; adds Serial0 to OIL
74
PIM SM Registering
Receiver Joins Group First
(171.68.37.121, 224.1.1.1)
Mcast Packets
Register Msgs
6
Source
171.68.37.121
E0
rtr-a
S0
RP
S0
S1
rtr-b
7 Register-Stop
6•
RP begins receiving (S,G) traffic down SPT.
7•
RP sends “Register-Stop” to “rtr-a”.
S0
S1
rtr-c
(*, 224.1.1.1)
Mcast Traffic
Shared Tree
75
PIM SM Registering
Receiver Joins Group First
(171.68.37.121, 224.1.1.1)
Mcast Packets
8
Source
171.68.37.121
E0
rtr-a
S0
RP
S0
S1
rtr-b
S3
S0
S1
rtr-c
(*, 224.1.1.1)
Mcast Traffic
Shared Tree
(*, 224.1.1.1), 00:04:28/00:01:32, RP 171.68.28.140, flags: SP
Incoming interface: Serial0, RPF nbr 171.68.28.191,
Outgoing interface list: Null
(171.68.37.121/32, 224.1.1.1), 00:04:28/00:01:32, flags: FT
Incoming interface: Ethernet0, RPF nbr 0.0.0.0, Registering
Outgoing interface list:
Serial0, Forward/Sparse, 00:04:28/00:01:32
“rtr-a” stops sending Register messages
(Final State in “rtr-a”)
8•
(S,G) Traffic now flowing down a single path (SPT) to RP.
76
PIM SM Registering
Receiver Joins Group First
(171.68.37.121, 224.1.1.1)
Mcast Packets
RP
Source
171.68.37.121
E0
S0
rtr-a
S0
S1
rtr-b
S0
S1
rtr-c
(*, 224.1.1.1)
Mcast Traffic
Shared Tree
(*, 224.1.1.1), 00:04:28/00:01:32, RP 171.68.28.140, flags: SP
Incoming interface: Serial1, RPF nbr 171.68.28.140,
Outgoing interface list: Null
(171.68.37.121/32, 224.1.1.1), 00:04:28/00:01:32, flags: T
Incoming interface: Serial0, RPF nbr 171.68.28.190
Outgoing interface list:
Serial1, Forward/Sparse, 00:04:28/00:01:32
Final state in “rtr-b”
77
PIM SM Registering
Receiver Joins Group First
(171.68.37.121, 224.1.1.1)
Mcast Packets
171.68.28.139
RP
Source
171.68.37.121
E0
rtr-a
S0
S0
S1
rtr-b
S3
S0
S1
rtr-c
(*, 224.1.1.1)
Mcast Traffic
Shared Tree
(*, 224.1.1.1), 00:09:21/00:02:38, RP 171.68.28.140, flags: S
Incoming interface: Null, RPF nbr 0.0.0.0,
Outgoing interface list:
Serial0, Forward/Sparse, 00:09:21/00:02:38
Serial1, Forward/Sparse, 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,
Outgoing interface list:
Serial0, Forward/Sparse, 00:00:49/00:02:11
Serial1, Forward/Sparse, 00:00:49/00:02:11
Final state in the “RP”
(with receivers on Shared Tree)
78
PIM SM Register Examples
• Receivers Join Group First
• Source Registers First
79
PIM SM Registering
Source Registers First
RP
E0
S0
S0
rtr-a
S1
rtr-b
S3
S0
S1
rtr-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)
80
PIM SM Registering
Source Registers First
RP
E0
S0
rtr-a
S0
S1
rtr-b
S3
S0
S1
rtr-c
rtr-b>show ip mroute 224.1.1.1
Group 224.1.1.1 not found.
State in “rtr-b” before any source registers
(with receivers on Shared Tree)
81
PIM SM Registering
Source Registers First
RP
E0
S0
rtr-a
S0
S1
rtr-b
S3
S0
S1
rtr-c
rtr-a>show ip mroute 224.1.1.1
Group 224.1.1.1 not found.
State in “rtr-a” before any source registers
(with receivers on Shared Tree)
82
PIM SM Registering
Source Registers First
(171.68.37.121, 224.1.1.1)
Mcast Packets
RP
1
Source
171.68.37.121
1•
E0
rtr-a
S0
S0
S1
rtr-b
S3
S0
S1
rtr-c
“Source” begins sending group G traffic.
83
PIM SM Registering
Source Registers First
2
(171.68.37.121, 224.1.1.1)
Mcast Packets
Register Msgs
RP
Source
171.68.37.121
E0
rtr-a
S0
S0
S1
S3
rtr-b
S0
S1
rtr-c
(*, 224.1.1.1), 00:00:03/00:02:56, RP 171.68.28.140, flags: SP
Incoming interface: Serial0, RPF nbr 171.68.28.191,
Outgoing interface list: Null
(171.68.37.121/32, 224.1.1.1), 00:00:03/00:02:56, flags: FPT
Incoming interface: Ethernet0, RPF nbr 0.0.0.0, Registering
Outgoing interface list: Null
“rtr-a” creates (S, G) state for source
(After automatically creating a (*, G) entry)
1•
“Source” begins sending group G traffic.
2• “rtr-a” encapsulates packets in Registers; unicasts to RP.
84
PIM SM Registering
Source Registers First
(171.68.37.121, 224.1.1.1)
Mcast Packets
Source
171.68.37.121
E0
rtr-a
Register Msgs
171.68.28.139
S0
S0
S1
RP
3
S3
rtr-b
S0
S1
rtr-c
(*, 224.1.1.1), 00:01:15/00:01:45, RP 171.68.28.140, flags: S
Incoming interface: Null, RPF nbr 0.0.0.0,
Outgoing interface list: 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,
Outgoing interface list: Null
“RP” processes Register; creates (S, G) state
(After automatically creating the (*, G) entry)
3•
“rtr-c” (RP) has no receivers on Shared Tree; discards packet.
85
PIM SM Registering
Source Registers First
(171.68.37.121, 224.1.1.1)
Mcast Packets
Register Msgs
RP
Source
171.68.37.121
E0
rtr-a
S0
S0
S1
rtr-b
S3
S0
S1
rtr-c
Register-Stop 4
3•
“rtr-c” (RP) has no receivers on Shared Tree; discards packet.
4• RP sends “Register-Stop” to “rtr-a”.
86
PIM SM Registering
Source Registers First
(171.68.37.121, 224.1.1.1)
Mcast Packets
RP
Source
171.68.37.121
E0
rtr-a
S0
5
S0
S1
rtr-b
S3
S0
S1
rtr-c
3•
“rtr-c” (RP) has no receivers on Shared Tree; discards packet.
4• RP sends “Register-Stop” to “rtr-a”.
5• “rtr-a” stops encapsulating traffic in Register Messages;
drops packets from Source.
87
PIM SM Registering
Source Registers First
(171.68.37.121, 224.1.1.1)
Mcast Packets
RP
Source
171.68.37.121
E0
rtr-a
S0
S0
S1
S3
rtr-b
S0
S1
rtr-c
(*, 224.1.1.1), 00:01:28/00:01:32, RP 171.68.28.140, flags: SP
Incoming interface: Serial0, RPF nbr 171.68.28.191,
Outgoing interface list: Null
(171.68.37.121/32, 224.1.1.1), 00:01:28/00:01:32, flags: FPT
Incoming interface: Ethernet0, RPF nbr 0.0.0.0
Outgoing interface list: Null
State in “rtr-a” after Registering
(without receivers on Shared Tree)
88
PIM SM Registering
Source Registers First
(171.68.37.121, 224.1.1.1)
Mcast Packets
RP
Source
171.68.37.121
E0
S0
rtr-a
S0
S1
rtr-b
S3
S0
S1
rtr-c
rtr-b>show ip mroute 224.1.1.1
Group 224.1.1.1 not found.
State in “rtr-b” after “rtr-a” Registers
(without receivers on Shared Tree)
89
PIM SM Registering
Source Registers First
(171.68.37.121, 224.1.1.1)
Mcast Packets
171.68.28.139
RP
Source
171.68.37.121
E0
rtr-a
S0
S0
S1
rtr-b
S3
S0
S1
rtr-c
(*, 224.1.1.1), 00:01:15/00:01:45, RP 171.68.28.140, flags: S
Incoming interface: Null, RPF nbr 0.0.0.0,
Outgoing interface list: 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,
Outgoing interface list: Null
State in “RP” after “rtr-a” Registers
(without receivers on Shared Tree)
90
PIM SM Registering
Source Registers First
(171.68.37.121, 224.1.1.1)
Mcast Packets
RP
Source
171.68.37.121
E0
rtr-a
S0
S0
S1
rtr-b
S3
S0
S1
rtr-c
(*, G) Join 6
Receivers begin joining the Shared Tree
6•
RP (“rtr-c”) receives (*, G) Join from a receiver on Shared Tree.
91
PIM SM Registering
Source Registers First
(171.68.37.121, 224.1.1.1)
Mcast Packets
Join 7
Source
171.68.37.121
E0
rtr-a
S0
S0
S1
RP
S3
rtr-b
S0
S1
rtr-c
(*, 224.1.1.1), 00:09:21/00:02:38, RP 171.68.28.140, flags: S
Incoming interface: Null, RPF nbr 0.0.0.0,
Outgoing interface list:
Serial1, Forward/Sparse, 00:00:14/00:02:46
(171.68.37.121/32, 224.1.1.1, 00:01:15/00:02:46, flags: T
Incoming interface: Serial3, RPF nbr 171.68.28.139,
Outgoing interface list:
Serial1, Forward/Sparse, 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.
92
PIM SM Registering
Source Registers First
(171.68.37.121, 224.1.1.1)
Mcast Packets
Join 7
8
Join S0
Source
171.68.37.121
E0
S0
rtr-a
S0
S1
RP
S3
rtr-b
S0
S1
rtr-c
171.68.28.190
(*, 224.1.1.1), 00:04:28/00:01:32, RP 171.68.28.140, flags: SP
Incoming interface: Serial1, RPF nbr 171.68.28.140,
Outgoing interface list: Null
(171.68.37.121/32, 224.1.1.1), 00:04:28/00:01:32, flags:
Incoming interface: Serial0, RPF nbr 171.68.28.190
Outgoing interface list:
Serial1, Forward/Sparse, 00:04:28/00:01:32
“rtr-b” processes Join, creates (S, G) state
(After automatically creating the (*, G) entry)
7•
8•
RP sends (S,G) Joins for all known Sources in Group.
“rtr-b” sends (S,G) Join toward Source to continue building SPT.
93
PIM SM Registering
Source Registers First
(171.68.37.121, 224.1.1.1)
Mcast Packets
9
Source
171.68.37.121
E0
rtr-a
S0
RP
S0
S1
rtr-b
S3
S0
S1
rtr-c
10 (*, 224.1.1.1)
Mcast Traffic
(*, 224.1.1.1), 00:04:28/00:01:32, RP 171.68.28.140, flags: SP
Incoming interface: Serial0, RPF nbr 171.68.28.191,
Outgoing interface list: Null
(171.68.37.121/32, 224.1.1.1), 00:04:28/00:01:32, flags: FT
Incoming interface: Ethernet0, RPF nbr 0.0.0.0, Registering
Outgoing interface list:
Serial0, Forward/Sparse, 00:04:28/00:01:32
“rtr-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.
94
PIM SM Registering
Source Registers First
(171.68.37.121, 224.1.1.1)
Mcast Packets
RP
Source
171.68.37.121
E0
S0
rtr-a
S0
S1
rtr-b
S3
S0
S1
rtr-c
171.68.28.190
(*, 224.1.1.1)
Mcast Traffic
(*, 224.1.1.1), 00:04:28/00:01:32, RP 171.68.28.140, flags: SP
Incoming interface: Serial1, RPF nbr 171.68.28.140,
Outgoing interface list: Null
(171.68.37.121/32, 224.1.1.1), 00:04:28/00:01:32, flags: T
Incoming interface: Serial0, RPF nbr 171.68.28.190
Outgoing interface list:
Serial1, Forward/Sparse, 00:04:28/00:01:32
Final state in “rtr-b” after Receivers Join
95
PIM SM Registering
Source Registers First
(171.68.37.121, 224.1.1.1)
Mcast Packets
171.68.28.139
RP
Source
171.68.37.121
E0
rtr-a
S0
S0
S1
rtr-b
S3
S0
S1
rtr-c
(*, 224.1.1.1)
Mcast Traffic
(*, 224.1.1.1), 00:09:21/00:02:38, RP 171.68.28.140, flags: S
Incoming interface: Null, RPF nbr 0.0.0.0,
Outgoing interface list:
Serial1, Forward/Sparse, 00:03:14/00:02:46
(171.68.37.121/32, 224.1.1.1, 00:01:15/00:02:46, flags: T
Incoming interface: Serial3, RPF nbr 171.68.28.139,
Outgoing interface list:
Serial1, Forward/Sparse, 00:00:49/00:02:11
Final state in “RP” after Receivers Join
96
PIM SM SPT-Switchover
• 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”.
• Threshold triggers Join of Source Tree
– Sends an (S,G) Join up SPT for next “S” in “G” packet
received.
• Pros
– Reduces Network Latency
• Cons
– More (S,G) state must be stored in the routers.
97
PIM SM SPT-Switchover
SPT-Switchover Mechanism
Once each second
– Compute new (*, G) traffic rate
– If threshold exceeded, set “J” flag in (*, G)
For each (Si , G) packet received:
– If “J” flag set in (*, G)
• Join SPT for (Si , G)
• Mark (Si , G) entry with “J” flag
• Clear “J” flag in (*,G)
98
PIM SM SPT-Switchover
To RP (10.1.5.1)
rtr-c
10.1.4.1
rtr-a
S1
S0
S2
S1
To Source “Si”
S0
10.1.4.2
E0
10.1.2.1
S0
10.1.2.2
rtr-d
E0
E1
E0
rtr-b
Rcvr A
(Si, G) Traffic Flow
Shared (RPT) Tree
SPT Tree
Rcvr B
(*, 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,
Outgoing interface list:
Serial1, Forward/Sparse, 00:01:43/00:02:11
Serial2, Forward/Sparse, 00:00:32/00:02:28
State in “rtr-c” before switch
99
PIM SM SPT-Switchover
To RP (10.1.5.1)
rtr-c
10.1.4.1
rtr-a
S1
S0
S2
To Source “Si”
S1
S0
10.1.4.2
E0
10.1.2.1
S0
10.1.2.2
rtr-d
E0
E1
E0
rtr-b
(Si, G) Traffic Flow
Shared (RPT) Tree
Rcvr A
SPT 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 10.1.4.8,
Outgoing interface list:
Ethernet0, Forward/Sparse, 00:01:43/00:02:11
State in “rtr-d” before switch
100
PIM SM SPT-Switchover
To RP (10.1.5.1)
rtr-c
10.1.4.1
rtr-a
S1
S0
S2
To Source “Si”
S1
S0
10.1.4.2
E0
10.1.2.1
S0
10.1.2.2
rtr-d
E0
E1
E0
rtr-b
(Si, G) Traffic Flow
Shared (RPT) Tree
Rcvr A
SPT Tree
Rcvr B
(*, 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,
Outgoing interface list:
Ethernet0, Forward/Sparse, 00:01:43/00:02:11
State in “rtr-a” before switch
101
PIM SM SPT-Switchover
To RP (10.1.5.1)
rtr-c
10.1.4.1
rtr-a
S1
S0
S2
S1
To Source “Si”
S0
10.1.4.2
E0
10.1.2.1
S0
10.1.2.2
rtr-d
E0
E1
E0
rtr-b
Rcvr A
(Si, G) Traffic Flow
Shared (RPT) Tree
SPT Tree
Rcvr B
(*, 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,
Outgoing interface list:
Ethernet1, Forward/Sparse, 00:01:43/00:02:11
State in “rtr-b” before switch
102
PIM SM SPT-Switchover
To RP (10.1.5.1)
rtr-c
10.1.4.1
rtr-a
S1
S0
S2
To Source “Si”
S1
S0
10.1.4.2
E0
10.1.2.1
S0
10.1.2.2
rtr-d
E0
E1
E0
1 Group “G” rate > Threshold
rtr-b
(Si, G) Traffic Flow
Shared (RPT) Tree
Rcvr A
SPT Tree
Rcvr B
(*, 224.1.1.1), 00:01:43/00:02:13, RP 10.1.5.1, flags: SC J
Incoming interface: Ethernet0, RPF nbr 10.1.2.1,
Outgoing interface list:
Ethernet1, Forward/Sparse, 00:01:43/00:02:11
1
2
2
Group “G” rate exceeds SPT Threshold at “rtr-b”;
Set J Flag in (*, G) and wait for next (Si,G) packet.
103
PIM SM SPT-Switchover
To RP (10.1.5.1)
rtr-c
10.1.4.1
rtr-a
S1
S0
S2
S1
To Source “Si”
S0
10.1.4.2
E0
10.1.2.1
S0
10.1.2.2
rtr-d
E0
E1
E0
3
rtr-b
Rcvr A
(Si, G) Traffic Flow
Shared (RPT) Tree
SPT Tree
Rcvr B
(*, 224.1.1.1), 00:01:43/00:02:13, RP 10.1.5.1, flags: SC J
Incoming interface: Ethernet0, RPF nbr 10.1.2.1,
Outgoing interface list:
Ethernet1, Forward/Sparse, 00:01:43/00:02:11
3
4
4
(Si,G) packet arrives down Shared tree.
Clear J Flag in the (*,G) & create (Si,G) state.
104
PIM SM SPT-Switchover
To RP (10.1.5.1)
rtr-c
10.1.4.1
rtr-a
S1
S0
S2
To Source “Si”
S1
S0
10.1.4.2
E0
10.1.2.1
S0
10.1.2.2
rtr-d
E0
E1
E0
rtr-b
(Si, G) Traffic Flow
Shared (RPT) Tree
Rcvr A
Rcvr B
(*, 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,
Outgoing interface list:
Ethernet1, Forward/Sparse, 00:01:43/00:02:11
SPT Tree
J Flag indicates
(S, G) created by
exceeding the
SPT-threshold
(171.68.37.121/32, 224.1.1.1), 00:13:28/00:02:53, flags: CJT
Incoming interface: Ethernet0, RPF nbr 10.1.2.1
Outgoing interface list:
Ethernet1, Forward/Sparse, 00:13:28/00:02:53
New State in “rtr-b”
105
PIM SM SPT-Switchover
To RP (10.1.5.1)
rtr-c
10.1.4.1
rtr-a
S1
S0
S2
To Source “Si”
S1
S0
10.1.4.2
E0
10.1.2.1
S0
10.1.2.2
rtr-d
E0
E1
E0
Rcvr A
5 (Si,G) Join
rtr-b
(Si, G) Traffic Flow
Shared (RPT) Tree
SPT Tree
Rcvr B
5
Send (Si,G) Join towards Si .
106
PIM SM SPT-Switchover
To RP (10.1.5.1)
rtr-c
10.1.4.1
rtr-a
S1
S0
S2
S1
To Source “Si”
S0
10.1.4.2
E0
10.1.2.1
S0
10.1.2.2
rtr-d
E0
E1
E0
rtr-b
(Si, G) Traffic Flow
Shared (RPT) Tree
Rcvr A
SPT Tree
Rcvr B
(*, 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,
Outgoing interface list:
Ethernet0, Forward/Sparse, 00:01:43/00:02:11
(171.68.37.121/32, 224.1.1.1), 00:13:28/00:02:53, flags: T
Incoming interface: Serial1, RPF nbr 10.1.9.2
Outgoing interface list:
Ethernet0, Forward/Sparse, 00:13:25/00:02:30
New state in “rtr-a”
107
PIM SM SPT-Switchover
To RP (10.1.5.1)
rtr-c
10.1.4.1
S1
S0
7
(Si,G)RP-bit Prune
S2
rtr-a
S1
6 (Si,G) Join
S0
10.1.4.2
To Source “Si”
E0
10.1.2.1
S0
10.1.2.2
rtr-d
E0
E1
E0
rtr-b
Rcvr A
(Si, G) Traffic Flow
Shared (RPT) Tree
SPT Tree
Rcvr B
6
“rtr-a” forwards (Si,G) Join toward Si.
7
SPT & RPT diverge, triggering (Si,G)RP-bit Prunes toward RP.
108
PIM SM SPT-Switchover
To RP (10.1.5.1)
rtr-c
10.1.4.1
rtr-a
S1
S0
S2
S1
8 (S ,G) Traffic
i
S0
10.1.4.2
To Source “Si”
E0
10.1.2.1
S0
10.1.2.2
rtr-d
E0
E1
E0
rtr-b
Rcvr A
(Si, G) Traffic Flow
Shared (RPT) Tree
SPT Tree
Rcvr B
8
(Si, G) traffic begins flowing down SPT tree.
109
PIM SM SPT-Switchover
To RP (10.1.5.1)
rtr-c
10.1.4.1
rtr-a
S1
S0
S2
To Source “Si”
S1
S0
10.1.4.2
E0
10.1.2.1
S0
10.1.2.2
rtr-d
E0
E1
E0
rtr-b
(Si, G) Traffic Flow
Shared (RPT) Tree
Rcvr A
SPT Tree
Rcvr B
(*, 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,
Outgoing interface list:
Serial1, Forward/Sparse, 00:01:43/00:02:11
Serial2, Forward/Sparse, 00:00:32/00:02:28
(171.68.37.121/32, 224.1.1.1), 00:13:28/00:02:53, flags: R
Incoming interface: Serial0, RPF nbr 10.1.5.1
Outgoing interface list:
Serial2, Forward/Sparse, 00:00:32/00:02:28
State in “rtr-c” after receiving the (Si, G) RP-bit Prune
110
PIM SM SPT-Switchover
To RP (10.1.5.1)
rtr-c
10.1.4.1
rtr-a
S1
S0
S2
9
S1
To Source “Si”
S0
10.1.4.2
E0
10.1.2.1
S0
10.1.2.2
rtr-d
E0
E1
E0
Rcvr A
rtr-b
(Si, G) Traffic Flow
Shared (RPT) Tree
SPT Tree
Rcvr B
•9 Unnecessary (Si, G) traffic is pruned from the Shared tree.
111
PIM SM SPT-Switchover
To RP (10.1.5.1)
rtr-c
10.1.4.1
rtr-a
S1
S0
S2
10
S1
To Source “Si”
S0
10.1.4.2
E0
10.1.2.1
S0
10.1.2.2
rtr-d
E0
E1
E0
Rcvr A
rtr-b
(Si, G) Traffic Flow
Shared (RPT) Tree
SPT Tree
Rcvr B
•9 Unnecessary (Si, G) traffic is pruned from the Shared tree.
10
•
(Si, G) traffic still flows via other branches of the Shared tree.
112
PIM SM SPT-Switchover
Shared Tree Switchback Mechanism
• Once each second when the
(S,G) state is older than 1 minute
– If “J” flag set in (Si , G) entry
• Compute new (Si , G) traffic rate
• If rate < SPT-threshold
– Rejoin (*, G) Tree for (Si , G) traffic
– Send (Si , G) prune up SPT toward Si
– Delete (Si , G) entry
113
PIM-SM Protocol Mechanics
•
•
•
•
•
•
PIM SM State
PIM SM Forwarding
PIM SM Joining
PIM SM Registering
PIM SM SPT-Switchover
PIM SM Pruning
114
PIM SM Pruning
• IGMP group times out / last host sends Leave
• Interface removed from all (*,G) and (S,G) entries
– IF all interfaces in “oilist” for (*,G) are pruned;
THEN send Prune up shared tree toward RP
– Any (S, G) state allowed to time-out
• Each router along path “prunes” interface
– IF all interfaces in “oilist” for (*,G) are pruned;
THEN send Prune up shared tree toward RP
– Any (S, G) state allowed to time-out
115
PIM SM Pruning
Shared Tree Case
S1
To RP (10.1.5.1)
rtr-a
S0
(Si, G) Traffic Flow
Shared Tree
SPT Tree
10.1.4.2
E0
10.1.2.1
10.1.2.2
E1
E0
rtr-b
Rcvr A
(*, 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,
Outgoing interface list:
Ethernet1, Forward/Sparse, 00:01:43/00:02:11
State in “rtr-b” before Pruning
116
PIM SM Pruning
Shared Tree Case
S1
To RP (10.1.5.1)
rtr-a
S0
(Si, G) Traffic Flow
Shared Tree
SPT Tree
10.1.4.2
E0
10.1.2.1
10.1.2.2
E1
E0
rtr-b
Rcvr A
(*, 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,
Outgoing interface list:
Ethernet0, Forward/Sparse, 00:01:43/00:02:11
State in “rtr-a” before Pruning
117
PIM SM Pruning
Shared Tree Case
S1
To RP (10.1.5.1)
rtr-a
S0
(Si, G) Traffic Flow
Shared Tree
SPT Tree
10.1.4.2
10.1.2.1
10.1.2.2
Rcvr A
E1
X
1 IGMP Leave
E0
E0
3 (*,G) Prune
rtr-b
2
1
“rtr-b” is a Leaf router. Last host “Rcvr A”, leaves group G.
2
“rtr-b” removes E1 from (*,G) and any (Si,G) “oilists”.
3
“rtr-b” (*,G) “oilist” now empty; sends (*,G) Prune toward RP.
118
PIM SM Pruning
Shared Tree Case
X
To RP (10.1.5.1)
(*,G) Prune
(Si, G) Traffic Flow
Shared Tree
SPT Tree
5
6
S1
rtr-a
S0
10.1.4.2
10.1.2.2
X
E0
E1
4
E0
10.1.2.1
4
rtr-b
“rtr-a” receives Prune; removes E0 from (*,G) “oilist”.
(After the 3 second Multi-access Network Prune delay.)
5
“rtr-a” (*,G) “oilist” now empty; send (*,G) Prune toward RP.
6
Pruning continues back toward RP.
119
PIM SM Pruning
Source (SPT) Case
S1
To RP (10.1.5.1)
rtr-a
S0
(Si, G) Traffic Flow
Shared Tree
SPT Tree
10.1.4.2
To Source “Si”
E0
10.1.2.1
10.1.2.2
E1
E0
rtr-b
Rcvr A
(*, 224.1.1.1), 00:01:43/00:02:59, RP 10.1.5.1, flags: SC
Incoming interface: Ethernet0, RPF nbr 10.1.2.1,
Outgoing interface list:
Ethernet1, Forward/Sparse, 00:01:43/00:02:11
(171.68.37.121/32, 224.1.1.1), 00:01:05/00:01:55, flags: CJT
Incoming interface: Ethernet0, RPF nbr 10.1.2.1
Outgoing interface list:
Ethernet1, Forward/Sparse, 00:01:05/00:02:55
State in “rtr-b” before Pruning
120
PIM SM Pruning
Source (SPT) Case
S1
To RP (10.1.5.1)
rtr-a
S0
(Si, G) Traffic Flow
Shared Tree
SPT Tree
10.1.4.2
To Source “Si”
E0
10.1.2.1
10.1.2.2
E1
E0
rtr-b
Rcvr A
(*, 224.1.1.1), 00:01:43/00:02:59, RP 10.1.5.1, flags: S
Incoming interface: Serial0, RPF nbr 10.1.4.1,
Outgoing interface list:
Ethernet0, Forward/Sparse, 00:01:43/00:02:11
(171.68.37.121/32, 224.1.1.1), 00:01:05/00:01:55, flags: T
Incoming interface: Serial1, RPF nbr 10.1.9.2
Outgoing interface list:
Ethernet0, Forward/Sparse, 00:01:05/00:02:55
State in “rtr-a” before Pruning
121
PIM SM Pruning
Source (SPT) Case
S1
To RP (10.1.5.1)
rtr-a
S0
(Si, G) Traffic Flow
Shared Tree
SPT Tree
10.1.4.2
E1
X
Rcvr A
E0
10.1.2.1
10.1.2.2
1 IGMP Leave
To Source “Si”
E0
3 (*,G) Prune
rtr-b
2
1
“rtr-b” is a Leaf router. Last host “Rcvr A”, leaves group G.
2
“rtr-b” removes E1 from (*,G) and any (Si,G) “oilists”.
3
“rtr-b” (*,G) “oilist” now empty; sends (*,G) Prune toward RP.
122
PIM SM Pruning
Source (SPT) Case
S1
To RP (10.1.5.1)
rtr-a
S0
(Si, G) Traffic Flow
Shared Tree
10.1.4.2
10.1.2.1
10.1.2.2
X
E1
Rcvr A
E0
E0
X
SPT Tree
To Source “Si”
4 Periodic
(S, G) Join
rtr-b
1
“rtr-b” is a Leaf router. Last host “Rcvr A”, leaves group G.
2
“rtr-b” removes E1 from (*,G) and any (Si,G) “oilists”.
3
“rtr-b” (*,G) “oilist” now empty; sends (*,G) Prune toward RP.
4
“rtr-b” stops sending periodic (S, G) joins.
123
PIM SM Pruning
Source (SPT) Case
S1
To RP (10.1.5.1)
(*,G) Prune
(Si, G) Traffic Flow
Shared Tree
SPT Tree
6
E1
5
rtr-a
S0
10.1.4.2
10.1.2.2
X
E0
To Source “Si”
E0
10.1.2.1
5
rtr-b
“rtr-a” receives Prune; removes E0 from (*,G) “oilist”.
(After the 3 second Multiaccess Network Prune delay.)
6
“rtr-a” (*,G) “oilist” now empty; sends (*,G) Prune toward RP.
124
PIM SM Pruning
Source (SPT) Case
S1
To RP (10.1.5.1)
rtr-a
S0
(Si, G) Traffic Flow
Shared Tree
SPT Tree
10.1.4.2
To Source “Si”
E0
10.1.2.1
10.1.2.2
E1
E0
rtr-b
(*, 224.1.1.1), 00:02:32/00:02:59, RP 10.1.5.1, flags: SP
Incoming interface: Ethernet0, RPF nbr 10.1.2.1,
Outgoing interface list:
(171.68.37.121/32, 224.1.1.1), 00:01:56/00:00:53, flags: PT
Incoming interface: Ethernet0, RPF nbr 10.1.2.1
Outgoing interface list:
State in “rtr-b” after Pruning
125
PIM SM Pruning
Source (SPT) Case
S1
To RP (10.1.5.1)
rtr-a
S0
(Si, G) Traffic Flow
Shared Tree
SPT Tree
10.1.4.2
To Source “Si”
E0
10.1.2.1
10.1.2.2
E1
E0
rtr-b
(*, 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,
Outgoing interface list:
(171.68.37.121/32, 224.1.1.1), 00:01:56/00:00:53, flags: PT
Incoming interface: Serial1, RPF nbr 10.1.9.2
Outgoing interface list:
State in “rtr-a” after Pruning
126
PIM SM Pruning
Source (SPT) Case
(Si,G) Data 7
S1
To RP (10.1.5.1)
rtr-a
S0
(Si, G) Traffic Flow
Shared Tree
SPT Tree
10.1.4.2
To Source “Si”
8 (Si,G) Prune
E0
10.1.2.1
10.1.2.2
E1
E0
rtr-b
7
Another (Si,G) data packet arrives via Serial1.
8
‘rtr-a’ responds by sending an (Si,G) Prune toward source.
127
PIM SM Pruning
Source (SPT) Case
9
S1
To RP (10.1.5.1)
rtr-a
S0
(Si, G) Traffic Flow
Shared Tree
SPT Tree
10.1.4.2
To Source “Si”
E0
10.1.2.1
10.1.2.2
E1
E0
rtr-b
7
Another (Si,G) data packet arrives via Serial1.
8
‘rtr-a’ responds by sending an (Si,G) Prune toward source.
9
(Si,G) traffic ceases flowing down SPT.
128
Multicast Protocols
• Multicast Addressing Basics
• IGMP
• PIM
• MSDP
• MBGP
129
MSDP—Multicast Source
Discovery Protocol
•
•
•
•
•
•
MSDP concepts
MSDP design points
MSDP example
Cisco MSDP implementation
MSDP configuration
MSDP application—Anycast RP
130
MSDP Concept
• Simple but elegant
– Utilize inter-domain source trees
– Reduces problem to locating
active sources
– RP or receiver last-hop can join
inter-domain source tree
131
MSDP Concepts
• Works with PIM-SM only
– RP’s knows about all sources in a domain
• Sources cause a “PIM Register” to the RP
• Can tell RP’s in other domains of its sources
– Via MSDP SA (Source Active) messages
– RP’s know about receivers in a domain
• Receivers cause a “(*, G) Join” to the RP
• RP can join the source tree in the peer domain
– Via normal PIM (S, G) joins
132
MSDP Overview
MSDP Example
Domain E
MSDP Peers
Source Active
Messages
RP
SA
r
SA
Domain C
Join (*, 224.2.2.2)
RP
SA
Domain B SA
SA
RP
SA
SA
SA Message
192.1.1.1, 224.2.2.2
RP
RP
SA Message
192.1.1.1, 224.2.2.2
Domain D
s
Domain A
Register
192.1.1.1, 224.2.2.2
133
MSDP Overview
MSDP Example
Domain E
MSDP Peers
RP
r
Domain C
RP
Domain B
RP
RP
Domain D
RP
s
Domain A
134
MSDP Overview
MSDP Example
Domain E
MSDP Peers
RP
Multicast Traffic
r
Domain C
RP
Domain B
RP
RP
Domain D
RP
s
Domain A
135
MSDP Overview
MSDP Example
Domain E
MSDP Peers
RP
Multicast Traffic
r
Domain C
RP
Domain B
RP
RP
Domain D
RP
s
Domain A
136
MSDP Overview
MSDP Example
Domain E
MSDP Peers
RP
Multicast Traffic
r
Domain C
RP
Domain B
RP
RP
Domain D
RP
s
Domain A
137
MSDP Design Points
• MSDP peers talk via TCP connections
• Source Active (SA) messages
– Peer-RPF forwarded to prevent loops
• RPF check on AS-PATH back to the peer RP
– other rules from draft apply
• If successful, flood SA message to other peers
• Stub sites can be configured to accept all SA messages
(similar to static default for routing)
– Since they have only one exit (e.g., default peer)
– MSDP speaker may cache SA messages
• Reduces join latency
138
MSDP Peers
• MSDP establishes a neighbor relationship
between MSDP peers
– Peers connect using TCP port 639
– Peers send keepalives every 60 secs (fixed)
– Peer connection reset after 75 seconds if no MSDP packets
or keepalives are received
• MSDP peers must run BGP!
– May be an MBGP peer, a BGP peer or both
– Exception: BGP is unnecessary when
peering with only a single MSDP peer.
139
MSDP SA Messages
• MSDP SA Message Contents
– One or more messages (in TLV format)
•
•
•
•
Keepalives
Source Active (SA) Messages
Source Active Request (SA-Req) Messages
Source Active Response (SA-Resp) Message
– Source Active (SA) Messages
• Used to advertise active Sources in a domain
• Can also carry initial multicast packet from source
– Hack for Bursty Sources (ala SDR)
• SA Message Contents:
– IP Address of Originator (usually an RP)
– Number of (S, G)’s pairs being advertised
– List of active (S, G)’s in the domain
– Encapsulated Multicast packet
140
MSDP SA Messages
• MSDP Message Contents (cont.)
– SA Request (SA-Req) Messages
• Used to request a list of active sources for a group
– Sent to an MSDP SA Cache Server
– Reduces Join Latency to active sources
• SA Request Messages contain:
– Requested Group Address
– SA Response (SA-Resp) Messages
• Sent in response to an SA Request message
• SA Response Messages contain:
– IP Address of Originator (usually an RP)
– Number of (S, G)’s pairs being advertised
– List of active (S, G)’s in the domain
– Keepalive messages
• Used to keep MSDP peer connection up
141
Receiving SA Messages
• Skip RPF Check and process SA if:
– Sending MSDP peer = only MSDP peer
(i.e. the ‘default-peer’ or only ‘msdp-peer’ configured.)
– Sending MSDP peer = Mesh-Group peer
• RPF Check the received SA message.
– Lookup best BGP path to RP in SA message
• Search MBGP RIB first then BGP RIB
– If path to RP not found, RPF Check Fails; ignore SA message
– Sending MSDP Peer = BGP peer?
• Yes: Is best path to RP via this BGP peer?
– If yes, RPF Check Succeeds; process SA message
• No: Is next AS in best path to RP = AS of MSDP peer?
– If yes, RPF Check Succeeds; process SA message
142
Receiving SA Messages
• Detailed RPF Check rules
– Case 1: Sending MSDP Peer = iBGP peer
• Is best path to RP via this BGP peer?
– Translation: Is the address of the iBGP peer that advertised
the best path to the RP = address of the sending MSDP peer?
– Case 2: Sending MSDP Peer = eBGP peer
• Is best path to RP via this BGP peer?
– Translation: Is the AS of eBGP peer = next AS in the best path
to the RP?
– Case 3: Sending MSDP Peer != BGP peer
• Is the next AS in best path to RP = AS of the sending
MSDP peer?
– Translation: None needed.
143
RPF Check Example
RPF rule when MSDP == internal (m)BGP peer
BGP Table router B
Network
*> 172.16.0.2/32
B
4.2
MSDP Peers router B
4.1
2.1
RP
A
Path
i
Who is the iBGP peer adverting this route,
in our example 172.16.3.1
AS1
3.1
Next Hop
172.16.3.1
MSDP Peer
172.16.3.1
172.16.4.1
AS
1
1
State
UP
UP
C
Is the MSDP == BGP peer
Source
ip pim rp-address 172.16.0.2
RPF Success!
MSDP SA
MSDP/iMBGP mesh-peering
144
RPF Check Example
RPF rule when MSDP == internal (m)BGP peer
BGP Table router B
Network
*> 172.16.0.2/32
B
4.2
MSDP Peers router B
4.1
2.1
RP
A
Path
i
Who is the iBGP peer adverting this route,
In our example 172.16.3.1
AS1
3.1
Next Hop
172.16.3.1
MSDP Peer
172.16.3.1
172.16.4.1
AS
1
1
State
UP
UP
C
Is the MSDP == BGP peer
Source
ip pim rp-address 172.16.0.2
RPF Failure!
MSDP SA
MSDP/iMBGP mesh-peering
145
RPF Check Example
MSDP Peers router B
RPF rule when MSDP == external (m)BGP peer
MSDP Peer
172.16.3.1
172.16.4.1
AS 2
B
State
UP
UP
BGP Neighbours router B
4.2
3.1
Neighbor
172.16.3.1
172.16.4.1
AS
1
3
Up/Down
06:06:08
06:09:06
4.1
2.1
RP
AS
1
3
BGP Table
A
C
AS3
AS1
Network
*> 172.16.0.2/32
172.16.0.2/32
Next Hop
172.16.3.1
172.16.4.1
Path
1 i
3 1 i
Is the MSDP AS == Last AS in RP route
ip pim rp-address 172.16.0.2
Source
RPF Success!
MSDP SA
MSDP/eMBGP mesh-peering
Who is the BGP peer adverting this route
146
RPF Check Example
MSDP Peers router B
RPF rule when MSDP == external (m)BGP peer
MSDP Peer
172.16.3.1
172.16.4.1
AS 2
B
State
UP
UP
BGP Neighbours router B
4.2
3.1
Neighbor
172.16.3.1
172.16.4.1
AS
1
3
Up/Down
06:06:08
06:09:06
4.1
2.1
RP
AS
1
3
BGP Table
A
C
AS3
AS1
Network
*> 172.16.0.2/32
172.16.0.2/32
Next Hop
172.16.3.1
172.16.4.1
Path
1 i
3 1 i
Is the MSDP AS == Last AS in RP route
ip pim rp-address 172.16.0.2
Source
RPF Failure!
MSDP SA
MSDP/eMBGP mesh-peering
Who is the BGP peer adverting this route
147
RPF Check Example
RPF rule when MSDP != (m)BGP peer
MSDP Peer
172.16.3.1
172.16.4.1
AS 2
B
MSDP Peers router B
AS
1
3
State
UP
UP
4.2
BGP Table router B
3.1
Network
*> 172.16.0.2/32
172.16.0.2/32
*> 172.16.4.0/24
*> 172.16.3.0/24
4.1
2.1
RP
A
Next Hop
172.16.3.1
172.16.4.1
172.16.4.1
172.16.3.1
Path
1 i
3 1 I
3 i
1 i
C
AS3
AS1
Is the MSDP AS == Last AS in RP route
ip pim rp-address 172.16.0.2
Source
RPF Success!
MSDP SA
MSDP/eMBGP mesh-peering
148
RPF Check Example
RPF rule when MSDP != (m)BGP peer
MSDP Peer
172.16.3.1
172.16.4.1
AS 2
B
MSDP Peers router B
AS
1
3
State
UP
UP
4.2
BGP Table router B
3.1
Network
*> 172.16.0.2/32
172.16.0.2/32
*> 172.16.4.0/24
*> 172.16.3.0/24
4.1
2.1
RP
A
Next Hop
172.16.3.1
172.16.4.1
172.16.4.1
172.16.3.1
Path
1 i
3 1 I
3 i
1 i
C
AS3
AS1
Is the MSDP AS == Last AS in RP route
ip pim rp-address 172.16.0.2
Source
RPF Failure!
MSDP SA
MSDP/eMBGP mesh-peering
149
Cisco MSDP Implementation
• Cisco implementation current with ID:
– draft-ietf-msdp-spec-02.txt
• Multiple peer support
– Peer with BGP, MBGP, or static peers
• SA caching (off by default)
• Sending and receiving SA-requests
• Sending and receiving SA-responses
150
Cisco MSDP Implementation
• SA input and output filtering
• SA-request input filtering
• Default peer support
– So a tail site can MSDP with a backbone provider without
requiring the two to BGP peer
• Triggered join support when creating an (S,G)
learned by MSDP
• Mesh groups
– Reduces RPF-flooding of SA messages between fully
meshed MSDP peers
151
MSDP Configuration
• Configure peers
ip msdp peer <ip-address> [connect-source <i/f>]
• Configure default peer
ip msdp default-peer <ip-address> [prefix-list acl]
• SA caching
ip msdp cache-sa-state [list <acl>]
• Mesh groups
ip msdp mesh-group <name> <ip-address>
152
MSDP Configuration
• Filtering
– Can filter SA in/out, groups, with acls or route-maps
• TTL Scoping
ip msdp ttl-threshold <ip-address> <ttl>
• For more configuration commands see:
ftp://ftpeng.cisco.com/ipmulticast/msdp-commands
153
ISP Requirements to Deploy Now
• Want an explicit join protocol for efficiency
PIM-SM (forwarding)
• Use existing (unicast) operation model
MBGP (routing)
• Need interdomain source discovery
MSDP (source discovery)
154
MSDP Application—Anycast RP
• draft-ietf-mboned-anycast-rp-05.txt
• Within a domain, deploy more than one
RP for the same group range
• Give each RP the same IP address assignment
• Sources and receivers use closest RP
• May be used intra-domain (enterprise) to provide
redundancy and RP load sharing
155
MSDP Application—Anycast RP
• Sources from one RP are known to other
RPs using MSDP
• When an RP goes down, sources and
receivers are taken to new RP via unicast
routing
– Fast convergence
156
Anycast RP—Convergence
Src
Rec
RP1
RP2
MSDP Rec
X
10.0.0.1
10.0.0.1
Rec
Rec
Src
157
Anycast RP—Convergence
Src
Rec
RP1
X
RP2
Rec
10.0.0.1
10.0.0.1
Rec
Rec
Src
158
Multicast Protocols
• Multicast Addressing Basics
• IGMP
• PIM
• MSDP
• MBGP
159
MBGP—Multiprotocol BGP
• MBGP overview
• MBGP capability negotiation
• MBGP NLRI exchange
160
MBGP Overview
• MBGP: Multiprotocol BGP
(aka multicast BGP in multicast networks)
– Defined in RFC 2283 (extensions to BGP)
– Can carry different types of routes
• Unicast
• Multicast
– Both routes carried in same BGP session
– Does not propagate multicast state info
– Same path selection and validation rules
• AS-Path, LocalPref, MED, …
161
MBGP Overview
• New multiprotocol attributes
– MP_REACH_NLRI
– MP_UNREACH_NLRI
• MP_REACH_NLRI and MP_UNREACH_NLRI
– Address Family Information (AFI) = 1 (IPv4)
• Sub-AFI = 1 (NLRI is used for unicast)
• Sub-AFI = 2 (NLRI is used for multicast
RPF check)
• Sub-AFI = 3 (NLRI is used for both unicast and multicast RPF
check)
162
MBGP Overview
• Separate BGP tables maintained
– Unicast Routing Information Base (RIB)
– Multicast Routing Information Base (MRIB)
• Unicast RIB (U-RIB)
– Contains unicast prefixes for unicast forwarding
– Populated with BGP unicast NLRI
• AFI = 1, Sub-AFI = 1 or 3
• Multicast RIB (M-RIB)
– Contains unicast prefixes for RPF checking
– Populated with BGP multicast NLRI
• AFI = 1, Sub-AFI = 2 or 3
163
MBGP Overview
• MBGP allows different unicast and multicast
topologies and different policies
– Same IP address may have different signification
• Unicast routing information
• Multicast RPF information
– For same IPv4 address two different NLRI with different nexthops
– Can use existing or new BGP peering topology for multicast
164
MBGP NLRI Exchange
• BGP/MBGP configuration allows you to:
– Define which NLRI type are exchanged
(unicast, multicast, both)
– Set NLRI type through route-maps (redistribution)
– Define policies through standard BGP attributes
(for unicast and/or multicast NLRI)
• No redistribution allowed between MBGP
and BGP tables
– NLRI type can be set with set nlri route-map command
165
MBGP NLRI Exchange
• MRIB is populated by:
– Receiving AFI/SAFI 1/2 MP_REACH_NLRI from
neighbors
– Configured/stored locally by:
network <foo> <foo-mask> [nlri multicast unicast]
redistribute <unicast> route-map <map>
aggregate-address <foo> <foo-mask> [nlri multicast unicast]
neighbor <foo> default-originate [nlri multicast unicast]
• Note: Syntax changes in 12.07T/12.1 forward
166
MBGP — NLRI Information
Congruent Topologies
BGP Session for Unicast and
Multicast NLRI
AS 123
.1
192.168.10.0/24
Receiver
192.168.100.0/24
AS 321
.2
router bgp 321
neighbor 192.168.100.1 remote-as 123 nlri unicast multicast
network 192.192.25.0 255.255.255.0 nlri unicast multicast
no auto-summary
192.192.25.0/24
Sender
167
MBGP — NLRI Information
Congruent Topologies
BGP Session for Unicast and
Multicast NLRI
AS 123
.1
192.168.100.0/24
AS 321
.2
Unicast Information
192.168.10.0/24
NLRI: 192.192.25/24
AS_PATH: 321
MED:
Next-Hop: 192.168.100.2
...
192.192.25.0/24
Multicast Information
Receiver
MP_REACH_NLRI: 192.192.25/24
AFI: 1, Sub-AFI: 2 (multicast)
AS_PATH: 321
MED:
Next-Hop: 192.168.100.2
...
Sender
Routing Update
168
MBGP — NLRI Information
Incongruent Topologies
AS 123
AS 321
.1
.1
Unicast Traffic
192.168.100.0/24
Multicast Traffic
.2
.2
192.168.200.0/24
192.192.25.0/24
router bgp 321
. . .
network 192.192.25.0 nlri unicast multicast
neighbor 192.168.100.1 remote-as 123 nlri unicast
neighbor 192.168.200.1 remote-as 123 nlri multicast
Sender
169
MBGP — NLRI Information
Incongruent Topologies
AS 123
AS 321
.1
Unicast Traffic
192.168.100.0/24
Multicast Traffic
.1
.2
.2
192.168.200.0/24
192.192.25.0/24
Sender
Unicast Information
NLRI: 192.192.25/24
AS_PATH: 321
MED:
Next-Hop: 192.168.100.2
Routing Update
170
MBGP — NLRI Information
Incongruent Topologies
AS 123
AS 321
.1
Unicast Traffic
192.168.100.0/24
Multicast Traffic
.1
.2
.2
192.168.200.0/24
192.192.25.0/24
Multicast Information
Sender
MP_REACH_NLRI: 192.192.25/24
AFI: 1, Sub-AFI: 2
AS_PATH: 321
MED:
Next-Hop: 192.168.200.2
Routing Update
171
MBGP — NLRI Information
Incongruent Topologies
AS 123
AS 321
.1
.1
Unicast Traffic
192.168.100.0/24
Multicast Traffic
.2
.2
192.168.200.0/24
192.192.25.0/24
Unicast RIB
Network
Next-Hop
Path
192.192.25.0/24 192.168.100.2 321
Sender
Multicast RIB
Network
Next-Hop
Path
192.192.25.0/24 192.168.200.2 321
172
Populating the MRIB
• Just to restate
network <foo> <foo-mask> [nlri multicast unicast]
redistribute <unicast> route-map <map>
aggregate-address <foo> <foo-mask> [nlri multicast unicast]
neighbor <foo> default-originate [nlri multicast unicast]
173
MBGP—Summary
• Solves part of inter-domain problem
– Can exchange multicast routing information
– Uses standard BGP configuration knobs
– Permits separate unicast and multicast
topologies if desired
• Still must use PIM to:
– Build distribution trees
– Actually forward multicast traffic
– PIM-SM recommended
• But there’s still a problem using PIM-SM here… (more on that
later)
174
Midterm Exam
Which protocol...
– ...is used to propagate forwarding state?
PIM-SM - Protocol Independent Multicast-Sparse Mode
– ...maintains routing information for interdomain RPF
checking?
MBGP - Multiprotocol Border Gateway Protocol
– …exchanges active source information between RPs?
MSDP - Multicast Source Discovery Protocol
175
Agenda
•
•
•
•
•
•
What Is Multicast
Multicast Protocols
Multicast Configurations
Troubleshooting
Futures
Useful Links
176
Putting it all together..
• PIM-SM, MBGP, MSDP
• Public multicast peering (MIX)
• Transit topology examples
• Address allocation
– GLOP draft-ietf-mboned-static-allocation-00.txt
177
ISP Requirements at the MIX
• Current solution: MBGP + PIM-SM + MSDP
– Environment
• ISPs run iMBGP and PIM-SM (internally)
• ISPs multicast peer at a public interconnect
– Deployment
•
•
•
•
Border routers run eMBGP
The interfaces on interconnect run PIM-SM
RPs’ MSDP peering is fully meshed
All peers set a common distance for eMBGP
178
ISP Requirements at the MIX
Peering Solution: MBGP + PIM-SM +MSDP
ISP A
Public
Interconnect
PIM-SM
PIM-SM
RP
RP
iMBGP
ISP B
iMBGP
Redistribute old MBONE
DVMRP routes into MBGP
eMBGP
iMBGP
RP
ISP C
PIM-SM
RP
iMBGP
AS
10888
179
Multicast Transit Design Objectives
• PIM Border Constraints
–
–
–
–
Confine registers within domain
Confine local groups
Confine RP announcements
Control SA advertisements via MSDP
• Border RPF check
– RPF check against unicast routes to multicast sources
• MSDP RPF check
– RPF check toward RP in received SAs
180
Recommended MSDP SA Filter
ftp://ftp-eng.cisco.com/ipmulticast/msdp-sa-filter.txt
! domain-local applications
access-list 111 deny
ip any host 224.0.2.2
!
access-list 111 deny
ip any host 224.0.1.3
! Rwhod
access-list 111 deny
ip any host 224.0.1.24
! Microsoft-ds
access-list 111 deny
ip any host 224.0.1.22
! SVRLOC
access-list 111 deny
ip any host 224.0.1.2
! SGI-Dogfight
access-list 111 deny
ip any host 224.0.1.35
! SVRLOC-DA
access-list 111 deny
ip any host 224.0.1.60
! hp-device-disc
! auto-rp groups
access-list 111 deny
ip any host 224.0.1.39
access-list 111 deny
ip any host 224.0.1.40
! scoped groups
access-list 111 deny
ip any 239.0.0.0 0.255.255.255
! loopback, private addresses (RFC 1918)
access-list 111 deny
ip 10.0.0.0 0.255.255.255 any
access-list 111 deny
ip 127.0.0.0 0.255.255.255 any
access-list 111 deny
ip 172.16.0.0 0.15.255.255 any
access-list 111 deny
ip 192.168.0.0 0.0.255.255 any
access-list 111 permit ip any any
181
Multicast Boundary Filter
Minimum Recommended
!deny auto-rp groups
access-list 1 deny 224.0.1.40
access-list 1 deny 224.0.1.39
!deny scoped groups
access-list 1 deny 239.0.0.0 0.255.255.255
!permit the rest of 224/4
access-list 1 permit 224.0.0.0 15.255.255.255
182
Single-Homed, ISP RP, Non-MBGP
PIM Border Constraints
Transit AS109
Tail-site Customer
pos0/0 1.1.1.2
pos0/0 1.1.1.1
RP
int pos0/0
ip pim sparse-dense-mode
192.168.100.0/24
Receiver
ip pim send-rp-announce Loopback0 scope 255
ip pim send-rp-discovery Loopback0 scope 255
int pos0/0
ip pim sparse-dense-mode
183
Single-Homed, ISP RP, Non-MBGP
Checking PIM Border (RP mapping)
Transit AS109
Tail-site Customer
pos0/0 1.1.1.1
pos0/0 1.1.1.2
RP
tail-gw#show ip pim rp mapping
PIM Group-to-RP Mappings
Receiver
Group(s) 224.0.0.0/4
192.168.100.0/24
RP 3.3.3.7 (loopback.transit.net), v2v1
Info source: 1.1.1.2 (tail.transit.net), via Auto-RP
Uptime: 21:57:41, expires: 00:02:08
184
Single-Homed, ISP RP, Non-MBGP
Checking PIM Border (RP mapping)
Transit AS109
Tail-site Customer
pos0/0 1.1.1.1
Receiver
pos0/0 1.1.1.2
RP
Transit-tail#show ip pim rp mapping
192.168.100.0/24
PIM Group-to-RP Mappings
This system is an RP (Auto-RP)
This system is an RP-mapping agent
Group(s) 224.0.0.0/4
RP 3.3.3.7 (loopback.transit.net), v2v1
Info source: 3.3.3.7 (loopback.transit.net), via Auto-RP
Uptime: 22:08:47, expires: 00:02:14
185
Single-Homed, ISP RP, Non-MBGP
Border RPF Check
Transit AS109
Tail-site Customer
pos0/0 1.1.1.1
pos0/0 1.1.1.2
RP
ip route 0.0.0.0 0.0.0.0 1.1.1.2
192.168.100.0/24
Receiver
ip route 192.168.100.0 255.255.255.0 1.1.1.1
router bgp 109
...
network 192.168.100.0 nlri unicast multicast
186
Single-Homed, ISP RP, Non-MBGP
MSDP RPF Check
Transit AS109
Tail-site Customer
pos0/0 1.1.1.1
pos0/0 1.1.1.2
RP
- no RP / no MSDP
192.168.100.0/24
Receiver
- no downstream RP
- no downstream MSDP peering
187
Single-Homed, Customer RP, Non-MBGP
PIM Border Constraints
Transit AS109
Tail-site Customer
pos0/0 1.1.1.1
pos0/0 1.1.1.2
RP
int pos0/0
ip pim sparse-mode
ip pim bsr-border
ip multicast boundary 1
192.168.100.0/24
Receiver
ip msdp sa-filter out 1.1.1.2 111
ip msdp sa-filter in 1.1.1.2 111
Note: Access-list 111 = Recommended SA Filter
188
Single-Homed, Customer RP, Non-MBGP
PIM Border Constraints
Transit AS109
Tail-site Customer
pos0/0 1.1.1.2
pos0/0 1.1.1.1
192.168.100.0/24
Receiver
int
ip
ip
ip
RP
pos0/0
pim sparse-mode
pim bsr-border
multicast boundary 1
ip msdp sa-filter out 1.1.1.1 111
ip msdp sa-filter in 1.1.1.1 111
Note: Access-list 111 = Recommended SA Filter
189
Single-Homed, Customer RP, Non-MBGP
Border RPF Check
Transit AS109
Tail-site Customer
pos0/0 1.1.1.1
pos0/0 1.1.1.2
RP
ip route 0.0.0.0 0.0.0.0 1.1.1.2
192.168.100.0/24
Receiver
ip route 192.168.100.0 255.255.255.0 1.1.1.1
router bgp 109
...
network 192.168.100.0 nlri unicast multicast
190
Single-Homed, Customer RP, Non-MBGP
MSDP RPF Check
Transit AS109
Tail-site Customer
pos0/0 1.1.1.1
pos0/0 1.1.1.2
RP
ip msdp peer 1.1.1.1 connect-source pos0/0
192.168.100.0/24
Receiver
ip msdp peer 1.1.1.2 connect-source pos0/0
191
Single-Homed, Customer RP, MBGP
PIM Border Constraints
Transit AS109
Tail-site Customer
pos0/0 1.1.1.1
pos0/0 1.1.1.2
RP
int pos0/0
ip pim sparse-mode
ip pim bsr-border
ip multicast boundary 1
192.168.100.0/24
Receiver
ip msdp sa-filter out 1.1.1.2 111
ip msdp sa-filter in 1.1.1.2 111
Note: Access-list 111 = Recommended SA Filter
192
Single-Homed, Customer RP, MBGP
PIM Border Constraints
Transit AS109
Tail-site Customer
pos0/0 1.1.1.2
pos0/0 1.1.1.1
192.168.100.0/24
Receiver
int
ip
ip
ip
RP
pos0/0
pim sparse-mode
pim bsr-border
multicast boundary 1
ip msdp sa-filter out 1.1.1.1 111
ip msdp sa-filter in 1.1.1.1 111
Note: Access-list 111 = Recommended SA Filter
193
Single-Homed, Customer RP, MBGP
Border RPF Check
Transit AS109
Tail-site Customer
pos0/0 1.1.1.1
pos0/0 1.1.1.2
RP
router bgp 100
network 192.168.100.0 nlri unicast multicast
neighbor 1.1.1.2 remote-as 109 nlri unicast multicast
neighbor 1.1.1.2 update-source pos0/0
192.168.100.0/24
Receiver
router bgp 109
neighbor 1.1.1.1 remote-as 100 nlri unicast multicast
neighbor 1.1.1.1 update-source pos 0/0
194
Single-Homed, Customer RP, MBGP
MSDP RPF Check
Transit AS109
Tail-site Customer
pos0/0 1.1.1.1
pos0/0 1.1.1.2
RP
ip msdp peer 1.1.1.1 connect-source pos0/0
192.168.100.0/24
Receiver
ip msdp peer 1.1.1.2 connect-source pos0/0
195
Which Mode—Sparse or Dense
• Sparse mode
– Must configure a Rendezvous Point (RP)
• Statically (on every Router)
• Using Auto-RP (Routers learn RP automatically)
• Using BSR (Routers learn RP automatically)
– Very efficient
• Uses Explicit Join model
• Traffic only flows to where it’s needed
– Separate control and data planes
• Router state only created along flow paths
• Deterministic topological behavior
– Scales better than dense mode
• Works for both sparsely or densely populated networks
196
Which Mode—Sparse or Dense
CONCLUSION
Virtually all production networks should
be configured to run in Sparse mode!
197
RP Placement
• Q: “Where do I put the RP?”
– A: “Generally speaking, it’s not critical”
• SPT’s are normally used by default
– RP is a place for source and receivers to meet
– Traffic does not normally flow through the RP
– RP is therefore not a bottleneck
• Exception: SPT-Threshold = Infinity
– Traffic stays on the shared tree
– RP could become a bottleneck
198
Static RP’s
• Hard-coded RP address
– When used, must be configured on every router
– All routers must have the same RP address
– RP fail-over not possible
• Exception: If Anycast RPs are used.
• Command
ip pim rp-address <address> [group-list <acl>] [override]
– Optional group list specifies group range
• Default: Range = 224.0.0.0/4 (Includes Auto-RP Groups!!!!)
– Override keyword “overrides” Auto-RP information
• Default: Auto-RP learned info takes precedence
199
Auto-RP Overview
• All routers automatically learn RP address
– No configuration necessary except on:
• Candidate RPs
• Mapping Agents
• Makes use of Multicast to distribute info
– Two specially IANA assigned Groups used
• Cisco-Announce - 224.0.1.39
• Cisco-Discovery - 224.0.1.40
– Typically Dense mode is used forward these groups
• Permits backup RP’s to be configured
• Can be used with Admin-Scoping
200
Auto-RP Fundamentals
• Candidate RPs
– Configured via global config command
ip pim send-rp-announce <intfc> scope <ttl> [group-list acl]
– Multicast RP-Announcement messages
• Sent to Cisco-Announce (224.0.1.39) group
• Sent every rp-announce-interval (default: 60 sec)
– RP-Announcements contain:
• Group Range (default = 224.0.0.0/4)
• Candidate’s RP address
• Holdtime = 3 x <rp-announce-interval>
201
Auto-RP Fundamentals
• Mapping agents
– Configured via global config command
ip pim send-rp-discovery scope <ttl>
– Receive RP-Announcements
• Select highest C-RP IP addr as RP for group range
• Stored in Group-to-RP Mapping Cache with holdtimes
– Multicast RP-Discovery messages
• Sent to Cisco-Discovery (224.0.1.40) group
• Sent every 60 seconds or when changes detected
– RP-Discovery messages contain:
• Contents of MA’s Group-to-RP Mapping Cache
202
Auto-RP Fundamentals
• All Cisco routers
– Join Cisco-Discovery (224.0.1.40) group
• Automatic
• No configuration necessary
– Receive RP-Discovery messages
• Stored in local Group-to-RP Mapping Cache
• Information used to determine RP for group range
203
C-RP
1.1.1.1
C
Announce
Announce
A
Announce
MA
B
Announce
Announce
MA
D
Announce
Announce
Auto-RP—From 10,000 Feet
Announce
C-RP
2.2.2.2
RP-Announcements multicast to the
Cisco Announce (224.0.1.39) group
Announce
204
Auto-RP—From 10,000 Feet
MA
A
C-RP
1.1.1.1
C
MA
B
D
C-RP
2.2.2.2
RP-Discoveries multicast to the
Cisco Discovery (224.0.1.40) group
Discovery
205
BSR Overview
• A single Bootstrap Router (BSR) is elected
– Multiple Candidate BSR’s (C-BSR) can be configured
• Provides backup in case currently elected BSR fails
– C-RP’s send C-RP announcements to the BSR
• C-RP announcements are sent via unicast
• BSR stores ALL C-RP announcements in the “RP-set”
– BSR periodically sends BSR messages to all routers
• BSR Messages contain entire RP-set and IP address of BSR
• Messages are flooded hop-by-hop throughout the network away
from the BSR
– All routers select the RP from the RP-set
• All routers use the same selection algorithm; select same RP
• BSR cannot be used with Admin-Scoping
206
BSR Fundamentals
• Candidate RPs
– Configured via global config command
– ip pim rp-candidate <intfc> [group-list acl]
– Unicast PIMv2 C-RP messages to BSR
• Learns IP address of BSR from BSR messages
• Sent every rp-announce-interval (default: 60 sec)
– C-RP messages contain:
• Group Range (default = 224.0.0.0/4)
• Candidate’s RP address
• Holdtime = 3 x <rp-announce-interval>
207
BSR Fundamentals
• Bootstrap router (BSR)
– Receive C-RP messages
• Accepts and stores ALL C-RP messages
• Stored in Group-to-RP Mapping Cache w/holdtimes
– Originates BSR messages
• Multicast to All-PIM-Routers (224.0.0.13) group
– (Sent with a TTL = 1)
• Sent out all interfaces. Propagate hop-by-hop
• Sent every 60 seconds or when changes detected
– BSR messages contain:
• Contents of BSR’s Group-to-RP Mapping Cache
• IP Address of active BSR
208
BSR Fundamentals
• Candidate bootstrap router (C-BSR)
– Configured via global config command
ip pim bsr-candidate <intfc> <hash-length> [priority
<pri>]
– <intfc>
» Determines IP address
– <hash-length>
» Sets RP selection hash mask length
– <pri>
» Sets the C-BSR priority (default = 0)
– C-BSR with highest priority elected BSR
– C-BSR IP address used as tie-breaker
» (Highest IP address wins)
– The active BSR may be preempted
» New router w/higher BSR priority forces new election
209
BSR Fundamentals
• All PIMv2 routers
– Receive BSR messages
• Stored in local Group-to-RP Mapping Cache
• Information used to determine active BSR address
– Selects RP using Hash algorithm
• Selected from local Group-to-RP Mapping Cache
• All routers select same RP using same algorithm
• Permits RP-load balancing across group range
210
BSR—From 10,000 feet
G
BSR Msgs
PIMv2
Sparse Mode
BSR Msgs
BSR
F
BSR Msgs
A
BSR Msgs
D
C-RP
B
C
C-RP
E
BSR Msgs Flooded Hop-by-Hop
211
Auto-RP vs BSR
• Auto-RP
– Easy to configure
– Supports Admin. Scoped Zones
– Works in either PIMv1 or PIMv2 Cisco networks
– Cisco proprietary
• BSR
– Easy to configure
– Does not support Admin. Scoped Zones
– Non-proprietary (PIMv2 networks only)
212
Anycast RP—Overview
• Uses single statically defined RP address
– Two or more routers have same RP address
• RP address defined as a Loopback Interface.
• Loopback address advertised as a Host route.
– Senders & Receivers Join/Register with closest RP
• Closest RP determined from the unicast routing table.
• MSDP session(s) run between all RPs
– Informs RPs of sources in other parts of network
– RPs join SPT to active sources as necessary
213
Anycast RP—Convergence
Src
Rec
RP1
RP2
MSDP Rec
X
10.0.0.1
10.0.0.1
Rec
Rec
Src
214
Anycast RP—Convergence
Src
Rec
RP1
X
RP2
Rec
10.0.0.1
10.0.0.1
Rec
Rec
Src
215
PIM Configuration Steps
• Enable Multicast Routing on every router
• Configure every interface for PIM
• Use Sparse-Dense Mode (to support Auto-RP)
• Configure the RP (if using Sparse Mode)
– Static RP addressing
• RP address must be configured on every router
– Using Auto-RP or BSR
• Configure certain routers as Candidate RP(s)
• All other routers automatically learn elected RP
216
Fool-Proof Multicast Configuration
RP/Mapping Agent
A
B
PIM
Sparse Mode
C
RP/Mapping Agent
D
On every router:
ip multicast-routing
ip pim accept-RP Auto-RP
On every interface:
ip pim sparse-dense-mode
On routers B and C:
ip pim send-rp-announce loopback0 scope <ttl>
ip pim send-rp-discovery loopback0 scope <ttl>
217
Classic Partial Multicast Cloud Mistake
src
T1
no ip pim dense-mode
56K
ip pim dense-mode
X
We’ll just use
the spare 56K line
for the IP Multicast
traffic and not
the T1.
RPF Failure!!!!!
Network
Engineer
rcvr
218
Beginner’s Guide to IP Multicast
JUST DO IT!
Enable multicast on ALL interfaces in ALL
routers in a given network. Failure to do
so will require complex (and typically
unnecessary) Multicast Traffic Engineering.
219
Agenda
•
•
•
•
•
•
What Is Multicast
Multicast Protocols
Multicast Configurations
Troubleshooting
Futures
Useful Links
220
Debugging and Troubleshooting
• Monitoring Tools
– sdr_monitor
• Kamil Sarac and Kevin Almeroth - UCSB
• http://www.cs.ucsb.edu/~ksarac/sdr-desc.html
• Several sites on Abilene and vBNS
– mlisten
• http://www.cc.gatech.edu/computing/Telecomm/mbone/
– Abilene Core Node Router Proxy
• http://hydra.uits.iu.edu/~abilene/proxy/
221
Debugging and Troubleshooting
• Multicast Looking Glass
– Written by NLANR Engineering Services
– Based on DIGEX Looking Glass
– Queries Pittsburgh GigaPoP multicast border
router for multicast information
– http://www.ncne.nlanr.net/tools/mlg2.html
222
Debugging and Troubleshooting
• Mtrace
– No longer gives coherent stats
– Won’t even traverse some routers
– Basically useless
• Multicast Debugging Handbook
– draft-ietf-mboned-mdh-02.txt
223
Debugging and Troubleshooting (cont.)
• Useful Cisco Commands
show ip sdr [detail | address | <“session name”>]
show ip mroute [summary | address | active]
show ip rpf <ip address>
show ip msdp [ summary | peer | count |
sa-cache ]
show ip mbgp [address | neighbor [ ip [adv]]
224
>show ip sdr
SDR Cache - 67 entries
2/5 ASSIST J Kerr Repeat
3/4 LAN Systems - NT & SMS in Labs
4J KRVM Radio
ABONE Discussion
BGMP/MASC discussion
CANARIE 5th Annual Advanced Networks Workshop(MPEG1)
dslab-test
ECG - Tunnel Test from UB
GT test
High Bandwidth Bird (HBB)
iBAND3 Keynotes [MP3] at Stardust.com
IMJ -- Channel 1
IMJ -- Channel 2
Korea Radio Broadcasting from SNU
...
225
>show ip sdr detail
SDR Cache - 68 entries
Session Name: BGMP/MASC discussion
Description: BGMP/MASC discussion
Group: 0.0.0.0, ttl: 0, Contiguous allocation: 1
Lifetime: from 12:30:00 EDT May 31 1999 until 19:50:00 EDT Jun 9 2000
Uptime: 12:17:02, Last Heard: 11:27:03
Announcement source: 128.9.160.100, destination:
224.2.127.254
Created by: pavlin 3136737610 3136737920 IN IP4 128.9.160.100
Phone number: Pavlin Radoslavov (USC/ISI) +1 310 822 1511 (ext. 8125)
Email: Pavlin Radoslavov (USC/ISI) <pavlin@catarina.usc.edu>
URL: http://netweb.usc.edu/bgmp/
Media: audio 17396 RTP/AVP 0
Media group: 224.2.134.153, ttl: 127
Attribute: ptime:40
Media: whiteboard 48173 udp wb
Media group: 224.2.188.133, ttl: 127
Media: text 56770 udp nt
Media group: 224.2.168.204, ttl: 127
226
>show ip sdr "NASA TV - Broadcast from NASA HQ"
SDR Cache - 68 entries
Session Name: NASA TV - Broadcast from NASA HQ
Description: NASA TV Multicasting from NASA HQ
Group: 0.0.0.0, ttl: 0, Contiguous allocation: 1
Lifetime: from 12:36:16 EDT Jun 11 1999 until 11:36:16 EST Dec 11 1999
Uptime: 1d17h, Last Heard: 18:21:10
Announcement source: 131.182.10.250, destination: 224.2.127.254
Created by: ellery 3132060082 3138107776 IN IP4 131.182.10.250
Phone number: +202 651 8512
Email: Ellery.Coleman@hq.nasa.gov
URL: http://www.nasa.gov/ntv
(Ellery D. Coleman)
Media: audio 23748 RTP/AVP 0
Media group: 224.2.203.38, ttl: 127
Media: video 60068 RTP/AVP 31
Media group: 224.2.203.37, ttl: 127
Attribute: framerate:9
Attribute: quality:8
Attribute: grayed:0
227
>show ip bgp neighbors 192.88.115.113
BGP neighbor is 192.88.115.113, remote AS 145, external link
Index 2, Offset 0, Mask 0x4
NEXT_HOP is always this router
BGP version 4, remote router ID 204.147.128.139
BGP state = Established, table version = 2, up for 05:54:44
Last read 00:00:05, last send 00:00:07
Hold time 90, keepalive interval 30 seconds
Neighbor NLRI negotiation:
Configured for unicast and multicast routes
Peer negotiated unicast and multicast routes
Exchanging unicast and multicast routes
...
Number of unicast/multicast prefixes received 0/6773
...
228
>show ip mbgp neigh 192.88.115.113 adv
Network
Next Hop
*> 128.182.0.0
0.0.0.0
*> 192.88.115.64/24 0.0.0.0
Metric LocPrf Weight Path
0
0
32768 i
32768 i
229
Agenda
•
•
•
•
•
•
What Is Multicast
Multicast Protocols
Multicast Configurations
Troubleshooting
Futures
Useful Links
230
Futures
• PIM modes designed for specific scalings
and applications
– Bidir-PIM
– Single Source Multicast (SSM)
231
Bidir PIM
• Designed for many to many multicast
groups
• Builds a single (*,G) shared tree which all
sources use
• Relieves the router from having to keep
state for each and every source
232
SSM
• Designed to allow receivers to specify the
single source which they wish to receive
traffic from, such as when viewing a
broadcast from a single provider
• Requires IGMPv3 so that receivers can tell
the first hop router which source they
want
• RP is not used
• Requires an out of band method to
discover the proper source (e.g. a web pag
or email
233
Agenda
•
•
•
•
•
•
What Is Multicast
Multicast Protocols
Multicast Configurations
Troubleshooting
Futures
Useful Links
234
Useful Links
• Multicast Documentation (FAQ and Tools):
http://www.ncne.nlanr.net/faq/multicast.html
• Cisco IOS Documentation
• Cisco IP Multicast:
ftp://ftp-eng.cisco.com/ipmulticast/
• Introduction to Multicast Routing:
http://www.3com.com/nsc/501303.html
• Send mail to ncne@nlanr.net
235