This lab tests your understanding regarding uRPF for multicast. R1 and R5 have a high speed link, ie. FastEthernet connecting them, they also have another path through frame-relay and through other routers making it a less preferred path, however, pim isn't configured across the high speed link. This is where multicast gets "broken". Because data traffic will flow through the high speed link and will also carry multicast traffic, you either need to enable PIM on the high speed link OR use static mroutes to point through the less preferred path.
Config:
R1 - R5 have a high speed connection, FastE, with no PIM configured - they also have a low speed connection with PIM configured.
R5#sh run
Building configuration...
Current configuration : 2247 bytes
!
hostname R5
!
ip cef
!
no ip domain lookup
ip multicast-routing
no ipv6 cef
!
multilink bundle-name authenticated
!
interface Loopback0
ip address 150.1.5.5 255.255.255.255
!
interface Serial1/0
no ip address
encapsulation frame-relay
serial restart-delay 0
no frame-relay inverse-arp
!
interface Serial1/0.54 point-to-point
ip address 150.1.45.5 255.255.255.0
ip pim dense-mode
snmp trap link-status
frame-relay interface-dlci 504
!
interface FastEthernet2/0
ip address 150.1.56.5 255.255.255.0
ip pim dense-mode
duplex auto
speed auto
!
interface FastEthernet2/1
ip address 150.1.15.5 255.255.255.0
duplex auto
speed auto
!
router ospf 1
log-adjacency-changes
network 0.0.0.0 255.255.255.255 area 0
!
ip forward-protocol nd
no ip http server
no ip http secure-server
!
!
ip mroute 10.1.37.7 255.255.255.255 Serial1/0.54
Verification:
Before applying the static mroute to R4 and R5
R5#sh ip mroute
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
L - Local, P - Pruned, R - RP-bit set, F - Register flag,
T - SPT-bit set, J - Join SPT, M - MSDP created entry,
X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
U - URD, I - Received Source Specific Host Report,
Z - Multicast Tunnel, z - MDT-data group sender,
Y - Joined MDT-data group, y - Sending to MDT-data group,
V - RD & Vector, v - Vector
Outgoing interface flags: H - Hardware switched, A - Assert winner
Timers: Uptime/Expires
Interface state: Interface, Next-Hop or VCD, State/Mode
(*, 224.0.1.40), 00:00:02/00:02:57, RP 0.0.0.0, flags: DCL
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
FastEthernet2/0, Forward/Dense, 00:00:02/00:00:00
Serial1/0.54, Forward/Dense, 00:00:02/00:00:00
R5#
After applying the static mroute to R4 and R5
R5#sh ip mroute
IP Multicast Routing Table
Flags: D - Dense, S - Sparse, B - Bidir Group, s - SSM Group, C - Connected,
L - Local, P - Pruned, R - RP-bit set, F - Register flag,
T - SPT-bit set, J - Join SPT, M - MSDP created entry,
X - Proxy Join Timer Running, A - Candidate for MSDP Advertisement,
U - URD, I - Received Source Specific Host Report,
Z - Multicast Tunnel, z - MDT-data group sender,
Y - Joined MDT-data group, y - Sending to MDT-data group,
V - RD & Vector, v - Vector
Outgoing interface flags: H - Hardware switched, A - Assert winner
Timers: Uptime/Expires
Interface state: Interface, Next-Hop or VCD, State/Mode
(*, 224.1.1.1), 00:00:14/stopped, RP 0.0.0.0, flags: D
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
FastEthernet2/0, Forward/Dense, 00:00:14/00:00:00
Serial1/0.54, Forward/Dense, 00:00:14/00:00:00
(10.1.37.7, 224.1.1.1), 00:00:14/00:02:52, flags: T
Incoming interface: Serial1/0.54, RPF nbr 150.1.45.4, Mroute
Outgoing interface list:
FastEthernet2/0, Forward/Dense, 00:00:14/00:00:00
(*, 224.0.1.40), 00:03:16/00:01:53, RP 0.0.0.0, flags: DCL
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
FastEthernet2/0, Forward/Dense, 00:03:16/00:00:00
Serial1/0.54, Forward/Dense, 00:03:16/00:00:00
R5#
