一、问题：
在r3和r1之间使用了GRE通道，所有的路由器接口配置为sparse-mode,R4 ip为（1.1.4.4）但Ｒ１无法ping通多播源。
二、示意图如下：
multicast source -----R5------R3-------R223----R1--e0
............................................|
............................................|
............................................R4
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
三、原配置如下：
R1#mtrace 1.1.15.1 150.100.2.1 239.255.8.8
Type escape sequence to abort.
Mtrace from 1.1.15.1 to 150.100.2.1 via group 239.255.8.8
From source (?) to destination (?)
Querying full reverse path...
0 150.100.2.1
-1 1.1.12.5 PIM [default]
-2 1.1.12.3 PIM [default]
-3 1.1.16.4 PIM Reached RP/Core [1.1.15.0/24]
-4 1.1.16.3 PIM [default]
-5 1.1.16.4 PIM Reached RP/Core [1.1.15.0/24]
-6 1.1.16.3 PIM [default]
-7 1.1.16.4 PIM Reached RP/Core [1.1.15.0/24]
-8 1.1.16.3 PIM [default]
-9 1.1.16.4 PIM Reached RP/Core [1.1.15.0/24]
-10 1.1.16.3 PIM [default]
-11 1.1.16.4 PIM Reached RP/Core [1.1.15.0/24]
-12 1.1.16.3 PIM [default]
-13 1.1.16.4 PIM Reached RP/Core [1.1.15.0/24]
-14 1.1.16.3 PIM [default]
-15 1.1.16.4 PIM Reached RP/Core [1.1.15.0/24]
-16 1.1.16.3 PIM [default]
-17 1.1.16.4 PIM Reached RP/Core [1.1.15.0/24]
-18 1.1.16.3 PIM [default]
-19 1.1.16.4 PIM Reached RP/Core [1.1.15.0/24]
-20 1.1.16.3 PIM [default]
-21 1.1.16.4 PIM Reached RP/Core [1.1.15.0/24]
-22 1.1.16.3 PIM [default]
-23 1.1.16.4 PIM Reached RP/Core [1.1.15.0/24]
-24 1.1.16.3 PIM [default]
-25 1.1.16.4 PIM Reached RP/Core [1.1.15.0/24]
-26 1.1.16.3 PIM [default]
-27 1.1.16.4 PIM Reached RP/Core [1.1.15.0/24]
-28 1.1.16.3 PIM [default]
-29 1.1.16.4 PIM Reached RP/Core [1.1.15.0/24]
-30 1.1.16.3 PIM [default]
-31 1.1.16.4 PIM Reached RP/Core [1.1.15.0/24]
-32 1.1.16.3 PIM [default]
R1#
04:55:18: MRT: Update (*, 224.0.1.40), RPF Null, PC 0x354F1F4
R1#sh run
Building configuration...
Current configuration : 1546 bytes
!
version 12.1
no service single-slot-reload-enable
service timestamps debug uptime
service timestamps log uptime
no service password-encryption
!
hostname R1
!
logging rate-limit console 10 except errors
!
ip subnet-zero
no ip finger
no ip domain-lookup
!
ip multicast-routing
cns event-service server
!
!
!
interface Loopback0
ip address 1.1.1.1 255.255.255.0
ip ospf network point-to-point
!
interface Tunnel0
ip address 1.1.103.1 255.255.255.252
ip pim sparse-mode
tunnel source Loopback0
tunnel destination 1.1.3.3
!
interface Ethernet0
ip address 1.1.15.1 255.255.255.0
ip pim sparse-mode
!
interface Ethernet1
ip address 1.1.11.1 255.255.255.0
!
interface Serial0
no ip address
encapsulation frame-relay
no frame-relay inverse-arp
frame-relay lmi-type cisco
BR!
interface Serial0.1 point-to-point
ip address 1.1.8.1 255.255.255.252
frame-relay interface-dlci 106
!
interface Serial1
no ip address
shutdown
!
router ospf 64
router-id 1.1.1.1
log-adjacency-changes
area 0 authentication message-digest
area 11 virtual-link 1.1.3.3 message-digest-key 1 md5 cisco
passive-interface Tunnel0
network 1.1.1.1 0.0.0.0 area 11
network 1.1.8.1 0.0.0.0 area 11
network 1.1.11.1 0.0.0.0 area 11
network 1.1.15.1 0.0.0.0 area 10
!
ip kerberos source-interface any
ip classless
no ip http server
ip pim rp-address 1.1.4.4
ip mroute 150.100.2.0 255.255.255.0 Tunnel0
ip mroute 1.1.4.4 255.255.255.255 Tunnel0
!
!
!
line con 0
privilege level 15
logging synchronous
transport input none
line aux 0
line vty 0 4
login
!
end
```````````````````````````````````````````````````````````````
R1#sh ip pim interface
Address Interface Ver/ Nbr Query DR DR
Mode Count Intvl Prior
1.1.15.1 Ethernet0 v2/S 0 30 1 1.1.15.1
1.1.103.1 Tunnel0 v2/S 1 30 1 0.0.0.0
R1#sh ip pim nei
PIM Neighbor Table
Neighbor Interface Uptime/Expires Ver DR
Address Priority/Mode
1.1.103.2 Tunnel0 00:38:46/00:01:29 v2 1 / S
```````````````````````````````````````````````````````````````
R3#sh ip pim interface
Address Interface Ver/ Nbr Query DR DR
Mode Count Intvl Prior
1.1.16.3 Serial0/0 v2/S 1 30 1 1.1.16.4
1.1.12.3 Serial0/1.1 v2/S 1 30 1 1.1.12.5
1.1.103.2 Tunnel0 v2/S 1 30 1 0.0.0.0
R3#sh ip pim nei
R3#sh ip pim neighbor
PIM Neighbor Table
Neighbor Interface Uptime/Expires Ver DR
Address Prio/Mode
1.1.16.4 Serial0/0 04:21:08/00:01:26 v2 1 / DR S
1.1.12.5 Serial0/1.1 04:20:55/00:01:37 v2 1 / DR S
1.1.103.1 Tunnel0 00:40:26/00:01:20 v2 1 / S
R3#
R3#sh run
Building configuration...
Current configuration : 3174 bytes
!
! Last configuration change at 19:40:44 mgt Sun Feb 28 1993
!
version 12.2
service timestamps debug datetime msec
service timestamps log datetime msec
no service password-encryption
!
hostname R3
!
!
username R5 password 0 cisco
clock timezone mgt -8
ip subnet-zero
!
!
no ip domain lookup
ip multicast-routing
!
isdn switch-type basic-net3
!
!
voice call carrier capacity active
!
!
!
!
!
!
!
!
!
mta receive maximum-recipients 0
!
!
!
!
interface Loopback0
ip address 1.1.3.3 255.255.255.0
ip ospf network point-to-point
!
interface Tunnel0
ip address 1.1.103.2 255.255.255.252
ip pim sparse-mode
tunnel source Loopback0
tunnel destination 1.1.1.1
!
interface FastEthernet0/0
ip address 1.1.9.3 255.255.255.0
duplex auto
speed auto
standby use-bia
standby ip 1.1.9.1
standby priority 105
standby preempt
standby track Serial0/0
!
interface BRI0/0
no ip addres
s
encapsulation ppp
dialer pool-member 1
isdn switch-type basic-net3
!
interface Serial0/0
ip address 1.1.16.3 255.255.255.0
ip pim sparse-mode
encapsulation frame-relay
ip ospf network point-to-point
frame-relay map ip 1.1.16.4 314 broadcast
no frame-relay inverse-arp
frame-relay lmi-type cisco
!
interface FastEthernet0/1
ip address 1.1.10.3 255.255.255.0
duplex auto
speed auto
!
interface Serial0/1
no ip address
encapsulation frame-relay
no frame-relay inverse-arp
!
interface Serial0/1.1 multipoint
ip address 1.1.12.3 255.255.255.248
ip pim nbma-mode
ip pim sparse-mode
ip ospf message-digest-key 1 md5 cisco
ip ospf hello-interval 5
ip ospf priority 255
frame-relay map ip 1.1.12.2 302 broadcast
frame-relay map ip 1.1.12.5 305 broadcast
!
interface Dialer0
ip address 1.1.32.34 255.255.255.252
encapsulation ppp
ip ospf demand-circuit
