Multicast ip-pim-sparse mode

Question

Hi, my consideration are correct  for the multicast protocol ?
As for the command "ip pim rp-address 173.17.2.1 VALID_GROUP" which is on the site of Padriciano I did a search and, practically, it automatically creates a tunnel interface.
  This thing, as I said, you need to create / enable multicast. Being something of CCNP R & S do not know the different syntax but "PIM" stands for Protocol-Independent Multicast.
  Because you do not have to do often directly with the multicast explain it to follow but it is as a reality check for me:
  Multicast uses the connectionless protocol UDP for transport (transport layer, Layer 4 - L4) and allows you to send, with just sending the same packet to multiple nodes; since UDP does not guarantee delivery. You can think of as a multicast broadcast changed.
  For example: if you have 6 nodes (node = router), for simplicity called ABCDEF, and the node A has to send a packet only to nodes BCDF (excluding the node E) then, with multicast, the packet is sent only once and is delivered to all hosts BCD F.
  That's the theory but in practice petty commands ip pim NOT know them being the subject of CCNP R & S.
>> A concrete example of multicast: the election of the DR (Designated Router) and the Des BDR (Backup ignated Router) in multiaccess networks (such as Frame Relay networks) with OSPF.
  All routers in the network that are NOT DR or BDR are Drothers (read as DR-Others). The Drothers can only communicate with the DR (simultaneously with the BDR).
This feature allows you to NOT flood the LSA (Link State Advertisement) to all routers in the network so that only the Drothers send their LSA to the DR and BDR using the multicast address 224.0.0.6 IPv4 or IPv6 multicast address ff02 :: 6.
  224.0.0.6 and ff02 :: 6 = all routers DR
  When the DR receives packets is responsible for forwarding these LSA to all other routers. The DR uses the multicast address 224.0.0.5 IPv4 or IPv6 multicast address ff02 :: 5. The end result is that there is only one router that does the flooding of all LSA in the multiaccess network.
>> 224.0.0.5 and ff02 :: 5 = all OSPF routers
ip multicast-routing
interface GigabitEthernet0/1.134
 description LAN EDA
 encapsulation dot1Q 134
 ip address 134.1.192.31 255.255.255.240
 no ip redirects
 ip directed-broadcast
 standby 134 ip 134.1.192.33
 standby 134 timers msec 300 msec 950
 standby 134 priority 90
 standby 134 preempt delay reload 10
 no shutdown
router ospf 1
 network 134.1.192.32 255.255.255.240 area 15    ! LAN PMU
! Avalaible Routing Multicast for LAN EDA
ip multicast-routing
interface GigabitEthernet0/0
 ip pim sparse-mode
interface GigabitEthernet0/1.500
 ip pim sparse-mode
interface Serial0/1/0.36 point-to-point
 ip pim sparse-mode
interface GigabitEthernet0/1.134
 ip pim sparse-mode
 ip igmp join-group 224.0.224.1
ip pim rp-address 173.17.2.1 VALID_GROUP
ip access-list standard VALID_GROUP
 permit 224.0.224.1
router ospf 1
 network 134.1.192.32 255.255.255.240 area 15    ! LAN PMU
! Avalaible Routing Multicast for LAN EDA
ip multicast-routing
interface GigabitEthernet0/0
 ip pim sparse-mode
interface GigabitEthernet0/1.500
 ip pim sparse-mode
interface Serial0/1/0.39 point-to-point
 ip pim sparse-mode
interface GigabitEthernet0/1.134
 ip pim sparse-mode
 ip igmp join-group 224.0.224.1
ip pim rp-address 173.17.2.1 VALID_GROUP
ip access-list standard VALID_GROUP
 permit 224.0.224.1
I did some tests simulated and I think I figured out why is assigned an IP address instead of another.
 Given that the interface Tunnel0 is created when you type the command "ip pim rp-address 173.17.2.1 VALID_GROUP", in the tests I've done, I Tunnel0 Bind to the IP address associated with the FastEthernet0/0.
R-SCTI-PADRICIANO-1#sh ip int b
>>     Interface                  IP-Address      OK? Method Status             Protocol
>>     FastEthernet0/0            173.27.200.22   YES manual up                    up
>>     FastEthernet0/1            unassigned      YES manual up                    up
>>     FastEthernet0/1.20         172.27.195.118  YES manual up                    up
>>     FastEthernet0/1.30         172.27.230.100  YES manual up                    up
>>     FastEthernet0/1.31         173.27.254.118  YES manual up                    up
>>     FastEthernet0/1.32         173.27.216.28   YES manual up                    up
>>     FastEthernet0/1.134        134.1.192.33    YES manual up                    up
>>     FastEthernet0/1.500        172.27.250.37   YES manual up                    up
>>     Serial1/0                  unassigned      YES unset  administratively down down
>>     Serial1/1                  unassigned      YES unset  administratively down down
>>     Serial1/2                  unassigned      YES unset  administratively down down
>>     Serial1/3                  unassigned      YES unset  administratively down down
>>     Loopback0                  172.27.254.10   YES manual up                    up
>>     Tunnel0                    173.27.200.22   YES unset  up                    down
R-SCTI-PADRICIANO-1#conf t
>>     R-SCTI-PADRICIANO-1(config)#int f0/0
>>     R-SCTI-PADRICIANO-1(config-if)#sh
>>     *Feb  6 16:09:31.439 CET: %LINK-5-CHANGED: Interface FastEthernet0/0, changed state to administratively down
>>     *Feb  6 16:09:32.439 CET: %LINEPROTO-5-UPDOWN: Line protocol on Interface FastEthernet0/0, changed state to down
>>     R-SCTI-PADRICIANO-1(config-if)#do sh ip int b
>>     Interface                  IP-Address      OK? Method Status                Protocol
>>     FastEthernet0/0            173.27.200.22   YES manual administratively down down
>>     FastEthernet0/1            unassigned      YES manual up                    up
>>     FastEthernet0/1.20         172.27.195.118  YES manual up                    up
>>     FastEthernet0/1.30         172.27.230.100  YES manual up                    up
>>     FastEthernet0/1.31         173.27.254.118  YES manual up                    up
>>     FastEthernet0/1.32         173.27.216.28   YES manual up                    up
>>     FastEthernet0/1.134        134.1.192.33    YES manual up                    up
>>     FastEthernet0/1.500        172.27.250.37   YES manual up                    up
>>     Serial1/0                  unassigned      YES unset  administratively down down
>>     Serial1/1                  unassigned      YES unset  administratively down down
>>     Serial1/2                  unassigned      YES unset  administratively down down
>>     Serial1/3                  unassigned      YES unset  administratively down down
>>     Loopback0                  172.27.254.10   YES manual up                    up
>>     Tunnel0                    172.27.250.37   YES unset  up                    down
>> 
>> IP address Tunnel0 = IP address FastEthernet0/1.500

Answer 1

Well, this is all looks like it is has to be. What confuses you?
Tun0 created by pim process to decapsulate multicast traffic coming to RP from source router. It doesn't matter what ip used inside of this interface.