Go CCIE Go!! - A Cisco Certified Internetwork Expert

Hi Backbone,
Just do “deb ip pack det”. It will show you that the router will send a copy to each ip-enabled interface using each interface IP address as the source.
The story is different on the receiving side (RPF check, group membership ..etc)……
Rack1R1#deb ip pack det IP packet debugging is on (detailed) Rack1R1#ping 224.1.1.1
Type escape sequence to abort. Sending 1, 100-byte ICMP Echos to 224.1.1.1, timeout is 2 seconds:
*Dec 31 15:45:23.340: IP: s=145.1.125.1 (local), d=224.1.1.1 (Serial0/0), len 100, sending broad/multicast *Dec 31 15:45:23.340: ICMP type=8, code=0 *Dec 31 15:45:23.340: IP: s=145.1.12.1 (local), d=224.1.1.1 (Serial0/1.12), len 100, sending broad/multicast *Dec 31 15:45:23.340: ICMP type=8, code=0 *Dec 31 15:45:23.340: IP: s=145.1.13.1 (local), d=224.1.1.1 (Serial0/1.13), len 100, sending broad/multicast *Dec 31 15:45:23.344: ICMP type=8, code=0 *Dec 31 15:45:23.344: IP: s=145.1.17.1 (local), d=224.1.1.1 (FastEthernet2/0), len 100, sending broad/multicast *Dec 31 15:45:23.344: ICMP type=8, code=0 *Dec 31 15:45:23.344: IP: s=144.144.144.253 (local), d=224.1.1.1 (FastEthernet2/1), len 100, sending broad/multicast *Dec 31 15:45:23.344: ICMP type=8, code=0 *Dec 31 15:45:23.344: IP: s=150.1.1.1 (local), d=224.1.1.1 (Loopback0), len 100, sending broad/multicast *Dec 31 15:45:23.348: ICMP type=8, code=0 *Dec 31 15:45:23.348: IP: s=145.1.111.111 (local), d=224.1.1.1 (Loopback1), len 100, sending broad/mult
Rack1R1#shint Interface IP-Address OK? Method Status Protocol Serial0/0 145.1.125.1 YES NVRAM up up Serial0/1 unassigned YES NVRAM up up Serial0/1.12 145.1.12.1 YES NVRAM up up Serial0/1.13 145.1.13.1 YES NVRAM up up Ethernet1/0 unassigned YES NVRAM up down FastEthernet2/0 145.1.17.1 YES NVRAM up up FastEthernet2/1 144.144.144.253 YES NVRAM up up Loopback0 150.1.1.1 YES NVRAM up up Loopback1 145.1.111.111 YES manual up up
On 12/31/07, backbone systems wrote: > if i ping to > ping 224.1.1.1 than there must be some dource from which i am pinging ??? > what is the source > > On Dec 31, 2007 6:27 PM, Joseph Saad wrote: > > > It doesn’t. It sends the packet on all interfaces, unless you force it via > > extended ping. > > > > On Dec 31, 2007 5:36 PM, backbone systems > > wrote: > > > > > Hey, > > > > > > sorry for this basic question . on a router if i have 3 ethernet and 1 > > > loop > > > back interface with sparse-mode enabled. When i ping from the serial > > > interface across the FR cloud > > > how does the multicast choose the source interface. > > > > > > when i do debug ip mpacket i can see for different ping chooses > > > different > > > ether/lo interfaces > > > > > > What is the logic? > > > > > > BB > > > > > > _______________________________________________________________________ > > > Subscription information may be found at: > > > http://www.groupstudy.com/list/CCIELab.html > > _______________________________________________________________________ > Subscription information may be found at: > http://www.groupstudy.com/list/CCIELab.html >
— Kind Regards,
Bajo