Re: Re: Multicast Loopback strange behaviour

Nadeem,

As I said previously, you are sending two pings, one from each PIM enabled
interface. Not sure the purpose, but this has always been my experience.

On Tue, Dec 1, 2009 at 7:02 AM, <nrafia_at_gmail.com> wrote:

> Thanks Bryan for taking your time..
>
> out put of ip ICMP on sender and receive both
>
>
> Aluminum#ping 236.82.134.23
>
> Type escape sequence to abort.
> Sending 1, 100-byte ICMP Echos to 236.82.134.23, timeout is 2 seconds:
>
> *Mar 1 00:08:39.099: ICMP: echo reply rcvd, src 172.16.2.241, dst
> 172.16.2.233
> *Mar 1 00:08:39.127: ICMP: echo reply rcvd, src 172.16.2.241, dst
> 172.16.1.1
>
> Reply to request 0 from 172.16.2.241, 16 ms
> Reply to request 0 from 172.16.2.241, 40 ms
>
>
> Iron#
> *Mar 1 00:08:39.343: ICMP: echo reply sent, src 172.16.2.241, dst
> 172.16.2.233
> *Mar 1 00:08:39.375: ICMP: echo reply sent, src 172.16.2.241, dst
> 172.16.1.1
>
> why two ICMP replies are being received? Thanks again for any input...
>
>
> Best Regards,
>
> Nadeem Rafi
>
>
> On Dec 1, 2009 4:26pm, Bryan Bartik <bbartik_at_ipexpert.com> wrote:
> > Nadeem,
> >
> > The router is probably sending multiple pings, one for each interface
> enabled with PIM. You should be able to do "debug ip icmp" to verify this.
> >
> > On Tue, Dec 1, 2009 at 3:26 AM, nrafia_at_gmail.com> wrote:
> >
> > Hi GS,
> >
> >
> >
> > i have configured few routers in series Aluminum-->Platinum -->Brass (RP)
> >
> > -->TIN -->Iron (Jeff-vol-2 chapter 5,page:505). On Aluminum i have
> >
> > configured one l0 ip add 172.16.1.1 255.255.255.0 instead of attaching
> host.
> >
> >
> >
> > when i ping 236.82.134.23 (iron multicast group joined by loopback). i
> got
> >
> > following output...
> >
> >
> >
> > Aluminum#ping 236.82.134.23 rep 3
> >
> >
> >
> > Type escape sequence to abort.
> >
> > Sending 3, 100-byte ICMP Echos to 236.82.134.23, timeout is 2 seconds:
> >
> >
> >
> > Reply to request 0 from 172.16.2.241, 20 ms
> >
> > Reply to request 0 from 172.16.2.241, 24 ms
> >
> > Reply to request 1 from 172.16.2.241, 12 ms
> >
> > Reply to request 1 from 172.16.2.241, 16 ms
> >
> > Reply to request 2 from 172.16.2.241, 8 ms
> >
> > Reply to request 2 from 172.16.2.241, 12 ms
> >
> >
> >
> > why i am getting duplicate replies?
> >
> >
> >
> >
> >
> > second sh ip mroute on Aluminum (ping originator) shows
> >
> >
> >
> > Aluminum#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
> >
> > Outgoing interface flags: H - Hardware switched, A - Assert winner
> >
> > Timers: Uptime/Expires
> >
> > Interface state: Interface, Next-Hop or VCD, State/Mode
> >
> >
> >
> > (*, 236.82.134.23), 00:02:08/stopped, RP 172.16.224.1, flags: SPF
> >
> > Incoming interface: Serial1/0, RPF nbr 172.16.2.234
> >
> > Outgoing interface list: Null
> >
> >
> >
> > (172.16.1.1, 236.82.134.23), 00:02:08/00:03:21, flags: FT
> >
> > Incoming interface: Loopback0, RPF nbr 0.0.0.0
> >
> > Outgoing interface list:
> >
> > Serial1/0, Forward/Sparse, 00:01:48/00:02:40
> >
> >
> >
> > (*, 224.0.1.40), 00:02:11/00:02:19, RP 172.16.224.1, flags: SJCL
> >
> > Incoming interface: Serial1/0, RPF nbr 172.16.2.234
> >
> > Outgoing interface list:
> >
> > Loopback0, Forward/Sparse, 00:02:11/00:02:19
> >
> >
> >
> > all other routers shows
> >
> >
> >
> > Iron#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
> >
> > Outgoing interface flags: H - Hardware switched, A - Assert winner
> >
> > Timers: Uptime/Expires
> >
> > Interface state: Interface, Next-Hop or VCD, State/Mode
> >
> >
> >
> > (*, 236.82.134.23), 00:09:04/stopped, RP 172.16.224.1, flags: SJCL
> >
> > Incoming interface: Serial1/0, RPF nbr 172.16.2.242
> >
> > Outgoing interface list:
> >
> > Loopback0, Forward/Sparse, 00:09:04/00:02:46
> >
> >
> >
> > (172.16.2.233, 236.82.134.23), 00:06:34/00:02:52, flags: LJT
> >
> > Incoming interface: Serial1/0, RPF nbr 172.16.2.242
> >
> > Outgoing interface list:
> >
> > Loopback0, Forward/Sparse, 00:06:34/00:02:46
> >
> >
> >
> > (172.16.1.1, 236.82.134.23), 00:06:34/00:02:52, flags: LJT
> >
> > Incoming interface: Serial1/0, RPF nbr 172.16.2.242
> >
> > Outgoing interface list:
> >
> > Loopback0, Forward/Sparse, 00:06:34/00:02:46
> >
> >
> >
> > (*, 224.0.1.40), 00:09:04/00:02:49, RP 172.16.224.1, flags: SJCL
> >
> > Incoming interface: Serial1/0, RPF nbr 172.16.2.242
> >
> > Outgoing interface list:
> >
> > Loopback0, Forward/Sparse, 00:09:04/00:02:49
> >
> >
> >
> > my second question. why on originator its mapping to loopback 172.16.1.1,
> >
> > instead of serial interface? and why on all the rest of the routers i can
> >
> > see two mapping, one for loopback and one for serial?
> >
> >
> >
> > Thanks in advance for any help.
> >
> >
> >
> >
> >
> > Best Regards,
> >
> >
> >
> > Nadeem Rafi
> >
> >
> >
> >
> >
> > Blogs and organic groups at http://www.ccie.net
> >
> >
> >
> > _______________________________________________________________________
> >
> > Subscription information may be found at:
> >
> > http://www.groupstudy.com/list/CCIELab.html
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> >
> > --
> > Bryan Bartik
> > CCIE #23707 (R&S, SP), CCNP
> > Sr. Support Engineer - IPexpert, Inc.
> > URL: http://www.IPexpert.com
> >
>

-- 
Bryan Bartik
CCIE #23707 (R&S, SP), CCNP
Sr. Support Engineer - IPexpert, Inc.
URL: http://www.IPexpert.com
Blogs and organic groups at http://www.ccie.net