03-12-2009 05:50 PM - edited 03-06-2019 04:33 AM
Good Evening,
This morning when I went to multicast an I2 stream I discovered somehow my multicast is broken to my perimeter router. I can receive SAP announcements, IGMP memberships establish and PIM joins look good. By all accounts it should work.
I spent 14 hours working on this today and am extremely frustrated. I also contacted my local loop provider. Everything seems ok but except for one multicast stream that for some un-explainable reason works⦠no other multicast streaming works. I have tried multiple laptops on the right on the perimeter router, outside all firewalls. Also tried rebooting my router. I spanned my Internet 2 port to another port and put Wireshark on it. The one stream that works shows up plain as day in Wireshark. All the other streams I try don't show up anywhere in Wireshark. Internet 2 sees the traffic increase on their interface to me when I start a stream. My local loop provider also sees the increase in traffic but I don't seem to receive it on my router.
When I compare my router config to my backup from the Presidential Inauguration when I last personally used it...none of the changes made since then affect the I2 connection in any way. Unicast routing works fine. I am completely stumped on this. Has anyone ever seen anything like this on their end? Can someone offer up some advice please.
Regards,
Joe
03-13-2009 01:12 AM
Hello Joe,
a possible reason could be an RPF check failure:
a multicast stream that is not received on the interface on the best path to the source is dropped
So focus on multicast stream sources and verify with
sh ip rpf
see the following example
sh ip rpf 10.104.80.250
RPF information for ? (10.104.80.250)
RPF interface: TenGigabitEthernet7/1
RPF neighbor: ? (10.82.2.178)
RPF route/mask: 10.104.0.0/16
RPF type: unicast (isis)
RPF recursion count: 0
Doing distance-preferred lookups across tables
if multicast traffic sourced by 10.104.80.250 arrives on a different interface then te7/1 it is dropped
to be noted that this check doesn't allow parallel links:
unicast routing may support them but RPF takes only one path as best (highest ip address on interface)
Hope to help
Giuseppe
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide