Associate
- Joined
- 14 Apr 2008
- Posts
- 1,230
- Location
- Manchester
We've come across a problem on one of our client sites to do with the way their multicast routing is setup.
Now, they have a requirement for this for some of their systems, our system was originally on their normal network (an office VLAN), when we ran up our system - which uses multicast for the bulk of it's data transfer it ground the core router to a halt.
From the packet trace it appears that the traffic was being forwarded onto all of the other VLANS (the packets appear multiple times with the same payload but differing MACs, indicating it's been routed)
The router was configured for ip pim sparse-dense-mode for each vlan which from my understanding would forward on all multicast packets it sees to every node on that network if there is no RP set up.
Since we didn't want or need to route our multicast data out of the VLAN we created a new VLAN and didn't define the use if ip pim sparse-dense mode so the config looked somthing like
interface vlan 76
ip address 172.16.76.3 255.255.255.0
No shutdown
Just a basic router interface, however we were still getting the problem that the router would grind to a halt when we reconnected the system.
Some suggestions on this would be very helpful - we're at a bit of a loss. So far the future ideas are to:
Find a way to properly disable multicast routing on a specific interface
ACL deny all traffic in and out of this interface (apart from a specific single TCP connection)
Fix the routing properly so that if there is a future requirement to route the data it'll then work!
Now, they have a requirement for this for some of their systems, our system was originally on their normal network (an office VLAN), when we ran up our system - which uses multicast for the bulk of it's data transfer it ground the core router to a halt.
From the packet trace it appears that the traffic was being forwarded onto all of the other VLANS (the packets appear multiple times with the same payload but differing MACs, indicating it's been routed)
The router was configured for ip pim sparse-dense-mode for each vlan which from my understanding would forward on all multicast packets it sees to every node on that network if there is no RP set up.
Since we didn't want or need to route our multicast data out of the VLAN we created a new VLAN and didn't define the use if ip pim sparse-dense mode so the config looked somthing like
interface vlan 76
ip address 172.16.76.3 255.255.255.0
No shutdown
Just a basic router interface, however we were still getting the problem that the router would grind to a halt when we reconnected the system.
Some suggestions on this would be very helpful - we're at a bit of a loss. So far the future ideas are to:
Find a way to properly disable multicast routing on a specific interface
ACL deny all traffic in and out of this interface (apart from a specific single TCP connection)
Fix the routing properly so that if there is a future requirement to route the data it'll then work!
