PIM in a flat network

[vigneswaran]

Hello,

I am trying to use PIM (v2.1.8) in a network where all the links are in the same subnet (with /0 netmask). This is a kind of MANET and nodes can move and connect to any other node. So, we are using flat network with OLSR as the routing protocol. (As of now, this is being simulated using wired network only. Later we will use wireless.)

The problem we face is if multiple Interfaces are there in the same subnet, pimd listens only on one Interface and ignores the rest. Is there any way to overcome this? Thank you.

Regards,
Vignesh

[troglobit]

Not that I know of, without hacking the source.

[vigneswaran]

On 02/26/2013 11:02 AM, Joachim Nilsson wrote:

Not that I know of, without hacking the source.

Thanks for your quick reply. Whether ignoring Interface is
implementation dependent or by design (RFC)?

Regarding hacking the code, I tried a bit by just commenting the lines
in 'config.c' which seem to be ignoring the Interfaces in same subnet.

/* if ((addr & v->uv_subnetmask) == v->uv_subnet ||
(v->uv_subnet & mask) == subnet) {
logit(LOG_WARNING, 0, "Ignoring %s, same subnet as %s",
ifr.ifr_name, v->uv_name);
break;
}*/

However, it is not enough. Does it require any data structure level
change too? (like, instead of using only the 'Subnet' as the key to
maintain the 'Neighbors' list, using 'Local-Address' + 'Subnet' as the
combined key. I am just asking based on the 'Virtual Interface Table'
output). Thank you once again.

Regards,
Vignesh

[troglobit]

I'm not really sure if what you're trying to do will work in practise.
Aren't you better of setting up GRE tunnels and running pimd
between the end points you want to forward multicast?

[vigneswaran]

On 02/26/2013 11:32 AM, Joachim Nilsson wrote:

I'm not really sure if what you're trying to do will work in practise.
Aren't you better of setting up GRE tunnels and running pimd
between the end points you want to forward multicast?

Ok. I will try PIMd with GRE tunnels then. Thank you.