FreeBSD as multicast router

[Victor Gamov]

On 19/11/2019 03:49, Mike Karels wrote:
>> Hi All
> 
>> Still trying to run FreeBSD-box as multicast router :-)
> 
>> FreeBSD upgraded to 11.3-STABLE #1 r354778. netstat pacth by Mike Karels
>> manually applied and netstat -gs looks OK now.
> 
>> Latest pimd version 3.0beta1 downloaded from git and configured. While
>> configure it report following:
> 
>> =====
>> ------------------ Summary ------------------
>>    pimd version 3.0-beta1
>>     Prefix................: /usr/local
>>     Sysconfdir............: /usr/local/etc
>>     Localstatedir.........: /usr/local/var
>>     C Compiler............: cc -g -O2
> 
>> Optional features:
>>     Kernel register encap.: no
>>     Kernel (*,G) support..: no
>>     Kernel MAX VIFs.......: 32
>>     Memory save...........: no
>>     RSRR (experimental)...: no
>>     Exit on error.........: yes
>> =====
> 
>> What does "Kernel (*,G) support..: no" means?
> 
> 
>> Then my test multicast network configured (again)
>>           --------------------          ----------
>> -vlan298-| FreeBSD PIM router |-vlan299-| client |
>>          |208.34/29   205.2/29|         |205.5/29|
>>           --------------------          ----------
> 
> 
>> Two multicast generated by FreeBSD-router: one (232.232.9.43) sended
>> from vlan299 and another (232.232.88.173) from vlan298 both with TTL=20
> 
>> Pimd started with following config:
>> =====
>> phyint vlan299 enable ttl-threshold 20
>> phyint vlan298 enable ttl-threshold 20
>> rp-address 10.200.205.2 232.232.0.0/16
>> =====
> 
> If the threshold is 20 and the TTL is 20, does that mean that the TTL is
> just high enough, or is it at the cutoff?  I'd try lowering the threshold
> and/or increasing the TTL to see which it is.  If the TTL is 20 on the
> incoming side, it would be 19 on the outgoing side.

ttl-threshold changed to 10 in pimd.conf.  `netstat -g` reports 
Thresh=10 now.

Locally FreeBSD-router generated multicast vlan299 comes to receiver 
with ttl=20. And it's OK.

Locally FreeBSD-router generated multicast vlan298 does not comes to 
receiver.

Multicast generated from another sender on vlan298 comes to router with 
TTL=20 but never comes to receiver via vlan299

>> Now client is requesting multicast which router is sending from vlan299
>> and client successfully receiving it.  But when client is requests
>> multicast sending (by router) from vlan298 it doesn't receive it.
> 
> 
>> My first question: (in theory) is router must send multicast to client
>> in this situation?
> 
> In theory yes, modulo TTL and other checks.

I will reconfigure my test network to use dedicated FreeBSD-box as 
multicast router with two only multicast interfaces to get more clear 
info from `netstat -gs`


Also pimd periodically reports following
=====
Kernel busy, retrying (1/3) routing socket read in one sec
=====

Is it OK?


And more about pimd.  It creates register_vif0 on startup.  I assume it 
uses this interface (not reported by `ifconfig`) to route all multicast 
via.  But `netstat -g` reports this interface with threshold=1.  Is it OK?


-- 
CU,
Victor Gamov