[f-nsp] Fwd: Multicasting config example?

debbie fligor fligor at illinois.edu
Tue Feb 24 12:45:11 EST 2009 


On Feb 24, 2009, at 11:10, Kenneth Hellmann wrote:

> Good feedback Debbie, but I have to remind everyone that this isn't  
> magic.
> Everything happens for a reason, and throwing out every config  
> config line
> in the book and hoping that something sticks isn't the correct way to
> proceed.

Absolutely right Ken.  I wrote that longer example before the config  
had been posted with no idea what he'd set or not set yet.


>
>
> Bjorn,
>
> The reason that your original config worked is because both ports  
> were on
> the same vlan. Even though they had separate ip addresses, they were  
> both on
> vlan 1. Because they were on the same vlan and you had ip multicast  
> active,
> igmp would allow the join.
>
> When you changed the vlan to 13, they were not on the same vlan, and  
> since
> pim wasn't configured on the ve, there was no multicast routing  
> protocol to
> route from one subnet to the other.

sorry about that Bjorn, we usually use "route-only" in devices where  
we put IP addresses on physical interfaces, and so that was how I was  
thinking about it.  we very seldom put IP addresses directly on ports,  
we do almost everything with VEs.  I think Ken has pegged your problem.

>
>
> If you want to send a multicast from one subnet to another, simply  
> enable
> pim on both subnets.

That will work while everything is in box A, but if he wants it to  
work between interfaces in box A and box B as he asked originally, I  
think he'll still need to get OSPF on some more interfaces or things  
wont go.


>
>
> It is not magic. And Foundry doesn't do it any differently from  
> anyone else.

We're constantly being told by Foundry that we can do certain things  
only on routed ports, not on VEs, so there are some things that can be  
different.  I think you're right though, this isn't one of them.

>
>
> Ken
>
> -----Original Message-----
> From: foundry-nsp-bounces at puck.nether.net
> [mailto:foundry-nsp-bounces at puck.nether.net] On Behalf Of debbie  
> fligor
> Sent: Wednesday, February 25, 2009 1:03 AM
> To: foundry-nsp at puck.nether.net
> Subject: [f-nsp] Fwd: Multicasting config example?
>
> I hadn't meant to take this off list. In case someone else is
> following along and having fun with multicast on the MLXs, here's what
> I sent yesterday.
>
> Begin forwarded message:
>
>> From: debbie fligor <fligor at illinois.edu>
>> Date: February 23, 2009 15:09:06 CST
>> To: Bjørn Skovlund Rydén <BSR at fullrate.dk>
>> Cc: debbie fligor <fligor at illinois.edu>
>> Subject: Re: [f-nsp] Multicasting config example?
>>
>> For multicast between subnets to work you need more info than you'll
>> find in the MLX config guides (IMO).
>>
>> Some of this you might have done, but here's the steps:
>>
>> globally enable ip multicast-routing.  reboot even if it doesn't
>> tell you to.  turn on pim routing
>>
>> tell pim routing to use your favorite mix of routes in what order.
>> we do multicast specific, unicast specific, multicast default, and
>> unicast default, in that order.   our default leaves campus though,
>> and multicast leaves in a different path than unicast does.  If your
>> multicast and unicast networks are identical, it's not too important
>> which order is setup.
>>
>> Pick an IP address to be your RP.  preferably one on a loopback so
>> it's not tied to a specific subnet or device.  set that to be the RP
>> candidate on the MLX it's configured on.  Tell all the MLXs that is
>> the RP address. you can use BSR, but best practice is currently to
>> hard code it and not use BSR.
>>
>> Then make sure you've got ip pim-sparse set on the ve for the vlan,
>> as well as the routed interface and the loopback that is the RP and
>> all the routing links between the two boxes.
>>
>>
>> so for the device that's the RP here's an example bit of config:
>>
>>
>> ip multicast-routing
>>
>> router pim
>> route-precedence mc-non-default uc-non-default mc-default uc-default
>>
>> interface loopback 2
>> port-name RP for on-campus
>> ip ospf area 0
>> ip address 130.126.0.145/32
>> ip pim-sparse
>>
>> router pim
>> rp-address 130.126.0.145
>> rp-candidate loopback 2
>> !
>> interface ve 3502
>> port-name uiuc-core1-dist11-lnk
>> ip ospf area 0
>> ip address 172.20.20.5/30
>> ip pim-sparse
>> ip mtu 9000
>> !
>>
>>
>> and then here's the config bits on distribution devices that matter
>> for getting things between the MLXs and to the user networks.
>>
>>
>> router pim
>> route-precedence mc-non-default uc-non-default mc-default uc-default
>>
>> router pim
>> rp-address 130.126.0.145
>>
>>
>> interface ve 3502
>> port-name uiuc-core1-dist11-lnk
>> ip ospf area 0
>> ip address 172.20.20.6/30
>> no ip redirect
>> ip pim-sparse
>>
>> interface ve 499
>> port-name uiuc-test2wireless-net
>> ip ospf area 1
>> ip ospf passive
>> ip address 192.17.201.1/24
>> no ip redirect
>> ip helper-address 128.174.45.8
>> ip pim-sparse
>>
>>
>>
>> If this wasn't enough detail, let me know what questions you still
>> have.  Some weeks we feel like we are Foundry's only multicast QA
>> department.
>>
>> I almost forgot, you want to be running something really current
>> like 3.9.00a or later for them to have fixed most of the multicast
>> bugs.
>>
>> -debbie
>>
>>
>> On Feb 23, 2009, at 14:45, Bjørn Skovlund Rydén wrote:
>>
>>> Hi everyone,
>>>
>>> Sorry to bother you for this, but my technical friend at Foundry
>>> seems to have gone on vacation for a few weeks, and I’d like to get
>>> on with this.
>>>
>>> We’re running a mesh of 6 MLX’s with distribution rings based on
>>> FES/FESX. I’m now starting to look at multicasting and having read
>>> back and forth in the config-guide, I’m still a bit clueless as to
>>> how to get the simplest thing to work.
>>>
>>> I would like to receive multicast traffic on a VLAN on MLX A and
>>> have recipient on MLX B on a routed interface. Very basic stuff,
>>> I’d say, but after a day in the test-lab, I’m still not successful :
>>> ( So can someone give me the most basic configuration example on
>>> how to do this?
>>>
>>> Kind regards,
>>> Bjørn
>>> _______________________________________________
>>> foundry-nsp mailing list
>>> foundry-nsp at puck.nether.net
>>> http://puck.nether.net/mailman/listinfo/foundry-nsp
>>
>> -----
>> -debbie
>> Debbie Fligor, n9dn       Network Engineer, CITES, Univ. of Il
>> email: fligor at illinois.edu          <http://www.uiuc.edu/ph/www/
>> fligor>
>>                  "My turn."  -River Tam
>>
>>
>>
>>
>>
>
> -----
> -debbie
> Debbie Fligor, n9dn       Network Engineer, CITES, Univ. of Il
> email: fligor at illinois.edu          <http://www.uiuc.edu/ph/www/ 
> fligor>
>                    "My turn."  -River Tam
>
>
>
>
>
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-----
-debbie
Debbie Fligor, n9dn       Network Engineer, CITES, Univ. of Il
email: fligor at illinois.edu          <http://www.uiuc.edu/ph/www/fligor>
                    "My turn."  -River Tam

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