[j-nsp] Use of lt-Interfaces on Juniper MX for binding multiple VPLS Instances to several CCC (unidirectional Ethernet P2P) Servcies RxTx-loop to same interface

[roger ratcliff]

Hallo Gerhard !

I was meditating over your question if just a single interface can be used
to bind VPLS instances to CCC. As you discussed the lt- interface and your
example shows that you are using vlan tags on your interface i assume you
want to have not only one VPLS bound to a ccc service but several vpls
instances bound to one ccc each.

So to stich the services together you have to be able to feed the traffic
which is egressing your port and which is looped back to the same port to a
DIFFERENT unit !!

>From my understanding of the concept of units you can not have the same
vlan-id twice on the same physical interface on different units. So you have
to change the vlan-id to move traffic to a different unit. If you do
something like,

xe-5/2/0 {
 per-unit-scheduler;
 flexible-vlan-tagging;
 encapsulation flexible-ethernet-services;
  unit 1 {
     encapsulation vlan-ccc;
     vlan-id 1;
     input-vlan-map {
         swap;
         vlan-id 2;
     }
     output-vlan-map swap;
     family ccc;
 }
}

then unit 1 is the vlan-id seen on the physical port and vlan-id 2 is the
vid used on the service pipe. So the unit and its vlan-id is glued together.
The swap is done on the vlan-id which is communicated within the service. A
packet arriving from a service can be swapped to the id of the port but a
frame egressing the port will alwas have the port vlan-id 1. So of you loop
this with a transmitt/receive loop it will hit the same unit.

You are NOT able to move it to a different unit by doing vlan-tag
operations. What you would need is a swap between the unit and the physical
port but what is done here is a swap between the unit and the service behind
the unit.

So from my point of view you can NOT bind any service using vlan-tags over a
transmitt/receive loop. The LT-Interface would be the right thing to use
here. If it does not work for you it is definitly a bug for the syntax you
proposed is correct.

In the forum there are people with more experience than i have so please
comment on my response for i am not totally sure my arguments are correct
here.
So can soneone do a comment on this please.

roger


On Fri, Oct 8, 2010 at 2:17 PM, Prochaska Gerhard <
gerhard.prochaska at a1telekom.at> wrote:

>
> Hi Roger !
>
> I am able to glue a VPLS Instance together with a CCC Service using a
> physical Hairpin. But alas to spend two 10G Interfaces just to stich a
> service ....
>
> Next thing i tried was to use the LT-Interface. I was surprised to see that
> i can only replicate unidirectional Traffic (eg Audio or Video) on a VPLS
> Instanz and then send it over the Netzwork with
> P2MP LSPs by stitching the services on an lt-Interface and that it does NOT
> work in the other direction.
>
> I wanted to replicate the streams on in the Target Node (as i do on the
> source node) using a VPLS Instance and binding the lt- port to the VPLS.
> Its strange but this did NOT work.
>
> So i like to find out if this is a bug or if there is a reason for this
> behaviour.
>
> Next i tried to use just a single port for the physical loop. Two ports are
> too expensive. Maybe i do something wrong in my config here for i m not
> familiary what can be done with
> VLAN Tag swapping and what restrictions exist here.
>
> What i mean with single port physical loop is that i connect the Rx and Tx
> Fiber of the same port and loop back the traffic exiting from one interface
> back to the same physical interface.
> I guess i can do this as VLAN-CCC wont do any MAC learning.
>
> The only thing is when i define the whole port with:
>
> encapsulation flexible-ethernet-service
> flexible-vlan-tagging
>
> and then define a unit which i like to connect to the VPLS Instance and one
> to bind to the CCC Service i can not find the correct syntax to swap
> VLAN-IDs to make traffic arriving on one the CCC unit
> go to the VPLS unit when reinserted to the port by the RxTx-Loop.
>
> Do you know if this can be done ?
>
> greetings
> Gerhard
>
>
>  ------------------------------
> *Von:* roger ratcliff [mailto:ratcliff.roger at googlemail.com]
> *Gesendet:* Freitag, 08. Oktober 2010 13:42
> *An:* Prochaska Gerhard
> *Betreff:* Re: [j-nsp] Use of lt-Interfaces on Juniper MX for binding
> multiple VPLS Instances to several CCC (unidirectional Ethernet P2P)
> Servcies
>
>  Hi Gerhard !
>
> As ccc is an uniderectional service it might be possible that the behaviour
> on an LT Interface differs for vpls to ccc stitching an ccc to vpls
> stitching.
> Is an interesting question as ccc is much easier to implement than standard
> Layer 2 point to point services. Please let me know the results if you get
> out of forum response for that problem.
>
> roger
>
> On Thu, Oct 7, 2010 at 7:05 PM, Prochaska Gerhard <
> gerhard.prochaska at a1telekom.at> wrote:
>
>>
>> When i tie a VPLS Instance to a CCC Service using an lt-Interface:
>>
>> Interface lt-x/x/x
>>  unit 100
>>  encapsulation vlan-vpls
>>    vlan-id 100
>>    peer-unit 200
>>
>>  unit 200
>>   encapsulation vlan-ccc
>>   vlan-id 100
>>   peer-unit 100
>>
>> protocol connections
>>
>> p2mp-receive switch "name"
>>  transmitt-p2mp-lsp "p2mp-lsp-name"
>>  input-interface lt-x/x/x.200
>>
>> Everything works as expected. So the lt-Interface transports traffic from
>> the VPLS Instance to the p2mp Tree.
>> When i change my config to pass traffic from the CCC Side to a VPLS
>> Instance via an lt-Interface my troubles start.
>>
>> Interface lt-x/x/x
>>  unit 100
>>  encapsulation vlan-vpls
>>    vlan-id 100
>>    peer-unit 200
>>
>>  unit 200
>>   encapsulation vlan-ccc
>>   vlan-id 100
>>   peer-unit 100
>>
>> protocol connections
>>
>> p2mp-receive switch "name"
>>  receive-p2mp-lsp "p2mp-lsp-name"
>>  output-interface lt-x/x/x.200
>>
>>  monitor interface lt-x/x/x shows traffic arriving at the lt-Interface
>> from the CCC Side but it is not passed on to the VPLS.
>>
>> Is this expected behaviour or a bug ? In other words:
>>
>> As CCC is a unidirectional service did Juniper only implement the VPLS ->
>> CCC direction and skip the CCC -> VPLS Part or should an LT-Interface
>> alsways be usable to tie VPLS and CCC together in both directions.
>>
>> VPLS -> CCC as well as CCC -> VPLS.
>>
>> Quick response would be very welcome !!
>>
>> Thx
>> Gerhard
>>
>>
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>
>