[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

Fri Oct 8 09:34:12 EDT 2010

Hi !

We have a very special customer which is very sensible on packet loss. We tried VPLS with P2MP LSP and we have untolerable packet loss when we add/remove a
leaf to/from the P2MP Tree. We also have to provide the "make befor break" feature in situations when a wan link is taken out of order (at a previously known point of time; = scheduled repair work)
without packet loss an ongoing video transmission.

So now we use P2MP-LSPs with CCC, to distibute the traffic but we have two problems:

1. We need several copies of the Signal on the Node where the video source is.

The solution was a local VPLS instance (local means only inside a node not spanning several nodes).

So when we feed a signal to a node we have to be able to replicate a signal on the same node to make it possible to have a tester or other equippment connected to the node where the signal source resides.
So this need for local replication before even P2MP LSPs come into play is one reason why we use LT-Interfaces and physical loops to bind a local VPLS (which only exists on this one node and does not span over the network).

2. The second problem is, that we have packet loss when we add/remove an output-interfaces on the Target Node.

 We have to be able to have the same stream on multiple ports at the target site. We noticed that when we add or remove an output interface on the receive switch on the target node
we have massiv packet loss on the other interfaces which are part of the same connection (which means part of the same p2mp-receive-switch statement on this node).

As we do NOT have packet loss when we add and remove an interface in a VPLS we wanted to use the VPLS - LT-Interface - CCC Translation which we use on the side of the signal source
also on the target sites (video destinations).

But here the CCC - Lt-Interface - VPLS translation does not work at all. So we tried the physical loop which needs two dedicated 10G Interfaces and this works. But its an expensive solution.
Thats why i try tu use just a single 10G port and a Tx to Rx loop on this port.

does this explain it ?

greetings
gerhard

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________________________________
Von: Krasimir Avramski [mailto:krasi at smartcom.bg]
Gesendet: Freitag, 08. Oktober 2010 15:02
An: Prochaska Gerhard
Cc: juniper-nsp at puck.nether.net
Betreff: Re: [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

Hi,

Can you share more details of application requiring such transitions?
Why not just use p2mp lsps inside vlps for flooded traffic:
http://www.juniper.net/techpubs/en_US/junos10.0/information-products/topic-collections/config-guide-vpns/vpns-flooding-unknown-traffic-using-point-to-multipoint-lsps.html#id-11510467

HTH,
Krasi

On Fri, Oct 8, 2010 at 3:17 PM, Prochaska Gerhard <gerhard.prochaska at a1telekom.at<mailto: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<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<mailto:gerhard.prochaska at a1telekom.at><mailto:gerhard.prochaska at a1telekom.at<mailto: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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