Will EoMPLS carry STP BPDU's over SP Core?

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May 11th, 2010
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Hi All,


I have a query. With Ethernet over MPLS (either port or vlan mode) connecting two different locations, is it possible to have STP BPDU's carrying over the SP core. Any recent enhancements in the IOS allow it.


Our design requires two datacenters to be connected over EoMPLS and run STP over the SP. I heard in EoMPS, SP will not learn and store any MAC from customers but would eager to know if such options exist now.


We could not do VPLS (which does our requirement) because of hardware limitation.


thanks in advance.


regards,

Arun Kumar

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Giuseppe Larosa Tue, 05/11/2010 - 05:37
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Hello Arun,

MAC address learning is disabled but EoMPLS should be blind enough to carry STP BPDUs on the other side of the pipe


I remember that during testing some years ago, even frames with MAC DA = MAC address of router port were propagated over the pseudowire!


Hope to help

Giuseppe

judebryant Thu, 05/13/2010 - 00:26
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the answer is yes.


I have occomplished with the following way. The configuration is called BPDU relay.


the interface the switch is plugged up to on my mpls 7609 router.


description BPDU_Relay_Cisco_Switch


mtu 1596
no ip address
mls qos trust dscp
mpls ip
service instance 1 ethernet
  description BPDU_Relay
  encapsulation dot1q 1
  l2protocol forward
  bridge-domain 1

there is also a vpls instance for vlan1

l2 vfi bpdu-pw manual
  vpn id 1
  forward permit l2protocol all
  neighbor 1.1.1.2 encapsulation mpls

Regards
Jude Bryant
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Giuseppe Larosa Thu, 05/13/2010 - 06:56
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Hello Jude,

original poster said he has to use point to point EoMPLS


however, your post confirms that even in VPLS can be possible to perform this task


Hope to help

Giuseppe

judebryant Thu, 05/13/2010 - 10:12
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I understand.  The only issues I had was spanning tree would be a loop type environment for protection.  ie;


so maybe I didnt understand the topology.  Can he create drawing or something.


and yes it does work.  Im using it today.


Regards

Jude

Giuseppe Larosa Thu, 05/13/2010 - 10:22
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Hello Jude,

I've found your config template interesting and I've rated it.


Best Regards

Giuseppe

arun kumar Fri, 05/14/2010 - 06:21
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Hi Francisco & Guiseppe,


Thank you both for your valuable responses and it is of great help to me. I am using 7206 router.

Gustavo Q. Mast... Mon, 07/12/2010 - 13:08
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Arun,


I'm facing the same problem as you. How did you fix it? Here is my topology.


_________              __________              _________              __________
|___CE1___|=====|___PE1___|=====|___PE2___|=====|___CE2___|

  VLAN 100                                                                                         VLAN 100


Between the PEs, we're running MPLS.

Between the PE and the CE, it's Layer 2, running MST.


For example, we have VLAN 100 in both CEs and we want them to act as a one broadcast domain, how could be the configuration? We want to transport STP BPDU over the MPLS and use SVI in both PEs acting as gateways of VLAN 100.


Thanks in advance.


Best regards,


Gustavo Mastroianni

Chetan Kumar Ress Tue, 07/13/2010 - 11:44
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Hi Guys


Many times I had faced this question but still not Satisfy with any answer.


But Cisco Says :


As per my understanding Router or Switch will forward the BPDU if they are having advance BRAIN i.e Supervisor Engine .


So if you are using Router without Supervisor Engine ( 7200  or other )then it will not forward STP BPDU over EoMPLS but if you have 7600 Series router with specific hardware the it will support STP BPDU over MPLS.

EoMPLS Guidelines and Restrictions

The following restrictions apply to using trunks with EoMPLS:

To support Ethernet spanning tree bridge protocol data units (BPDUs) across an EoMPLS cloud, you must disable the supervisor engine spanning tree for the Ethernet-over-MPLS VLAN. This ensures that the EoMPLS VLANs are carried only on the trunk to the customer router. Otherwise, the BPDUs are directed to the supervisor engine and not to the EoMPLS cloud.

– The native VLAN of a trunk must not be configured as an EoMPLS VLAN.

• In PFC3BXL or PFC3B mode, all protocols (for example, CDP, VTP, BPDUs) are tunneled across the MPLS cloud without conditions.



http://www.cisco.com/en/US/docs/routers/7600/ios/12.2SXF/configuration/guide/pfc3mpls.html#wp1109041




Regards

Chetan Kumar

Gustavo Q. Mast... Thu, 07/15/2010 - 07:12
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Chetan,


I do have two Cisco 7600 with a specific routing and switching cards.

I was just wondering if anyone knows the configuration on these routers, on the topology that I "drew" just above.

I'd appreciate if I get this answer.

Thanks in advance.


Regards,


Gustavo Mastroianni

judebryant Thu, 07/15/2010 - 07:35
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Gustavo,


Look at my configuration above.  All you have todo is allow the native vlan to traverse your mpls link.  In otherwords create service instance for vlan(native vlan).  In my configuration the native vlan is 1.


Bridge Protocol Data Unit (BPDU) s are sent untagged using the native vlan.


so in your case


_________              __________              _________              __________
|___CE1___|=====|___PE1___|=====|___PE2___|=====|___CE2___|

  VLAN 100                                                                                         VLAN 100


ce1

interface gig0/1

encapsulation dot1q 100


pe1

interface gig0/1

service instance 1 ethernet

encapsulation dot1q 1

l2protocol forward

bridge-domain 1 or xconnect ip-address vc-id encapsulation mpls


service instane 100 ethernet

encapsulation dot1q 100

bridge-domain 100 or xconnect ip-address vc-id encapsulation mpls


and the same for the other two


Regards

Jude Bryant

Network Engineer

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Gustavo Q. Mast... Fri, 07/16/2010 - 11:43
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Jude,


Thanks for you help!

And if I want to transport BPDUs from more VLANs, for example, 200 VLANs?! How the configuration would be?

We use X-Connect or VFIs to communicate between the distribution (PEs) nodes.


Thanks again!


Regards,


Gustavo Mastroianni

judebryant Mon, 07/19/2010 - 06:07
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Gustavo,


The following configuration will carry BPDUs for all VLans


interface gig0/1

service instance 1 ethernet

encapsulation dot1q 1

l2protocol forward

bridge-domain 1 or xconnect ip-address vc-id encapsulation mpls


dont forget to add the line

"forward permit l2protocol all "

in your l2 vfi configuration


Regards

Jude Bryant

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arun kumar Tue, 07/20/2010 - 02:49
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Hi,


It seems 7200 routers can also pass STP BPDU's by default (no special configuration done on PE only xconnect configured). The above is the setup that I tried. PE1 is NPEG1 running SRC and PE2 is NPEG2 running 12.4T images. Both the ends I configured VLAN 100 and I could able to find that STP BPDU's are relayed over SP core. The alternate link is put into blocking.


Moreover if one end of the VLAN is changed to other value then STP blocks the PE connecting port in switches due to Peer VLAN ID inconsistency.


thanks

Arun

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