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Community Member

MPLS IP-VPN compatibility

Hi, we've lots of members running on 2 Cisco 2611 with HA configured (HSRP, ISDN backup, etc). There is 2 scenarios here as follow:

i. 2 units of 2611 routers with each 2611 have a dedicated LL, one connected to HQ, the other connected to DR.

ii. 2 units of 2611 routers with only one have a dedicated LL, the other provide ISDN DDR when the LL on the other failed.

iii. 1 unit of 2611 routers with trunking to a 2950 switch, have a dedicated LL and ISDN DDR.

For the first scenario, when the members having 2 dedicated LL, normally it is from different telco providers. Now there's one single telco offering us the chance to upgrade to MPLS IP-VPN for an interesting rate. What I'm wondering is, can it work that way?

I have my 6509s with Sup720 at both HQ and DR, I have a good vendor all the while, if part of the members start to accept the MPLS-VPN, is there any integration problem? The HA configured will still work?

The thing that worried me most is the core layer part, since the member get the router through a router distribution from the core router in EIGRP, and the ISDN DDR will redistribute the static when the ISDN is active. How MPLS fit into my network?

9 REPLIES

Re: MPLS IP-VPN compatibility

Hello,

In principle everything can work. The dessign in question has one leased line (or ISDN) to the HQ and another path through a MPLS VPN. The issue you will have to deal with is to carefully design your dynamic routing. In case you have EIGRP, then an internal route will always be prefered over an external route. It is most likely to get external routes through the MPLS VPN - depending on implementation details.

Thus you might have the problem of proper primary/backup path selection and also with routing loops. The underlying reason for both is the redistribution in MP-BGP at the MPLS PE router.

You need to get more details on the implementation in the SP network to avoid any pitfalls. EIGRP supports backdoors in an MPLS VPN environment, but the question is, whether your telco does as well.

So it might work, but careful routing design is a must and involves you and the telco. HA is still possible, ISDN backup is possible as well. Depending on your specific implementation details you might need some route tagging and redistribution filters implemented by yourself or the telco to avoid the aforementioned problems.

Hope this helps! Please rate all posts.

Regards, Martin

Community Member

Re: MPLS IP-VPN compatibility

Hi Martin,

Certainly you've been real helpful, but I did notice the point you mentioned, and I definitely dislike having different routing protocol doing redistribution around. And since the telco is offering higher bandwidth for their line, the other router running on the other telco can't comply to the same bandwidth, for example, 1 is running 256/512k LL, the other is running 2Mbps IP-VPN...how's the routing will ends up with?

Metric of different routing protocol need to be altered as well, troubleshooting gone more complicated for operation stuffs etc etc...

I've done some research yesterday, what about VPLS? Do VPLS fit in nicely? Since if we're running VPLS we're still the one that controlling all the routing, bandwidth,QoS etc etc...doesn't that seems to be nice? Any idea?

Re: MPLS IP-VPN compatibility

Hello,

AToM from a customer perspective is like a leased line, or better PVC service, because you are in charge of everything above Layer2. In this sense things are much more simple for you, as you already mentioned. The challenge with MPLS L3VPNs is the routing (and non-IP protocols).

VPLS is much more complex for the telco, so you might just get EoMPLS. As you are replacing a LL this is exactly what you might want.

In your case it wout not be a bad idea to ask the telco for such a service.

Hope this helps! Please rate all posts.

Regards, Martin

Community Member

Re: MPLS IP-VPN compatibility

I'm doing research on all these, but there's so many sub section of MPLS which made me a little unsure. VPLS and EoMPLS is it the same thing?

If not, what's the main differences?

Purple

Re: MPLS IP-VPN compatibility

Hi,

EoMPLS is used to create point-to-point "tunnels". Therefore, it's primary use is somewhat like a WAN link. When an EoMPLS tunnel is built between two points, all frames presented to one end of the tunnel are transmitted to the other end. There is no concept of MAC learning with such a service.

VPLS, on the other hand, emulates an wide-area ethernet segment. It is therefore multi-point in nature - there can be more than 2 end-points connected to the same VPLS service. The service-provider routers have to do a bit more work with VPLS, since they now have to perform MAC-address learning as is done with LAN switches, in order to prevent unnecessary traffic. To the end user, the service appears just as if the link was plugged into a LAN switch.

Hope that helps - pls do remember to rate posts that help.

Paresh

Community Member

Re: MPLS IP-VPN compatibility

Hi Paresh and Martin and all techies here,

I have a query!

I have an ATM circuit landing at my office. I have 7206 router with NO ATM interface.

One way I can terminate my ATM circuit on serial interface of my 7206 thro encapsulation atm-dxi,

here what can be the other way without adding ATM card to my 7206?

secondly what i thought is creat a pvc between source and destination routers, and here can i do something with mpls even if my service provider is providing just an ATM service?

can i enable mpls on both of my 7206 routers?

please let me know asap

thanks

Deepak Vyas

Purple

Re: MPLS IP-VPN compatibility

Deepak,

You can only use atm-dxi if the other end supports that as well so I would probably rule that out as an option.

ATM is a very special type of technology in that it requires special hardware support. Therefore, you have no option but to install an ATM card in your routers.

You can certainly enable MPLS on your routers but that does not mean that you can get away with not using an ATM interface to terminate the ATM link...

Hope that helps - pls do remember to rate posts that help.

Paresh

Community Member

Re: MPLS IP-VPN compatibility

just a thought out of the blue, if I want to simplified my branch design with IPVPN, is that possible that I request the following from the service provider?

i. The ethernet connection to service provider backbone to configure as a trunk.

ii. Then I extend another ethernet port from the CE router to the branch LAN segment and run in multiple vlan trunk through a switch

In real world is it possible? Means I need only a CE router trunk to a switch at the branch, my branch terminals, servers just connect to the switch assigned with vlans...possible? just a thought though

Community Member

Re: MPLS IP-VPN compatibility

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