How can you say if MPLS is running in the provider's network

[kunal-united]

Hi,

One branch connects in New York to the service provider.

Second branch connects in California to the same service provider.

Service provider says that they are running MPLS.

Service provider has disabled MPLS labels in the path. This is the Service provider's policy.

Question - How can one know if the service provider is running MPLS or not if they do not ebale label propagation?

Is there any way to say or we have to rely on what they say?

Thanks,

Kunal

[Ivan Krimmel]

Hi Kunal,

if you are able to route your private IP addresses across the ISP cloud and have connectivity between sites, then there's some level of abstraction enabled, which is MPLS.

Also, the traceroute output will be short, actually revealing only CE devices.

Hope that clarifies,

Ivan.

[kunal-united]

Hi,

I can still have private ip addresses routed on VRF basis and this need not be MPLS based.

From the trace I can from the router loopback ip. I see below

1. New York Branch ip 172.23.4.2

2. New York Service provider ip 172.23.4.1

3. California Service provider ip 172.23.6.1

4. California Branch ip 172.23.6.2

So how can you say that MPLS is enabled in the service provider's environment?

Thanks,

Kunal

[Peter Paluch]

Kunal,

I am not sure if there is any way to verify with certainty that the ISP is using MPLS for these services. The suggestion as given by Ivan is correct but not exclusive to MPLS. In fact, any tunelling technology will reveal itself in a similar manner by hiding the internal P router hops.

The only persuasive argument that would validate the use of MPLS would be to actually see some labels. However, that is practically impossible: labeled packets are never sent towards CE devices. The ICMP TTL-Exceeded messages can carry the MPLS label in their payload (to allow the sender to see which exact packet had to be discarded), however, this will probably not work for you because your ISP says that it is not propagating IP TTLs into MPLS TTLs, hence the packets will not expire on P routers using MPLS.

Sorry about this. Is it important for you to be exactly sure that the ISP is using MPLS?

Best regards,

Peter

[ashok_boin]

Hi Kunal,

There are 2 ways...

1. Use Extended Traceroute which will give you MPLS labels in the output assuming your provider is propagating TTL into MPLS header.

http://www.cisco.com/en/US/tech/tk436/tk428/technologies_tech_note09186a008020a42a.shtml

2. Otherwise, if your provider is not propagating TTL into MPLS header, then you will observe just Source end PE router and the destination office. I have not tried but you may see some labels with ext traceroute in this case as well.

As others suggested, it may be difficult if your provider is just utilizing end to end IP Sec tunnels etc but I guess there are ways to find it out.

Regards..

-Ashok.

[Ivan Krimmel]

I think OSPF routes will come as LSA type 3 instead of 1 in MPLS env due to redistribution.

Cheers,

Ivan.

[Mahesh Gohil]

Hi,

As peter said there is no perfect way of telling whether provider is running MPLS or not. But I am bit agree with Ivan about OSPF.

If Provider is not using shal-link then your intra-area route will be visible as Inter-area at other end. I am touching ospf after long time but still I am sure here.

But I must say that this is really a very good question and need some out of box thinking to answer it corectly.

Thanks and Regards

Mahesh

[Peter Paluch]

Hello Mahesh,

I guess that if the ISP wanted to fool us, he could easily do that. The routes in OSPF being visible as OIA routes instead of OE1/OE2 are only an indication of a BGP-to-OSPF redistribution within a VRF. However, the PE-to-PE routing could be done over a GRE tunnel, for example, and may have nothing to do with MPLS. Please correct me if I am wrong here...

Best regards,

Peter

[Mahesh Gohil]

Yes peter ,

U r right. OIA is the outcome of super backbone and if ISP use GRE we have no clue about that. This is the reason I told at the last that this is really very interesting question and yet need some efforts to answer that.

I came to this forum after long time and really feel nice that U r still active with same energy.

Regards

Mahesh

[Peter Paluch]

Hello Mahesh,

Thank you. You have been missed! Will you be able to attend more frequently again?

Best regards,

Peter

[Mahesh Gohil]

Hi Peter,

I had some projects assigned and neet to be completed before network freeze (before christmas) so will try to be

on this forum as much as possibe.

Regards

Mahesh