Re: Weird MPLS Label Switching Problem

Which IOS are you using?

--
Marko Milivojevic - CCIE #18427
Senior Technical Instructor - IPexpert
FREE CCIE training: http://bit.ly/vLecture
Mailto: markom_at_ipexpert.com
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On Sat, Feb 26, 2011 at 22:10, Malik Nouman Ahmad <djmalik_at_gmail.com> wrote:
> What I was trying to tell that the labels are not shown at all with or
> without "no mpls ip propagate-ttl" command. I know this command is to hide
> all the hops between PE1 and PE2.
>
> When I was not using that command it was showing the hops from
> CE1->PE1->P1->P2->PE1->CE2 BUT without labels like normal IPv4 traceroute. I
> used that command just to check if MPLS was working or not, just to be sure
>
> The problem is that I cannot see the labels for CE1 to CE2 traceroute at
> any hop but when I use the same source/destination subnet for tracing from
> PE1 to PE2 I am able to see label swapping at each hop
>
> I hope I am able to describe the problem that I am facing
>
> Thanks,
> Malik
>
>
> On Sun, Feb 27, 2011 at 12:29 AM, Marko Milivojevic <markom_at_ipexpert.com>wrote:
>
>>
>> Which shows you that your "no mpls ip propagate-ttl" did its job and MPLS
>> backbone is "hidden" from CE devices. Remove this command from PE1, run a
>> traceroute from CE1 and see the labels re-appear.
>>
>> --
>> Marko Milivojevic - CCIE #18427
>> Senior Technical Instructor - IPexpert
>>
>> FREE CCIE training: http://bit.ly/vLecture
>>
>> Mailto: markom_at_ipexpert.com
>> Telephone: +1.810.326.1444
>> Web: http://www.ipexpert.com/
>>
>> On Sat, Feb 26, 2011 at 21:10, Malik Nouman Ahmad <djmalik_at_gmail.com>wrote:
>>
>>> One thing I forgot to mention. For CE-CE trace there is no label seen in
>>> the
>>> traceroute but trace completes properly and I can ping between the CEs
>>> normally
>>>
>>> Thanks
>>>
>>> On Sun, Feb 27, 2011 at 12:07 AM, Malik Nouman Ahmad <djmalik_at_gmail.com
>>> >wrote:
>>>
>>> > Hi,
>>> >
>>> > I was studying MPLS VPN and while working on an example I am facing
>>> some
>>> > strange issue
>>> >
>>> > The connectivity is CE1 - PE1 - P1 - P2 - PE2 - CE2
>>> >
>>> > PE1(.1) - CE1 (.2) with subnet 172.16.1.0/24 with VRF A (RD=RT=1:1)
>>> > PE2(.1) - CE2 (.2) with subnet 172.16.2.0/24 with VRF A (RD=RT=1:1)
>>> >
>>> > PE1 & PE2 have MPLS VPN set up and I can see labels for everything when
>>> I
>>> > check "show mpls forwarding" on the PEs
>>> >
>>> > when I trace from PE1 to CE2 I can see labels being switches properly
>>> using
>>> > the following command
>>> > trace vrf A 172.16.2.2 source 172.16.1.1
>>> >
>>> > but when trace from CE1 to CE2, there are no labels whatsoever
>>> > trace 172.16.2.2 source 172.16.1.2
>>> >
>>> > Same thing is happening in the reverse direction (i.e. trace from CE2
>>> to
>>> > CE1). I have done several examples previously and never faced such
>>> issue.
>>> > Instead of doing it all over again I want to troubleshoot the problem
>>> for
>>> > learning purpose
>>> >
>>> > Can anybody suggest how to troubleshoot this problem? I have applied
>>> "no
>>> > mpls ip propagate-ttl" just to see if it was working and it worked
>>> >
>>> > Please advise what should I do?
>>> >
>>> > Thanks,
>>> > Malik
>>>
>>>
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