Re: Ping fails across VRF

All,

I finally figured it out. It appears to be an issue with the Provider
Backbone in the IGP process. I am running ospf on the Provider core, and
ospf was the cause of the issue. The /32 route by default on a Loopback
interface was the cause. The /24 route of the loopback had IMP-NULL, but
the /32 did not. I went to the Lo0 of R3 & R6 and made it a p2p interface,
and it corrected the issue.

Sorry for the long thread, I guess I had to write out the process for my
head to process.

Thanks,

Chris

On Sat, Aug 29, 2009 at 3:43 PM, Christopher Copley
<copley.chris_at_gmail.com>wrote:

> Bryan,
>
> I tried to remove the Lo0 from IGP and that did not work. R1/R3 and R5/R6
> are LDP peers. I have the MP-BGP peering on R3 and R6 via Lo0. And if I
> can not get the Lo0 to be a tagged packet then I think I have an IOS bug or
> limitation. would this be correct.
>
> Chris
>
>
> On Sat, Aug 29, 2009 at 3:34 PM, Bryan Bartik <bbartik_at_ipexpert.com>wrote:
>
>> Chris,
>>
>> You are right, you should see "pop" for PHP. If you see untagged this is
>> because you have not received a label for it. This is why I said check your
>> peerings and make sure CEF is enabled. In some older codes, CEF is not on by
>> default. Are R1/R3 and R5/R6 LDP Peers?
>>
>>
>> On Sat, Aug 29, 2009 at 4:17 PM, Christopher Copley <
>> copley.chris_at_gmail.com> wrote:
>>
>>> Bryan,
>>>
>>> This in my Topo...
>>>
>>> CE---R3---R1----R5----R6----CE
>>>
>>> If I look on R1 to see the ldp forwarding table I see...
>>>
>>> Rack2R1#sho mpls forwarding-table | inc (155.2.6.6/32|155.2.3.3/32<http://155.2.6.6/32%7C155.2.3.3/32>
>>> )
>>> 16 Untagged 155.2.3.3/32 12288 Se0/1/0 point2point
>>> 18 16 155.2.6.6/32 13036 Fa0/0 150.1.15.5
>>> Rack2R1#
>>>
>>>
>>> and on R5 I see...
>>>
>>> Rack2R5#sho mpls forwarding-table | inc (155.2.6.6/32|155.2.3.3/32<http://155.2.6.6/32%7C155.2.3.3/32>
>>> )
>>> 16 Untagged 155.2.6.6/32 8973 Fa0/1 150.1.56.6
>>> 18 16 155.2.3.3/32 16955 Fa0/0 150.1.15.1
>>> Rack2R5#
>>>
>>> If what I have been reading is correct, then R1 and R5 are sending the
>>> mpls lable as a ipv4 packet to R3 &R6 respectively.
>>> I have my MP-BGP peerings between R3&R6 via the Lo0 interface.
>>> I believe that instead of Untagged in the above output I should be seeing
>>> "Pop Label" that is the PHP process, right?
>>> Then R3 and R6 will untag the packet and direct it to the correct VRF and
>>> an IPv4 packet, Correct?
>>>
>>> If the above logic is correct will taking the Lo0 out of my IGP correct
>>> this issue? Or is this some strange IOS bug?
>>>
>>> Chris
>>>
>>>
>>> On Sat, Aug 29, 2009 at 3:06 PM, Bryan Bartik <bbartik_at_ipexpert.com>wrote:
>>>
>>>> Chris,
>>>>
>>>> You don't need to enable mpls on a loopback. Just out the loopback in
>>>> your IGP and labels will get advertised. What makes you think PHP is
>>>> happening to seen? If you see a "no-label" instead of "pop-label" in the
>>>> LFIB, this is not PHP. Make sure you have CEF enabled and your LDP peerings
>>>> are UP throughout the cloud. Let me know what you find.
>>>>
>>>> On Sat, Aug 29, 2009 at 3:57 PM, Christopher Copley <
>>>> copley.chris_at_gmail.com> wrote:
>>>>
>>>>> I think I know what is going on....The PHP process is occurring to
>>>>> soon, by
>>>>> one router. I tried to enable mpls ip on the Lo0 interface and get an
>>>>> error...
>>>>>
>>>>> % MPLS not supported on interface Loopback0
>>>>>
>>>>> Is this an IOS version limitation or a default behavior?
>>>>>
>>>>> Thanks,
>>>>> Chris
>>>>>
>>>>> On Sat, Aug 29, 2009 at 2:33 PM, Christopher Copley
>>>>> <copley.chris_at_gmail.com>wrote:
>>>>>
>>>>> > Sorry all pressed send by mistake WAY to early,
>>>>> >
>>>>> > Anyway...
>>>>> >
>>>>> > I have one VPN and at each of the CE routers I can see the routes
>>>>> from each
>>>>> > other across my MPLS backbone. But ping fails across the Core from
>>>>> CE to
>>>>> > CE, but the routes are there and look correct.
>>>>> >
>>>>> > I have MP-BPG between each PE and the router appear in each VPN.
>>>>> >
>>>>> > Any ideas?
>>>>> >
>>>>> > Chris
>>>>> >
>>>>> >
>>>>> > On Sat, Aug 29, 2009 at 2:29 PM, Christopher Copley <
>>>>> > copley.chris_at_gmail.com> wrote:
>>>>> >
>>>>> >> Experts,
>>>>> >>
>>>>> >> I have an interesting problem with my MPLS study. I am new to MPLS
>>>>> and
>>>>> >> MPLS VPNS and I have got to a place where I am stuck.
>>>>>
>>>>>
>>>>> Blogs and organic groups at http://www.ccie.net
>>>>>
>>>>> _______________________________________________________________________
>>>>> Subscription information may be found at:
>>>>> http://www.groupstudy.com/list/CCIELab.html
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Bryan Bartik
>>>> CCIE #23707 (R&S), CCNP
>>>> Sr. Support Engineer - IPexpert, Inc.
>>>> URL: http://www.IPexpert.com
>>>>
>>>
>>>
>>
>>
>> --
>> Bryan Bartik
>> CCIE #23707 (R&S), CCNP
>> Sr. Support Engineer - IPexpert, Inc.
>> URL: http://www.IPexpert.com

Blogs and organic groups at http://www.ccie.net
Received on Sat Aug 29 2009 - 16:27:08 ART