Re: MPLS VPN Label

That is expected. Since there is only one P-router, it will do PHP label pop
of IGP label (Top label) before sending it to egress PE. You can put another
P-router in between if you have and try traceroute again.

-Naveen.

On Fri, Jun 24, 2011 at 1:50 PM, Naufal Jamal <naufalccie_at_yahoo.in> wrote:

> When doing a tracert from CE2 to CE1 its showing me only one label which i
> think is the VPN label
>
> CE2(config-router)#do trace 1.1.1.1
>
> Type escape sequence to abort.
> Tracing the route to 1.1.1.1
>
> 1 30.30.30.2 236 msec 68 msec 40 msec
> 2 10.10.10.2 [AS 100] [MPLS: Label 19 Exp 0] 256 msec 172 msec 184 msec
> 3 10.10.10.1 [AS 100] 280 msec * 196 msec
>
> PE1(config-router)#do sh mpls forwarding-table
> Local Outgoing Prefix Bytes tag Outgoing Next Hop
> tag tag or VC or Tunnel Id switched interface
> 19 Untagged 1.1.1.1/32[V] <http://1.1.1.1/32%5BV%5D> 8814
> Fa0/0 10.10.10.1
>
> and the P router (which sits in the middle of PE1 and PE2). This is where I
> am getting confused. P-PE1-PE2 are running bgp vpnv4 and ospf amongst them.
> 1.1.1.1 is on CE1. LDP is up and running on all three of them and
> neighborship is up.
>
> P(config-router)#do sh ip bgp vpnv4 all 1.1.1.1
> % Network not in table
>
>
>
>
> --- On *Fri, 24/6/11, Naveen <navin.ms_at_gmail.com>* wrote:
>
>
> From: Naveen <navin.ms_at_gmail.com>
> Subject: Re: MPLS VPN Label
> To: "Brian McGahan" <bmcgahan_at_ine.com>
> Cc: "Naufal Jamal" <naufalccie_at_yahoo.in>, "ccielab_at_groupstudy.com" <
> ccielab_at_groupstudy.com>, "rahula_at_hcl.com" <rahula_at_hcl.com>
> Date: Friday, 24 June, 2011, 8:23 PM
>
>
> A traceroute from CE1 to CE2 should reveal both the IGP and VPN labels.
>
> 7600_CE2#traceroute ipv6
>
> Target IPv6 address: 2013::1
> Source address:
> Insert source routing header? [no]:
> Numeric display? [no]:
> Timeout in seconds [3]:
> Probe count [3]:
> Minimum Time to Live [1]:
> Maximum Time to Live [30]:
> Priority [0]:
> Port Number [0]:
> Type escape sequence to abort.
> Tracing the route to 2013::1
>
> 1 2010:1::1 0 msec 0 msec 0 msec
> 2 ::FFFF:44.1.1.1 [MPLS: Labels 16013/20077 Exp 0] 28 msec 28 msec 0 msec
> 3 ::FFFF:18.1.1.2 [MPLS: Labels 16018/20077 Exp 0] 4 msec 0 msec 4 msec
> 4 ::FFFF:77.1.1.2 [MPLS: Labels 24524/20077 Exp 0] 24 msec 0 msec 0 msec
> 5 ::FFFF:88.1.1.2 [MPLS: Label 20077 Exp 0] 28 msec 0 msec 0 msec
> 6 2011::2 0 msec 0 msec 0 msec
> 7600_CE2#
>
>
> Regards,
> Naveen.
> CCIE #25432
>
>
>
> On Fri, Jun 24, 2011 at 1:15 PM, Brian McGahan <bmcgahan@ine.com<http://mc/compose?to=bmcgahan@ine.com>
> > wrote:
>
> The prefix itself doesn't have two labels, the actual packets in the
> data plane will have two (or more) labels. The VPN label is the bottom-most
> label, not the top label. The top label is usually the transport label that
> is derived from LDP. In short the transport label tells the MPLS cloud
> which PE router the packet is destined to, then once it arrives there the
> VPN label tells the PE which CE facing interface the packet is destined to.
>
> On the PE routers you can see what the VPN label is by issuing the
> "show bgp vpnv4 unicast all w.x.y.z", where w.x.y.z is the VPNv4 prefix in
> question. In the actual MPLS cloud you can see both the transport (topmost)
> label and the VPN label by looking at the "debug mpls packet" output.
>
> "untagged" and "no label" mean the same thing, that the packet will
> be forwarded out an interface that is not running MPLS, or does not have a
> label binding to that prefix. For the PE to CE link this is normal, because
> the CE is not running MPLS.
>
> For more detail check this video on MPLS Layer 3 VPN Verification &
> Troubleshooting: http://goo.gl/Ys0lF
>
> HTH,
>
> Brian McGahan, CCIE #8593 (R&S/SP/Security)
> bmcgahan_at_INE.com
>
> Internetwork Expert, Inc.
> http://www.INE.com
>
>
> -----Original Message-----
> From: nobody@groupstudy.com <http://mc/compose?to=nobody@groupstudy.com>[mailto:
> nobody@groupstudy.com <http://mc/compose?to=nobody@groupstudy.com>] On
> Behalf Of Naufal Jamal
> Sent: Friday, June 24, 2011 2:26 PM
> To: ccielab@groupstudy.com <http://mc/compose?to=ccielab@groupstudy.com>
> Cc: rahula@hcl.com <http://mc/compose?to=rahula@hcl.com>
> Subject: MPLS VPN Label
>
> Hi,
> I have set up a MPLS VPN network and my end-to-end ping works fine over the
> MPLS. Ie I can ping CE1 from CE2 and vice-versa. I need to understand few
> things regarding MPLS VPN label.
> It was written on the books that the prefixes carry two labels with them
> while
> traversing through the MPLS network with VPN label being on the top. Can we
> see the VPN label for any prefix in the P routers?
> PE1(config-router)#do sh mpls forwarding-tableLocal Outgoing Prefix
> Bytes tag Outgoing Next Hoptag tag or VC or Tunnel Id
> switched interface19 Untagged 1.1.1.1/32[V]<http://1.1.1.1/32%5BV%5D> 3762 Fa0/0
> 10.10.10.1
> Why the outgoing tag is mentioned as Untagged. 1.1.1.1 is my route in CE1
> router which is inside the vrf.
> PE1(config-router)#do sh ip bgp vpnv4 all labels Network Next Hop
> In label/Out labelRoute Distinguisher: 100:100 (ABC) 1.1.1.1/32
> 10.10.10.1 19/nolabel
> Why is "nolabel" mentioned as the Out label here?
> Please help me understand.
>
>
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Received on Fri Jun 24 2011 - 18:17:21 ART