MPLS PE S6730 Label Issue

Hi @ptomasi,
(we noticed PE wasn't adding label to P to forward traffic based on LSP. ) ------- Is the P router the router D in the topology?
Kindly check the FIB on router S6730(router F) if the tunnel ID of traffic to the customer network is 0 or not.
Also, kindly check on router S6730(router F) if there is LSP towards router C.

Hi,

You're right. C (PE) isn't adding label to D (P) when try to forward traffic to customer behind F (PE);

Then, D uses OSPF default route to send traffic to F - this way forcing packet to go to edge router first. After packet reaches edge router it's guided through a LSP from A to F.

I forgot to mention that:
> both C an F have BGP session to A (that acts like edge router and RR);
> C has a label 2771 in LFIB assigned to F loopack;
> Traffic to hosts present in OSPF table uses LSP; traffic to hosts present in BGP table (even through recursivity to remote loopbacks) uses pure IP routing (without labels) until reach edge router;

Could you, kindly, guide me to the troubleshooting commands about these two suggestions? I have no experience yet with troubleshooting commands in Huawei Platform:
> Kindly check the FIB on router S6730(router F) if the tunnel ID of traffic to the customer network is 0 or not.
> Also, kindly check on router S6730(router F) if there is LSP towards router C.

Thanks!

Hi,

from your description, the tunnel ID of the entry which destination is the customer behind F should be 0x0, you can check it through command display fib, or display fib vpn-instance VPN-INSTANCE-NAME (for the vpn-instance fib table) 

example as below:

<HUAWEI> display fib

Route Flags: G - Gateway Route, H - Host Route,    U - Up Route                                 

Destination/Mask      Nexthop       Flag  TimeStamp  Interface      TunnelID  
192.168.150.111/32 127.0.0.1       HU    t[117]          InLoop0        0x0

Kindly confirm questions below:

1. Are you configuring the BGP/MPLS VPN?

2. Please refer the figure below, if I mark the traffic correctly.

   
   

   

Hi,

You're right again:

display fib W.X.Y.13

  Route Entry Count: 1

Destination/Mask   Nexthop         Flag  TimeStamp     Interface      TunnelID

W.X.Y.0/24         172.16.3.45     DGU   t[682857]     XGE0/0/11      0x0

TunnelID to BGP customer route is 0x0

Kindly confirm questions below:

1. Are you configuring the BGP/MPLS VPN?

   > At now, we're deploying only basic OSPF and MPLS cloud. No VPN involved in the scenario yet.

   
   

2. Please refer the figure below, if I mark the traffic correctly.

   > Your diagram is correct: traffic from C > D > B > A has no labels | traffic from A to F follows LSP correctly.

   
   

Customer --- F (PE) --- E --- D --- C (PE) --- CDN

                              |

                              B

                              |

                              A (PE) edge router

Hi
Let me ask a question.
Are you using vpn to carry this traffic  or just mpls label?

If you aren't using l3vpn nor l2vpn, pls check out this thread and in the and there are two reference so that you would solve your issue.

https://forum.huawei.com/enterprise/en/mpls-label-forwarding/thread/472331-865

Hi,

We're using only MPLS labels (basic scenario, LDP is managing the label distribution). No VPN (VRF, VPLS, VC, VSI) for now, but planned to future implementation.

I noticed C (PE) has a label in LFIB assigned to F (PE) loopback (to resolve the iBGP route next-hop), but it seems it isn't applying that label when forward the packet to D (P) router.

It seems it was solved

https://forum.huawei.com/enterprise/en/bgp-free-core/thread/581954-863 - Thanks to Sprout for that great post and examples

As soon as the command below was applied, traffic was guided to C > D > E > F > Customer through LSP:

route recursive-lookup tunnel

Now, PE C resolves iBGP next-hop and applies correspondent label to it.

Thanks to everyone :-)

hmmm

Good