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New Member

LDP/TDP breaks at core routers

Hi there,

I'm still new with MPLS/VPN.However, I would like to ask if there is a break in LDP/TDP at core router(P), which sometimes due to misconfiguration like not enabling ip cef, tag-switching ip at each interface,

in terms routing mechanism and update how does on each PE routers detect the break?

For a normal IP packet, I presummed the traffic will flow but if MPLS packet? Perhaps a routing issue?

thanks in advance.

maher

2 ACCEPTED SOLUTIONS

Accepted Solutions
Bronze

Re: LDP/TDP breaks at core routers

It will lead to LSP failure as there won't be any LDP label(outer label) to forward the traffic to the egress PE.

Pls have look at the url below.

http://www.cisco.com/warp/public/105/troubleshoot_mpls_vpn.html

Cisco Employee

Re: LDP/TDP breaks at core routers

Because of the IOS LDP implementation (Independent LSP Control as opposed to ordered LSP control), it might not always be possible to troubleshoot the issue solely by looking at the ingress PE. The ingress PE might have an assigned IGP label but that LSP might be imcomplete (not end to end). Tools like LSP ping and traceroute are a great help when trying to troubleshoot such cases. LSP ping/traceroute have been integrated in 12.0(27)

For more information on this feature, refer to the following URL:

http://www.cisco.com/en/US/products/sw/iosswrel/ps1829/products_feature_guide09186a00801eb054.html

Hope this helps,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
4 REPLIES
Bronze

Re: LDP/TDP breaks at core routers

It will lead to LSP failure as there won't be any LDP label(outer label) to forward the traffic to the egress PE.

Pls have look at the url below.

http://www.cisco.com/warp/public/105/troubleshoot_mpls_vpn.html

Cisco Employee

Re: LDP/TDP breaks at core routers

Because of the IOS LDP implementation (Independent LSP Control as opposed to ordered LSP control), it might not always be possible to troubleshoot the issue solely by looking at the ingress PE. The ingress PE might have an assigned IGP label but that LSP might be imcomplete (not end to end). Tools like LSP ping and traceroute are a great help when trying to troubleshoot such cases. LSP ping/traceroute have been integrated in 12.0(27)

For more information on this feature, refer to the following URL:

http://www.cisco.com/en/US/products/sw/iosswrel/ps1829/products_feature_guide09186a00801eb054.html

Hope this helps,

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
Cisco Employee

Re: LDP/TDP breaks at core routers

Oops, I meant 12.0(27)S.

Harold Ritter
Sr. Technical Leader
CCIE 4168 (R&S, SP)
harold@cisco.com
México móvil: +52 1 55 8312 4915
Cisco México 
Paseo de la Reforma 222 Piso 19
Cuauhtémoc, Juárez
Ciudad de México, 06600
México
New Member

Re: LDP/TDP breaks at core routers

Thanks for the info and link

maher

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