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mpls aggregated labels

i need to disable the label aggregation on mpls-vpn setup. i need to se on the PE router that for each static route for vrf, or actual vrf config for port, another label is added in the "sh mpls forwarding table". how can i do this?

4 REPLIES

Re: mpls aggregated labels

Hello,

first, "show mpls forwarding-table" will only list local labels other than implicit-null label.

With every connected network in global routing, the default is to announce a "pop" i.e. a null label. The resason is, that the PE needs to strip of the label and investigate the destination IP to figure out, whether the packet is for itself or not.

Assume f.e. a PE with a directly connected LAN with a couple of hosts. A PE can only determine the proper host to send a packet to, if the destination IP is known.

If a network is connected to a VRF, basically the same applies as above. Yet there needs to be a VPN label to identify the VRF context. So in "show mpls forwarding-table" those VPN labels will show up as aggregate. This simply means, that the PE needs the VPN label to identify the VRF, but then also needs to look up the destination IP to figure out the proper host to send the packet to.

Thus "aggregate" labels are inevitably necessary.

Finally: what is your intention to have no "aggregate" in the output?

Hope this helps! Please rate all posts.

Regards, Martin

New Member

Re: mpls aggregated labels

Martin thanks,

this is small lab setup of mpls-vpn network, and we have agent on the newtwork that listen and parse bgp updates from PEs.

i want to investigate some issues of 'add' and 'remove' routes from defined VRFs on specific PE so i need to have the ability add/remove labels on that PE.

actually, i know it worked for me before, since i have java test that was verifying this but now doesn't, and i tried ,manually configurations that did came with this result.

Re: mpls aggregated labels

Hello,

you can use ethereal to collect and investigate labeled and unlabeled packets. It will display and decode both sorts and also allow you to see BGP updates and the like.

Hope this helps! Please rate all posts.

Regards, Martin

New Member

Re: mpls aggregated labels

Hi,

my purpose is java test that correlates large amount of labels in the PE and in our developed device SCE2020 http://www.cisco.com/en/US/products/ps6151/products_data_sheet0900aecd801d8574.html

manually checks are surely done but aren't large scale and/or regressabily.

can i make sure that the PE will show in non-aggregated style the vpn labels?

i defined "no auto-summary" in the bgp definitions and in the address-family ipv4 vrf vrf_name sections but without different

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