Multiprotocol Label Switching - MPLS VPNs - MPLS VPN Data Plane

4 important questions on Multiprotocol Label Switching - MPLS VPNs - MPLS VPN Data Plane

What is the Inner label used for, which device create the label and in which table is it stored?

The inner label is used to label the prefix/network of a customer/vrf. So that the PE can identify the right outgoing interface

PE device


LFIB & FIB

What is the name of the entity used to locate the label to insert onto an unlabeled packet?

FIB

The Cisco Express Forwarding (CEF) Forwarding Information Base (FIB) contains forwarding information for incoming unlabeled packets. The Multiprotocol Label Switching (MPLS) Label Forwarding Information Base (LFIB) contains forwarding information for incoming labeled packets. Contained within the FIB is the label that must be inserted in front of the IP header so it can be passed onto the MPLS network.

What is the abbreviation for PHP?

Penultimate hop popping
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How does PHP work?

PHP causes the penultimate-hop (voorlaatste) LSR to pop the outer label

The ultimate router recieves a packet that has only the VPN label in it.

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