MPLS & PPVPN

In a PPVNP [Provider Provisioned Virtual Private Network], there may be more than one label. To begin with, IP [Internet Protocol] packets may have a number of labels or “tags” attached to them. MPLS [Multi-Protocol Label Switching] is just one type of label. Here are some terms associated with labeling:

• Push: add a label

• Swap: replace the label
• Pop: remove the label

PPVPNs may add more labels should the need arise to provide additional types of QoS [Quality of Service]. These labels may exist within the network but may be removed or “popped” as they leave the network to the customer premise or “edge” or LER-Label Edge Routers.

A PPVPN control module adds “push” labels and determines routing via LSR [Label Switch Routers] where labels may be “swapped” as they change or cross to other networks called AS [Autonomous Systems]. The term LVC [Label Virtual Channel] has been associated with this emerging concept. As long as each carrier or AS [Autonomous System] knows the value of QoS [Quality of Service] for the label and routes it accordingly, each carrier can determine their own labeling system. That is, if each AS carrier routes video as video or e-mail as e-mail or other known rules, then the packets will be treated with the desired QoS. When leaving the MPLS Network or “edge” the MPLS and other label(s) are popped (off).

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