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MPLS Tutorial

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QinAny Mode

First of all the thing which is to be noted is that the QinAny mode is only supported by the Cisco XR 12000 Series Router.

Actually the QinAny mode is just like the or maybe you can call that it is similar to the QinQ mode using Type 5 virtual connection (VC), instead of that the customer edge VLAN (inner) tag will be carried into the packet while it is sent over the psedowire. This is just because the customer edge VLAN (inner) tag is not known by the configuration.

Basically in the QinAny mode, the service provider VLAN (outer) tag is configured on both the ingress as well as the egress nodes of the provider edge VLAN.

ATM over MPLS

Introduction to ATM over MPLS VPNs

It is also called as Cell mode MPLS. Service Providers which are currently operating ATM or Frame Relay networks over and ATM backbone can gain the advantages provided by Multiprotocol Label Switching (MPLS).

The Service Providers and the carriers that are currently deploying ATM and Frame Relay services can use their existing infrastructure to provide managed Virtual Private Network (VPN) services using MPLS.

They can only gain benefits by using MPLS services if there ATM-switches are MPLS aware.

If the ATM-switches are NON MPLS then we can configure MPLS on MPLS-aware routers, and the underlying ATM Virtual Circuits (VCs) will be considered ATM links.

By Deploying MPLS IP VPNs over an MPLS-aware ATM backbone provide great advantages in the sense that VPN customers can be provisioned with hard QoS guarantees, similar to those found with ATM.

Actually ATM over MPLS provides tunneling for ATM traffic through an MPLS-enabled Layer 3 core.

MPLS solutions distinguish the IP application traffic of ATM and Frame Relay. It provides the ability to distinguish the IP traffic between ATM and Frame Relay.

The MPLS VPN feature allows service provider’s network to deploy scalable IPv4 Layer 3 VPN Core (Backbone) services. These services can be deployed over a Layer 3 routed backbone or over an MPLS –aware ATM backbone.

Cisco IOS XR software supports a point-to-point and end-to-end service, where two ATM circuits are connected together.

ATM over MPLS is supported on the following ATM interface elements:

  • ATM ports (also known as ATM port mode)
  • ATM Layer 2 Subinterfaces with a PVC
  • ATM Layer 2 Subinterfaces with a PVP

MPLS and Tag Switching Terminology

Cisco made fully standards-compliant with respect to MPLS and shift many Tag Switching procedures and formats to MPLS standards.

Its IOS supports mpls commands and also tag-switching commands.

There is a comparison between tag-switching and MPLS Terminology.

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