Mpls Diffserv Tunneling Restrictions And Usage Guidelines; Configuring Short Pipe Mode; Ingress Pe Router—Customer Facing Interface - Cisco WS-SUP32-GE-3B - Supervisor Engine 32 Software Configuration Manual

Configuring Short Pipe Mode

Uniform Mode Restrictions and Guidelines
The following restriction applies to the Uniform mode:
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MPLS DiffServ Tunneling Restrictions and Usage Guidelines

The MPLS DiffServ tunneling restrictions and usage guidelines are as follows:
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The following features are supported with the MPLS differentiated service (DiffServ) tunneling modes:
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Configuring Short Pipe Mode
The following sections describe how to configure the Short Pipe mode:
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Ingress PE Router—Customer Facing Interface
This procedure configures a policy map to set the MPLS EXP field in the imposed label entries.
To set the EXP value, the ingress LAN or OSM port must be untrusted. FlexWAN ports do not have the
trust concept, but, as with traditional Cisco IOS routers, the ingress ToS is not changed (unless a marking
policy is configured).
Catalyst Supervisor Engine 32 PISA Cisco IOS Software Configuration Guide, Release 12.2ZY
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If the egress IP ACLs or service policies are configured on the MPLS-to-IP exit point, the Uniform
mode is always enforced because of recirculation.
One label-switched path (LSP) can support up to eight classes of traffic (that is, eight PHBs) because
the MPLS EXP field is a 3-bit field.
MPLS DiffServ tunneling modes support E-LSPs. An E-LSP is an LSP on which nodes determine
the QoS treatment for MPLS packet exclusively from the EXP bits in the MPLS header.
MPLS per-hop behavior (PHB) layer management. (Layer management is the ability to provide an
additional layer of PHB marking to a packet.)
Improved scalability of the MPLS layer management by control on managed customer edge (CE)
routers.
MPLS can tunnel a packet's QoS (that is, the QoS is transparent from edge to edge). With QoS
transparency, the IP marking in the IP packet is preserved across the MPLS network.
The MPLS EXP field can be marked differently and separately from the PHB marked in the IP
precedence or DSCP field.
Ingress PE Router—Customer Facing Interface, page 39-34
Configuring Ingress PE Router—P Facing Interface, page 39-35
Configuring the P Router—Output Interface, page 39-37
Configuring the Egress PE Router—Customer Facing Interface, page 39-38
The steps that follow show one way, but not the only way, to configure Short Pipe mode.
The Short Pipe mode on the egress PE (or PHP) is automatically configured when you attach to the
interface an egress service policy that includes an IP class.
Chapter 39 Configuring MPLS QoS
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