Eompls Support; Eompls Restrictions; Eompls Quality Of Service - Cisco ONS 15454 SDH Configuration Manual

Chapter 18 Configuring Ethernet over MPLS

EoMPLS Support

EoMPLS on the ML-Series card has the following characteristics:
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EoMPLS Restrictions

EoMPLS on the ML-Series card has the following restrictions:
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Since MTU fragmentation is not supported across the MPLS backbone, the network operator must make
Caution
sure the MTU of all intermediate links between endpoints is sufficient to carry the largest Layer 2 PDU.

EoMPLS Quality of Service

The EXP is a 3-bit field and part of the MPLS header. It was created by the IETF on an experimental
basis, but later became part of the standard MPLS header. The EXP bits in the MPLS header carry the
packet priority. Each label switch router along the path honors the packet priority by queuing the packet
into the proper queue and servicing the packet accordingly.
EoMPLS is only supported on FastEthernet and GigabitEthernet interfaces or subinterfaces.
MPLS tag switching is only supported on SPR interfaces.
Class of service (CoS) values are mapped to the experimental (EXP) bits in the MPLS label, either
statically or by using the IEEE 802.1p bits (default).
The ingress PE-CLE ML-Series card sets the time-to-live field to 2 and the tunnel label to a value
of 255.
Ingress PE-CLE ML-Series cards set the S bit of the VC label to 1 to indicate that the VC label is at
the bottom of the stack.
Since EoMPLS traffic is carried over the RPR, whatever load balancing is applicable for the traffic
ingressing RPR is also applicable for the EoMPLS traffic.
EoMPLS is supported over RPR under GFP-F framing and HDLC framing.
The Ethernet over MPLS feature is part of the Cisco Any Transport over MPLS (AToM) product set.
The ML-Series card hosting the EoMPLS endpoint ports must be running the MPLS microcode
image to support EoMPLS. For more information on multiple microcode images, see the
Microcode Images" section on page
the MPLS microcode image.
Packet-based load balancing is not supported. Instead, circuit-ID based load balancing is used.
Zero hop or hairpin VCs are not supported. A single ML-Series card cannot be both the source and
destination for a VC.
MPLS control word for sequencing of data transmission is not supported. Packets must be received
and transmitted without control word.
Sequence checking or resequencing of EoMPLS traffic is not supported. Both depend on the control
word to function.
Maximum transmission unit (MTU) fragmentation is not supported.
Explicit-null label for back-to-back LDP sessions is not supported.
Cisco ONS 15454 and Cisco ONS 15454 SDH Ethernet Card Software Feature and Configuration Guide, R8.0
3-11. Other ML-Series cards in the RPR are not restricted to
EoMPLS Support
"Multiple
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