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Cisco ME 3800X and 3600X Switch Software Configuration Guide
OL-23400-01
Chapter 34 Configuring MPLS, MPLS VPN, MPLS OAM, and EoMPLS
Enabling EoMPLS
EoMPLS and QoS
EoMPLS supports QoS by using three experimental bits in a label to determine the priority of packets.
To support QoS between label edge routers (LERs), you set the experimental bits in both the virtual
connection and the tunnel labels. EoMPLS QoS classification occurs on ingress, and you can only match
on Layer 3 parameters (such as IP or DSCP) and Layer 2 parameters (CoS). See
Chapter 27,
“Configuring QoS”
for more information about EoMPLS and QoS.
EoMPLS Limitations
These restrictions apply to EoMPLS:
•
You cannot configure MPLS and EoMPLS on the same port.
•
MTU—EoMPLS does not support packet fragmentation and reassembly. Therefore, the maximum
transmission unit (MTU) of all intermediate links between endpoints must be sufficient to carry the
largest Layer 2 VLAN received. The ingress and egress provider-edge routers must have the same
MTU value.
•
Address Format—All loopback addresses on provider-edge routers must be configured with 32-bit
masks to ensure proper operation of MPLS forwarding. OSPF requires the use of loopback
addresses.
•
Packet Format—EoMPLS supports VLAN packets that conform to the IEEE 802.1Q standard. ISL
encapsulation is not supported between provider-edge and customer-edge routers.
•
Layer 2 connection restrictions:
–
You cannot have more than one Layer 2 connection between routers if those routers are
configured to transport Ethernet VLANs over the MPLS backbone. Adding a second Layer 2
connection causes the spanning-tree state to constantly toggle if you disable spanning tree on
the peer router.
•
STP— Do not enable per-VLAN spanning-tree (PVST) on the VLAN configured for an EoMPLS
session. STP instances are not supported on this VLAN. All PVST bridge protocol data units
(BPDUs) coming in on the EoMPLS VLAN from the customer side are tunneled transparently as
data packets over to the EoMPLS pseudowire and vice-versa.
•
Trunking—The native VLAN of a trunk cannot be an EoMPLS VLAN.
•
You can enable EoMPLS on IEEE 802.1Q interfaces by using the xconnect interface configuration
command. Use the xconnect command to configure pseudowire redundancy.
•
EFP—EFT with “POP 2 symmetric” and pseudowire cannot be configured in the same bridge
domain.
•
IGMP—Disable IGMP for any bridge domain where pseudowire is configured.
Enabling EoMPLS
This section includes this information about configuring EoMPLS on a switch used as a provider-edge
router:
•
Default EoMPLS Configuration, page 34-31
•
EoMPLS Configuration Guidelines, page 34-31
•
Configuring EoMPLS, page 34-31