Juniper JUNOSE 11.2.X BGP AND MPLS, Configuration Manual

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control word is not used due to configuration. You can only configure whether the
numbers are sent. MPLS always accepts zero sequence numbers and checks the order
of nonzero sequence numbers in received MPLS packets that are forwarded to an
MPLS shim interface. Out-of-order packets are discarded.
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The number of the load-balancing group of which the shim interface is a member. This
attribute is set to the current load-balancing group when the shim interface is implicitly
created with the
member interface command.
You can enable statistics collection for the MPLS shim interfaces.
Related Topics For information about the creation or implicit removal of shim interfaces from a
load-balancing group by the
member interface command when you configure the
group, see Understanding CE Load Balancing for Martini Layer 2 Transport on page 539
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For information about collecting statistics for the MPLS shim interfaces, see Monitoring
Layer 2 Services over MPLS on page 561
Multiple Layer 2 Services over MPLS Overview
When you configure an MPLS shim interface over an ATM, Frame Relay, or HDLC layer 2
interface, no other interface (for example, PPP or IP) can be stacked above the layer 2
interface.
By contrast, when you configure an MPLS shim interface over any Ethernet or
Ethernet/VLAN interface, both the MPLS shim interface and other interfaces (such as
IP, PPP, or PPPoE) can be stacked above the layer 2 interface.
When you configure both an MPLS shim interface and another interface over a layer 2
interface, traffic for a protocol explicitly configured in the interface stack is forwarded to
that protocol layer for further processing. Traffic for any nonconfigured protocols is
forwarded to the MPLS shim interface on the other side of the connection.
When the MPLS shim interface is the only layer stacked above the layer 2 interface, as
is the case with ATM, Frame Relay, and HDLC, then all traffic is forwarded to the MPLS
shim interface and across the MPLS tunnel.
Related Topics Example: Configuring Many Shim Interfaces with the Same Peer, VC Type, and VC ID
on page 540
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Configuring Load-Balancing Groups on page 542
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Load-Balancing Group Configuration on page 541
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MPLS Interfaces and Labels on page 542
ATM Layer 2 Services over MPLS Overview
ATM layer 2 services over MPLS provide ATM switch-like functionality for E Series routers.
This feature is useful for customers who run IP in the majority of their network but still
515 Copyright © 2010, Juniper Networks, Inc.
Chapter 8: Layer 2 Services over MPLS Overview