Juniper BGP - CONFIGURATION GUIDE V 11.1.X Configuration Manual page 550

JUNOSe 11.1.x BGP and MPLS Configuration Guide
Each MPLS shim interface points to a single MPLS next hop. When layer 2 frames
arrive on the layer 2 interface below the MPLS shim interface, they are encapsulated
in an MPLS packet and forwarded to that MPLS next hop. The details of the
encapsulation are determined by the attributes of the shim interface.
The MPLS next hop to which the shim interface points is set by an MPLS signaling
protocol, which adds a special entry with implicit null in label to the interface
label-space MPLS forwarding table of the shim interface. For traffic arriving from the
core, the MPLS signaling protocol adds a normal entry with a real in label to the
platform label-space MPLS forwarding table whose next hop points to the MPLS shim
interface.
You can configure the following attributes for each MPLS shim interface:
You can enable statistics collection for the MPLS shim interfaces.
Related Topics
514
MPLS Shim Interfaces for Layer 2 Services over MPLS
The administrative state, enabled or disabled, configured with the mpls-relay
disable command.
The IP address of the remote PE router for the layer 2 circuit, configured with
the mpls-relay command. The shim interface is cross-connected to an LSP
corresponding to the VC label received from the specified remote PE router, or
to another shim interface in the local cross-connects case. For local cross-connects
the IP address is local to the PE router.
The name of an RSVP-TE base tunnel to be used for the layer 2 circuit, configured
with the route interface command.
The group ID of the shim interface, configured using the group-id option of the
mpls-relay and route interface commands. Even though you can configure the
group ID, the JUNOSe software does not currently use it.
Whether the control word is used, configured with the control-word and
no-control-word options of the mpls-relay and route interface commands. The
layer 2 interface determines the default preference if this option is not configured.
Some layer 2 interfaces require a control word; others do not support it.
Whether sending nonzero sequence numbers in the control word is preferred,
configured with the sequencing and no-sequencing options of the mpls-relay
and route interface commands. The layer 2 interface determines the default
preference if this option is not configured. Even when preferred, the sequence
numbers might not be sent if the 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.
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.
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 Configuring CE-Side Load Balancing for Martini Layer 2 Transport
on page 540