packets on the pseudowire are encapsulated. The egress VC does not need the same
ATM address as the ingress circuit.
Figure 117: AAL5 Pseudowire and MPLS Tunnel
To use AAL5 SDU encapsulation, you must use the aal5all encapsulation keyword when
you configure ATM subinterfaces.
OAM Cells
The E Series router performs a similar operation for Operation, Administration, and
Maintenance (OAM) cells, except that they do not need reassembly.
The router passes the following OAM cells transparently:
•
F5 alarm indication signal (AIS) segment and end-to-end
•
F5 remote defect indication (RDI) segment and end-to-end
•
F5 loopback segment and end-to-end
•
Resource management
•
F5 continuity check segment and end-to-end
In addition, F4 OAM cell forwarding is supported.
JunosE Software does not allow for setting a segment endpoint on an ATM cross-connect
interface. Segment OAM cells are forwarded to the egress interface in the same manner
as end-to-end cells.
QoS Classification
Packets are subject to normal quality of service (QoS) classification according to service
categories assigned to ATM virtual circuits that make up the connection.
Limitations
The JunosE implementation of the Martini draft has the following limitations:
•
Only AAL5 packets and OAM cells are forwarded.
•
There is no equivalent of VP switching.
•
Point-to-multipoint connections are not supported.
•
Automatic connection setup using user-to-network interface (UNI) signaling and
private network-to-network interface (PNNI) is not supported.
•
The ATM MIB cross-connected table is not supported.
•
Connections between ATM circuits and non-ATM interfaces are not supported.
517Copyright © 2010, Juniper Networks, Inc.
Chapter 8: Layer 2 Services over MPLS Overview
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