Juniper JUNOSE, Configuration Manual

Page: 591 / 738

NOTE: The support for multiple VCs over a single pseudowire uses the the ATM
n-to-one VCC cell transport (0x0009) pseudowire (PW) type in LDP signalling
messages. This PW type is also used in the signaling messages by the ATM Martini
circuit feature, which enables cell relay encapsulation on an ATM subinterface, that
transports ATM cells associated with an ATM subinterface on a single pseudowire.
Because the same PW type is used for both the cell relay encapsulation for a single
VC and multiple VCs, you can successfully configure an ATM subinterface Martini
circuit (cell relay for a single VC) on one PE router and an ATM port Martini circuit
(cell relay for multiple VCs) on another PE router, and bring up the pseudowires for
this configuration. In such a scenario, traffic black holes might occur and rewriting
of the ATM cell header takes place. In this topology, on the PE router configured with
an ATM subinterface Martini circuit, the VPI/VCI values of all the ATM cells received
on the pseudowire are rewritten to match with the configuration on the ATM
subinterface. On the PE router configured with an ATM port Martini circuit, all the
ATM cells received on the pseudowire are examined to determine whether they fall
within the configured VPI/VCI range. If the ATM cells do not fall within the configured
VPI/VCI range, they are discarded.
Related Topics
■
Multiple ATM Virtual Circuits over a Single Pseudowire Overview on page 518
■
mpls-relay atm vpi-range vci-range
■
mpls-relay atm cell-packing mcpt-timer
Multiple ATM Virtual Circuits over a Single Pseudowire Example
■ 555
Chapter 7: Configuring Layer 2 Services over MPLS