Juniper BGP - CONFIGURATION GUIDE V 11.1.X Configuration Manual page 564

JUNOSe 11.1.x BGP and MPLS Configuration Guide
Guidelines for Configuring Cell Concatenation and Cell Packing Timer for an ATM Port
Observe the following guidelines when you configure the maximum number of ATM
cells that the router can concatenate in a single packet and the identifier of the ATM
Martini cell packing timer that you want to use to detect timeout of the cell collection
threshold:
Performance Impact and Scalability Considerations
Because the support for multiple ATM VCs over a single pseudowire requires one
pseudowire per ATM port and the number of ATM ports in a fully populated ERX
chassis is in the order of a few tens of ports, the number of pseudowires required is
also of the same range. As a result, no performance impact is caused by LDP signaling
and state management. The amount of memory needed and initial CPU activity on
the line module for a specified range are proportional to the number of VCs in the
range.
You can scale the number of virtual circuits configured on an ATM line module up
to 16,000. The VPI/VCI range specification on the ATM ports for this feature is
controlled by this limit. Depending on other VPI/VCI configuration on the ATM line
module, the range specification must not be greater than this scaled limit subtracted
from the other VPI/VCI configuration.
A VPI/VCI range with the maximum number of VCs does not cause the line module
to become unstable. Support for unified ISSU and high availability with a VPI/VCI
range configured with the maximum number of VCs is provided.
Related Topics
528
Multiple ATM Virtual Circuits over a Single Pseudowire Overview
When a VPI/VCI range that you enter is a subset of an already defined range,
the specified range is not saved and an appropriate message is displayed on the
CLI interface.
When a VPI/VCI range that you enter encompasses one or more of the previously
defined ranges, the configuration attempt fails and an appropriate message is
displayed on the CLI interface.
You can configure the mpls-relay atm cell-packing mcpt-timer command on
the ATM port only after you associated a pseudowire with the port by using the
mpls-relay or route interface tunnel command.
You can use this command only on an ATM port (ATM AAL5 over ATM major
interface). When you attempt to run this command on other interface types,
such as ATM subinterfaces or Ethernet interfaces, this setting is not saved and
an error message is displayed.
Multiple ATM Virtual Circuits over a Single Pseudowire Example on page 560
mpls-relay atm vpi-range vci-range
mpls-relay atm cell-packing mcpt-timer