Juniper JUNOSE 11.2, Configuration Manual, Page: 557 / 772

atm pvc Command
You use the atm pvc command to define the underlying circuit supporting an ATM 1483
subinterface. When you define a circuit with this command by using the aal5autoconfig
option, it causes the ATM 1483 encapsulation (LLC/SNAP encapsulation or VC
multiplexed) to be autodetected. Alternatively, if you use the
aal5snap or aal5mux ip
option, the ATM 1483 encapsulation becomes fixed, but higher layers can be dynamic.
For example, the following command configures a circuit for autodetection of the ATM
1483 encapsulation and all higher layers.
host1(config-subif)# atm pvc 100 0 100 aal5autoconfig 0 0 0
You can also include the atm pvc command in a base profile assigned to a dynamic ATM
1483 interface to apply encapsulation and traffic-shaping parameters to a bulk-configured
range of PVCs. For information, see “Configuring Dynamic Interfaces Using Bulk
Configuration” on page 619.
Configuration Example for Encapsulation Type Lockout for IWF PPPoE Sessions
Consider a sample configuration scenario in which subscriber access loops are connected
using ATM links to a DSLAM device. Figure 39 on page 393 shows a topology in which one
DSLAM is connected one PPPoE access concentrator. The ATM traffic is forwarded using
an Ethernet circuit from the DSLAM device to the PPPoE access concentrator. The PPPoE
over ATM or PPP over ATM (PPPoA) traffic is converted to PPPoE by the DSLAM device,
which is connected to an ATM access loop on one side and an Ethernet aggregate network
on the other side. The interworking function describes the set of mechanisms used to
convert a PPPoE over ATM or PPPoA session to a PPPoE session.
The conversion of PPP, PPPoE, Ethernet, ATM 1483, or ATM connections at the DSLAM
access loop interface to PPP, PPPoE, or Ethernet connections at the DSLAM aggregate
network interface signifies that the MAC addresses of all such IWF sessions are translated
to be the MAC address of the DSLAM Ethernet interface connected to the aggregate
network. Therefore, you cannot uniquely identify a subscriber using the MAC address
only. If the MAC address alone is used to identify a particular subscriber, a single erroneous
IWF session can cause other IWF sessions to be locked out.
In this setup, if the PPPoE session contains the IWF-Session DSL Forum VSA (26-254)
in the PPPoE active discovery request (PADR) packet that is sent from the PPPoE client,
the Agent-Circuit-Id DSL Forum VSA (26-1) is used in addition to the MAC address to
identify the PPPoE session to be locked out. This method enables backward compatibility
with all non-IWF topologies. The Agent-Circuit-Id is of the format,
DSLAM name Slot/Port
VPI: VCI , which enables unique identification of the subscriber that has initiated the
session. This feature of encapsulation type lockout based on the Agent-Circuit-Id, in
addition to the MAC address retrieved from the client, is enabled by default only for IWF
sessions.
Configuring PPP and PPPoE Dynamic Interfaces over Static ATM
E Series routers support dynamic PPP and PPPoE interfaces. The configuration procedure
is very similar for each.
525 Copyright © 2010, Juniper Networks, Inc.
Chapter 17: Configuring Dynamic Interfaces