Ilmi; Vpi/Vci Address Ranges; Vp Tunneling - Juniper JUNOSE SOFTWARE 11.2.X - LINK LAYER CONFIGURATION GUIDE 7-7-2010 Configuration Manual

ILMI

VPI/VCI Address Ranges

VP Tunneling

Copyright © 2010, Juniper Networks, Inc.
ATM interfaces support the ATM Forum integrated local management interface (ILMI),
versions 3.0, 3.1, and 4.0. An important feature of ILMI is the ability to poll or send keepalive
messages across the UNI. ATM interfaces always respond to such messages, which are
sent by an ATM peer device. Optionally, you can configure ATM major interfaces to
generate keepalive messages, a process that enables a continuous ATM-layer connectivity
verification; if the ATM peer stops responding to keepalive messages, the router disables
the ATM interface.
The ATM interface is not reenabled until the keepalive message's responses are received
(or until the keepalive feature is disabled on the ATM port). To enable ILMI and control
the generation of keepalive messages, use the atm ilmi-enable and atm ilmi-keepalive
commands.
The VPI/VCI address ranges allowed on ATM interfaces are module dependent. Certain
modules on ERX14xx models, ERX7xx models, or the Juniper Networks ERX310 Broadband
Services Router have a fixed allocation scheme, whereas others have a configurable
allocation scheme. In the configurable allocation scheme, a bit range is shared across
the VPI and VCI fields.
For example, if an ATM interface has a bit range of 18, and 4 bits are allocated to the VPI
space, then 14 bits are left for the VCI space. The resulting numeric range is 0 to 2n-1,
where n is the number of bits for each space. Completing the example, if 4 bits were
allocated for the VPI space and 14 for the VCI space, the configurable range would be 0
to 15 for VPI and 0 to 16,383 for the VCI space. To configure the bit range, use "atm
vc-per-vp" on page 29 .
See "Supported Features" on page 11 for details on how various line module and I/O
modules support configurable VPI/VCI address ranges.
NOTE: The E120 and E320 routers support the full VPI/VCI address range; therefore, it
has a fixed allocation scheme.
Virtual path (VP) tunneling enables traffic shaping to be applied to the aggregation of
all VCs within a single VP. Thus, VP tunnels can be used to ensure that the total traffic
transmitted on a VP does not exceed the specified PCR. VP tunneling uses a round-robin
algorithm to guarantee fairness among all of the VCs within the tunnel.
You can change the PCR associated with a tunnel even when VCs have already been
configured on the tunnel. The individual VCs within a tunnel must be specified as UBR
VCs. In other words, they may not have their own traffic-shaping parameters.
The level of support for VP tunneling is dependent on the specific I/O module. See
"Supported Features" on page 11 for details.
Chapter 1: Configuring ATM
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