Configuring Low-Cdv Mode For Per-Port Queuing On Atm Interfaces - Juniper JUNOSE 11.1.X - QUALITY OF SERVICE CONFIGURATION GUIDE 3-21-2010 Configuration Manual

TIP: For ATM interfaces on ERX7xx models, ERX14xx models, and the ERX310
router, you must specify port 0.
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Configuring Low-CDV Mode for Per-Port Queuing on ATM Interfaces

In low-CDV mode, the HRR scheduler and the SAR scheduler operate in concert. In
low-CDV QoS port mode, QoS automatically configures the shaping rate of the VPs,
VCs, or both based on the QoS profile and the scheduler profile. Therefore, the QoS
shaping mode must be set to the cell mode. In low-CDV mode, the SAR scheduler
converts frame-atomic bursts of cells to CDVT-conformant streams of interleaved
cells. There is no VC backpressure, and the port backpressure is loose, so several
megabytes of cells can reside in the SAR buffer pool.
When you configure low-CDV mode:
This procedure creates the low-CDV mode with per-VP CDVT configuration shown
in Figure 46 on page 172. Figure 47 on page 172 shows low-CDV mode with per-VC
CDVT.
Chapter 19: Configuring an Integrated Scheduler to Provide QoS for ATM
host1(config-if)#qos-profile low-latency-q-p
The qos-mode-port command:
Excludes non-UBR ATM QoS services on any VC on the ATM module; for
example, PCR, nrtVBR, and CBR
Cannot be used if shaping is currently configured on the SAR scheduler
Cannot be used with ATM VP tunnels with nonzero rates; however, can be
used with tunnels with rates of zero (shapeless tunnels).
Per-Packet Queuing on the SAR Scheduler Overview on page 163
Guidelines for Configuring QoS over ATM on page 166
interface atm
qos-mode-port
qos-profile
QoS synchronizes the shaping rates for VPs and VCs in the HRR and SAR
schedulers.
VC backpressure is disabled.
Port backpressure is set to default thresholds of 6 MB per OC3 port and 24 MB
per OC12 port.
SAR scheduler performs more buffering than in low-latency mode.
Use cell QoS shaping mode.
Configuring Low-CDV Mode for Per-Port Queuing on ATM Interfaces
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