Specifications
21-17
Cisco BPX 8600 Series Installation and Configuration
Release 9.3.0, Part Number 78-10674-01 Rev. D0, July 2001
Chapter 21 Configuring ATM Connections
rt-VBR and nrt-VBR Connections
With Rel. 9.2.20 and later,you specify rt-VBR and nrt-VBR connections separately when adding a
connection by using the addcon command.Todothis,entereitherrt-vbr or nrt-vbr to select the
rt-VBR or nrt-VBR connection class, respectively. Each connection is assigned the applicable
associated default parameters for its type of service.
For rt-VBR an additional queue, referred to as the rt-VBR queue, is used at a BXM port. At BXM or
BNI trunks, voice and rt-VBR traffic share a queue, referred to as the rt-VBR queue.
The rt-VBR and nrt-VBR service queues are configured differently from each other at both port ingress
and port egress queues. The rt-VBR typically uses smaller queues for low delay, whereas the nrt-VBR
queues are typically larger in size for more efficient bandwidth sharing with other non-real time service
types.
The rt-VBR connections are configured per class 3 service parameters. The nrt-VBR connections are
configured per class 2 service parameters.
You can configure the connection classes to whatever service and parameters you want by:
• Using the cnfcls and cnfatmcls commands.
• Or, you can enter the parameters individually for each connection by specifying ‘yes’ to the
extended parameters prompt of the addcon command.
For a new node running software release 9.2.20 or later, the rt-VBR connection class number is 3.
However, an upgraded node will retain existing connection classes. Therefore, it won’thavethert-VBR
connection class 3.
For nrt-VBR connections in a new node, running 9.2.20, a number of connection classes are
pre-configured, including 2, 4, 5, and 6.
Examplef cnfcls 3, for rt-VBR
pubsbpx1 TN silves:1 BPX 8620 9.2.20 July 16 2000 10:42 PDT
ATM Connection Classes
Class: 3 Type: rt-VBR
PCR(0+1) % Util CDVT(0+1) AAL5 FBTC SCR
4000/4000 100/100 10000/10000 n 4000/4000
MBS Policing
1000/1000 3
Description: "Default rt-VBR 4000 "
This Command: cnfcls atm 3
Enter class type (rt-VBR, nrt-VBR, CBR, UBR, ABRSTD, ABRFST, ATFR, ATFST, ATFT,
ATFTFST, ATFX, ATFXFST):