Table Of Contents

System Performance

Cell Transfer Delay

Switch Fabric Latency

High-Speed Frame Service Modules Switchover Timing Rates

Number of Connections Supported

System Performance

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Cell Transfer Delay

This section describes Cell Transfer Delay (CTD) on the MGX 8250.

Switch Fabric Latency

CTD on switching fabric + PXM1 OC-3 UNI Virtual Service Module (VSM) is on the order of 16-18 usec.

High-Speed Frame Service Modules Switchover Timing Rates

The Hot Standby feature reduces High-Speed FRSM switchover traffic loss to < 250 milliseconds (see Table 8-1). The average traffic loss on FRSM-CT3 cards with 4000 connections is less than 250 milliseconds. This compares to about 8 minutes of lost traffic without Hot Standby.

The Service Module failures were simulated by

•Resetting the card

•Removing and reinserting the card

The CIR was set to 100000 bps on one of the channels, this setting resulted in > 100 frames/secondans ensured that some traffic loss could be observed. The traffic was physically looped back through the FRSM-CT3 cards.

Table 8-1 Traffic Loss with and without Hot Standby

Number of Connections	Traffic Loss without Hot Standby	Traffic Loss with Hot Standby
4	31 sec	0.250 sec
2000	240 sec	0.250 sec
4000	473 sec	0.250 sec

Number of Connections Supported

The maximum number of connections supported by the different cards on the MGX 8250 are detailed in Table 8-2.

Table 8-2 MGX 8250 Supported Connections

Service Modules	Maximum Number of HW Connections Supported
PXM1-2T3E3	32K
PXM1-4-155	32K
PXM1-1-622	32K
AX-FRSM-8T1/E1	1K (*)
AX-FRSM-2CT3	4K
AX-FRSM-2T3E3	2K
AX-FRSM-HS1/B	200
AX-FRSM-HS2	2K
AX-AUSM/B-8T1/E1	1K
AX-CESM-8T1/E1	192 (8T1) or 248 (8E1)
AX-CESM-T3E3	1
MGX-VISM-8T1/E1	240
MGX-RPM	4K

(*) = the number of connections supported per port if LMI is enabled.

.Strata LMI: 560

.Annex A, Annex D for UNI and NNI: 898

.If Strata LMI is enabled for all ports, the total number of connections that can be configured is 1120, for other LMI it is 1996.