IBM3229P2035
IBM Packet Routing Switch Serial Interface Converter
Advance
The data transfer must have been stopped for long enough and in such a way that all buffers are empty
before the loopback is initiated. If the buffers are not empty, reset the path on which the loopback is to be
performed. To execute the loopback, the converter must be set in OBFC mode to avoid modifying the packet
qualifier byte.
3.7.1.3 Protocol Engine (PE) External Loopback
The PE bus is wrapped via the DASL interface. The switch is disconnected from the converter. A wrap plug is
connected to the DASL port corresponding to the path to be tested.
Note: The switch plane (or substitute) clock must be selected.
Figure 19: Protocol Engine External Loopback Through Path X
IBM Packet Routing Switch Serial Interface Converter
X/Y
External Wrap
Ingress
Egress
DASL
DASL
X
Y
Protocol
Engine
X/Y
The following operational sequence must be performed to execute PE external loopback:
1. Reset the path to be set in loopback.
2. Force X or Y switch plane in service.
3. Select the clock source (switch or microprocessor) for the plane to be wrapped.
4. Synchronize the DASL.
5. Initiate the traffic from the PE.
The PE external loopback can be performed without switch clock by using the microprocessor clock and prop-
erly programming the PLLs (the PLL must be reset to acquire its newly programmed value). In all cases the
objective is to be in the frequency range of 100 - 125 MHz to allow DASL operation.
3.7.1.4 Switch X/Y Loopback
Switch X/Y loopback provides a connection from the egress input to the ingress output to the ingress input
through either the X or the Y path. During this test RXENB is de-asserted so the PE cannot send data.The
result of this test is obtained through the switch control.
Functional Description
Page 44 of 154
prssi.02.fm
March 1, 2001
IBM [ IBM ]
