2. RapidIO Ports > Packet Trace and Filtering
CPS-1848 User Manual
53
June 2, 2014
Formal Status
This document is confidential and is subject to an NDA.
Integrated Device Technology
2.9
Packet Trace and Filtering
2.9.1
Packet Trace
Each S-RIO port can compare a received packet against a set of configurable predefined values, and, if a match occurs,
include a reference to a configurable output port as part of its forwarding information passed to the switch fabric. This function
is defined as the “Trace” function. When all bits of the packet data match corresponding bits in a specific programmable value
(after the value’s mask has been applied), the Trace Criteria is met and a copy of the packet is forwarded to the trace enabled
output port.
Each S-RIO port provides output port routing references derived from a received packet's destID (including multicast
references), as well as a routing reference to the configured trace port to the switch fabric. Each S-RIO port also provides a
uniquely configurable trace function so that trace can be enabled on up to 18 ports simultaneously. To enable the trace
function, set TRACE_EN to 1 in the
.
2.9.1.1
Trace Criteria
The property of an S-RIO port matching a packet with a “Trace Criteria” refers to a successful comparison of the first 160 bits
in a received packet to multiple pre-programmed values stored at that port. A successful match against a Trace Criteria will
trigger the S-RIO port to flag the trace port (to the switch fabric) for packet forwarding.
Each S-RIO port provides a set of four uniquely configurable 160-bit comparison values that can selectively be applied using a
bit mask to the first 160 bits of each packet that the block receives. Each S-RIO port also provides a bit mask for each of the
four programmable 160-bit comparison values that define which of the first 160 bits of packet data are relevant to the
comparison. A value of 1 in the comparison value mask indicates that the corresponding bits in the programmed value and the
corresponding bit in the packet data is compared. A value of 0 in the comparison value mask is used as a “don’t care”. A don’t
care value will result in an automatic match of the corresponding bits in the programmable value with the corresponding packet
data bits. When all bits of the packet data match with a corresponding bit in a specific programmable value (after the value’s
mask has been applied) the Trace Criteria has been met and a copy of the packet is forwarded to the trace enabled output
port. The packet trace is triggered by a logical “OR” of the comparison match results (packet data with the four programmable
values) such that if at least one match occurs, packet forwarding to the trace enabled port is enabled.
Note that the trace criteria is based on the entire contents of the comparison value and its corresponding bit mask. If the
number of bits in the packet being compared is less than 160 bits, the excess bits in the mask must be set as “don't care,” as
displayed in
Figure 8: Trace Criteria
The Trace Criteria architecture is displayed in
.
Packet Data
bit
0
.............................................
.bit
n<160
bit
0
.......................................................................................
.bit
160
Comparison Dat
a
Comparison Mask
bit
0
.............................................
.bit
n<160
X
n+1
................................X
160
X = don’t care