Brocade Network OS Administrator’s Guide v4.1.1 - Manual (Page 723)

Use the show fabric route pathinfo command to display routing information from a source port on the
local switch to a destination port on another switch. The command output describes the exact data path
between these ports, including all intermediate switches.
To use the show fabric route pathinfo command across remote fabrics, you must specify both the
VCS ID (or Fabric ID) and the RBridge ID (or domain ID) of the remote switch. When obtaining path
information across remote fabrics, the destination switch must be identified by its RBridge ID or domain
ID. Identifying the switch by name or WWN is not accepted.
For details about the show fabric route pathinfo command, refer to the Network OS Command
Reference.
Using the packet capture utility
When a packet is received at a switch’s source port, it is routed through the switch to the destination
port. If a problem occurs, SPAN or sFlow are commonly used. However, SPAN requires a network
analyzer, and sFlow requires a collector. The packet capture utility, executed by means of the capture
packet interface command, makes it possible to capture packets destined toward the CPU, as well as
transit packets if a trap is enabled by means of ACL logging. This command can provide significant help
in debugging, especially for Layer 2 TRILL and Layer 3 packets.
There are two ways to view the results of packet capture:
• By using the show capture packet interface command on the target switch.
• By viewing the results in an automatically generated file.
For command details, refer to the Network OS Command Reference.
Captured packets are stored in a circular buffer, and they are also written to an automatically generated
pktcapture.pcap file, which can store up to 1500 KB of data in flash memory (the equivalent of
approximately 10KB packets, each having an average size of 100 bytes). Once this file is full, it is saved
as *_old.pcap and data are written to a new pktcapture.pcap file. These files can be exported and
viewed through a packet analyzer such as Wireshark.
NOTE
Up to 100 packets per interface can be captured. Once the buffer is filled, the oldest packets are
replaced with the most recent.
Note the following limitations:
• Support is provided only on physical interfaces (1-, 10-, and 40-gigabit Ethernet), not on logical
interfaces. To capture packets on logical interfaces, first enable the capture on the corresponding
physical interfaces.
• Support for capturing transit traffic requires ACL logging.
• Packets that are dropped in the ASIC cannot be captured.
CAUTION
Capturing packets over multiple sessions and over long durations can affect system
performance.
Using the packet capture utility
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