Using The Show Platform Forward Command - Cisco WS-C3750-48PS-S Software Configuration Manual

Chapter 39 Troubleshooting
Possible destinations include the console, virtual terminals, internal buffer, and UNIX hosts running a
syslog server. The syslog format is compatible with 4.3 Berkeley Standard Distribution (BSD) UNIX
and its derivatives.
Be aware that the debugging destination you use affects system overhead. Logging messages to the
Note
console produces very high overhead, whereas logging messages to a virtual terminal produces less
overhead. Logging messages to a syslog server produces even less, and logging to an internal buffer
produces the least overhead of any method.
When stack members generate a system error message, the stack master displays the error message to
all stack members. The syslog resides on the stack master.
Make sure to save the syslog to flash memory so that the syslog is not lost if the stack master fails.
Note
For more information about system message logging, see
Logging."

Using the show platform forward Command

The output from the show platform forward privileged EXEC command provides some useful
information about the forwarding results if a packet entering an interface is sent through the system.
Depending upon the parameters entered about the packet, the output provides lookup table results and
port maps used to calculate forwarding destinations, bitmaps, and egress information.
For more syntax and usage information for the show platform forward command, refer to the switch
Note
command reference for this release.
Most of the information in the output from the command is useful mainly for technical support
personnel, who have access to detailed information about the switch application-specific integrated
circuits (ASICs). However, packet forwarding information can also be helpful in troubleshooting.
This is an example of the output from the show platform forward command on Gigabit Ethernet port 1
in VLAN 5 when the packet entering that port is addressed to unknown MAC addresses. The packet
should be flooded to all other ports in VLAN 5.
Switch# show platform forward gigabitethernet1/0/1 vlan 5 1.1.1 2.2.2 ip 13.1.1.1 13.2.2.2
udp 10 20
Global Port Number:24, Asic Number:5
Src Real Vlan Id:5, Mapped Vlan Id:5
Ingress:
Lookup
InptACL
L2Local
Station Descriptor:02340000, DestIndex:0239, RewriteIndex:F005
==========================================
Egress:Asic 2, switch 1
Output Packets:
78-16180-02
Key-Used
40_0D020202_0D010101-00_40000014_000A0000
80_00050002_00020002-00_00000000_00000000
Using the show platform forward Command
Chapter 29, "Configuring System Message
Index-Hit A-Data
01FFA 03000000
00C71 0000002B
Catalyst 3750 Switch Software Configuration Guide
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