Brocade FastIron SX, FCX, and ICX Diagnostic Reference - Manual (Page 25)

Brocade FastIron SX, FCX, and ICX Diagnostic Reference 13
53-1003076-02
Chapter
3
Layer 2 Diagnostics
This chapter contains the following sections:
• STP debug commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
• RSTP debug commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
• MSTP debug commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
• DHCP debug commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
• GVRP debug commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
• MAC address debug commands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
• MCT debug commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
• Packet-capture debug commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
• VXLAN debug commands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
• Link aggregation debug commands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
STP debug commands
The Spanning Tree Protocol (STP) eliminates Layer 2 loops in networks, by selectively blocking
some ports and allowing other ports to forward traffic, based on the global (bridge) and local (port)
parameters.
STP-related features, such as Rapid Spanning Tree Protocol (RSTP) and Per VLAN Spanning Tree
(PVST), extend the operation of standard STP, enabling you to fine-tune standard STP and avoid
some of its limitations.
You can enable or disable STP on a global basis (for the entire device), a port-based Virtual Local
Area Network (VLAN) basis (for the individual Layer 2 broadcast domain), or an individual port
basis. For more information on configuring STP, refer to the FastIron Configuration Guide.
A control protocol, such as STP, can block one or more ports in a protocol-based VLAN that uses a
virtual routing interface to route to other VLANs. For IP VLANs and IP subnet VLANs, even though
some of the physical ports of the virtual routing interface are blocked, the virtual routing interface
can still route as long as at least one port in the protocol-based VLAN is not blocked by STP.
The following are the commands used to enable the STP debugging.
debug span all_802_1d_events
Syntax: [no] debug span all_802_1d_events vlan decimal
This command monitors information about all the events, timers, and packets on a specific VLAN.
The decimal variable refers to the number of the VLAN.
The output from this command resembles the following example.
Brocade# debug span all_802_1d_events vlan 2
STP Enabling All events Debugging for VLAN 2