Brocade MLX Series and Brocade NetIron XMR Diagnostic Guide ...

802.1ag CFM for VPLS debug commands 3• The setting for POS keepalive messages must be the same on both ends of the link. Keepalivemessages are enabled by default for POS interfaces.• The Data-Link Connection Identifier (DLCI) is the circuit ID for the link and can be a number inthe range from 1 through 1023. The circuit ID must be the same on both ends of the link.• POS modules use their own field-programmable gate arrays (FPGAs).• Bandwidth – You can change a 2488 Mbps port to run at 622 Mbps if needed.• SPE scrambling is enabled by default. Both ends of a link must use the same scramblingalgorithm.• Cyclic Redundancy Check (CRC) – You can specify the length of the CRC field in each packetsent by the POS interface. The default length is 32 bits. You can change the length to 16 bits.• POS overhead flags – You can change the following values in the POS frame header:- c2 – Payload content type. The default is 0x16, which specifies PPP with scramblingenabled.- j1 – Path trace byte. Default is 0x0.- j0 – Section trace byte. Default is 0x1.Common diagnostic scenariosIssues with POS modules are usually hardware-related. The following problems may occur:• Memory defects are in the module hardware.• The module is not sending bridge protocol data units (BPDUs).• Free queue depth levels are rising and falling.• Modules in a particular chassis slot are showing similar errors. In this case, the chassis slotconnector may be faulty. Contact Brocade Technical Support if you suspect a faulty chassisslot.802.1ag CFM for VPLS debug commandsThe debug commands for troubleshooting 802.1ag Connectivity Fault Management (CFM) forVirtual Private LAN Service (VPLS) are described in this section.debug cfmSyntax: [no] debug cfm This command enables 802.1ag debugging. The variable is a value from 0 through 7.Setting the level to 7 enables debugging of all CFM packets.Command output resembles the following example.Brocade# debug cfm 1CFM: debug level is 1Dec 10 17:36:35 CFM: receive packet :rx_l2_bpdu 12Dec 10 17:36:35 CFM: receive packet :rx_l2_bpdu 12Dec 10 17:36:36 CFM: receive packet :rx_l2_bpdu 12Dec 10 17:36:36 CFM: receive packet :rx_l2_bpdu 17Dec 10 17:36:36 CFM: receive packet :rx_l2_bpdu 12Dec 10 17:36:36 CFM: receive packet :rx_l2_bpdu 12Dec 10 17:36:36 CFM: receive packet :rx_l2_bpdu 12Brocade MLX Series and Brocade NetIron XMR Diagnostic Guide 6953-1002426-02