3com 5500-ei pwr Instruccion De Instalación

 

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In practice, you need to implement the following in a cluster sometimes: 

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Know whether there is a loop in the cluster 

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Locate which port on which switch initiates a network attack 

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Determine the port and switch that a MAC address corresponds to 

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Locate which switch in the cluster has a fault 

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Check whether a link in the cluster and the devices on the link comply with the original plan 

In these situations, you can use the tracemac command to trace a device in the cluster by specifying a 

destination MAC address or IP address. 

The procedures are as follows: 

1)  Determine whether the destination MAC address or destination IP address is used to trace a 

device in the cluster 

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If you use the tracemac command to trace the device by its MAC address, the switch will query its 

MAC address table according to the MAC address and VLAN ID in the command to find out the port 

connected with the downstream switch. 

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If you use the tracemac command to trace the device by its IP address, the switch will query the 

corresponding ARP entry of the IP address to find out the corresponding MAC address and VLAN 

ID, and thus find out the port connected with the downstream switch. 

2)  After finding out the port connected with the downstream switch, the switch will send a multicast 

packet with the VLAN ID and specified hops to the port. Upon receiving the packet, the 

downstream switch compares its own MAC address with the destination MAC address carried in 

the multicast packet: 

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If the two MAC addresses are the same, the downstream switch sends a response to the switch 

sending the tracemac command, indicating the success of the tracemac command. 

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If the two MAC addresses are different, the downstream switch will query the port connected with 

its downstream switch based on the MAC address and VLAN ID, and then forward the packet to its 

downstream switch. If within the specified hops, a switch with the specified destination MAC 

address is found, this switch sends a response to the switch sending the tracemac command, 

indicating the success of the tracemac command. If no switch with the specified destination MAC 

address (or IP address) is found, the multicast packet will not be forwarded to the downstream any 

more. 

 

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If the queried IP address has a corresponding ARP entry, but the MAC address entry 

corresponding to the IP address does not exist, the trace of the device fails. 

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To trace a specific device using the tracemac command, make sure that all the devices passed 

support the tracemac function. 

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To trace a specific device in a management VLAN using the tracemac command, make sure that 

all the devices passed are within the same management VLAN as the device to be traced.