IBM 8239 Token-Ring Stackable Hub, Setup And User Manual

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In addition to providing the MAC address-to-port mapping assignments, you can
also find out the hub and port to which a specific MAC address is attached by using
the DISPLAY NETWORK_MAP MAC_ADDRESS terminal interface command. The
DISPLAY NETWORK_MAP PORT command allows you to find out what MAC
addresses are associated with the specified port.
The mapping algorithm relies on the neighbor notification process. If there is
network disruption such that the neighbor notification process does not complete
successfully, then the network_map may not be up-to-date.
Note: When a ports_io wrap point is wrapped (for example, due to performing
network problem isolation), the network_map may not be complete
depending on which ports_io wrap points are wrapped and which
network_map command is issued. Wrapping a ports_io wrap point is not
recommended for normal operation.
Port Security
The 8239 supports port security to allow the network to be secure against
unwanted stations. The 8239 can be configured with MAC addresses that are
allowed to insert at a given port. When an unauthorized station inserts into the ring
(referred to as a
security intrusion or security breach) and it is attached to an 8239
port, the 8239 will take the appropriate action based on what was configured.
To use port security, you must:
¹
Identify the MAC addresses that are authorized
¹
Configure the action on intrusion for that port
¹
Enable port security for the port
Identifying which MAC Addresses are Authorized
The list of MAC addresses that are authorized to insert at a given port is kept in a
table called the Secure MAC Address Table. Each 8239 maintains its own Secure
MAC Address Table. There can be a maximum of 16 MAC addresses per port in
the Secure MAC Address Table. Port security is supported for fanout devices that
are attached to the 8239.
Either of the following terminal interface commands can be used to specify which
MAC addresses are put in the Secure MAC Address Table:
¹
SET SECURITY_PORT MAC_ADDRESS to assign individual MAC addresses
¹
SET SECURITY_PORT CAPTURE to copy all of the MAC addresses currently
active on a given port into the Secure MAC Address Table
To display the MAC addresses in the Secure MAC Address Table, use the
DISPLAY SECURITY PORT terminal interface command.
To remove a MAC address that is currently in the Secure MAC Address Table, use
the CLEAR SECURITY_PORT terminal interface command.
Chapter 6. Concentrator Functions
6-7