Lucent Technologies P550 - Manual (Page 243)

Managing Address Forwarding Tables (Layer 2 & Layer 3)
Cajun P550/P220 Switch Operation Guide 14 -3
4. From the Hash Table/Size pull-down menu, select the new size to alter the space
available for this address table. The rule of thumb is: Tables with high Total Bucket
Utilization (greater than 75%) can be made smaller. Tables with low Total Bucket
Utilization (less than 40%) should be made larger. Note that the number of
addresses for a given hash table is 4:1 (for example, if you have a hash table of 16
bytes, the VLAN can hold 64 addresses in it’s table instance.
5. From the Hash Table/Auto Increment pull-down menu, select False to prevent
the table size from reconfiguring automatically.
6. Click APPLY to save your changes, or CANCEL to restore previous settings.
If you want to relearn the entire table, click Delete All Learned Entries.
If you want to delete all entries that are currently aged out, click Delete All
Invalid Learned Entries.
Note: If you change the Hash Table Size, the switch relearns all addresses in that
table, causing the switch to flood packets for a few seconds.
Entry Validity Displays the entry validity for this VLAN.
Options include:
• Valid - Entry exists.
• Invalid - Entry has aged out but still exists even
though the port binding is invalid.
Hash Table Displays the hash table parameters.
Options include:
• Size - It is recommended that the hash table size be
1/8th the size of the total number of addresses for the
VLAN.
• Auto Increment - Hash tables may grow dynamically
larger if more addresses are discovered. Disabling
auto-increment prevents these tables from growing
dynamically at the risk of extra flooding.
Bucket Info Displays parameters to monitor the efficiency of the hash
table allocations.
Options include:
• Count - Indicates the hash table count.
• Capacity - Indicates the hash table capacity.
• Utilization - High utilization indicates that a larger
hash table is needed.
Table 14-1. Address Table Instance Parameters (Continued)
Parameter Definition