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mac-lookup-length

 

Syntax

Hierarchy Level

Release Information

Statement introduced in Junos OS Release 11.4 for EX Series switches.

Description

Increase the maximum number of searchable hash indexes to mitigate situations in which hash index collisions are causing problems with the learning of MAC addresses in the forwarding database (FDB).

The FDB on EX3200, EX3300, EX4200, EX4500, EX4550, and EX6210 switches is a hash table with 8192 hash indexes (rows) of MAC addresses and four entries per hash index. When the FDB is searched, a configured hash function calculates the hash index at which to start the search. By default, after the search starts at the determined hash index, the maximum number of hash indexes that can be searched is one hash index, or four entries

Note

Increasing the number of hash indexes increases the chances of finding an open entry in which to add a newly learned MAC address. However, searching more hash indexes requires more bandwidth and may impact the FDB performance and line-rate traffic.

Default

4

Options

number-of-entries—Maximum number of searchable hash indexes in the FDB.

Range: 4, 8, 12

Required Privilege Level

system—To view this statement in the configuration.

system-control—To add this statement to the configuration.