Interface Hardware Queuing (tx_limited).
by David Sudjiman ~ June 23rd, 2008. Filed under: Cisco.There are two major queuing lines available. The one that we’ve been playing with is only software based. From this software queuing we implement CB-WFQ, PQ, LLQ and other queuing methods. Whatever done from this software queuing packets then passed to hardware queuing that is more strict and using only FIFO as queuing method.
Imagine you are sending a packet form one device to another. After the packet being processed with software queue, if any, then it is passed to hardware queue. Hardware queue will break it down to particles depends how much the length of the hardware queue consist.
R1#sh controllers f0/0 | i tx_limited tx_limited=0(64)
From the example above, FastEthernet 0/0 has can holds 64 particles as it is the length of FastEthernet 0/0 transmit queue available.
The number 0 shown above implies that the size of the queue is not limited (0 means false).
Now, we can actually tweak the number of the particles (Wendell Odom explains this using the word ‘packets length’) using command tx-ring-limit
R1(config)#int f0/0 R1(config-if)#tx-ring-limit 32 R1(config-if)#do sh controller f0/0 | i tx_limited tx_limited=0(32)
Sources.