ifferent queues. In queue 1, a packet of 1,500 bytes is waiting to be transmitted. Queue 2 has a packet of 800 bytes, and queue 3 has a packet of 1,200 bytes. On the first pass, the packet from Quantum = 1,000 Bytes First pass: 1-Packet not served, new DC = 1,000 1,500 Queue 1 2-Packet served, new DC = 200 Source bytes 3-Packet not served, new DC = 1,000 Queue 2 Source bytes Scheduler Queue 3 Source 1,200 Second pass: bytes 1-Packet served, new DC = 500 2-No packet, new DC = 0 3-Packet served, new DC = 800 DC = Deficit counter Figure 8.26 IP QoS queue scheduling: Deficit Round Robin IP QoS queue 1 is not served because it is 1,500 bytes, and the quantum is set at 1,000 bytes. We therefore create a new deficit counter of 1,000. The packet from queue 2 is served because it is less than the quantum. Because the quantum is 1,000 and the packet length is 800 bytes, the next deficit counter is reset to 200. With queue 3, the packet is not served because it is longer than the quantum. This packet is 1,200 bytes, and the quantum is 1,000, SO we reset the deficit counter to 1,000, based on the quantum value. On the second pass, with queue 1, we reset the deficit counter to 1,000 after the first pass. We add that value to the quantum, which is also 1,000, giving us 2,000 bytes. Now the packet can be served because it is 1,500 bytes, which is less than 2,000 bytes. The packet is served, and the deficit counter is then reset with the remainder, which is 500. In queue 2, we already served the packet, SO there's now nothing there, and we reset the deficit counter to 0. With queue 3, on the first pass, we reset the deficit counter to 1,000, so now we add the quantum of 1000, which results in a value of 2,000 bytes. The 1,200-byte packet is now served, and the deficit counter is reset to 800. The IP QoS Continuum IP QoS has a continuum that involves a range of cost and complexity (see Figure 8.27). At the bottom of the range is best effort. Basically, this implies fair access to all, FIFO queuing, and no priority. Next on the sc