Network reporting

Link Fragmentation and Interleaving (LFI) is a network reporting technique to minimize serialization delay on slow (typically less than 768-kbps) WAN links. Essentially, LFI tools chop large data packets into smaller ones and interleave these data packet fragments with voice packets.
Packets that are assigned to the PQ inside LLQ might escape the fragmentation engine (the fragmentation engine is represented by the box labeled fragment). Therefore, traffic with large packet sizes (such as interactive video) should not be assigned to priority classes on slow-speed links (typically less than 768 kbps). For example, if one priority class is assigned to VoIP and another is assigned to interactive video on a 512-kbps link, whenever a 1500-byte video packet is scheduled for transmission, it will require 23 ms to serialize ((1500 x 8) / 512,000). This exceeds the per-hop latency target for voice (10 ms) and nearly consumes the entire one-way jitter allowance target of 30 ms. If a second 1500-byte IP/VC packet also is scheduled for transmission, voice conversations audibly will become degraded. Therefore, voice and interactive video never should be assigned dual-LLQ policies on link speeds less than 768 kbps.