Configuring Link Services Delay-Sensitive Packet Interleaving

For link services FRF.15 and MLPPP interfaces only, you can configure link fragment interleaving (LFI). LFI reduces excessive delays of Frame Relay packets by fragmenting long packets into smaller packets and interleaving them with real-time frames. This allows real-time and non-real-time data frames to be carried together on lower-speed links without causing excessive delays to the real-time traffic. When the peer interface receives the smaller fragments, it reassembles the fragments into their original packet. For example, short delay-sensitive packets, such as packetized voice, can race ahead of larger delay-insensitive packets, such as common data packets.

Note: All Link Services PICs (4-multilink bundle, 32-multilink bundle, and 128-multilink bundle) support up to 256 link services interfaces with LFI enabled, if those link services interfaces contain only one constituent link each. For the Link Services PIC, multiple-link LFI bundles are simply multilink bundles, and are limited based on the type of PIC (4-multilink bundle, 32-multilink bundle, and 128-multilink bundle). In addition, the multilink bundles you configure subtract from the total of 256 possible LFI-enabled link services interfaces. For example, if a 32-multilink bundle Link Services PIC has 24 multilink bundles configured and active, then you can configure 256 – 24 = 232 LFI-enabled link services interfaces, each with a single constituent link. For link services IQ interfaces (lsq), the interleave-fragments statement is not valid. Instead, you can enable LFI by configuring fragmentation maps. For more information, see Configuring Fragmentation by Forwarding Class.

You can configure multiple links in a bundle and configure packet interleaving. However, if you use packet interleaving, high-priority, nonmultilink-encapsulated packets use a hash-based algorithm to choose a single link.

For detailed information about link services CoS, see Configuring CoS Components on Link Services PICs.

Per-bundle CoS queuing is supported on link services IQ interfaces (lsq). For more information about link services IQ interfaces, see Link Services IQ Interfaces Configuration Guidelines.

The JUNOS software supports end-to-end fragmentation in compliance with the FRF.12 Frame Relay Fragmentation Implementation Agreement standard. Unlike user-to-network interface (UNI) and network-to-network (NNI) fragmentation, end-to-end supports fragmentation only at the endpoints.

By default, packet interleaving is disabled. To enable packet interleaving, include the interleave-fragments statement:

You can include this statement at the following hierarchy levels:

• [edit interfaces interface-name unit logical-unit-number]
• [edit logical-systems logical-system-name interfaces interface-name unit logical-unit-number]