Which two statements are true about MLP interleaving? (Choose two.)

A.
It fragments and encapsulates all packets in a fragmentation header.

B.
Packets smaller than the fragmentation size are interleaved between the fragments of the larger packets.

C.
Packets larger than the fragmentation size are always fragmented, and cannot be interleaved, even if the traffic is voice traffic.

D.
It fragments and encapsulates packets that are longer than a configured size, but does not encapsulate smaller packets inside a fragmentation header.

Explanation:

Previous implementations of Cisco IOS Multilink PPP (MLP) include support for Link Fragmentation Interleaving (LFI). This feature allows the delivery of delay-sensitive packets, such as the packets of a Voice call, to be expedited by omitting the PPP Multilink Protocol header and sending the packets as raw PPP packets in between the fragments of larger data packets. This feature works well on bundles consisting of a single link. However, when the bundle contains

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Cisco 642-874 Exam

multiple links there is no way to keep the interleaved packets in sequence with respect to each other.

Interleaving on MLP allows large packets to be multilink encapsulated and fragmented into a small enough size to satisfy the delay requirements of real-time traffic; small real-time packets are not multilink encapsulated and are transmitted between fragments of the large packets.

Note: The following URL from Cisco’s website explains this feature:
http://www.cisco.com/univercd/cc/td/doc/product/software/ios122/122cgcr/fqos_c/fqcprt6/qcflfi.htm #wp1000907

“(Optional) Configures a maximum fragment delay. If, for example, you want a voice stream to have a maximum bound on delay of 20 milliseconds (ms) and you specify 20 ms using this command, MLP will choose a fragment size based on the configured value.” Packets are fragmented when they exceed the configured maximum delay.