Layer 2 Service Package Capabilities and Interfaces

As described in Enabling Service Packages, you can configure the AS or MultiServices PIC and the internal ASM in the M7i platform to use either the Layer 2 or the Layer 3 service package.

When you enable the Layer 2 service package, the AS or MultiServices PIC supports link services. On the AS or MultiServices PIC and the ASM, link services include the following:

• JUNOS CoS components—The section Configuring CoS Scheduling Queues on Logical LSQ Interfaces describes how the JUNOS CoS components work on link services IQ (lsq) interfaces. For detailed information about JUNOS CoS components, see the JUNOS Class of Service Configuration Guide.
• Data compression using the compressed Real-Time Transport Protocol (CRTP) for use in voice over IP (VoIP) transmission.

  Note: On LSQ interfaces, all multilink traffic for a single bundle is sent to a single processor. If CRTP is enabled on the bundle, it adds overhead to the CPU. Because T3 network interfaces support only one link per bundle, make sure you configure a fragmentation map for compressed traffic on these interfaces and specify the no-fragmentation option. For more information, see Configuring Delay-Sensitive Packet Interleaving and Configuring CoS Fragmentation by Forwarding Class on LSQ Interfaces.

• Link fragment interleaving (LFI) on Frame Relay links using FRF.12 end-to-end fragmentation—The standard for FRF.12 is defined in the specification FRF.12, Frame Relay Fragmentation Implementation Agreement.
• LFI on Multilink Point-to-Point Protocol (MLPPP) links.
• Multilink Frame Relay (MLFR) end-to-end (FRF.15)—The standard for FRF.15 is defined in the specification FRF.15, End-to-End Multilink Frame Relay Implementation Agreement.
• Multilink Frame Relay (MLFR) UNI NNI (FRF.16)—The standard for FRF.16 is defined in the specification FRF.16.1, Multilink Frame Relay UNI/NNI Implementation Agreement.
• MLPPP—The standard for MLPPP is defined in the specification RFC 1990, The PPP Multilink Protocol (MP).
• Multiclass extension to MLPPP—The standard is defined in the specification RFC 2686, The Multi-Class Extension to Multi-Link PPP.

For the LSQ interface on the AS or MultiServices PIC, the configuration syntax is almost the same as for Multilink and Link Services PICs. The primary difference is the use of the interface-type descriptor lsq instead of ml or ls. When you enable the Layer 2 service package on the AS or MultiServices PIC, the following interfaces are automatically created:

Interface types gr, ip, mt, pd, pe, and vt are standard tunnel interfaces that are available on the AS or MultiServices PIC whether you enable the Layer 2 or the Layer 3 service package. These tunnel interfaces function the same way for both service packages, except that the Layer 2 service package does not support some tunnel functions, as shown in Table 5 on page 24. For more information about tunnel interfaces, see Tunnel Interfaces Configuration Guidelines.

Note: Interface type sp is created because it is needed by the JUNOS software. For the Layer 2 service package, the sp interface is not configurable, but you should not disable it.

Interface type lsq-fpc/pic/port is the physical link services IQ interface (lsq). Interface types lsq-fpc/pic/port:0 through lsq-fpc/pic/port:N represent FRF.16 bundles. These interface types are created when you include the mlfr-uni-nni-bundles statement at the [edit chassis fpc slot-number pic pic-number] hierarchy level. For more information, see Configuring CoS Scheduling Queues on Logical LSQ Interfaces.

Note: On DS0, E1, or T1 interfaces in LSQ bundles, you can configure the bandwidth statement, but the routing platform does not use the bandwidth value if the interfaces are included in an MLPPP or MLFR bundle. The bandwidth is calculated internally according to the time slots, framing, and byte-encoding of the interface. For more information about these properties, see the JUNOS Network Interfaces Configuration Guide.