Link Services CoS on M-series and T-series Platforms

For Link Services PIC interfaces (ls) on M-series and T-series platforms, queue 0 is the only queue that you should configure to receive fragmented packets. Configure all other queues to be higher-priority queues.

Table 23 summarizes how CoS queues work on link services (ls) interfaces.

Table 23: Link Services CoS Queues

For M-series and T-series platforms, CoS on link services (ls) interfaces works as follows:

• On all platforms, the Link Services PIC currently supports up to four queues: 0, 1, 2, and 3.
• Queue 0 uses MLFR FRF.15, MLFR FRF.16, or MLPPP to bundle packets.
• Higher-priority queues (1, 2, and 3) use hash-based load balancing to bundle packets. IP and MPLS header information is included in the hash.
• MLPPP packets traversing link services interfaces using queue 0 are fragmented and distributed across the constituent links. Queue 0 packets are sent on the least utilized link, proportional to its bandwidth. The queue 0 load balancer attempts to maintain even distribution of all traffic across all constituent links. In situations with a small number of high-priority traffic flows (queues 1, 2, and 3), queue 0 traffic might be unevenly distributed.
• For the MLFR FRF.16 protocol, only queue 0 works. If you configure a bundled interface to use MLFR FRF.16 with queue 0, then you must ensure the classifier does not send any traffic to queues 1, 2, and 3 on that interface.
• To carry high-priority traffic correctly on MLFR FRF.16 interfaces, you must configure an output firewall filter that forces all traffic into queue 0 on the ls-fpc/pic/port.channel interface.
• MLFR FRF.15 and MLPPP interfaces support CoS through packet interleaving. The MLFR FRF.16 standard does not support packet interleaving, so all packets destined for an FRF.16 PVC interface must egress from the same queue.
• For constituent link interfaces of Link Services PICs, you can configure standard scheduler maps.
• For input packets and fragments received from constituent links, you can use regular input firewall filters and standard CoS classifiers on the link services interface.
• For packets that pass through a link services interface and are destined for a constituent link interface, all traffic using queue 0 is fragmented. Traffic using higher-priority queues (1, 2, and 3) is not fragmented.
• For MLFR FRF.15 and MLPPP, routing protocol packets smaller than 128 bytes are sent to queue 3; routing protocol packets that exceed 128 bytes are sent to queue 0 and fragmented accordingly. For MLFR FRF.16, queue 0 is used for all packet sizes.
• You must configure output firewall classification for egress traffic on the link services interface, not directly on the constituent link interface directly.
• Inverse multiplexing for ATM (IMA) is not supported on link services interfaces.

For more information, see Configuring Link Services Delay-Sensitive Packet Interleaving and the JUNOS Policy Framework Configuration Guide.

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