Class of Service

Support for additional IEEE 802.1 TLVs (QFX5110 and QFX5120-48Y)—Starting in Junos OS Release 22.2R1, QFX5110 and QFX5120-48Y switches support the IEEE 802.1 TLVs listed below. The TLVs advertise information to peers, and the Link Layer Discovery Protocol (LLDP) neighbors use the TLVs to discover a device’s capabilities.

• Enhanced transmission selection (ETS) configuration TLV—IEEE 802.1 subtype 9
• ETS recommendation TLV—IEEE 802.1 subtype A
• Priority-based flow control (PFC) configuration TLV—IEEE 802.1 subtype B

[See show lldp neighbors and show dcbx neighbors.]

Support for explicit congestion notification (ECN) (NFX Series, SRX380, SRX300, SRX320, SRX340, SRX345, and vSRX 3.0)—Starting with Junos OS Release 22.2R1, you can enable ECN marking for packets in scheduler queues on the listed devices. ECN enables end-to-end congestion notification between two endpoints on TCP/IP based networks. The two endpoints are an ECN-enabled sender and an ECN-enabled receiver. You must enable ECN on both endpoints and on all intermediate devices between the endpoints.

ECN notifies networks about congestion with the goal of reducing packet loss and delay by making the sending device decrease the transmission rate until the congestion clears, without dropping packets.

To enable ECN, issue the set class-of-service scheduler-name explicit-congestion-notification command.

To enable hierarchical scheduling, set hierarchical-scheduler at the [edit interfaces interface-name hierarchy level.

See [ Hierarchical Class of Service in ACX Series Routers.]