OcNOS 6.6.1 Available Now: Full AI Fabric on Tomahawk 5, SR Enhancements, and EVPN Expansion

OcNOS 6.6.1 is now generally available. This release delivers the complete AI fabric solution on Broadcom Tomahawk 5-based open hardware — building on the PFC and ETS foundations introduced in OcNOS 6.6 to provide a production-ready lossless RoCEv2 fabric for AI GPU clusters. Service provider deployments benefit from additional Segment Routing enhancements and expanded EVPN coverage.

Complete AI Fabric on Broadcom Tomahawk 5

OcNOS 6.6.1 DC delivers full lossless AI fabric support on Tomahawk 5 platforms including the UfiSpace S9321-64EO (64×800G OSFP, 51.2 Tbps). This includes Priority-Based Flow Control (PFC), Enhanced Transmission Selection (ETS), DCBX auto-negotiation, Explicit Congestion Notification (ECN), and RDMA-aware queue management — all validated for production RoCEv2 GPU workloads.

! OcNOS 6.6.1 DC -- AI fabric configuration
!
configure terminal
qos enable
qos statistics
!
! Step 1: DSCP to traffic-class mapping for RoCEv2 and control traffic
qos profile dscp-to-queue AI-FABRIC-MAP
  dscp 24 queue 3                 ! RoCEv2 (CS3) -> traffic-class 3
  dscp 46 queue 5                 ! Expedited (EF) -> traffic-class 5
  exit
!
! Step 2: bandwidth guarantees per traffic class
policy-map type queuing default AI-SCHEDULER
  class type queuing default q5
    bandwidth percent 10          ! routing and signaling
    exit
  class type queuing default q3
    bandwidth percent 70          ! RoCEv2 (GPU all-reduce)
    exit
  class type queuing default q0
    bandwidth percent 20          ! best-effort
    exit
  exit
!
! Step 3: apply to the fabric port and enable lossless PFC
interface cd0
  qos map-profile dscp-to-queue AI-FABRIC-MAP
  service-policy type queuing output AI-SCHEDULER
  priority-flow-control mode on
  priority-flow-control advertise-local-config
  priority-flow-control enable priority 3 5
  exit
!
commit
exit
!
! Verification:
show priority-flow-control details all
show priority-flow-control statistics all
show dcbx details interface cd0
show running-config qos

Segment Routing Enhancements (SP)

OcNOS 6.6.1 SP expands Segment Routing capabilities with additional Flex-Algo improvements including refined delay advertisement thresholds, improved algorithm convergence during topology changes, and enhanced SR-TE policy path computation. The RSVP Auto-Bypass feature is also introduced in this release — see the RSVP Auto Bypass guide for details.

EVPN Service Expansion

OcNOS 6.6.1 expands EVPN coverage with improvements to EVPN-ETREE service handling, enhanced multi-homed ESI mass withdrawal timing, and improved EVPN IRB (Integrated Routing and Bridging) gateway performance for data center environments requiring simultaneous L2 and L3 forwarding within the same VNI.

• OcNOS 6.6 Release
• OcNOS 7.0 — What’s New
• RSVP Auto Bypass in OcNOS
• OcNOS Feature Matrix
• Contact IP Infusion

IP Infusion Product Team