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Release notes


Device Support

New devices supported by the fabric:

  • Clos Spine

    • Celestica DS3000
    • Edgecore AS7712-32X-EC
    • Supermicro SSE-C4632SB
  • Clos Leaf

    • Celestica DS3000
    • Supermicro SSE-C4632SB
  • Collapsed Core ToR

    • Celestica DS3000
    • Supermicro SSE-C4632SB


  • Metadata describing switch capabilities, feature capacities, and resource naming mapping.
  • Switch Profiles are used for providing normalized name/id mapping, validation and internal resource management.
  • Switch Profiles are Mandatory. Each switch model must have a corresponding switch profile to be supported by the fabric.
  • Each switch defined in the wiring diagram should be pointing to the switch profile document.
  • Detailed overview
  • Catalog of switch profiles

New Universal Port Naming Scheme

  • E<asic>/<port>/<breakout> or M<port>
  • Enabled via switch profiles

Improved per switch-model/platform validation

  • Enabled via switch profiles


  • It’s now possible to explicitly specify a gateway to use in VPC subnets
  • StaticExternal now supports default routes

Inspection CLI

CLI commands are intended to navigate fabric configuration and state and allow introspection of the dependencies and cross-domain checking:

  • Fabric (overall control nodes and switches overview incl. status, serials, etc.)
  • Switch (status, used ports, counters, etc.)
  • Switch sort (connection if used in one, counters, VPC and External attachments, etc.)
  • Server (connection if used in one, VPC attachments, etc.)
  • Connection (incl. VPC and External attachments, Loobpback Workaround usage, etc.)
  • VPC/VPCSubnet (incl. where is it attached and what's reachable from it)
  • IP Address (incl. IPv4Namespace, VPCSubnet and DHCPLease or External/StaticExternal usage)
  • MAC Address (incl. switch ports and DHCP leases)
  • Access between pair of IPs, Server names or VPCSubnets (everything except external IPs will be translated to VPCSubnets)


  • Example Grafana Dashboards added to the docs
  • Syslog (/var/log/syslog) is now could be collected from all switches and forwarded to Loki targets

Bug Fixes

  • Fixed: Restricted subnet isn't accessible from other subnets of the same VPC



Telemetry - Prometheus Exporter

  • Hedgehog Fabric Control Plane Agents on switches function as Prometheus Exporters

  • Telemetry data provided by Broadcom SONiC is now supported:

    • port and interface status and counters
    • transceiver state
    • environmental information (temperature, fans, psu, etc.)
    • BGP state and counters
  • Export to Prometheus using Prometheus Remote-Write API or any API-compatible platform


  • Grafana Alloy is supported as a certified logging agent that is installed and managed by the Fabric

  • Data collected

    • Agent logs
    • Agent, switch, and host-level metrics
  • Export to API-compliant platforms and products such as Prometheus, Loki, Grafana Cloud, or any LGTM stack

Agent Status API Enhancements

  • Ports status and counters
  • Port breakout status and counters
  • Transceiver status and counters
  • Environmental and platform information
  • LLDP neighbors

Networking enhancements

  • Multiple direct control links per switch are now supported
  • Custom static routes could be installed into VPC using API
  • ExternalAttachment could be configured without VLAN now

Other improvements

  • PXE boot with HTTP
  • The hhfab and hhfctl (kubectl plugin) are now published for Linux/MacOS amd64/arm64
  • Switch users can now be configured as part of installation preparation (username, password hash, role, and public keys)

Bugs fixed

  • DHCP service assigning IP multiple times if restarted in between
  • Remote peering was configured as a local


Open Source

  • Apache License 2.0
  • The main repos are public:
    • Fabric
    • Fabricator
    • Das-boot
    • Toolbox
    • Docs
  • Items not open-sourced:
    • HONIE with front panel booting support

DHCP/PXE boot support for multi-homed connections

  • PXE URL support for on-demand DHCP service
  • LACP link (MCLAG and ESLAG) fallback allows support of one of the links without the use of a host-level bond


  • Native VLAN support for server-facing connections
  • Extended wiring validation at hhfab init/build time
  • External peering failover in case of using remote peering on the same switches as external connectivity



  • Fabric API reference

Host connectivity dual homing improvements

  • ESI for VXLAN-based BGP EVPN
  • Support in Fabric and VLAB
  • Host connectivity Redundancy Groups
  • Groups LEAF switches to provide multi-homed connectivity to the Fabric
  • 2-4 switches per group
  • Support for MCLAG and ESLAG (EVPN MH / ESI)
  • A single redundancy group can only support multi-homing of one type (ESLAG or MCLAG)
  • Multiple types of redundancy groups can be used in the fabric simultaneously

Improved VPC security policy - better Zero Trust

  • Inter-VPC
    • Allow inter-VPC and external peering with per subnet control
  • Intra-VPC intra-subnet policies
    • Isolated Subnets
      • subnets isolated by default from other subnets in the VPC
      • require a user-defined explicitly permit list to allow communications to other subnets within the VPC
      • can be set on individual subnets within VPC or per entire VPC - off by default
      • Inter-VPC and external peering configurations are not affected and work the same as before
    • Restricted Subnets
      • Hosts within a subnet have no mutual reachability
      • Hosts within a subnet can be reached by members of other subnets or peered VPCs as specified by the policy
      • Inter-VPC and external peering configurations are not affected and work the same as before
    • Permit Lists
      • Intra-VPC Permit Lists govern connectivity between subnets within the VPC for isolated subnets
      • Inter-VPC Permit Lists govern which subnets of one VPC have access to some subnets of the other VPC for finer-grained control of inter-VPC and external peering

Static External Connection

  • Allows access between hosts within the VPC and devices attached to a switch with user-defined static routes

Internal Improvements

  • A new, more reliable automated ID allocation system
  • Extra validation of object lifecycle (e.g., object-in-use removal validation)

Known Issues

  • External Peering Failover
    • Conditions: ExternalPeering is specified for the VPC, and the same VPC has Border Leaf VPCPeering
    • Issue: Detaching ExternalPeering may cause VPCPeering on the Border Leaf group to stop working
    • Workaround: VPCPeering on the Border Leaf group should be recreated


SONiC support

  • Broadcom Enterprise SONiC 4.2.0 (previously 4.1.1)

Multiple IPv4 namespaces

  • Support for multiple overlapping IPv4 addresses in the Fabric
  • Integrated with on-demand DHCP Service (see below)
  • All IPv4 addresses within a given VPC must be unique
  • Only VPCs with non-overlapping IPv4 subnets can peer within the Fabric
  • An external NAT device is required for peering of VPCs with overlapping subnets

Hedgehog Fabric DHCP and IPAM Service

  • Custom DHCP server executing in the controllers
  • Multiple IPv4 namespaces with overlapping subnets
  • Multiple VLAN namespaces with overlapping VLAN ranges
  • DHCP leases exposed through the Fabric API
  • Available for VLAB as well as the Fabric

Hedgehog Fabric NTP Service

  • Custom NTP servers at the controller
  • Switches automatically configured to use control node as NTP server
  • NTP servers can be configured to sync to external time/NTP server

StaticExternal connections

  • Directly connect external infrastructure services (such as NTP, DHCP, DNS) to the Fabric
  • No BGP is required, just automatically configured static routes

DHCP Relay to 3rd party DHCP service

Support for 3rd party DHCP server (DHCP Relay config) through the API



A single controller. No controller redundancy.

Controller connectivity

For CLOS/LEAF-SPINE fabrics, it is recommended that the controller connects to one or more leaf switches in the fabric on front-facing data ports. Connection to two or more leaf switches is recommended for redundancy and performance. No port break-out functionality is supported for controller connectivity.

Spine controller connectivity is not supported.

For Collapsed Core topology, the controller can connect on front-facing data ports, as described above, or on management ports. Note that every switch in the collapsed core topology must be connected to the controller.

Management port connectivity can also be supported for CLOS/LEAF-SPINE topology but requires all switches connected to the controllers via management ports. No chain booting is possible for this configuration.

Controller requirements

  • One 1 gig+ port per to connect to each controller attached switch
  • One+ 1 gig+ ports connecting to the external management network.
  • 4 Cores, 12GB RAM, 100GB SSD.

Chain booting

Switches not directly connecting to the controllers can chain boot via the data network.

Topology support

CLOS/LEAF-SPINE and Collapsed Core topologies are supported.

LEAF Roles for CLOS topology

server leaf, border leaf, and mixed leaf modes are supported.

Collapsed Core Topology

Two ToR/LEAF switches with MCLAG server connection.

Server multihoming


Device support


  • DELL:

    • S5248F-ON
    • S5232F-ON
  • Edge-Core:

    • DCS204 (AS7726-32X)
    • DCS203 (AS7326-56X)
    • EPS203 (AS4630-54NPE)


  • DELL:
    • S5232F-ON
  • Edge-Core:
    • DCS204 (AS7726-32X)

Underlay configuration:

Port speed, port group speed, port breakouts are configurable through the API

VPC (overlay) Implementation


Multi-subnet VPCs

A VPC consists of subnets, each with a user-specified VLAN for external host/server connectivity.

Multiple IP address namespaces

Multiple IP address namespaces are supported per fabric. Each VPC belongs to the corresponding IPv4 namespace. There are no subnet overlaps within a single IPv4 namespace. IP address namespaces can mutually overlap.

VLAN Namespace

VLAN Namespaces guarantee the uniqueness of VLANs for a set of participating devices. Each switch belongs to a list of VLAN namespaces with non-overlapping VLAN ranges. Each VPC belongs to the VLAN namespace. There are no VLAN overlaps within a single VLAN namespace.

This feature is useful when multiple VM-management domains (like separate VMware clusters connect to the fabric).

Switch Groups

Each switch belongs to a list of switch groups used for identifying redundancy groups for things like external connectivity.

Mutual VPC Peering

VPC peering is supported and possible between a pair of VPCs that belong to the same IPv4 and VLAN namespaces.

External VPC Peering

VPC peering provides the means of peering with external networking devices (edge routers, firewalls, or data center interconnects). VPC egress/ingress is pinned to a specific group of the border or mixed leaf switches. Multiple “external systems” with multiple devices/links in each of them are supported.

The user controls what subnets/prefixes to import and export from/to the external system.

No NAT function is supported for external peering.

Host connectivity

Servers can be attached as Unbundled, Bundled (LAG) and MCLAG

DHCP Service

VPC is provided with an optional DHCP service with simple IPAM

Local VPC peering loopbacks

To enable local inter-vpc peering that allows routing of traffic between VPCs, local loopbacks are required to overcome silicon limitations.


  • Maximum fabric size: 20 LEAF/ToR switches.
  • Routes per switch: 64k
  • [ silicon platform limitation in Trident 3; limits to number of endpoints in the fabric ]
  • Total VPCs per switch: up to 1000
  • [ Including VPCs attached at the given switch and VPCs peered with ]
  • Total VPCs per VLAN namespace: up to 3000
  • [ assuming 1 subnet per VPC ]
  • Total VPCs per fabric: unlimited
  • [ if using multiple VLAN namespaces ]
  • VPC subnets per switch: up to 3000
  • VPC subnets per VLAN namespace up to 3000
  • Subnets per VPC: up to 20
  • [ just a validation; the current design allows up to 100, but it could be increased even more in the future ]
  • VPC Slots per remote peering @ switch: 2
  • Max VPC loopbacks per switch: 500
  • [ VPC loopback workarounds per switch are needed for local peering when both VPCs are attached to the switch or for external peering with VPC attached on the same switch that is peering with external ]

Software versions

  • Fabric: v0.23.0
  • Das-boot: v0.11.4
  • Fabricator: v0.8.0
  • K3s: v1.27.4-k3s1
  • Zot: v1.4.3
  • SONiC
  • Broadcom Enterprise Base 4.1.1
  • Broadcom Enterprise Campus 4.1.1

Known Limitations

  • MTU setting inflexibility:
  • Fabric MTU is 9100 and not configurable right now (A3 planned)
  • Server-facing MTU is 9136 and not configurable right now (A3+)
  • no support for Access VLANs for attaching servers (A3 planned)
  • VPC peering is enabled on all subnets of the participating VPCs. No subnet selection for peering. (A3 planned)
  • peering with external is only possible with a VLAN (by design)
  • If you have VPCs with remote peering on a switch group, you can't attach those VPCs on that switch group (by definition of remote peering)
  • if a group of VPCs has remote peering on a switch group, any other VPC that will peer with those VPCs remotely will need to use the same switch group (by design)
  • if VPC peers with external, it can only be remotely peered with on the same switches that have a connection to that external (by design)
  • the server-facing connection object is immutable as it’s very easy to get into a deadlock, re-create to change it (A3+)


  • Controller:

    • A single controller connecting to each switch management port. No redundancy.
  • Controller requirements:

    • One 1 gig port per switch
    • One+ 1 gig+ ports connecting to the external management network.
    • 4 Cores, 12GB RAM, 100GB SSD.
  • Seeder:

    • Seeder and Controller functions co-resident on the control node. Switch booting and ZTP on management ports directly connected to the controller.
  • HHFab - the fabricator:

    • An operational tool to generate, initiate, and maintain the fabric software appliance. Allows fabrication of the environment-specific image with all of the required underlay and security configuration baked in.
  • DHCP Service:

    • A simple DHCP server for assigning IP addresses to hosts connecting to the fabric, optimized for use with VPC overlay.
  • Topology:

    • Support for a Collapsed Core topology with 2 switch nodes.
  • Underlay:

    • A simple single-VRF network with a BGP control plane. IPv4 support only.
  • External connectivity:

    • An edge router must be connected to selected ports of one or both switches. IPv4 support only.
  • Dual-homing:

    • L2 Dual homing with MCLAG is implemented to connect servers, storage, and other devices in the data center. NIC bonding and LACP configuration at the host are required.
  • VPC overlay implementation:

    • VPC is implemented as a set of ACLs within the underlay VRF. External connectivity to the VRF is performed via internally managed VLANs. IPv4 support only.
  • VPC Peering:

    • VPC peering is performed via ACLs with no fine-grained control.
  • NAT

    • DNAT + SNAT are supported per VPC. SNAT and DNAT can't be enabled per VPC simultaneously.
  • Hardware support:

    • Please see the supported hardware list.
  • Virtual Lab:

    • A simulation of the two-node Collapsed Core Topology as a virtual environment. Designed for use as a network simulation, a configuration scratchpad, or a training/demonstration tool. Minimum requirements: 8 cores, 24GB RAM, 100GB SSD
  • Limitations:

    • 40 VPCs max
    • 50 VPC peerings
    • [ 768 ACL entry platform limitation from Broadcom ]
  • Software versions:

    • Fabricator: v0.5.2
    • Fabric: v0.18.6
    • Das-boot: v0.8.2
    • K3s: v1.27.4-k3s1
    • Zot: v1.4.3
    • SONiC: Broadcom Enterprise Base 4.1.1

Last update: July 9, 2024
Created: October 30, 2023