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Limitations

Some Forward Error Correction (FEC) modes may be unavailable

Depending on the switch ASIC used, some FEC modes may be unavailable to configure:

  • Helix 4 based switches like Accton AS4610 only support Base-R on their 20G ports.
  • Trident II+ based switches like the Agema AG7648 only support Base-R.
  • Tomahawk based switches like the Agema AG5648 (non V1) only support Base-R on 25G ports. RS support is limited to 100G ports. Tomahawk+ based switches like the Agema AG5648V1 does not have this limitation.

No VxLAN support on Accton AS4610

The Broadcom Switch ASIC used in Accton AS4610 does not support VxLAN.

Celestica Questone 2A fans spinning at 100%

Please ensure that both PSUs are connected and have power. The switch will fall back to a fail-safe mode with all fans spinning at 100% if only one of the PSUs is available.

Table size differences

There might be discrepancies in the maximum number of entries in the unicast routing table (30) announced by of-dpa and how many it accepts.

The AG7648 switch announces a maximum of 32k entries for the unicast routing table(30) and of-dpa takes 16k host routes and 16k network routes.

Linux namespaces

baseboxd is not compatible with Linux namespaces. Moving basebox’s interfaces to a namespace will duplicate them.

Upgrade of BISDN Linux via onie-bisdn-upgrade

The script onie-bisdn-upgrade allows to use static IP configuration instead of DHCP. However, using the current ONIE installer, there is no route set towards the gateway, so images outside the configured network or, when using the “current” option, outside the switch management network (‘enp0s20f0’) can not be pulled and installed automatically.

Enabling auto-negotiation on ports may not work as expected

Depending on the switch and the link partner, we have observed the following behaviors:

  • Intel X552 10 GbE SFP+ network cards do not support auto-negotiation. This causes the link to take more than 30 seconds to come up when the port is set to autonegotiation.

  • The 10G ports on AS4610 only support advertising 1G, so the speed will be limited to 1G regardless of the link partner’s ability.

  • There is an issue in the Broadcom SDK version 6.5.21 and following, which affects all BISDN Linux releases after 3.7, where the 10G ports on AS4610 will not transfer packets when autonegotiating down to 1G after being configured for 10G. Forcing the speed to 1G with disabled autonegotiation avoids this issue.

  • The 25G ports on AG5648 do not support simultaneous detection of 1G with SGMII and 1G with KX, and will treat it as 1G with KX. If you use 1G SFP modules, configure the port to a fixed speed with 1G to work around this.

In all of these cases forcing the port on the switch to the desired speed works as expected.

Open issues

Ports default to no FEC even if the SFP module type inserted requires FEC

Affected versions: 3.0 - current

Currently ports will always default to no FEC regardless of the SFP module used. If the remote side follows the requirement, this can prevent the link from being established. In that case configure the FEC mode manually.

No support for VXLAN and STP on bonded interfaces

Affected versions: 3.5 - current

Currently VXLAN is not supported on bonded interfaces. The same is true for the spanning tree protocols STP, RSTP and MSTP.

Missing routes for EIGRP with flapping ports

Affected versions: 3.0 - current

As documented in the currently open upstream FRR issue #7299, some routes may get dropped or are not correctly received when ports are flapping during EIGRP session establishment. For now, we recommend the workaround of restarting FRR after all ports are up if this behavior is observed.

Resolved issues

DHCP packets not forwarded correctly

Affected versions: 3.0 - 4.0

In BISDN Linux prior to the release 4.1, switches would sometimes stop forwarding DHCP packets correctly due to an issue in handling multicast subscriptions within OF-DPA. The only known workaround (starting with BISDN Linux v4.0) is to disable IGMP/MLD Snooping. To avoid the issue completely, we recommend upgrading to release 4.1 or higher.

Celestica Questone 2A port LEDs do not light up

Affected versions: 4.0

In BISDN Linux prior to the release 4.1 the LEDs on Celestica Questone 2A ports do not light up when a link is established.

Agema-5648 PCIe Bus error

Affected versions: 3.0 - 3.5.1

The driver for the PCI bus may report an error leading to the controller not receiving any traffic and causing the platform to completely stop working until restarted. This is a sporadic bug and can be verified by running dmesg where the following logs are available to confirm the presence of the error.

[...] pcieport 0000:00:01.0: AER: Uncorrected (Non-Fatal) error received: 0000:01:00.0
[...] linux-kernel-bde 0000:01:00.0: AER: PCIe Bus Error: severity=Uncorrected (Non-Fatal), type=Transaction Layer, (Requester ID)
[...] linux-kernel-bde 0000:01:00.0: AER:   device [14e4:b967] error status/mask=00004000/00000000
[...] linux-kernel-bde 0000:01:00.0: AER:    [14] CmpltTO                (First)
[...] pcieport 0000:00:01.0: AER: Device recovery successful

The message AER: Device recovery successful shown above is misleading, since the Error can only be resolved by fully rebooting the switch itself.

Ports connected during boot may sometimes show as having no carrier in Linux

Affected versions: 3.0 - 3.7.2

All releases of BISDN Linux prior to version 3.7.3 suffer from an issue where the port state might end up out of sync.

This is caused by a race in OF-DPA, where OF-DPA first initializes ports with their current state, and only then registers the linkscan handler, which is responsible for updating OF-DPA’s port state. This creates a window where OF-DPA will miss any physical link state changes happening.

Any port state changes happening between the initial read out and the successful registration of the handler will be missed.

The port sync issue may be identified by the link’s inability to set a port up even though the port is connected. Using port2 as an example we run

ip link set port2 up
ip link show port2

port2: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc pfifo_fast state DOWN mode DEFAULT group default qlen 1000

Which shows NO-CARRIER and state DOWN. You can resolve the issue by using the OF-DPA api to first disable and then enable the port again.

client_drivshell port 2 Enable=false client_drivshell port 2 Enable=true