Cisco ME-3600X-24CX Series Switch Chassis Configuration Guide, Release 15.2(4)S
Configuring BFD Offload
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Configuring BFD Offload

Table Of Contents

Configuring BFD Offload

Restrictions for BFD Offload Support

Configuring BFD Offload Support

Verifying BFD Offload Support


Configuring BFD Offload


Bidirectional Forwarding Detection (BFD) offload support provides the functionality to offload a BFD session to the field-programmable gate array (FPGA). BFD is a forwarding path failure detection protocol and reduces the overall network convergence time by sending rapid failure detection packets (messages) to the routing protocols for recalculating the routing table. Previously the performance of BFD was restricted to the capabilities of CPU and IOS on the RP of the switch. Effective failure detection requires BFD to run at high frequencies (using aggressive timers as low as 50ms), which was not possible because of CPU and IOS restrictions.

For information on configuring BFD see Configuring BFD section of ME 3800x and ME 3600x Switches Software Configuration Guide.


Note On the Cisco ME 3600X-24CX, BFD session will be supported only on the FPGA, BFD sessions on the RP are not supported.


Restrictions for BFD Offload Support

Only BFD version 1 is supported.

Only FPGA offloaded BFD sessions are supported, BFD sessions on RP are not supported on ME 3600X-24CX-M.

The switch supports BFD only in Asynchronous mode or no echo mode.

The switch supports 511 asynchronous BFD sessions.

BFD hardware offload is supported for IPv4 sessions with non-echo mode only.

BFD offload is supported on port-channel interfaces.

BFD offload is supported only for the ethernet interface.

BFD offload is not supported for IPv6 BFD sessions.

BFD offload is not supported for BFD with TE/FRR

Configuring BFD Offload Support

The BFD offload functionality is enabled by default. You can configure BFD hardware offload on the route processor. For more information, see Configuring BFD, page 35-71

Verifying BFD Offload Support

You must ensure that the Session host is showing as Hardware. Use the show bfd neighbors detail to verify the configuration of BFD Offload. Hardware BFD sessions have a LD of 1-511.


Note Sometimes if BFD session is brought up after the registered protocol is up the session may come up in Software. Shutdown the interface and apply the BFD config to ensure that session comes back up in Hardware.


Switch# show bfd neighbours details
NeighAddr                              LD/RD         RH/RS     State     Int
34.34.34.3                            1/11         Up        Up        Vl3336
Session state is UP and not using echo function.
Session Host: Hardware
OurAddr: 34.34.34.1     
Handle: 295
Local Diag: 0, Demand mode: 0, Poll bit: 0
MinTxInt: 50000, MinRxInt: 50000, Multiplier: 3
Received MinRxInt: 100000, Received Multiplier: 3
Holddown (hits): 0(0), Hello (hits): 100(0)
Rx Count: 574748
Tx Count: 673965
Elapsed time watermarks: 0 0 (last: 0)
Registered protocols: ISIS CEF OSPF
Uptime: 14:22:46
Last packet: Version: 1                  - Diagnostic: 0
             State bit: Up               - Demand bit: 0
             Poll bit: 0                 - Final bit: 0
             C bit: 0                                   
             Multiplier: 3               - Length: 24
             My Discr.: 11               - Your Discr.: 294
             Min tx interval: 100000     - Min rx interval: 100000
             Min Echo interval: 0 ould