# evb vdp timer keepalive exponent

Use **evb ****vdp timer ****keepalive**** exponent** to configure a VDP keepalive exponent.

Use **undo evb ****vdp timer ****keepalive**** exponent** to restore the default.

## Syntax

**evb vdp ****timer ****keepalive ****exponent** *value*

**undo evb vdp ****timer ****keepalive ****exponent**

## Default

The VDP keepalive exponent is 20.

## Views

Layer 2 Ethernet interface view, Layer 2 aggregate interface view

## Predefined user roles

network-admin

## Parameters

*value*: Specifies a VDP keepalive exponent in the range of 14 to 31.

## Usage guidelines

The value for VDP keepalive time is expressed by the following equation:

VDP keepalive time (seconds) = 1.5 × [ 2^{VDP} ^{keepalive} + (2 × ECP maximum retransmission time + 1) × 2^{ECP retransmission }] × 10^{—}^{5}

For detailed values, see Table 7.

Table 7 uses **3** and **16** (the defaults) as the ECP maximum retransmission time and the ECP retransmission exponent to calculate the VDP keepalive time. These two variables use the larger values proposed by the station and bridge through EVB TLV.

The network environment and configurations on the EVB bridge and station determine whether to use the defaults or the actual proposed values for the following ECP values:

ECP maximum retransmission time.

ECP retransmission exponent.

Table 7: Values for VDP keepalive time

VDP keepalive exponent | Calculated value (seconds) | Result value (seconds) |
---|---|---|

14 | 7.12704 | 8 |

15 | 7.37280 | 8 |

16 | 7.86432 | 8 |

17 | 8.84736 | 9 |

18 | 10.81344 | 11 |

19 | 14.7456 | 15 |

20 | 22.60992 | 23 |

21 | 38.33856 | 39 |

22 | 69.795084 | 70 |

23 | 132.7104 | 133 |

24 | 258.53952 | 259 |

25 | 510.19776 | 511 |

26 | 1013.51424 | 1014 |

27 | 2020.1472 | 2021 |

28 | 4033.41312 | 4034 |

29 | 8059.94496 | 8060 |

30 | 16113.00864 | 16114 |

31 | 32219.136 | 32220 |

## Examples

# Configure the VDP keepalive exponent on FortyGigE 1/0/1 as **23**.

<Sysname> system-view [Sysname] interface FortyGigE 1/0/1 [Sysname-FortyGigE1/0/1] evb vdp timer keepalive exponent 23

# Configure the VDP keepalive exponent on Bridge-Aggregation 1 as **23**.

<Sysname> system-view [Sysname] interface bridge-aggregation 1 [Sysname-Bridge-Aggregation1] evb vdp timer keepalive exponent 23