Ldp graceful restart for pseudowire
Download
1 / 9

LDP Graceful Restart for Pseudowire - PowerPoint PPT Presentation


  • 233 Views
  • Uploaded on

LDP Graceful Restart for Pseudowire. draft-jiang-pwe3-ldp-gr-01.txt. Kan. Hu Jian. Luo Bo. Wu ZTE Corporation. Introduction. LDP graceful restart mechanism defined in [RFC 3478] can be applied to pseudowire graceful restart.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' LDP Graceful Restart for Pseudowire ' - adonis


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Ldp graceful restart for pseudowire

LDP Graceful Restart for Pseudowire

draft-jiang-pwe3-ldp-gr-01.txt

Kan. Hu

Jian. Luo

Bo. Wu

ZTE Corporation


Introduction
Introduction

  • LDP graceful restart mechanism defined in [RFC 3478] can be applied to pseudowire graceful restart.

  • Pseudowire graceful restart (GR) mechanism can be optimized by extending capability negotiation in [RFC 3478] .


Problem statement i
Problem statement (I)

Pseudowire

  • PE1 support both LSP-FEC and PW-FEC graceful restart.

  • PE2 only support graceful restart for LSP-FEC.

  • Through Fault Tolerant (FT) Session TLV in the LDP Initialization message, negotiated result is:

    • PE1 will assume PE2 also supports graceful restart for both LSP-FEC and PW-FEC.

    • PE2 will assume PE1 only supports graceful restart for LSP-FEC.

AC

AC

CE1

CE2

PE1

PE2


Problem statement ii
Problem statement (II)

Pseudowire

  • PE2 restarts its control plane.

  • PE1 detects that its LDP session with a neighbor went down.

  • PE1 retains the LSP-FEC and PW-FEC label bindings, and continue traffic forwarding.

  • PE2 will not retain PW-FEC in the data plane, and remove the label and PW-FEC binding.

  • The traffic black hole will be caused on PE1 until recovery time out

AC

AC

CE1

CE2

PE1

PE2

LSP&PW GR

LSP GR


Problem statement iii
Problem statement (III)

Pseudowire

Black hole time =

PE1 LDP session established time +

Minimum {FT Recovery Time, Maximum Recovery Time}

AC

AC

CE1

CE2

PE1

PE2

LSP&PW GR

LSP GR


Ldp graceful restart capability encoding
LDP graceful restart capability encoding

  • FT FEC type TLV

    0 1 2 3

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    |1|0| FT FEC type TLV (tbd) | Length (= 4) |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    |F| Reserved | FEC Element | Reserved |

    | | Flag | Type | |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  • This draft defines FT FEC type TLV to indicate the FEC element type that support graceful restart.

  • FEC element type: One octet FEC Element Type that specifies the FEC Element Type that supports graceful restart. Please see section 3.4.1 of RFC5036, and RFC4447.


Ldp graceful restart capability encoding1
LDP graceful restart capability encoding

  • Several FT FEC type TLVs can be appended behind FT Session TLV

  • Each FT FEC type TLV will carry a FEC element type which indicates the FEC that support graceful restart.

    0 1 2 3

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    |1|0| FT Session TLV (0x0503) | Length (= 12) |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    | FT Flags | Reserved |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    | FT Reconnect Timeout (in milliseconds) |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    | Recovery Time (in milliseconds) |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    |1|0| FT FEC type TLV (tbd) | Length (= 4) |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    |F| Reserved | FEC Element | Reserved |

    | | Flag | Type | |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    | ................. |

    ~ ~

    | |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    |1|0| FT FEC type TLV (tbd) | Length (= 4) |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    |F| Reserved | FEC Element | Reserved |

    | | Flag | Type | |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


Pe operation during restart with the extension
PE operation during restart with the extension

Pseudowire

  • PE1 detects that its LDP session with PE2 went down. It already knew that the neighbor is only capable of preserving its LSP-FEC forwarding state across the restart By negotiating through FT FEC type TLV.

  • PE1 will delete the PW-FEC and label binding immediately, but it will retains the LSP-FEC and label bindings received via that session and marks them as "stale".

  • PE1 will notify CE1 that network side is down, and CE1 will not send traffic toPE1.

AC

AC

CE1

CE2

PE1

PE2

LSP&PW GR

LSP GR


Next steps
Next steps

  • Need comments from work group

Thank you


ad