Re: [Roll] Clarification on parent / destination prefix / route removal

["Pascal Thubert (pthubert)" <pthubert at cisco.com>]

Hi Mathilde:

 

In a general manner, when you lose a next-hop/link you clean all routes via that next-hop/link.

 

A one hop loss can be detected by NUD. So the retry/remove thing  only applies to a destination, since you cannot NUD it hops away.

 

Parents used to be removed after missing periodic RAs in  a row, like MIP does, but that’s harder with trickle. I think that’s gone from the spec now.

 

Cheers,

 

Pascal

From: roll-bounces at ietf.org [mailto:roll-bounces at ietf.org] On Behalf Of Mathilde Durvy (mdurvy)
Sent: mardi 3 novembre 2009 11:48
To: roll
Subject: [Roll] Clarification on parent / destination prefix / route removal

 

Hi All,

 

This is my current understanding:

 

- Parents are removed based on OF selection (decision to move within the DAG, change DAG, etc)

- Destination prefixes are removed after the retry / RemoveTimer procedure described in section 5.10.1.1.1. This is essentially a keep alive mechanism based on DIO (D bit set) - DAO exchanges.

- Route corresponding to destination prefixes are removed when DAO lifetime expires? Are they also removed when the corresponding destination prefix is removed?

- When are routes corresponding to parents removed? Do they also have a lifetime?

- What happens when a neighbor disappears, are the corresponding parents/destination/routes removed?

 

The current behavior seems quite asymmetric... There is some kind of keep alive mechanism for destination prefixes, but not for parents. There is a lifetime associated with routes corresponding to destination prefixes but not for routes corresponding to parents. Is that a design choice? I would appreciate some clarifications.

 

Best,

Mathilde

 

Durvy Mathilde Software Engineer Technology center mdurvy at cisco.com Phone: +41 21 822 1725 Mobile: +41 76 396 8116	Cisco Systems International Sàrl Av. des Uttins, 5 CH-1180 Rolle Cisco home page

 

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