RE: [Manet-dt] Proposed New Dymo Text - Judging Information Usefulness

["Koojana Kuladinithi" <[e-mail]>]

Hi Ian

Text is bit confusing. 


In "5.Superior" says that " Routing information that does not match any
of the 
above criteria is loop-free and better than the information existing in
the routing table". That means reader thinks that you are considering
"1. Fresh" is also not used to update the routing table.

I don't see under any of those conditions, you have not addressed,
Node.HopCnt > Route.HopCnt when Node.SeqNum == Route.SeqNum as Loop
probable. This case is different from Node.HopCnt > Route.HopCnt + 1

Kind regards

koojana 
 

> -----Original Message-----
> From: Ian Chakeres [mailto:[e-mail]] 
> Sent: 28 August 2006 18:02
> To: [e-mail]
> Subject: [Manet-dt] Proposed New Dymo Text - Judging 
> Information Usefulness
> 
> 
> Please let me know what you think of this text.
> 
> Ian
> 
> Note: that broken is kind of like invalid. I'm still 
> experimenting with the term.
> 
> 5.2.1.  Judging Routing Information's Usefulness
> 
>    Given a routing table entry (Route.SeqNum, Route.HopCnt, and
>    Route.Broken) and new routing information for a particular 
> node in a
>    RM (Node.SeqNum, Node.HopCnt, and RM message type - RREQ/RREP), the
>    quality of the new routing information is evaluated to 
> determine its
>    usefulness.  The following comparisons are performed in order:
> 
>    1. Fresh
>       If Node.SeqNum - Route.SeqNum > 0 (using signed 16-bit 
> arithmetic)
>       the information is fresh.  This information is newer than that
>       known and should be used to update the routing table.
> 
>    2. Stale
>       If Node.SeqNum - Route.SeqNum < 0 (using signed 16-bit 
> arithmetic)
>       the information is stale.  Using stale routing 
> information is not
>       allowed, since doing so might result in routing loops.
> 
>    3. Loop-possible
>       If Node.SeqNum == Route.SeqNum the information may 
> cause loops if
>       used, in this case additional information must be examined.  If
>       Route.HopCnt is unknown or set to zero (0), then the routing
>       information is loop-possible.  Likewise, if Node.HopCnt 
> is unknown
>       or set to zero (0), then the routing information is 
> loop-possible.
>       If Node.HopCnt > Route.HopCnt + 1, then the routing 
> information is
>       loop-possible.  Using loop-possible routing information is not
>       allowed, since doing so might result in routing loops.
> 
>    4. Inferior
>       If Node.SeqNum == Route.SeqNum the information may be inferior,
>       additional information must be examined.  If the Node.HopCnt ==
>       Route.HopCnt + 1 or Route.HopCnt, the current route is 
> not Broken
>       and the message is a RREQ, then the new information is inferior.
>       Inferior routes will not cause routing loops if introduced, but
>       should not be used since better information is already 
> available.
> 
>    5. Superior
>       Routing information that does not match any of the 
> above criteria
>       is loop-free and better than the information existing in the
>       routing table.  This type of information is used to update the
>       routing table.  For completeness, the following other cases are
>       possible:
> 
>          Node.HopCnt == Route.HopCnt + 1 or Route.HopCnt and the route
>          is Broken.
> 
>          Node.HopCnt == Route.HopCnt + 1 or Route.HopCnt and the route
>          is not Broken and the message is a RREP,
> 
>          Node.HopCnt < Route.HopCnt.
> 
> _______________________________________________
> Manet-dt mailing list
> [e-mail] https://www1.ietf.org/mailman/listinfo/manet-dt
> 


_______________________________________________
Manet-dt mailing list
[e-mail]
https://www1.ietf.org/mailman/listinfo/manet-dt