RE: questions in LMP (draft-ietf-ccamp-lmp-08)

["Jonathan Lang" <Jonathan.Lang@RinconNetworks.com>]

Sugadeesh,

> -----Original Message-----
> From: owner-ccamp@ops.ietf.org [mailto:owner-ccamp@ops.ietf.org] On
Behalf
> Of Gudipalli, Sugadeesh
> Sent: Monday, April 07, 2003 5:16 AM
> To: 'ccamp@ops.ietf.org'; 'jplang@ieee.org'
> Cc: Gudipalli, Sugadeesh
> Subject: questions in LMP (draft-ietf-ccamp-lmp-08)
> 
> Hi Lang and all,
> 
>        Are the link verification procedures required to generate
automatic
> remote TE link id and
> local TE link ID  mapping along with the local interface id and remote
> interface id mapping.
LMP link verification procedure is a mechanism that can be used to
dynamically bind the local/remote identifiers.

> I got the above understanding from the following statement:
> 
> "5. Verifying Link Connectivity In this section, an optional procedure
is
> described that may be used
>  to verify the physical connectivity of the data links and dynamically
> learn (i.e., discover) the TE link and Interface_Id associations. "
> 
> 
> From my understanding of the LMP spec the mapping of the remote and
local
> TE-link ID can't be discovered it needs to be configured,
you misunderstand the procedure.  See below.

> due to the following points:
> 
> i)
>   "Support for this procedure is indicated by setting the "Link
>    Verification Supported" flag in the TE_LINK object of the
>    LinkSummary message."
The next sentence says:
"  If a BeginVerify message is received and link verification is not
   supported for the TE link, then a BeginVerifyNack message MUST be
   transmitted with Error Code indicating, "Link Verification Procedure
   not supported for this TE Link."
You do not need to send a LinkSummary message before you send a
BeginVerify message.

> 
> If the remote TE link ID is not mentioned in the link summary message
sent
> to the remote node with the verification supported flag set,
This is not allowed.  See Section 13.11.

> how will the
> remote
> node identify for which local TE-link id link verification procedure
is
> supported.
> Since there is no 1 to 1 map between the control channel and TE link,
the
> remote node has no way of identifying the TE-link for which this link
> summary message is addressed.
> 
> ii)
> "If the message is a LinkSummary message and the Message_Id value is
>    less than the largest Message_Id value previously received from the
>    sender for the TE Link, then the message SHOULD be treated as being
>    out-of-order."
> 
> If the remote TE link ID is not mentioned in the link summary message
sent
> to the remote node,
This is not allowed.  See Section 13.11.

> how will the remote node identify for which local
> TE-link id
> the message id in the linksummary has to be verified.
> Since there is no 1 to 1 map between the control channel and TE link,
the
> remote node has no way of identifying the TE-link for which this link
> summary message is addressed. Also for sending the linksummaryack or
> linksummarynack you need the message id specific to the local TE link,
> which
> we can't identify if the remote link id is 0.
> 
> 
> Can you please clarify.
Hope this helps.

-Jonathan

> 
> 
> Regards
> Sugadeesh