Subject: [Idr] Question about BGP mandatory attribute missing behavior

From: Ajay L <[email-masked]>
Date: Fri, 29 Apr 2016 11:32:38 -0700

Hi Experts,

Had a question about expected behavior about error handling scenario for an
BGP implementation

Per RFC 4271, if mandatory path attribute is not present in the UPDATE
message, NOTIFICATION message with appropriate error code and subcode must
be generated. If multiple mandatory path attributes are missing (e.g.
ORIGIN and AS_PATH), is the expected behavior to generate multiple separate
NOTIFICATION messages one for each missing attribute, or just
one NOTIFICATION message for the first detected missing attribute?

   If any of the well-known mandatory attributes are not present, then
   the Error Subcode MUST be set to Missing Well-known Attribute.  The
   Data field MUST contain the Attribute Type Code of the missing,
   well-known attribute.

Thanks

Ajay

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From: Ajay L <[email-masked]>
Date: Fri, 29 Apr 2016 13:08:23 -0700

The section on NOTIFICATION message says that BGP connection is closed
immediately after sending it. So in my scenario, looks like the expected
behavior is to send NOTIFICATION message with details of the first detected
missing mandatory attribute and close the connection. Please let me know if
this interpretation is not correct

4.5 <https://tools.ietf.org/html/rfc4271#section-4.5>.  NOTIFICATION
Message Format

   A NOTIFICATION message is sent when an error condition is detected.
   The BGP connection is closed immediately after it is sent.

Thanks

Ajay

On Fri, Apr 29, 2016 at 11:32 AM, Ajay L <[email-masked]> wrote:

> Hi Experts,
>
> Had a question about expected behavior about error handling scenario for
> an BGP implementation
>