Subject: Unknown C-Type

From: Lakshmi Narayanan R <[email-masked]>
Date: Thu, 8 Jun 2000 18:48:23 +0530

Hi,
I'm a newbie to the Rsvp world

Can anybody help me on these doubts: (Rfc -2205) (page 62)

1)
Is the Unknown C-type is required for Traffic Controller or                          
Is ths Traffic Controller is to do anything with the Unknown C -type?

2)
While receiving an Unknown C-type for the Known Class we are forming an Error message(PathErr or ResvErr)
Here the Known class means all the object classes or only the FlowSpec, AdSpec and Policy Objects ?

Thanks in advance

- Lakshminarayan

---

From: David Charlap <[email-masked]>
Date: Thu, 08 Jun 2000 15:42:34 -0400

> Is ths Traffic Controller is to do anything with the Unknown C -type?

The generation of unknown C-Type errors when object with unknown C-Types
are provided is a requirement.

The module of your RSVP code that actually generates the error is an
implementation detail.  Depending on your architecture, it might make
sense for various parts of your code (like traffic control, admission
control, policy control, etc.) to generate the error, depending on the
object class.  It might also make sense for one part of the code to have
knowledge about all classes and C-Types that are supported, so that the
error is always generated from one place.

> 2)
> While receiving an Unknown C-type for the Known Class we are forming
> an Error message(PathErr or ResvErr) Here the Known class means all
> the object classes or only the FlowSpec, AdSpec and Policy Objects ?

It is possible to receive an unknown C-Type for any class.  A
neighboring router might be using an RSVP extension that you do not
support, or your code might not support every single class and C-Type,
or the object might have become corrupted in transit.  An appropriate
error message should always be generated.

(Note, for example, that the MPLS extesions to RSVP add new C-Types to
many existing object classes - including session, sender-template, and
filterspec.  If a non-MPLS router receives an RSVP message with one of
these, it would be appropriate to send an unknown C-Type error.)

The reason certain kinds of objects are specifically mentioned in the
RFC is that some subsystems (like traffic control and policy control)
might be developed separately from the rest of the RSVP code.  Since
objects for those subsystems are not manipulated by the rest of RSVP, an
implementation may choose to leave c-type checking of those objects to
their corresponding subsystems.

-- David