30% TANIEJ!

Thinking in Java. Edycja polska. Wydanie IV

67.90 zł   97.00 zł

RFC 3289              Differentiated Services MIB               May 2002


   The designers of this MIB expect that every path through a policy
   should have a corresponding counter.  In early versions, it was
   impossible to configure an action without implementing a counter,
   although the current design makes them in effect the network
   manager's option, as a result of making actions consistent in
   structure and extensibility.  The assurance of proper debugging and
   accounting is therefore left with the policy designer.

   When the MIB is used for configuration, diffServCountActNextFree
   always contains a legal value for diffServCountActId that is not
   currently used in the system's configuration.

3.4.3.  diffServDscpMarkActTable - The Mark Action Table

   The Mark Action table is an unusual table, both in SNMP and in this
   MIB.  It might be viewed not so much as an array of single-object
   entries as an array of OBJECT-IDENTIFIER conventions, as the OID for
   a diffServDscpMarkActDscp instance conveys all of the necessary
   information: packets are to be marked with the requisite DSCP.

   As such, contrary to common practice, the index for the table is
   read- only, and is both the Entry's index and its only value.

3.4.4.  diffServAlgDropTable - The Algorithmic Drop Table

   The Algorithmic Drop Table identifies a dropping algorithm, drops
   packets, and counts the drops.  Classified as an action, it is in
   effect a method which applies a packet to a queue, and may modify
   either.  When the algorithm is "always drop", this is simple; when
   the algorithm calls for head-drop, tail-drop, or a variety of Active
   Queue Management, the queue is inspected, and in the case of Active
   Queue Management, additional parameters are REQUIRED.

   What may not be clear from the name is that an Algorithmic Drop
   action often does not drop traffic.  Algorithms other than "always
   drop" normally drop a few percent of packets at most.  The action
   inspects the diffServQEntry that diffServAlgDropQMeasure points to in
   order to determine whether the packet should be dropped.

   When the MIB is used for configuration, diffServAlgDropNextFree
   always contains a legal value for diffServAlgDropId that is not
   currently used in the system's configuration.

Baker, et. al.              Standards Track                    [Page 13]