Subject: Accounting at ANR intermediate nodes

From: "jim (j.) cobban" <[email-masked]>
Date: Wed, 3 Apr 1996 10:26:00 -0500

Many of our customers will be providing APPN/HPR as a network service.  Since
the full power of HPR is only achieved when it is extended to the end nodes
all of the network nodes in the service provider network will be operating as
ANR transit nodes.  This creates some difficulties for billing back for the
network service.

In the IP world it never has been possible to bill back for the network
service based upon usage, therefore nobody expects to be able to.  However in
an APPN/ISR network the intermediate nodes are aware of every session passing
through them, and therefore can provide detailed accounting.  When the ISR
backbone is replaced with an ANR backbone these service providers, and their
customers, see a major loss of functionality.

This topic came up as we considered the statistical data which an ANR node
could accumulate for the HPR MIB.  The existing draft specification for the
HPR MIB is based upon the 6611 implementation, which implemented a separate
ANR routing instance, or NCL, on each processor.  The 6611 MIB reflects their
implementation in which an NLP is forwarded by an NCL either to an outgoing
TG on the same processor, to an RTP instance (NCE), or to an NCL on another
processor.  It was agreed in the HPR MIB discussion at the AIW that this was
too specific to this implementation, and could not reflect other HPR
implementations in a general way.

The only information which an ANR node has available to it is the information
in the ANR header:

  - transmission priority
  - flow control indicators (time sensitive, slowdown)
  - ANR label

Although this is not required by the architecture the ANR label is normally
in a one to one relationship with a transmission group.  This is all that is
required for ANR to work, but it is not sufficient for accounting at an
intermediate node.  The following is an example which shows this:

The customer wishes to bill for APPN services based upon "distance".  There
is one tariff for APPN sessions within a single country, a higher tariff for
APPN sessions between countries within a continent, and a higher yet tariff
for APPN sessions between continents.  However if ANR labels are in a
one-to-one relationship to transmission groups then the intermediate node
cannot tell, by inspection, which category a particular NLP belongs to.

I would like the assembled minds of this discussion group to consider whether
there are any architectural or implementation problems if during route setup
processing the intermediate node assigns a unique ANR label to each route,
in each direction, and associates that label with the next transmission group
in that direction.  Statistics can then be maintained on a route basis and
reported under the ANR labels assigned to the two directions of the route.