Greetings list,

I'm looking for anyone with experience in using SNMP to monitor
BorderManager's HTTP proxy cache utilization. The goal is to provide both
long-term and near-real-time graphs showing data throughput. Simple
interface utilization won't suffice.

I have BorderManager's MIB but it's, umm, "tersely" documented. I am able
to retrieve stats though, and can in some cases see that they correlate to
numbers available from the console's Proxy Cache Activity screen or
NWAdmin32's Cache Statistics or Proxy Cache Monitor displays.

What I'd like to fetch via SNMP is cache hits and misses in total bytes.
We have three stats that *might* match these. From the MIB:

proxyStatsObjCacheDataXfered - "Total amount of object data transfered to
browsers in Kbytes."

proxyStatsObjCacheIcpFetchedData - "Amout [sic] of object data fetched
from Neighbors in Kbytes."

proxyStatsObjCacheDirectFetchedData - "Amout [sic] of object data fetched
from direct source in Kbytes."

Fetching values from the third variable matches figures from NWADmin
labeled variously "Fetched from Source" and "Bytes Transferred". (On two
different screens, the same number appears, labelled differently.) It also
matches the number seen at the console labeled "Data Filled". From the App
Notes article of 8/2002 "Data Filled", "shows the total number of bytes
received by HTTP Client from origin hosts. This data is filled in the
proxy cache." Of the three SNMP values, this is the largest.

Is this cache misses? Does this number include non-cacheable data, or only
data "filled in the proxy cache"?

The smallest of the SNMP values is "proxyStatsObjCacheDataXfered".
Fetching this value returns a number that matches NWAdmin's "Bytes Cached"
and "Volume in Requests Serviced".

Because of the similarity in terminology, we might think this should match
the console's "Data Transmitted" field. And in fact, it's *very* close -
about 3% difference. The console's value in my case is currently ~36
billion; the others are at about 35 billion at the same time.

But (from the App Note) the console's Data Transmitted, "shows the total
byes transferred from HTTP Server to browsers...straight from the Proxy
Cache or after contacting the origin server."

So this number is total throughput - or hits plus misses. Why is it so
close then to SNMP's *smallest* available value? If it represents all data
through the system, shouldn't it be bigger than "Data Filled"?

A note on SNMP's returned values:
GET any of the three OID's above and you'll get a ten digit hex string
returned. (Depending on the tool you use, you may see a two-byte prefix of
04:05. Ignore it.) The string is in reverse word order. For example, SNMP
returns 8967452301. But to convert to the correct integer, it should read

Thanks in advance for any insight, info or N.V.Rao's email address :)

Dan Lynch, CISSP
County of Placer
Auburn, CA