Page 439 - Handbook of Modern Telecommunications

3-230 CRC Handbook of Modern Telecommunications, Second Edition

Internet Partner

Gateway Gateway
SS7 SS7

Core Core
Switch Switch
Switches Switches

Core Core
Switch Switch
Edge Routers Edge Routers

Data Center 1 Data Center 2

= Device-based and CDR-based data collection point

FIGu RE 3.9.3 Deploying device-based and CDR sensor networks.

Management Protocol (SNMP), and data models such as the IETF (Internet Engineering Task Force)
RFCs and the Telemanagement Forum’s NGOSS-SID. Also common is a wide degree of variation and
proprietary extension introduced by device manufacturers, often as a means of market/feature differ-
entiation. With the move to IP as a primary transport and service technology, device management
interface variety is declining and converging on SNMP. The most recent iteration of SNMP, version 3
(SNMPv3) includes adaptations for scale and security that are necessary to assure integrity within large
communications services environments.
In order to gather device-based data from SNMP, CMIP, TL1, or other device management interfaces,
sensor approaches need to include polling systems to regularly harvest data and make it available for
aggregation and analysis. Deployment of device-based sensory monitoring is presented in Figure 3.9.3.
The primary advantages of the device viewpoint for service assurance are the broad availability of
SNMP-based data provided by IP infrastructure vendors. Much of this is standards based in terms of
MIB (Management Information Base) data structures, though most all equipment manufacturers also
have important proprietary extensions that must be referenced to gather a complete view of the health
of the device and the aggregate measures of traffic flowing through it.
While these sensory data sources are prevalent and relatively low cost, the level of information that
can be interpreted from them is inherently limited to summary statistics regarding the flow of service
traffic to/from/through them, along with internal device/node health measurements. Consequently,
while they can be used to gauge service activity and quality on an aggregate basis, they cannot be used
for recognizing or troubleshooting individual service sessions or experiences.