Collector is being used, that number should be increased by 20-30 NEs. Higher
bandwidth maybe required under special cases where above average data is attempted to
be transferred between SAM and the network elements. For example, large statistics files,
NE backups, or software images.
Network latency considerations
Network latency considerations
Network latency can potentially impact the performance of the 5620 SAM workstations.
The following are known impacts of latency between the various 5620 SAM
workstations:
•
5620 SAM Server to 5620 SAM Clients (GUI/OSS): event notification rates of
network changes
•
5620 SAM Auxiliary Statistics Collector to the network elements: ftp connection for
statistics collection and SNMP stats collection
•
5620 SAM Server to the network elements: resync times, provisioning, ftp
connections for statistics and network element backups, trap handling, and SNMP
stats collection (See
“Scaling guidelines for statistics collection” (p. 6-8)
for more
information on latency impact on SNMP stats collection)
•
5620 SAM Server and 5620 SAM Auxiliary Collector to 5620 SAM Database: 5620
SAM performance is sensitive to latency in this area. The round trip latency between
the active 5620 SAM components (Server, Database, Auxiliary) must be no longer
than 1 ms., otherwise overall 5620 SAM performance will be significantly impacted.
Since SNMP communication to a single Network Element is synchronous, the impact of
latency is directly related to the number of SNMP gets and responses. Operations to a
Network Element with a round trip latency of 50 ms will have the network transmission
time increase by ten times compared to a Network Element with a round trip latency of
only 5 ms. For example, is a specific operation required 5620 SAM to send 1,000 SNMP
gets to a single Network Element, 5620 SAM will spend a total of 5 seconds sending and
receiving packets when the round trip latency to the network element if 5 ms. The time
that 5620 SAM spends sending and receiving the same packets would increase to 50
seconds if the round trip latency were increased to 50 ms.
Network Element re-sync can be especially sensitive to latency as the number of packets
exchanged can number in the hundreds of thousands. For example, if a re-sync consists of
the exchange of 100,000 packets (50,000 gets and 50,000 replies), 50 ms of round trip
latency would add almost 42 minutes to the overall re-sync time and 100 ms of round trip
latency would add almost 84 minutes to the overall re-sync time.
Network requirements
5620 SAM bandwidth requirements for communicating with
network elements
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5-16
5620 SAM
3HE-09809-AAAG-TQZZA 13.0 R7
Issue 1
December 2015
