As of SAM 12.0R1, a proprietary mechanism is used to discover and resync specific node
types and versions, that can dramatically reduce resync and discovery times to network
elements with high network latency. TCP Streaming is supported on the following
Network Element types with a release of 11.0R5 or later:
•
7950 XRS
•
7750 SR
•
7450 ESS
•
7710 SPR
Common geographical location of 5620 SAM workstations
It is ideal to ensure that all 5620 SAM workstations and the 5620 SAM OSS clients are
collocated within a geographical site on a high availability network to avoid the impact of
network latency.
In cases where geographic redundancy is configured, all active 5620 SAM workstations
(5620 SAM Server, 5620 SAM Auxiliary, and 5620 SAM Database) should be located
within a geographical site on a high availability network to avoid the impact of network
latency. When a 5620 SAM workstation (server, auxiliary, or database) switchover or
failover occurs, a manual intervention may be required to align the workstations on the
same geographical site to minimize the performance impact of network latency. This task
can be automated by enabling the DB Alignment feature within 5620 SAM.
Optimizing throughput between 5620 SAM workstations
In high-speed, high-latency networks the TCP socket buffer size controls the maximum
network throughput that can be achieved. If the TCP socket buffer is too small it will limit
the network throughput, despite the fact that the available bandwidth might support much
higher transfer rates.
Adjusting the TCP socket buffer size to achieve optimal network throughput may be
necessary if the network bandwidth is more than 10Mbps and roundtrip latency is higher
than 25ms.
The optimal TCP socket buffer size is the bandwidth delay product (BDP). The
bandwidth delay product is a combination of the network bandwidth and the latency, or
round-trip time (RTT); basically, it is the maximum amount of data that can be in transit
on the network at any given time.
For example, given a 20Mbps network with a RTT of 40ms the optimal TCP socket buffer
size would be computed as follows:
BDP = 20 Mbps * 40ms = 20,000,000 bps * .04s = 800,000 bits / 8 = 100,000
bytes socket buffer size = BDP
= 100,000 bytes
The RHEL documentation should be consulted to determine how to modify the TCP
socket buffer size and ensure that the change is persistent.
Network requirements
Network latency considerations
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5620 SAM
3HE-09809-AAAG-TQZZA 13.0 R7
Issue 1
December 2015
5-17
