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Keeping in Sync with your Timing, Test and Access Solutions |
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November 2008 |
Volume 3, Number 1 |
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In This Issue · Timing the Next Generation · Product Spotlight- 6850 ·
Featured Links Contact Us . . . . . . . . . .
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Published by: CXR Larus
Corporation Phone:
408-573-2700 Copyright
© 2008, CXR Larus Corp.
This newsletter is being sent as a free
service and is provided to keep our customer partners informed of
the latest news about of CXR Larus Corporation. |
Timing the Next Generation:In the core network
Next Generation Networks (NGN) implies a consolidation of
several (dedicated or overlay) transport networks each historically
built for a different service into one core packet based transport
network, often based on Internet Protocol (IP) and Ethernet. It also
implies the migration of voice from a circuit-switched architecture,
traditionally Time Division Multiplexing, (TDM) (such as T1 or E1
circuits), to VoIP using IP based network devices such as Media
Gateways and Softswitches. As these NGN services evolve,
network timing requirements evolve with them, r CXR Larus is hard at work to provide the telecommunications industry the very latest NGN timing technologies, such as Network Time Protocol (NTP) and the newly ratified Precision Time Protocol, (PTP), per the IEEE-1588V2 standard. Our Models StarSync 6850 Grandmaster Clock and StarSync 6800 Edge NTP/PTP Client, provide superior PTP and NTP time stamping accuracy unparalleled in the industry. (How accurate? How does NTP precision measured in not milliseconds, not microseconds, but nanoseconds sound?) In addition, a new PTP accessory module for the StarClock TiemPo 6400 is currently under development which will make it the most versatile BITS clock available from ANY manufacturer. The evolution of the industry to NGN won't happen overnight, and there will always be requirements and opportunities for traditional TDM circuits. This leaves us currently in a period of network convergence and requirements for both traditional and NGN timing. CXR Larus was one of the early pioneers in network timing, and all of us here genuinely look forward to carrying on that tradition into this converging world and into the Next Generation. If you are required to
abide by the requirements set forth by the Health Insurance
Portability and Accountability Act of 1996 (HIPAA, Title II), the
Sarbanes-Oxley Act of 2002,
or have
QoS or QoE Service Level Agreements (SLAs) to
Product Spotlight:
The StarSyncTM
6850 from CXR Larus is a 19-inch
rack-mountable Network Time Protocol (NTP)/Precise Time Protocol (PTP)
reference source that provides superior timestamping accuracy and
redundant configurability. The server is also optionally capable of
accepting a Stratum level reference signal via NTP from a network
peer. Stratum 1 is maintained with a highly precise GPS receiver,
within 100 nS to UTC when either locked to GPS, or a network peer. The StarSyncTM 6850 provides timing for traditional services as well, with up to (8) DS1or E1 outputs, (2) Composite Clock, (1) IRIG-B output, and (1) TTL level Pulse Per Second (PPS) output. For more information on the CXR Larus StarSync 6850, follow this link.
For more information on the full line of CXR Larus Next Generation
Timing Products, follow this link.
Q: Can
I have the StarSync 6800 Edge NTP/PTP Client use any NTP time server
source as a timing reference? A:
No. The StarSync 6800 Edge NTP/PTP Client is designed to work in harmony with
the CXR Larus StarSync 6850 NTP/PTP Server. In order for the NTP
packets to be useable as a true Stratum reference source they must
have nanosecond precision that only precise time servers, such as
the StarSync 6850 can provide.
For more information on the StarSync Edge 6800, follow this link Q:
Do I need to worry about coax length when connecting my GPS antenna
to my BITS Clock or NTP/PTP Server? A:
This is really a multi-part answer because there are several factors
in play here. The first is the fact that by the time the GPS signal
reaches ground level it is extremely weak, on the order of -125 dBm.
To put that number into perspective, that is about 1,000 times
weaker than a typical FM radio signal! The second is that the GPS L1
band signal is a microwave signal (1.574 GHz), and at microwave frequencies
coaxial attenuation becomes a very large factor to consider.
Typical GPS clock link budgets for losses are around 25-30 dB, and
the combination of coaxial and connector losses will vary, depending
on what is used. When
dealing with precise NTP or PTP, latency in the coaxial run can be a
factor as latency increases the system error compared to true UTC
time. Typical RG-58 coaxial cable has approximately 1.25 nS/ft of
latency. This is not a problem when you are dealing with a few feet,
or with NTP/PTP servers that deal in milliseconds or even
microseconds. However, nanosecond accuracy servers can be affected
by an extended coaxial run. Fortunately,
all CXR Larus precise timing products have software that can be
easily configured to offset this delay.
Ensuring that GPS signal coaxial losses are within prescribed
limits, and coaxial latency delays are dealt with will ensure that
you timing system provides the heartbeat to keep your network at
full capacity.
All CXR Larus products are available from any of these
distribution partners:
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