Stream Statistics; System Security - Harris CM-30 Installation & Operation Manual

2 –Functional Design
Table 2-1. NetXpress LX Stream User and Computed Parameters
User Parameter
Number of TDM
Channels
TDM Frames per
Payload
Jitter Buffer Size
(8 – 128 packets)
Computed Parameter
TDM Channel Data Rate
Packet Payload Size
Packet Interval
Packet Rate
Jitter Buffer Delay
Ethernet Frame Size
Ethernet Stream Data
Rate
IP Packet Size
Stream Data Rate
* In most instances, Ethernet overhead is stripped before the packet is transported over a WAN link.
However, in certain instances (such as Metro Ethernet networks that transport the entire frame);
the Ethernet overhead is left on the packet.
2.2.9

Stream Statistics

NetXpress LX stream statistics are receiver-based. The time interval for collecting stream statistics is
user-selectable (from 5-10 seconds for each stream). It is a good practice to review your stream
statistics on a regularly scheduled basis (Section 4.3.6.1 – Stream Statistics). You may be able to
modify your NetXpress LX system for optimum throughput, bandwidth efficiency, and reduced errors.
As an example, you may wish to alter the size of the jitter buffer if you are experiencing too many
lost, underrun, early, or late packets. Specifically, if you are experiencing too many late packets, you
might need to increase the jitter buffer size.

2.3 System Security

System security is controlled through
● Logon and password control.
● Interface protocol management enabling and disabling.
● An IP access list.
Harris Corporation
Intraplex Products
NetXpress LX & CM-30 Installation & Operation Manual
Value
1 Number of TDM channels to transport in a stream
160 Number of TDM frames per payload (packet)
64 Configured jitter buffer size in packets
Value
64 kB/S Calculated TDM channel data rate in kB/S
160 bytes Calculated payload size in each packet in
bytes
20 mS Calculated packet interval (time between
packets) in mS
50 Calculated packet rate for a stream in
packets/S packets/S
640 mS Calculated jitter buffer delay in mS
Note: This delay assumes a receive
queue of half the jitter buffer size
242 bytes Calculated Ethernet frame size in bytes =
Packet Payload Size + Ethernet overhead
(38 bytes – no VLAN) + IP overhead (20
bytes IP + 8 bytes UDP + 16 bytes RTP)
96.8 kB/S Calculated Ethernet stream data rate in
kB/S *
204 bytes Calculated IP packet size in bytes =
Packet Payload Size + IP overhead (20
bytes IP + 8 bytes UDP + 16 bytes RTP)
81.6 kB/S Calculated IP stream data rate in kB/S *
Description
Description
Version 1, September 2010
Formula
Number of TDM Channels x 64
Number of TDM Channels x
TDM Frames per Payload
Number of TDM Frames per
Payload ÷ 8
(1 ÷ Packet Interval) x 1000
Jitter Buffer Size x Packet
Interval ÷ 2
Packet Payload Size + 38 + 44
Ethernet Frame Size x Packet
Rate x 8 ÷ 1000
Packet Payload Size + 44
IP Packet Size x Packet Rate x
8 ÷ 1000
2-7