IP-NET VQE1 User manual

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VQE1
E1 over RF/Ethernet Multiplexer
V 1.3
User’s Manual
IP-NET, LLC

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VQE1
E1 over RF/Ethernet Multiplexer
User’s Manual
IP-NET, LLC.
2008.2

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Disclaimer
The information contained in this document is subject to change without notice
and does not represent a commitment on the part of IP-NET, LLC. The information
in this document is believed to be accurate and reliable; however, IP-NET assumes
no responsibility or liability for any errors or inaccuracies that may appear in the
document.
Copyright©2008 by IP-NET, LLC. All rights reserved. No part of this publication may
be reproduced or distributed in any form or by any means, without prior written
permission of IP-NET.
Product Model: VEQ1
Product Name: VQE1 Virtual Quad E-1 over RF/Ethernet Multiplexer
Manual Version: 1.3
Last Update: 2008. 2
IP-NET, LLC.
Address: 10256 N.W. 47th Street,
Sunrise, Florida 33351
U.S.A.
Tel: [phone]
Fax: [phone]
Web: www.hfcnet.net
E-mail: [email protected], [e-mail]

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TABLE OF CONTENTS
1. GENERAL....................................................................................................................... 1
1.1 OVERVIEW ........................................................................................................................ 1
1.2 FEATURES.......................................................................................................................... 1
1.3 APPLICATIONS .................................................................................................................. 2
1.4 TIMING MODES ................................................................................................................. 3
2. SYSTEM ARCHITECTURE ..................................................................................... 5
2.1 BLOCK DIAGRAM............................................................................................................... 5
2.2 DESCRIPTION.................................................................................................................... 5
2.3 FRONT PANEL .................................................................................................................... 5
2.3.1 Diagram.................................................................................................................. 5
2.3.2 LEDs......................................................................................................................... 6
2.3.3 Dip switch.............................................................................................................. 6
2.4 REAR PANEL ...................................................................................................................... 6
2.4.1 Grounding screw................................................................................................. 6
2.4.2 System alarm....................................................................................................... 6
2.4.3 E1 Port.................................................................................................................... 7
2.4.4 Ethernet ports...................................................................................................... 7
2.4.5 Power ...................................................................................................................... 7
3. INSTALLATION ......................................................................................................... 7
3.1 MECHANICAL..................................................................................................................... 7
3.2 ELECTRICAL ...................................................................................................................... 8
3.2.1 Power connection............................................................................................... 8
3.2.2 E1 connections .................................................................................................... 8
3.2.3 DOCSIS or Ethernet connection................................................................... 9
4. OPERATION............................................................................................................... 10
4.1 LED DEFINITION............................................................................................................ 10
4.2 LOOP BACK CONTROL ..................................................................................................... 11
4.3 DIP SWITCHES DEFINITION .......................................................................................... 11
5. COMMON FAULTS .................................................................................................. 12
5.1 E1 ALARMS...................................................................................................................... 12
5.2 LNK/ACT LED OFF ......................................................................................................... 12
5.3 READY LED DOES NOT BLINK ....................................................................................... 13
5.4 CANNOT SET UP E1 CHANNEL ....................................................................................... 13
5.4.1 Same LAN domain............................................................................................ 13
5.4.2 Different LAN domain ..................................................................................... 13
5.5 DOWNSTREAM REPORTING SLIPS .................................................................................. 13
6. WEB MANAGER ....................................................................................................... 13
6.1 SHOW CURRENT STATUS MENU ..................................................................................... 13
6.2 LINE TEST ....................................................................................................................... 15

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6.3 CONFIGURATION............................................................................................................. 16
7. SPECIFICATION...................................................................................................... 21
7.1 CAPACITY ........................................................................................................................ 21
7.2 DOCSIS RF INTERFACE............................................................................................... 21
7.3 E1 INTERFACE ................................................................................................................ 21
7.4 10/100BASE-T PORT ................................................................................................... 21
7.5 POWER ............................................................................................................................ 21
7.6 OPERATING CONDITION ................................................................................................. 21
7.7 DIMENSIONS................................................................................................................... 21
7.8 WEIGHT........................................................................................................................... 21

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VQE1 User Manual V1.3 -1-
1.  General
1.1 Overview
Thank you for selecting the VQE1 product designed and made by IP-NET, LLC. The product
can be used to provide E1 communication channels over DOCSIS 1.0, 1.1, or 2.0 and/or directly
over Ethernet/IP networks.
The VQE1 has many optional parameters, which can be modified by the user to suite
different application requirements. Please read this manual carefully before installing the
product.
It is well known that the E1 signal comes from PCM technology which is TDM in nature. It
transmits information in a constant bit rate of E1_2048kbit/s, T1_1544 kbit/s(future). TDM
technology occupies fixed transmission bandwidth, with QoS features suitable for real-time
applications such as voice and video. The QoS features include short and stable transmission
delay, low jitter and wander, etc.
On the other hand, Ethernet is based on statistical multiplexing, transmitting and exchanging
information in packets. It does not take up a fixed transmission bandwidth, which is good for
achieving higher bandwidth utilization. But Ethernet technology does not provide adequate QoS
for many real time applications.
Until recently, voice and data were, and still are to a large extent, transported over two
separate networks. But the requirement for both types of information to be carried over unified
networks is growing rapidly. Techniques to integrate data Packets over SONET/SDH into TDM
networks have been around for many years. But for voice over packet based data networks,
most of the efforts are spent on creating special equipment that packetizes voice or video
signals, such as VoIP techniques.
However, to take advantage of the data network, it is neither cost effective, nor necessary to
hastily replace all the TDM based legacy equipment with new packet based equipment. The VQE1
can be used to emulate transparent E1 channels over a DOCSIS or Ethernet network with
adequate QoS, so that most of the existing E1-based applications can be readily setup over
Ethernet LANs and WANs.
1.2 Features
zUser-friendly Web server supported for easy setup and maintenance
zPoint to point and point to multipoint supported
zUplink ports 1+1 backup supported
zFour E1 Ports supported, E1 or T1 (future) easy selected by Web Manager
zStable E1 clock recovery, low jitter and wander
zLow processing delay for E1 channels, high bandwidth usage efficiency
zResistant to packet loss, with PCM frame synchronization protection
zUser definable encapsulation packet size for different application
zEnough jitter buffer to resist packet delay variation (PDV)
zLocal Ethernet port throughput limiting, assuring E1 QoS
zLocal and remote E1 LOS and AIS and packet loss indication for trouble-shooting and
maintenance
zSupports cascaded concatenation or Daisy-Chaining for more than 4 E1 ports

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VQE1 User Manual V1.3 -2-
1.3 Applications
VQE1 is used to setup 1~4 clear E1 channels over LAN or IP networks, as depicted
in Fig. 1.3-1.
(a) Point to Point Application
(b) Point to Multipoint Application
Fig. 1.3-1 VQE1 application paradigm
In the figure, a pair of VQE1’s create clear E1 channels over a DOCSIS packet
network, providing connections between a PBX and a telephone exchange, or other
terminal devices. At the same time, computers talk to each other through the local
Ethernet ports on the VQE1’s. This configuration guarantees that the E1 channels get
higher priority over computer data for maximum QoS.
In addition to robust data and E1 transmissions over DOCSIS or Ethernet networks,
the VQE1s can also be configured to work with wireless bridges. One common application
of VQE1 is to set up point to point wireless E1 links using low cost wireless LAN bridges
or IP-NET WIRELESS CAPs. VQE1 can work with most LAN bridges on the market. It may
be necessary to adjust different parameters such as packet size and packet jitter
absorption buffer size for best operation for different LAN bridges.
Be aware that wireless LAN bridges may have a very limited bandwidth. If Ethernet
data is to be transferred at the same time, the traffic must be restricted. Otherwise it will
affect the E1 packets. Since the LAN bridges usually don’t have adequate QoS
mechanism to guarantee the E1 priority, it is strongly recommended that the data traffic
be routed through the VQE1 local data port, as depicted in Fig. 1.3-2.

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VQE1 User Manual V1.3 -3-
Fig. 1.3-2 Preferred connections for LAN traffic
WARNING: When connecting to a wireless LAN bridge, the uplink Ethernet
cable often connects to the outdoor unit, posing danger to lightning strikes that
can seriously damage the equipment. To protect the equipment as well as
people, surge protection devices with good earth connection is strongly
recommended. Poor earth connection may also hinder the operation of the
Ethernet port, causing severe packet losses.
1.4 Timing modes
To emulate a clear E1 channel over a packet network, the VQE1 not only conveys data
stream content correctly from the source to the destination, but also passes timing.
Packet networks do not provide such built-in timing transparency mechanism as TDM
networks do. VQE1 uses a proprietary algorithm to reconstruct the E1 clock at the
destination. The recovered clock is of very high quality, with low jitter and wander.
Typical frequency offset is within ±5ppm, and jitter is below 0.1UI. It can be adapted in
most applications. This timing mode of rebuilding the E1 clock at the destination is called
Adaptive Timing.
For applications where separate clock distribution network exists, another timing
mode, Loop back Timing, may be used for maximum clock quality.
The two timing modes of VQE1 are depicted in Fig.1.4-1.
Fig.1.4-1 E1 Timing modes

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VQE1 User Manual V1.3 -4-
Correct timing mode setting is important for smooth operations. In most cases,
setting both units to adaptive timing mode is sufficient. But sometimes, setting one unit
to loop timing mode may work better. For example, setting the VQE1 unit connected with
the clock master (such as local exchange) to loop back mode, and the other unit
connected with the clock slave (such as PBX or remote module) to adaptive mode, is
probably better than setting both to adaptive modes.
One typical error in telecom applications is to connect two communication devices
that are both clock slaves. Neither VQE1 will support such operation no mater how the
timing modes are set.
Note: that the E1channel emulation takes several minutes to stabilize.
During that period, clock drift may exceed the limit, errors and slips may occur.
Various timing schemes are enlisted in Table 1.4-1, for applications depicted in
Fig.1.4-2.
Fig.1.4-2 Timing mode scheme reference diagram
Table 1.4-1 Timing mode schemes
Equipment
A clock
mode
Equipment
B clock
mode
A side
EthMux V4
Timing
mode
B side
EthMux V4
Timing
mode
Note
loop back loop back
master master
adaptive adaptive
Equipment A & B
clocks synchronous
master master adaptive adaptive
Equipment A & B
clocks
plesiochronous
loop back adaptive
master slave
adaptive adaptive
adaptive loop back
slave master
adaptive adaptive
slave slave Not allowed
Note that setting both units to adaptive timing mode works well for all the conditions,
although the other option may work better.
Equipment
A DOCSIS
or Packet
Network
A side
V
Q
E1
B side
V
Q
E1
Equipment
B
RF or
10/100 Base T
RF or
10/100 Base T

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VQE1 User Manual V1.3 -5-
2.  System architecture
2.1 Block diagram
The internal functional structure of VQE1 is depicted below:
Fig. 2.1-1 Functional diagram
2.2 Description
The heart of VQE1 is the TDM/Packet processing unit. It truncates E1 data stream,
putting the data into Ethernet packet with or without IP headers. The packets are
passed to the Ethernet switch unit via MII interface, and are sent out adaptive through
the uplink port to the WAN port of the RF MODEM module for transmission via a DOCSIS
network, or through a Daisy-Chain up to another VQE1. Ethernet data from two local
data port are also sent out through the uplink ports, but with lower priority than those
packets containing E1 data.
In the reverse direction, packets from the RF MODEM or the uplink ports are sorted
at the switch unit. All but E1 packets are passed to the local data ports. The packets
containing E1 data are sent to the TDM/Packet processing unit for reassembly of the
original data stream, and recovery of the E1 clock which is the key element of the
device. A very sophisticated algorithm is used to ensure that the reconstructed clock will
meet the stringent requirement of TDM applications. The most important parameters
are jitter, wander, and signal delay.
The control unit interfaces with the user through a console port so that various
operational parameters can be modified.
2.3 Front panel
2.3.1 Diagram
VQE1 is shown in Fig. 2.3.1-1.
Fig. 2.3.1-1 Front panel of VQE1
DIP SwitchE1 Alarm StatusEthernet StatusCable Modem Status
RF
Modem
Main Status Far-End Status