Hirschmann Dragon PTN Series User manual

User Manual
Installation
Dragon PTN
Interface Module PTN-4-CODIR
Interface Module PTN-4-CODIR Technical Support
Release 01 02/2018 https://hirschmann-support.belden.com

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2 Interface Module PTN-4-CODIR
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Contents
1. INTRODUCTION .............................................................................................................. 5
1.1 General........................................................................................5
1.2 Manual References......................................................................6
2. MODULE DESCRIPTION......................................................................................................7
2.1 Front Panel ..................................................................................7
2.1.1 Handle ............................................................................................ 7
2.1.2 LEDs.................................................................................................. 8
2.1.3 RJ-45 Ports and Cables..................................................................... 8
2.2 Functional Operation...................................................................9
2.2.1 General ...........................................................................................9
2.2.2 ITU-T G.703 Code Conversion 64kbps........................................... 10
2.2.3 CES: SAToP (Future) ....................................................................... 10
2.2.4 CES: CESoPSN ................................................................................. 11
2.2.5 Hitless Switching ............................................................................ 11
2.2.6 Single Path...................................................................................... 12
2.2.7 Delay Comparison in CES (Features) ............................................. 14
2.2.8 I/O with the Central Switching Module (=CSM)............................ 14
2.2.9 Synchronization / Clock Distribution / Network Timing........................... 14
2.2.10 Test and Loopback Selftests .......................................................... 16
2.3 Onboard Interfaces....................................................................17
2.3.1 Straps............................................................................................17
2.3.2 DIP Switches................................................................................... 17
3. TDM FRAMES/PACKET.................................................................................................. 18
3.1 General......................................................................................18
3.2 Bandwidth.................................................................................18
3.3 Delay .........................................................................................18
3.3.1 General .........................................................................................18
3.3.2 Delay Parameters........................................................................... 19
3.3.3 Estimated Delay Calculation and Formulas................................... 20
3.3.4 Estimated Delay Examples............................................................. 20
3.3.5 Differential Delay.......................................................................... 20
3.4 Tuning CES = Tuning TDM Frames/Packet .................................21
4. MODULE SPECIFICATIONS............................................................................................. 21
4.1 General Specifications ...............................................................21
4.2 Other Specifications ..................................................................21
4.3 Ordering Information ................................................................21
5. ABBREVIATIONS ........................................................................................................... 22
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List of figures
Figure 1 Codirectional Interface ......................................................................................................... 5
Figure 2 General 64 kbps Example................................................................................................... 6
Figure 3 Front Panel ......................................................................................................................... 7
Figure 4 RJ-45 Connector ................................................................................................................. 8
Figure 5 Detailed Function 64 kbps Example................................................................................... 9
Figure 6 ITU-T G.703 Code Conversion 64 kbps............................................................................. 10
Figure 7 General SAToP Example ................................................................................................... 11
Figure 8 General CESoPSN Example ............................................................................................... 11
Figure 9 Hitless Switching............................................................................................................... 12
Figure 10 Single Path Enabled .......................................................................................................... 13
Figure 11 Single Path Disabled ....................................................................................................... 13
Figure 12 Clocking: Application D Slaves to Application A via Dragon PTN .................................. 15
Figure 13 Clocking: Both Application A and D Slave to Dragon PTN Clock Master ....................... 15
Figure 14 4-CODIR: Side View........................................................................................................... 17
Figure 15 Hardware Edition............................................................................................................ 18
Figure 16 CESoPSN Bandwidth
....................................................................................................... 18
Figure 17 Delays ............................................................................................................................. 19
Figure 18 Differential Delay............................................................................................................ 20
List of Tables
Table 1 Manual References.............................................................................................................. 6
Table 2 LED Indications In Boot Operation ...................................................................................... 8
Table 3 LED Indications In Normal Operation.................................................................................. 8
Table 4 RJ-45 Connector: Pin Assignments...................................................................................... 9
Table 5 Difference Between Protection and Hitless Switching ..................................................... 12
Table 6 Delay Comparison in CES (Features) ................................................................................. 14
Table 7 Clocking Parameters on Port & Service Level ................................................................... 16
Table 8 Estimated Delay Formulas................................................................................................. 20
Table 9 Estimated Delay (µs) Examples ......................................................................................... 20
Table 10 Other Specifications ........................................................................................................ 21
4 Interface Module PTN-4-CODIR
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1. INTRODUCTION
1.1 General
This document is valid as of Dragon PTN Release 3.0DR.
The 4-CODIR interface module (=IFM) can transport four 64 kbps links, point-to-point over
the Dragon PTN network according the ITU G.703 standard, see §2.2.2 for more information.
4-CODIR refers to ‘4 ports – Codirectional Interface’. The term 'Codirectional' is used to
describe an interface in which the information and its associated timing signal are
transmitted into the same direction. The information and timing signal are both embedded
in the same data stream, there is no separate clock transmission. The receiver will derive the
clock from the incoming data stream. See figure below.
Figure 1 Codirectional Interface
This IFM converts the incoming data from the 64 kbps link into MPLS-TP packets over the
Dragon PTN network, and vice versa. The destination IFM must also compensate for possible
jitter and network delays to keep everything synchronized. A packetized TDM service is
called a Circuit Emulation Service (=CES). A maximum of 4 CESs can be configured per 4-
CODIR module.
NOTE: A 64kbps link = E0 link; An E1 link can carry 32 E0 links.
This IFM can be used in any IFM slot of any node. An IFM slot overview can be found in Ref.
[3] in Table 1.
The main supported features are:
Packetizing of 64 kbps data
Codirectional
LAN function
Services
SAToP (=future) (=Structured Agnostic TDM over Packet);
CESoPSN (=CES over Packet Switched Network);
Hitless Switching / Single Path ;
A general 64 kbps CODIR example can be found in the next figure:
Equipment
one signal including
data + timing
Equipment
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Figure 2 General 64 kbps Example
1.2 Manual References
Table 1 is an overview of the manuals referred to in this manual. ‘&’ refers to the language
code, ‘*’ refers to the manual issue. All these manuals can be found in the HiProvision
(=Dragon PTN Management System) Help function.
Table 1 Manual References
Ref. Number Title
[1] DRA-DRM821-&-* Dragon PTN and HiProvision Operation
[2] DRA-DRM801-&-* Dragon PTN Installation and Operation
[3] DRB-DRM802-&-* Dragon PTN Nodes: PTN2210, PTN2209, PTN2206, PTN1104
[4] DRB-DRM803-&-* Dragon PTN Switching Module: PTN-CSM310-A
[5] DRE-DRM805-&-* Dragon PTN Interface Module: PTN-4-E1-L/PTN-4-T1-L
[6] DRA-DRM810-&-* Dragon PTN General Specifications
[7] DRE-DRM818-&-* Dragon PTN Interface Module: PTN-16-E1-L/PTN-16-T1-L
Dragon
PTN Node
64 kbps
Module
4-CODIR
MPLS-TP Dragon PTN Network
WAN (via SFP on fiber)
64 kbps
Links
Packetized 64 kbps via
SAToP or CESoPSN
64 kbps
Links
Line Protection
Relais
Line Protection
Relais
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2. MODULE DESCRIPTION
2.1 Front Panel
Figure 3 Front Panel
2.1.1 Handle
a. Insert the Module into the Node
Take the front panel handles to insert or slide the module into the Dragon PTN node. Push
the module thoroughly into the node’s backplane. Next, tighten the two fastening screws in
the front panel corners.
b. Remove the Module from the Node
Untighten the two fastening screws in the front panel corners. Take the front panel handles
to pull out and finally remove the module from the Dragon PTN node.
Fastening screw
Handle
Spare
LED
LEDs
Port 1, 2, 3, 4:
64 kbps ports
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2.1.2 LEDs
The meaning of the LEDs depends on the mode of operation (= boot or normal) in which the
4-CODIR module currently is running. After plugging in the module or rebooting it, the
module turns into the boot operation, see Table 2. After the module has gone through all
the cycles in the table below (=rebooted successfully), the module turns into the normal
operation, see LEDs in Table 3.
Table 2 LED Indications In Boot Operation
Cycle PI PF FLT Spare LED RX[1..4] TX[1..4]
1 x --- Slow blinking --- --- ---
2 x --- Fast blinking --- --- ---
3 x --- --- --- --- ---
4 x --- x x x x
x : LED is lit / --- : LED is not lit
The sub cycle times may vary. The entire boot cycle time [1 4] takes approximately 2 minutes.
Table 3 LED Indications In Normal Operation
LED Color Status
PI (=Power Input) Not lit, dark +12V power input to the board not OK
Green +12V power input to the board OK
PF (=Power Failure) Not lit, dark power generation on the board itself is OK
Red power generation on the board itself is erroneous
FLT (=FauLT) Not lit, dark no other fault or error situation, different from PF, is active on the module
Red a fault or error situation, different from PF, is active on the module
Spare Not lit, Green spare
RX<port n°> Not lit, dark No service programmed on port<n>
Green, lit Service programmed on port<n>, data received on front port<n>
Green, blinking Service programmed on port<n>, no data received on front port<n>
TX<port n°> Not lit, dark No service programmed on port<n>, no TX AIS sent
Green, lit Service programmed on port<n>, data received on backplane (=network) side
Green, blinking Service programmed on port<n>, no data received on backplane (=network) side
2.1.3 RJ-45 Ports and Cables
The 4-CODIR module provides four of these ports and each port connector has eight pins.
Each port provides one tip/ring pair. See the figure and table below for an overview and
description. The 120 ΩE1 cable (942 256-201) can be ordered to connect these ports.
Figure 4 RJ-45 Connector
1 8
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Table 4 RJ-45 Connector: Pin Assignments
Pin Number Description Cable Wire Colors
1 Rx (Receive) RING OG
2 Rx (Receive) TIP WH/OG
3 Not connected -
4 Tx (Transmit) RING BU
5 Tx (Transmit) TIP WH/BU
6, 7, 8 Not connected -
2.2 Functional Operation
2.2.1 General
An application network (e.g. LAN1) can be connected to the MPLS-TP Dragon PTN network
via one of the 4 front ports. The 4-CODIR module can interface with four 64kbps lines. In
Figure 2, a common functional setup is shown.
In Figure 5 below, a more detailed functional setup is shown. A LAN1 network interfaces the
Dragon PTN node via the front ports on the 4-CODIR module. The 4-CODIR converts this
traffic into Ethernet traffic on the backplane. The Central Switching Module (=CSM310-A)
converts this Ethernet traffic into packetized MPLS-TP and transmits it via an Ethernet IFM
(e.g. 4-GC-LW) onto the Dragon PTN MPLS-TP network. The packetizing of 64 kbps occurs via
CES: SAToP (=future) (see §2.2.3) or CES: CESoPSN (see §2.2.4) technique.
LAN: 64 kpbs link (on copper)  externaldevices
WAN: MPLS-TP (on fiber, copper)  between Dragon PTN nodes
Ethernet  nodeinternal
Figure 5 Detailed Function 64 kbps Example
4-CODIR
Module
MPLS-TP Dragon PTN Network
WAN (via SFP on fiber)
Packetized 64 kbps via
SAToP or CESoPSN
WAN
Dragon PTN Node
IFM1 IFM2
4-CODIR 4-GC-LW
CSM
CSM310-A
Dragon PTN Node
IFM1 IFM2
4-CODIR 4-GC-LW
CSM
CSM310-A
64 kbps
LAN Port
Switch
ETH

MPLS-TP
Switch
ETH

MPLS-TP
LAN
64 kbps
Links
LAN
64 kbps
Links
Line Protection
Relais
Line Protection
Relais
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2.2.2 ITU-T G.703 Code Conversion 64kbps
The ITU-T G.703 standard defines for the 64 Kbps codirectional interface the following five
steps for AMI coding (step1->5) / decoding (step5->1) a binary data stream:
1. (network side) A 64 kbps bit period is divided into four unit intervals;
2. A binary one is coded as a block of the following four bits: 1100;
3. A binary zero is coded as a block of the following four bits: 1010;
4. The binary signal is converted into a three-level signal by alternating the polarity of
consecutive blocks; This is the AMI encoding or Alternate Mark Inversion.
5. (front side) The alternation in polarity of the blocks is violated every eighth block. The
violation block marks the last bit in an octet.
The figure below illustrates these conversion rules. The physical interface consists of four
signals (Transmit, Tip, Transmit Ring, Receive Tip and Receive Ring). A 64 kbps Tip-Ring pair is
a balanced twisted pair (120 Ω). The data transmission through a pair is bipolar and AMI, i.e.
an impulse on the line corresponds to a logical “1” (mark) and a space with a logical “0”.
data on backplane
Step 4
data on front ports
Step 5
Octet
Timing
Figure 6 ITU-T G.703 Code Conversion 64 kbps
2.2.3 CES: SAToP (Future)
SAToP is a point-to-point CES which sends transparently an entire E1 frame from the source
to the destination 4-CODIR over the MPLS-TP network. One timeslot is used for transporting
the 64 kbps channel 'X'. The entire frame = all data + synchronization + alignment timeslots =
32 timeslots. One SAToP service can be configured per port.
This way of transportation consumes more bandwidth over the Dragon PTN network than
CESoPSN (see next paragraph), but has less differential delay than CESoPSN. If delay must be
as low as possible, use SAToP instead of CESoPSN to transport your 64 k CESoPSN bps
channel.
NOTE: Each end-point or 64 kbps port must be located in a different node. Future: end-
points can also be located intra-module or intra-node.
Polarity
Violation
Polarity
Violation
DECODING CODING
Bit Number
7
8
1
2
3
4
5
6
7
8
1
64Kbps Data 1 0 0 1 0 0 1 1 1 0 1
Steps 1 - 3
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Figure 7 General SAToP Example
2.2.4 CES: CESoPSN
CESoPSN is a point-to-point CES which only sends one E1 timeslot including the 64 kbps
channel, over the MPLS-TP Dragon PTN network. This way of transportation consumes less
bandwidth over the Dragon PTN network than SAToP, but has more differential delay than
SAToP. If delay is not an issue, use CESoPSN to transport your 64 kbps channel.
Each end-point or port must be located in a different node.
Figure 8 General CESoPSN Example
2.2.5 Hitless Switching
Hitless Switching is a feature within SAToP(future)/CESoPSN that provides a safe 64 kbps
redundant connection where no data or synchronization is lost when switching from the
active to the backup path or vice versa, e.g. because of cable break. The total delay over the
network remains nearly constant during switch-over. Redundancy via Hitless Switching is
obtained via completing the list below:
creating two independent point-to-point tunnels without protection;
setting the Hitless Switching on at service creation time in HiProvision.
NOTE: See Ref.[1] for the creation of tunnels and services;
On the source side, with Hitless Switching enabled, the E1/T1 IFM duplicates each packet on
a second tunnel (e.g. Tunnel y, see figure below). Each packet also contains a 16 bit
sequence number. Different tunnels mean different paths through the network, with each
path its own delay. Different delays result in a slow and a fast path.
On the destination side, with Hitless Switching enabled, the 4-CODIR IFM buffers the fastest
path and forwards packets from the slowest path on the 64 kbps link. Packets will be
processed according a packet sequence number.
64 kbps channel ‘X’
64 kbps port
MPLS-TP Dragon PTN
CESoP
‘X’
64 kbps port
1 used
timeslot
Optimal bandwidth usage
64 kbps channel ‘X’
64 kbps channel ‘X’
‘X’
64 kbps port
MPLS-TP Dragon PTN
SAToP
64 kbps port
1 used
timeslot
1 signaling + 30
empty timeslots
Optimal delay
64 kbps channel ‘X’
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Hitless Switching is a redundant mechanism but differs from Protection Switching, see the
table below for an overview. So if redundancy is needed in the service, either choose Hitless
Switching or Protection Switching, mixing up both mechanisms is not allowed. Depending on
the choice, settings must be done at tunnel creation time and/or service creation time.
When Hitless Switching has been enabled, the CES can only start up with two links up,
coming out of a two-links-down situation (except when Single Path has been enabled, see
§2.2.6).
See §2.2.7 for a delay comparison within CES depending on the enabled sub features, see
also further on.
Table 5 Difference Between Protection and Hitless Switching
64 kbps Protection Switching 64 kbps Hitless Switching
required tunnel type 1 point-to-point tunnel 2 point-to-point tunnels
tunnel protection type 1:1; none; the redundancy is created via two
independent point-to-point tunnels.
service parameter Hitless Switching = disabled Hitless Switching = enabled
at switch-over possible data loss no data or synchronization loss
total delay less than hitless switching more than protection switching
Figure 9 Hitless Switching
2.2.6 Single Path
The Single Path feature is a sub feature of Hitless Switching (see §2.2.5). It influences the
start-up behavior of the Hitless Switching mechanism:
enabled: The CES can already start up with only one link up, coming out of a two-links-
down situation; this setting results in bigger delays because of bigger buffers.
if the fastest path came up first:
the CES starts up according to the fastest path;
possible CES interrupt or minor packet loss when the slowest path comes up
later on;
data data
Tunnel x has more nodes
= slow path
64 kbps
64 kbps
MPLS-TP Dragon PTN
64 kbps  WAN:
duplicates
and transmits
data twice
Tunnel y has less nodes
= fast path
WAN  64 kbps:
data buffering = constant
delay;
no packet loss at switch-over
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if the slowest path came up first:
the CES starts up according to the slowest path;
no CES interrupt or packet loss when the fastest path comes up later on;
See §2.2.7 for a delay comparison within CES depending on the enabled sub features, see
also further on.
no links up:
 no CES
MPLS-TP Dragon PTN
64 kbps
MPLS-TP Dragon PTN
64 kbps
Figure 10 Single Path Enabled
no links up:
 no CES
MPLS-TP Dragon PTN
64 kbps
MPLS-TP Dragon PTN
64 kbps
Figure 11 Single Path Disabled
only with both links up
 CES starts
already with one link up
 CES starts
Single Path ENABLED:
ONE link required
Single Path DISABLED:
BOTH links required
data data
data data
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2.2.7 Delay Comparison in CES (Features)
Table 6 Delay Comparison in CES (Features)
CES Hitless Switching Single Path Resulting Delay
X --- --- lowest
X X --- medium
X X X highest
X = enabled; --- = disabled
2.2.8 I/O with the Central Switching Module (=CSM)
The 4-CODIR module receives 64 kbps traffic via its front panel ports and converts this into
Ethernet traffic which is forwarded to the CSM via the backplane. The CSM does all the
processing on this data (synchronization, CRC checks, conversions, switching…). The CSM
converts this data into MPLS-TP packets and transmits it an Ethernet IFM (e.g. 4-GC-LW)
onto the WAN. On the destination side, the same processing occurs in reverse order.
2.2.9 Synchronization / Clock Distribution / Network Timing
The Dragon PTN network provides a number of mechanisms to perform synchronization /
clock distribution / network timing per CES. The CSM synchronizes all the included IFMs in
the node.
The application endpoints in a 'Circuit Emulation: CODIR' service can communicate in a
synchronized way. Which method can be used depends on:
the ‘Clock source’ port setting of the two endpoints;
the 'Differential Clocking' setting in this service;
SyncE availability in the endpoint nodes;
The figures below show relevant end-to-end clocking configurations for this IFM. The PRC
(=Primary Reference Clock) is a very stable high quality clock that can be used as a reference
clock delivered via SyncE to the node:
A, D = Application ports;
B, C = IFM front ports;
CAUTION: Make sure to configure/verify the clocking parameters below.
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Figure 12 Clocking: Application D Slaves to Application A via Dragon PTN
Figure 13 Clocking: Both Application A and D Slave to Dragon PTN Clock Master
Rx
Internal
Internal
Rx
A
B
Dragon
PTN
C
D
SyncE, PRC
SyncE, PRC
Rx
Internal
Adaptive
Rx
A
B
Dragon
PTN
C
D
Clock
Slave
Clock
Master
Clock
Slave
Internal
Rx
Differential
Rx
A
B
Dragon
PTN
C
D
SyncE, PRC
SyncE, PRC
Internal
Rx
Adaptive
Rx
A
B
Dragon
PTN
C
D
Clock
Slave
Clock
Master
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Table 7 Clocking Parameters on Port & Service Level
Port A:
Clock
Source
Port B:
Clock
Source
Service:
Differential
Clocking
Port C:
Clock
Source
Port D:
Clock
Source
Description
Application D slaves to application A via Dragon PTN
‘Internal
Clock'
‘Rx Clock' Unchecked ‘Adaptive/
Differential’
‘Rx Clock' Node (B) recovers the clock from the incoming
data stream from Application (A) and uses it to
decode/encode the packet stream.
Node (C) recovers the clock from the incoming
packet stream from the network and uses it to
encode/decode the data stream. Application (D)
slaves its clock to this stream.
‘Internal
Clock'
‘Rx Clock'
+ SyncE
Checked ‘Adaptive/
Differential’
+ SyncE
‘Rx Clock' Node (B) recovers the clock from the incoming
data stream from Application (A) and uses it to
decode/encode the packet stream. Node (B)
embeds extra RTP timing information in that
packet stream when forwarding it on the
Dragon PTN network.
Node (C) generates the clock based on the PRC
and the embedded RTP timing information in
the incoming packet stream.
The generated clock is used to encode/decode
the data stream. Application (D) slaves its clock
to this stream.
Both Applications A and D slave to Dragon PTN Clock Master
‘Rx Clock' ‘Internal
Clock’
Unchecked ‘Adaptive/
Differential’
‘Rx Clock' Node (B) transmits packets to node (C) based on
an Internal Clock. This clock is delivered by the
local oscillator on the IFM. Node (C) recovers
the clock from the incoming packet stream from
the network and uses it to encode/decode data
streams.
Both applications (A) and (D) slave their clock to
the data streams delivered by node (B) and (C).
‘Rx Clock' ‘Internal
Clock’
+ SyncE
Unchecked ‘Internal
Clock’
+ SyncE
‘Rx Clock' Both nodes (B) and (C) encode/decode the data
stream to/from the end applications based on
the ‘Internal Clock’ on the IFM. This clock is
delivered by the CSM and is based on a PRC
delivered via SyncE to the node.
Both applications (A) and (D) slave their clock to
the data streams delivered by node (B) and (C).
NOTE: SyncE: See the manuals in Ref.[1] and Ref.[4] for more detailed information;
2.2.10 Test and Loopback Selftests
Test and Loopback selftests can be performed in CESes, e.g. when configuring or
troubleshooting a CES. Following two functions can be used in a programmed CES:
Loopbacks: on backplane or front port, direction towards line (=application) or network
can be configured;
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BERT: test traffic generation and verification via Bit Error Ratio Tester.
For more information and configuration settings, see 'Test and Loopback' in Ref.[1] in
Table 1.
2.3 Onboard Interfaces
Figure 14 4-CODIR: Side View
2.3.1 Straps
No user relevant straps.
2.3.2 DIP Switches
a. Hardware Edition
The Hardware Edition (Figure 14) is set in decimal code using rotary switches S2 to S3 (=most
significant). It can be read out as well via HiProvision. This edition has been factory set and
MUST NOT BE CHANGED! Example: Setting S3=’0’ and S2=’5’ indicates Hardware Edition ‘5’
(dec).
Hardware
Edition
CAUTION: enabling selftests disables or disturbs normal service traffic on a port!
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Figure 15 Hardware Edition
3. TDM FRAMES/PACKET
3.1 General
In a CES service, the amount of TDM Frames per Ethernet packet is an important setting
because it influences the amount of consumed bandwidth and delay through the network.
The more TDM Frames/Packet, the less bandwidth is used but the bigger the total delay
through the network.
In HiProvision, it can be configured how many TDM Frames/Packet can be encoded.
Default TDM Frames/Packet = 4;
Maximum TDM Frames/Packet, no Hitless Switching: 24;
Maximum TDM Frames/Packet, Hitless Switching: 10.
3.2 Bandwidth
If only one TDM frame per packet is encoded, it generates a lot of header information on the
network resulting in a lot of consumed bandwidth. Encoding more frames into one packet
will decrease the amount of header information and as a result the consumed bandwidth as
well. As of 8 frames per packet and higher, the bandwidth consumption stabilizes towards
the minimum bandwidth consumption. See the graph below.
Figure 16 CESoPSN Bandwidth
3.3 Delay
3.3.1 General
The total delay between two end points over the Dragon PTN network depends on:
P (=Packetization Delay): Delay to encode 64 kbps input into MPLS-TP packets;
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Path Delay: Delay from source to destination over the MPLS-TP network path; can be
measured by HiProvision via OAM delay measurement for the specific service; Path
Delay = Delay external network (if any) + 5µs/km + 10µs/node;
DP (=Depacketization Delay): Delay to decode MPLS-TP packets into 64 kbps output;
DPh: Extra Depacketizing Delay due to hitless switching;
Total Delay = Total Network delay between two 64 kbps applications;
Total Delay = (Packetization + Path + Depacketization + Hitless Switching) Delay;
Figure 17 Delays
3.3.2 Delay Parameters
These delays in §3.3.1 depend on the selected service in HiProvision and its configured delay
parameters. HiProvision offers the delay parameters listed below to tune the delay.
TDM Frames per Packet: The lower the value, the lower the delay.
Jitter Buffer Size (µs): advice: Set this value to ‘Packetizing Delay + expected peak-to-
peak jitter (µs)’; The default peak-to-peak jitter could be 250 µs; The expected peak-to-
peak jitter (µs) must be measured in the network. If the packetizing delay ‘P’ <2000 µs,
set the buffer size to at least 2000 µs. If the packetizing delay ‘P’ > 2000 µs (e.g. 2500 µs),
set the buffer size to at least e.g. 2500 µs.
Maximum Network Path Delay Difference (µs) (only for Hitless Switching): advise: Set
this value to ‘(Two Paths nodes difference)*10 + expected peak-to-peak jitter(µs)’. If
path1 has 17 nodes and path2 has 8 nodes, this is a difference of 9 nodes. You could set
MaxNetwPathDelayDiff = 9*10 + 250 = 340 µs;
CAUTION: By default, the jitter buffer will reset once for optimal processing 15 sec-
onds after a change in the service occurs. This reset will cause a minimal loss of da-
ta. See ‘jitter buffer’ in the ‘Dragon PTN and HiProvision Operation’ Manual (=Ref.
[1]) for more information.
CAUTION: If you are not familiar with these parameters, keep the default values.
64 kpbs
APPLICATION
64 kbps
APPLICATION
(De)Packetization Delay
+ Hitless Switching Delay
Path Delay
(De)Packetization Delay
+ Hitless Switching Delay
MPLS-TP Dragon PTN
Total Delay
Interface Module PTN-4-CODIR
Release 01 02/2018
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3.3.3 Estimated Delay Calculation and Formulas
Table 8 shows formulas to calculate an estimated delay. Once you have the desired
estimated delay, fill out the parameter values in HiProvision, which shows the calculated
‘P+DP+DPh’.
Table 8 Estimated Delay Formulas
Delay No Hitless Switching Hitless Switching
P TDMFramesPerPacket * 125
Path Delay measured by HiProvision
DP (JitterBufferSize – P) / 2
DPh 0 2P + MaxNetwPathDelayDiff + 1087
Total P + Path Delay + DP + DPh
3.3.4 Estimated Delay Examples
Find some example values below. Fill them out in the formulas to find the estimated total
delay:
TDMFramesPerPacket = 10
Pathdelay (measured by HiProvision) = 500 µs
JitterBufferSize = 4000 µs
MaxNetwPathDelayDiff = 340 µs
Table 9 Estimated Delay (µs) Examples
Delay No Hitless Switching Hitless Switching
P 10 * 125 = 1250
Path Delay 500
DP (4000 – 1250) / 2 = 1375
DPh 0 2*1250 + 340 + 1087 = 3927
Total 1250 + 500 + 1375 + 0 = 3125 µs 1250 + 500 + 1375 + 3927 = 7052 µs
3.3.5 Differential Delay
Differential Delay is the difference in Path Delays between two end-points, measured in two
opposite directions over the same path.
Figure 18 Differential Delay
64 kbps
APPLICATION
Path Delay1
64 kbps
APPLICATION
Path Delay2
Differential Delay = Difference (Path Delay 1;Path Delay2)
MPLS-TP Dragon PTN
20 Interface Module PTN-4-CODIR
Release 01 02/2018