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Installation PTN-4-2/4WEM
Release 01 02/2018
3.
TDM FRAMES/PACKET FOR CES
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 (due
to small Ethernet packet sizes) 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 11
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 Serial input into MPLS-TP packets;
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 Serial output;
DPh
: Extra Depacketizing Delay due to hitless switching;
Total Delay
= Total Network delay between two Serial applications;
Total Delay
= (Packeti Path + Depacketi Hitless Switching) Delay;
CESoPSN Bandwidth:
Y: Average Network Bandwidth (kbps)
X: TDM Frames / Ethernet Packet
Y
X
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