Specifications

Chapter 1 Introduction Installation and Operation Manual
1-4 Functional Description MiTOP-E1/T1 Ver. 1.0
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Frame
1
Frame
2
Frame
N
Frame 1
425 425 425
Frame 2 Frame N
L2/L3
Header
Control
Word
CRC Ethernet Packet
TDM Payload
FRG bits = 00
(no fragmentation)
Figure 1-4. CESoPSN Encapsulation (E1, Bundle with Timeslots 4 and 25)
SAToP
The SAToP (Structure Agnostic TDM over Packet) encapsulation method is used to
convert unframed E1/T1 data flows into IP or MPLS packets and vice versa
according to ITU-T Y.1413 and IETF RFC 4553. It provides flexible packet size
configuration and low end-to-end delay.
L2/L3
Header
Control
Word
TDM Payload CRC
Ethernet
Packet
N TDM Bytes
TDM
Bitstream
FRG bits = 00
(no fragmentation)
Figure 1-5. SAToP Encapsulation
Packet Delay Variation
TDMoIP packets are transmitted by MiTOP-E1/T1 at a constant rate towards the
PSN (Packet-Switched Network). Packet Delay Variation is the maximum deviation
from the nominal time the packets are expected to arrive at the far end device.
MiTOP-E1/T1 has a jitter buffer that compensates for the deviation from the
expected packet arrival time to ensure that the TDM traffic is sent to the TDM
device at a constant rate.
The jitter buffer needs to be configured to compensate for the jitter level
introduced by the PSN. If the PSN jitter level exceeds the configured jitter buffer
size, underflow/overflow conditions occur, resulting in errors at the TDM side.