Datasheet

____________________________________________________ DS34T101, DS34T102, DS34T104, DS34T108
71 of 366
Figure 10-33. E1 MF Interface TSIG Timing Diagram
TDMn_TCLK
TDMn_TX_MF_CD
TDMn_TSIG
A B C D A B C D
Timeslot 30 Timeslot 31 Timeslot 0
once in 2 milliseconds
Figure 10-34. T1 ESF Interface TSIG Timing Diagram
TDMn_TCLK
TDMn_TX_MF_CD
TDMn_TSIG
A B C D A B C D A B C D
Timeslot 22 Timeslot 23 Timeslot 0
Once in 3 milliseconds
Figure 10-35. T1 SF Interface TSIG Timing Diagram
TDMn_TCLK
TDMn_TX_MF_CD
TDMn_TSIG
A B A B A B A B A B A B
Timeslot 22 Timeslot 23 Timeslot 0
Once in 1.5 milliseconds
TDMn_TX_MF_CD can be left unconnected or connected to ground if the framer cannot drive it. The TDMoP block
has an internal free running counter that generates this signal internally when not driven by external source. This
internally generated multiframe sync signal is synchronized to the TDMn_TX_SYNC input pulse when present.
10.6.6 AAL1 Payload Type Machine
For the prevalent case for which the timeslot allocation is static and no activity detection is performed, the payload
can be efficiently encoded using constant bit rate AAL1 adaptation.
The AAL1 payload type machine maps E1, T1, E3, T3, STS-1 or serial data flows into IP, MPLS or Ethernet
packets, and vice versa, according to ITU-T Y.1413, Y.1453, MEF 8, MFA 4.1 and IETF RFC 5087 TDMoIP. In this
mapping method, data is actually mapped into 48-byte AAL1 SAR PDUs as described in I.361.1 section 2.4.2
rather than full 53-byte ATM cells.
10.6.6.1 TDM-to-Ethernet Direction
In the TDM-to-Ethernet direction, the AAL1 payload type machine concatenates the bundle’s timeslots into
structures and then slices and maps the structures into 46- or 47-octet AAL1 SAR PDU payloads. After adding the
AAL1 SAR PDU header and pointer as needed, the AAL1 SAR PDUs are concatenated and inserted into the
payload of the layer 2/layer 3 packet.