The document proposes a solution to migrate legacy traffic for ethio Telecom to a new hybrid IP and packet backhaul network. Key points of the proposal include: 1) Replacing legacy microwave backhaul with a new hybrid system and mapping legacy TDM traffic to CES over IP while keeping 2G/3G as packet traffic. 2) Legacy services like MISU, CDMA and PSTN will be carried over the new network using CES to encapsulate TDM signals for transport over IP. 3) The solution will require configurations of network elements like TCUs, SPs, TN nodes and Tellabs equipment to implement CES mapping and ensure services continue functioning over the new infrastructure

1. ethio Telecom Legacy Traffic
Migration Solutions
BY: Khalil Al-alami

2. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 2
Proposal solution
› Swap out legacy MBH with a new Hybrid & IP backhaul at
LRAN & HRAN respectively.
› 2G/3G Traffic will be pure packet
› TDM legacy traffic will be backhauled as TDM over Packet
using Circuit Emulation (CES) through Pseudowire
mechanism (PW) which is here will use CESoPSN because
it support time slot mapping, PW mechanism encapsulate
the IP and UDP port as one packet and to have DSCP value.
› Legacy Traffic includes the three services:
– MISU (Site Monitoring)
– CDMA
– PSTN

3. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 3
Proposal solution
› Legacy swap proposed solution
New MBHCES Termination
TDM traffic
TDM traffic
Legacy service Legacy service
LRAN HRAN
CES Termination
TDM
IPBH
TDM

4. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 4
Background Knowledge
› Circuit Emulation (CES) technology will be used in this solution
to combine the TDM traffic (E1’s) through the IP Backhaul.
› Each E1 need one CES channel and one UDP port.
› Each service need VLAN and VLAN IP.
› TCU/SIU & SP configurations as according to LLD base on:
– CES E2E mapping (from TCU at cell site till SP in the optical site then
Tellabs node in the switch site).
– Because MISU use time slot so need special config to map time slot
with CES with the IP, and connect the IP with the C-VLAN then
connected to the WAN interface.
– VLAN configuration.
– Synchronization. (note: it’s important to configure synchronization
else the CES will not be connected).

5. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 5
Background Knowledge
– QoS. We need to configure QoS because CES is sensitive to delay
and jitter like the voice.
TCU
E1
VLANCES
IP
WAN
BVI bridge
IP traffic
TDM
CES channel UDP port
TDM E1 over CESoPSN over UDP over IP over Vlan over UDP over WAN
CES technology config
PW

6. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 6
Background Knowledge
› ML TN configuration will be based on:
– E1’s termination and routing in case we have pure TDM traffic.
– C-VLAN mapping just in TN at cell site and TN at Opt site.
– E1 routing and drop down in case we route the Legacy E1’s
through the MW as pure TDM and to be dropped in Opt site where
the SIU located.
› Tellabs 8660 configuration based on CES mapping back to
TDM traffic. (will be done by dedicated team).

7. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 7
Background Knowledge
› Each legacy service have it’s own VLAN and VLAN IP and each E1
have CES channel. (VLAN and CES mapping)
› The Vlan configuration will be done on TCU/SIU, SP, Tellabs, and for
TN that connected direct to TCU/SIU and SP only.
S-VLAN
Legacy C-VLAN’s
 Abis C-Vlan
 Iub C-Vlan
 Mub C-Vlan
S-VLAN
 Abis C-Vlan
 Iub C-Vlan
 Mub C-Vlan
 CDMA C-Vlan
 PSTN C-Vlan
 MISU C-Vlan
 Synch C-Vlan
Previously
With Legacy
 CDMA C-Vlan
 PSTN C-Vlan
 MISU C-Vlan
 Synch C-Vlan

8. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 8
Background Knowledge
 Assume we have 4E1 for CDMA and 2E1 for PSTN and always have 1E1 for MISU the
CES channels will be:
CES0 MISU
CES1 PSTN
CES2 PSTN
CES3 CDMA
CES4 CDMA
CES5 CDMA
CES6 CDMA

9. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 9
Legacy Scenarios
› Legacy swap proposed solution
IPBH
CES Termination CES Termination
TDM traffic
TDM traffic
Legacy service

10. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 10
misu
› MISU always exists in any site and need one E1 only which is in this
solution will always connected to 1st E1 of ET-D of TCU.
› CES mapping will be implemented between TCU at cell site and
Tellabs 8660 at switch site.
› Once the CES of the MISU terminated to the first SP then it will be
available at all other SP in the VPN.
TCU-02
1xDS0
MISU
SP420
SP420
MISU
ML-TN
ML-TN
ML-TN
Tellabs
8660
TDM VPN
IP
TDM

11. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 11
pstn
› Traffic is always terminated at same Circle unlike the
CDMA which some times the site located in a circle and the
BSC in another circle.
› Will be backhauled as either:
– Pure TDM through the ML-MW. (located in the same MW cluster)
– Or By CES over IPBH between SP420 & Tellabs. (located in
different MW cluster)

12. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 12
PSTN Scenario one
SP420
SP420
ML-TN
ML-TN
ML-TN
Tellabs
8660
PSTN
TDM VPN
PSTN
ICF
ML-TN
ML-TN
TDM
TDM
TDM
 The PSTN and the destination PSTN are located in the
same MW cluster.
 The traffic will remains as pure TDM till the destination
PSTN through the ML-MW so no need for CES mapping
and configuring.
IP
TDM
IP
TDM

13. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 13
Pstn Scenario one TN config
› The ML-TN connected direct to PSTN need to drop E1’s from the out
going packet and make cross connection these E1’s with the E1’s of
NPU (4A:4C) for TN 6Pc or (2A:2D / 3A:3D) as according to the number
of required E1’s.
› At the TN in the next site in the route, we will drop the same sequence of
E1’s that dropped in the first TN form the facing MMU and make cross
connection with dropped E1’s of the MMU of the opposite direction, and
so on till the TN that direct connected with destination PSTN will do the
same as what we did in the first TN that direct connected to source
PSTN.
PSTN NPU MMU
MMU MMU
PSTN NPU MMU
MMU MMU
TN
TN
TN
TN

14. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 14
PSTN Scenario Two
SP420
SP420
ML-TN
ML-TN
ML-TN
Tellabs
8660
PSTN
TDM VPN
PSTN
ICF
ML-TN
ML-TN
TDM
 The PSTN and the destination PSTN are located in different MW
clusters.
 The TDM traffic will be routed through the ML-MW then mapped as
CES in SP and pass to the other SP as IP traffic.
ICF
TDM
TDM IP
TDM
TDM
TDM
IP
TDM

15. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 15
Pstn Scenario two TN config
1. The ML-TN connected direct to the source PSTN need to drop E1’s from
the out going packet and make cross connection these E1’s with the E1’s of
NPU (4A:4C) for TN6Pc or (2A:2D + 3A:3D) TN20p as according to the
number of required E1’s.
2. At the TN in next site in the route, we will drop the same sequence of E1’s
form the facing MMU and make cross connection with dropped E1’s of the
MMU of opposite direction, and so on till TN that direct connected with SP
of this cluster we will drop E1’s from the MMU and cross connect them with
E1’s (4A:4C) of the NPU.
3. The points 1 & 3 are the same for the TN’s of the destination PSTN route (in
the second MW cluster)
PSTN NPU MMU
MMU NPU
PSTN NPU MMU
MMU NPU
SP
SP
TN
TN
TN TN

16. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 16
PSTN Scenario Three
SP420
SP420
ML-TN
ML-TN
ML-TN
Tellabs
8660
PSTN
TDM VPN
PSTNBL
ML-TN
ML-TN
 The destination PSTN are located in switch site.
 The TDM traffic will be mapped as CES cell site TCU and
complete as IP traffic till the Tellabs.
IP
IP
IP
IP
TDM
TDMTCU-02
TDM
IP
IP IP
SSR
Balun
IP
TDM

17. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 17
Pstn Scenario three TN config
› Here all we have to do is just in the TN connected direct to
TCU at the site where the PSTN located and the TN direct
connected with the SP at the aggregation site we will configure
the provider bridge to add C-Vlan’s of the Legacy services to
the S-Vlan. These steps are same for MISU and CDMA
services.

18. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 18
CDMA service
› Ethi Telecom CDMA Traffic distributed at 4 BSCs:
– Shashemene (E///)
– Jima (E///)
– Addis Ababa (Non-E///)
– Dire Dawa (Non-E///)
› Traffic is not always terminated at same Circle
› Will be backhauled as:
– Native TDM at Microwave NW
– CES at IPBH between SP420 & Tellabs

19. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 19
CDMA Scenario ONE
SP420
SP420
ML-TN
ML-TN
ML-TN
Tellabs
8660
TDM VPN
ML-TN
ML-TN
 The CDMA BSC is located in switch site.
 The TDM traffic will be mapped as CES cell site TCU and
complete as IP traffic till the Tellabs.
IP
IP IP
IP
TDM
TDM
TCU
TDM
IP
IP IP
SSR
Balun
CDMA
BSC
N x E1
CDMA
IP
TDM

20. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 20
CDMA/PSTN scenario (SIU)
SP420
SP420
ML-TN
ML-TN
ML-TN
Tellabs
8660
TDM VPN
ML-TN
ML-TN
 The CDMA BSC & PSTN is located in switch site.
 In case like this we haven't enough E1’s at TCU for CDMA
the CDMA traffic will remains TDM till the Opt site where the
SIU located then loaded over CES as IP.
IP
IP
IP
TDM
TDM
TCU
TDM
IP
IP IP
SSR
CDMA
BSC
N x E1
PSTNBL
TDM
CDMA SP420
SIU
PSTN
TDM
TDM TDM
IP
IP
TDM

21. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 21
Different possible scenarios
› Some repeaters have no MISU and PSTN but just have
CDMA.
› All I/D sites MISU is wall mounted we will not relocate it.
› Some O/D sites haven’t a vailable space for the MISU. Like
RBS 6101 with TN6Pc. Or RBS 6301. in case RBS6101
with CN we can relocate the MISU in side RBS6101.
› In some cases of O/D we need to relocate the MISU inside
the ZTE power cabinet.
› In some cases if we have NPU 3D and we need more than
4E1’s so we to add LTU like LTU-32 /1 for TN20 and LTU-
12/1 for TN6PC.
› Different services combination and different number of E1’s
and different topologies so we will have many scenarios.

22. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 22
discussions
› In case we have SIU we need one who are familiar with
SIU to generate the script.
› Synch config is very important for legacy solution to be work
and it’s more difficult than previous TCU configuration and is
sensitive so we need one TCU competent to take this
activity.
› We need to manage to utilize the idle teams to start with
legacy activity and as initially we need to start with Y-cable
swap and to reconfigure the TCU accordingly (maybe
remotely).
› We need to confirm whether this activity MOP will done at
night or on day time.
› we need some knowledge about the legacy CDMA in terms
of how to check the status and alarms before and after the
MOP.

23. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 23
discussions
› Maybe will need to put a procedure to test the new legacy
channels before do the swap.
› The guys how will configure the SP and generat TCU script
need to attend online meeting with Ahmed Al-hadary when
he finish the LLD sheet for how to use this sheet for each
site configurations.
› Site supervisor basically will visit the sites with the ASP and
start transferring the knowledge to them.
› The site will not need more than two technicians and their
engineer, Because we don’t have too much physical
installations on ground, it’s as a max as below:
– Y-cable installation.
– MISU relocating for O/D sites.
– E1’s termination at cell site and tellabs side at switch or at Opt sites.
– LTU installation in some little cases.

24. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 24
discussions
› ICF installation between TN and PSTN termination.
› Balun installation between TCU and PSTN termination.
› SIU installation and scripting.
› For TN we need to route the TDM traffic in all the route.

25. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 25
TCU configuration
› Suppose the legacy in one site is: MISU and PSTN with
3E1’s capacity located at site with 4 DUG , then the
configuration and connection as below:
TCU E1 Port E1# Service
ET-A
0 DUG1
1 DUG2
ET-B
2 DUG3
3 DUG4
ET-C
4 PSTN E1_1
5 PSTN E1_2
ET-C
6 PSTN E1_3
7 MISU

26. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 26
› startTransaction trans1
› createMO trans1 STN=0,E1T1Interface=7
› setMOAttribute trans1 STN=0,E1T1Interface=7 type E1
› createMO trans1 STN=0,CESChannel=0
› setMOAttribute trans1 STN=0,CESChannel=0 depE1T1Interface 7
› setMOAttribute trans1 STN=0,CESChannel=0 startTS 1
› setMOAttribute trans1 STN=0,CESChannel=0 endTS 2
› setMOAttribute trans1 STN=0,CESChannel=0 PWGW_IPAddress <refer to LLD excel>
› setMOAttribute trans1 STN=0,CESChannel=0 PWGW_UDP_Port <refer to LLD excel >
› setMOAttribute trans1 STN=0,CESChannel=0 depIP_Interface STN=0,IPInterface=<LLD xls>
› setMOAttribute trans1 STN=0,CESChannel=0 STN_PWE_UDP_Port <refer to LLD excel >
› setMOAttribute trans1 STN=0,CESChannel=0 DSCP_PWE <<refer to QoS Design>
› checkConsistency trans1
› commit trans1
TCU config for misu

27. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 27
› createmo trans1 STN=0,Bridge=MISU
› createmo trans1 STN=0,VLANGroup=WAN,VLAN=MISU
› setmoattribute trans1 STN=0,VLANGroup=WAN,VLAN=MISU tagValue <LLD sheet>
› setmoattribute trans1 STN=0,VLANGroup=WAN,VLAN=MISU tagged true
› setmoattribute trans1 STN=0,VLANGroup=WAN,VLAN=MISU depBridge STN=0,Bridge=MISU
› createmo trans1 STN=0,IPInterface=MISU
› setmoattribute trans1 STN=0,IPInterface=MISU primaryIP_Address <LLD sheet>
› setmoattribute trans1 STN=0,IPInterface=MISU primarySubNetMask 255.255.255.252
› setmoattribute trans1 STN=0,IPInterfaceMISU depLinkLayer STN=0,Bridge=MISU
› setmoattribute trans1 STN=0,IPInterface=MISU trustDSCP true

28. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 28
Synchronization
› Usually time synchronization is derived from NTP server which is basically the
TP5000 server, but TP5000 server is not yet configured so this NTP server cannot
act the sync for the TCU now.
› Now the Synchronization based on NTP server configured in the TCU, then the
TCU will acts as an NTP server. We need to configure BVI bridge for sync and
connect it to Vlan.
› The TCU OAM IP address is used by default for the Time Synchronization.

29. Khalil Al-Alami | Ericsson Internal | © Ericsson AB 2013 | 215-9-10 | Page 29
› startTransaction trans1
› createmo trans1 STN=0,IPInterface=Sync
› setmoattribute trans1 STN=0,IPInterface= Sync primaryIP_Address <LLD sheet>
› setmoattribute trans1 STN=0,IPInterface= Sync primarySubNetMask 255.255.255.252
› setmoattribute trans1 STN=0,IPInterface= Sync depLinkLayer STN=0,Bridge=Z
› setmoattribute trans1 STN=0,IPInterface= Sync trustDSCP true
› createmo trans1 STN=0,Bridge=Z
› setmoattribute trans1 STN=0,VLANGroup=WAN,VLAN=Synch depBridge STN=0,Bridge=Z
› setmoattribute trans1 STN=0,synchronization=0 synchType timeServer
› setmoattribute trans1 STN=0,synchronization=0 depIP_Interface STN=0,IPInterface=Sync
› setmoattribute trans1 STN=0,Synchronization=0 DSCP_synchronization 54
› setmoattribute trans1 STN=0 systemClockTimeServer <LLD sheet>
› setmoattribute trans1 STN=0 systemClockTimeServerType NTP
› setmoattribute trans1 STN=0 STN_systemClockUDP_Port 123
› checkConsistency trans1
› commit trans1
TCU config. for sync

30. Thank you all