SIU02/TCU02 Overview , Technical
Description & Troubleshooting.
Content
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Overview
Types of STN
STN Hardware Description
Network Topology
TCU Features (AbisovIP,Synch,Circuit Emulation,....)
How to access TCU/Basic commands
Trouble shooting
Benefits
Operator Value
Summary
Overview
Overview
TYPE OF STN
SIU-01 HARDWARE
SIU-02 HARDWARE
TCU-02 HARDWARE
BASEBAND T605 HARDWARE
North Bound
North Bound
RNC
BSC
North Bound
SGSN
Router1
M120
Router2
M120
North Bound
L2 MUX
Active
Path
MUX (3PP)
OSS
Passive
Path
Active path VLAN: Abis1 , IuB1 ,MuB1
TRANSPORT
NETWORK
Passive path VLAN: Abis2,IuB2,MuB2
Local Cell Site
TCU
MUX (3PP)
TRANSPORT
2G RBS
NE
TCU used as router for both 2G and NB
traffic. Static routes used with BFD.
TCU acts as next hop for NB traffic.
NB
SIU-02/TCU-02 SW
Features & ROADMAP
SIU-02/TCU-02 SW
Features & ROADMAP
FEATURES
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Bidirectional Forwarding Detection
ABIS over IP
Circuit Emulation
Synchronization
IP Loopback
Policy based Routing
Bidirectional Forwarding Detection
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BFD facilitates minimal traffic
interruption in case of link/path
failures
BFD rapidly detects failures along
the path within milliseconds
(depending on configured
transmission intervals and retry
attempts). This facilitates rapid
repair mechanisms to minimize
service disruption.
The feature reduces the impact of
faults in the backhaul network by
providing fast detection and fast
reroute to an alternate path (if
present).
Abis over IP
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GSM RBSs use TDM (E1/T1) as their transport connection
The Abis over IP function enables the RBS to use an IP/Ethernet transport network for backhauling instead
Using the existing TDM backhaul for IP transport facilitates the migration to all-IP. The benefits if IP transport
can be reaped without replacing the existing TDM backhaul.
Circuit Emulation
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The Circuit Emulation (CES) feature enables the TCU/SIU to backhaul TDM based equipment
over IP networks. The TDM service provided is structured E1/T1s with support for 1-31/24
DS0s per E1/T1.
Moving from a TDM based transport network to one based on IP enables higher capacities at
lower costs. To fully utilize IP networks and to avoid operating parallel transport
infrastructures it is important to be able to move all traffic on an RBS site to IP.
Using this feature, the customer is able to backhaul legacy RBSs and other TDM based
equipment over an IP based network.
Frequency Synchronization Client with NTP
over IP
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This feature enables NTP frequency
synchronization for an IP-only connected
SIU/TCU.
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This solution is cost efficient compared to the
alternative of providing an external clock source,
such as a GPS receiver.
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The feature also supports quick roll-out of new IPbased RBSs, or move from TDM to IP backhaul,
as no synchronization support in the transport
network is required.
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Stable oscillator in TCU/SIU provides long-term
stability
IP Loopback
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IP services at the TCU/SIU depend on an IP interface to terminate traffic. In the past, an IP
interface has been bound only to a physical network interface. The IP loopback interface
provides an IP termination point that is not associated with a particular physical interface.
Traffic to/from the loopback interface can be routed via alternate physical interfaces.
Policy Based Routing
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Existing routing methods use
only the destination IP address
of each packet to determine its
route. Policy Based Routing
examines a larger set of packet
attributes such as protocol type,
priority, source/destination
address and source/destination
ports and uses these in route
determination. The route taken
by the packet can thus be more
finely controlled than with
conventional routing.
Access TCU
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Connect TCU via Local Management Terminal
RJ45 connector to Local Management port
telnet 192.168.1.1/24
username: admin
password: hidden
TCU prompt: OSmon>
BASIC COMMANDS &
TROUBLESHOOTING
• Check Neighbour status :-
MAC from DUW
MAC from Router
Conclusion:If MAC address is getting learned it means that layer
2 connectivity from TCU to Router is clear. .
Connected Interface
BASIC COMMANDS & TROUBLESHOOTING
• Check BFD status :
Conclusion : If BFD status is Up that means L3 connectivity is through
between router and TCU .
BASIC COMMANDS & TROUBLESHOOTING
• BFD session Counter
perfSessUpCount : The number of times this BFD session has
gone into the "up" state.
BASIC COMMANDS & TROUBLESHOOTING
• To check whether TCU is reachable for all Interfaces regarding Abis, IUB and MUB
For Abis Service : # ping <PGW_IP> -I <VIPDATA_IP> -i .107 -c 1000 –s 1500
For IuB Service :
# ping <NTP_IP> -I <VIPDATA_IP> -i .107 -c 1000 –s 1500
For MuB Service : # ping <OSS_IP> -I <VIPOAM_IP> -i .107 -c 1000 –s 1500
If 0% packet Loss , its clear that no transmission path issue is there from TCU to Router i.e in south bound part.
If partial packet loss is observed , then there might be issue in Transmission path or some local cabling interface in TCU end that
need to taken care of…Mostly issue is being observed in transmission MW path.
Such ping drop will result in HS drops and throughput issues.
Also to check TCU port health , TCU may be replaced at Site with Laptop and configure VLAN & interface IP and check the ping
status. In this way we can isolate TCU from network and isolate media issues.
In critical cases we can suggest for End to end media testing with Ethernet tester.
BASIC COMMANDS & TROUBLESHOOTING
• PATH & ROUTE CHECKTCU_5895-OSmon> show ip route
Codes: K - kernel, C - connected, S - static, R - RIP, B - BGP
O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, L1 - IS-IS level-1, L2 - IS-IS level-2, ia - IS-IS inter area
ew - East-West API
* - candidate default
C
C
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S
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C
10.28.23.108/32 is directly connected, lo
10.28.55.108/32 is directly connected, lo
10.40.20.64/30 is directly connected, eth4.1630
10.40.20.68/30 is directly connected, eth4.1631
10.40.20.72/30 is directly connected, eth4.1632
10.40.20.76/30 is directly connected, eth4.1633
10.40.20.80/30 is directly connected, eth4.1634
10.40.20.84/30 is directly connected, eth4.1635
10.40.20.88/30 is directly connected, eth6.100
10.40.20.92/30 is directly connected, eth6.200
10.223.6.0/24 [2/0] via 10.40.20.69, eth4.1631
10.223.36.128/26 [2/0] via 10.40.20.65, eth4.1630
10.223.60.0/24 [2/0] via 10.40.20.73, eth4.1632
127.0.0.0/8 is directly connected, lo
show ip route command output
will show all the ip routes,
which helped us to structure
the ping command quickly.
BASIC COMMANDS & TROUBLESHOOTING
• Traceroute
With traceroute command from TCU we can check the IP routes
via which traffic is reaching destination node.
TCU_4113-OSmon> traceroute 10.223.2.6
traceroute to 10.223.2.6 (10.223.2.6), 30 hops max, 60 byte packets
1 10.30.47.81 (10.30.47.81) 14.794 ms 13.615 ms 11.559 ms
2 10.220.66.169 (10.220.66.169) 6.330 ms 7.234 ms 10.749 ms
3 10.223.2.6 (10.223.2.6) 5.457 ms 6.379 ms 5.919 ms
In several occasion during integration process destination Node like OSS/NTP is not
reachable from TCU where as next hop address is reachable ,we may use traceroute
command to isolate the issue after which hop IP packet is getting dropped.
BASIC COMMANDS & TROUBLESHOOTING
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To get the TG detail and PGW IP- getmoattribute STN=0, TGtransport=all
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To get the Virtual IP address - getmoattribute STN=0, VirtualIPInterface=all
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To get the NTP IP address - getmoattribute STN=0, synchronization=0,timeserver=all
BASIC COMMANDS & TROUBLESHOOTING
BASIC COMMANDS & TROUBLESHOOTING
BASIC COMMANDS & TROUBLESHOOTING
• To check packet drop on respective P-bits (QOS) on NB/WAN interface:-
BASIC COMMANDS & TROUBLESHOOTING
• To get alarms in TCU :
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To check the Status of E1 in TCU :
The status of the E1T1 interface should be enabled
and port labels are marked in yellow.
BASIC COMMANDS & TROUBLESHOOTING
• To check TCU Sync quality status:-
• To check the routing table of TCU :-
• To Check The System Logs