mcRNC Architecture and Configurations
mcRNC Architecture and Configurations
Module Objectives
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Describe mcRNC architecture and configurations.
List mcRNC functional units.
Describe mcRNC hardware items and interfaces.
Explain signaling and data flow in mcRNC.
Describe redundancy system in mcRNC.
Describe the different capacity steps in the mcRNC.
Describe the mcRNC site solutions.
mcRNC architecture and configurations
mcRNC overview
The Multicontroller Radio Network Controller (mcRNC) is based on new, faulttolerant, future proof Multicontroller Platform. The main function of the mcRNC is to
control and manage the Radio Access Network (RAN) and radio channels. The
mcRNC is designed for efficient use of radio resources as well as easy installation,
operation and maintenance. It is optimized for all-IP network environment.
Figure 1: mcRNC unit
Use of Multi-controller platform is common with Multicontroller BSC (mcBSC) and
Multicontroller Transcoder (mcTC) for smooth upgrade from Global System for
Mobile Communications (GSM) to Wideband Code Division Multiple Access
(WCDMA). It is based on easily installable, standard-sized, compact modules.
Minimum configuration is of two modules. It is expandable through capacity licenses
and addition of modules. Two, four, six, and eight modules are possible.
Following are the benefits of mcRNC:
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Figure 2: mcRNC benefits
mcRNC differences with IPA-RNC
The following illustration brings out the difference between the mcRNC and the IPARNC:
Figure 3: mcRNC differences with IPA-RNC
mcRNC in comparison to IPA-RNC
Figure 4: mcRNC in comparison to IPA-RNC
Following is a description of the mcRNC in comparison to the IPA-RNC:
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Small size
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Low Hardware (HW) price
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Easy installation (75% shorter commissioning time)
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mcRNC Architecture and Configurations
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Improved product architecture enabling easy fault diagnostics and bug fixing as
well as shorter release lead times
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Low power consumption
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Flexible network building and topology
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IP interfaces only
mcRNC HW architecture
The major architectural change with the mcRNC is the move from multi-subrack
blade system to a few identical rack mount modules. Depending on the capacity
needs, one mcRNC can consist of two up to several modules.
A multicontroller module is tightly integrated and has only a few field-replaceable
parts. The key enablers of this approach are Internet Protocol (IP)/Ethernet
technology and advanced CPU technology. They simplify Network Element (NE)
architecture especially when IP proliferates in mobile networks.
The new hardware and software platform allows new, optimized placement of the
RNC functionalities in the system.
The mcRNC consists of maximum eight 4U rack mount boxes, interconnected by
10Gbps 10-gigabit Attachment Unit Interface (XAUI) cables.
Each Box Controller Node (BCN) contains a motherboard with a management
processor and eight separate add-on cards containing Octeon processors that are
connected to the motherboard through PCI Express (PCI-E) connectors.
The two releases of the mcRNC hardware are as follows:
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BCN-A (HW release 1) containing Octeon+ add-on cards
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BCN-B (HW release 2) containing Octeon II add-on cards
There are three physical switches in every box for the following purposes:
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External network communication
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Internal network communication
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Local management
The following figure shows thei motherboard and processor add-in cards:
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Figure 5: Motherboard and processor add-in cards
The following figure shows the provided interfaces and supported standards in the
BCN-A Ethernet interfaces:
Figure 6: Provided interfaces and supported standards BCN-A Ethernet
interfaces
The following are the provided interfaces and supported standards in the BCN-A
Ethernet interfaces:
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Provided network interfaces for UTRAN traffic (Iu, Iur, Iub interfaces) are:
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mcRNC Architecture and Configurations
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6x 10 GE: 10GBASE-SR/LR, SFP+ (LC-type connector), four of these ports
are reserved for internal connections
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16x 1 GE: 1000BASE-SX/LX/TX, Small Form-Factor Pluggable (SFP) (LCtype or RJ-45)
Provided network interfaces for NetAct/Element Manager connectivity are:
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1x 1 GE: 1000BASE-SX/LX/TX, SFP (LC-type or RJ-45)
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2nd SFP reserved for future use
Provided network interfaces for local HW maintenance and service terminal are:
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1x 1 GE: 1000BASE-TX, RJ-45
The following figure shows the provided interfaces and supported standards in the
BCN-B Ethernet interfaces:
Figure 7: Provided interfaces and supported standards in BCN-B Ethernet
interfaces
HW configuration
Following are the configurations available in BCN-A1 and BCN-B2:
Figure 8: Configurations in BCN-A1 and BCN-B2
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BCN-A1 modules (available since Multicontroller RNC 2.0)
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Octeon+ processor 1 Gigabit Ethernet (GE) network connectivity
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S1-A1 is no longer supported in mcRNC4.1 and is upgraded to S5-A1
BCN-B2 modules (introduced with Multicontroller RNC 3.0)
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Octeon II processor
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1 and 10 GE network connectivity
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S7-B2 is new in mcRNC 4.1 (RU50EP1)
The following table brings out the Octeon processor comparison:
Table 2: Octeon processor comparison
Cavium Octeon+ CN5650
Cavium Octeon II CN6680
64 bit
64 bit
12 cores
32 cores
800 MHz
1.2 GHz
4 x 2MB DDR DIMS
4 x 8MB DDR DIMS
The same Octeon hardware can be used for processing of User, Control, Transport
and Management plane functions.
The following figure shows the BCN-A module (HW release 1):
Figure 9: BCN-A module (HW release 1)
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Dimensions (H x W x D): 178 mm (4U) x 444 mm x 450 mm
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Weight: Fully equipped, approximately 25-30 kg depending on the configuration
The following figure shows the BCN-B module (HW release 2):
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mcRNC Architecture and Configurations
Figure 10: BCN-B module (HW release 2)
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Dimensions (H x W x D): 178 mm (4U) x 444 mm x 450 mm
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Weight: Fully equipped, approximately 25-30 kg depending on the configuration
The following figure illustrates the BCN-A block diagram:
Figure 11: BCN-A block diagram
The following figure illustrates the BCN-B block diagram:
Figure 12: BCN-B block diagram
Capacity targets
The following table lists the mcRNC capacity targets with BCN-A1 HW in RU50EP1
(mcRNC 4.1):
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Table 3: mcRNC HW Release1 capacity
Configuration ID
S5-A1
NE level performance
Number of subscribers per RNC coverage
area
1380000
AMR Busy Hour Call Attempts
1380000
PS BHCA (HSPA)
1940000
NAS Busy hour call attempts on top of
maximum call capacity
5250000
AMR Erlangs
34500
AMR Erlangs (including soft handover)
48300
NE level capacity
Iub max total UP throughput (CS+PS, FP,
UL+DL)/ Mbps
5190
Iub max total HSDPA UP throughput
(CS+PS, FP, DL)
3660
Iub max total HSDPA UP throughput
(CS+PS, FP, UL)
1530
Connectivity
Max number of cells
3110
Max number of BTS sites
1037
Max number of RRC connected UE's
780000
The following table lists the mcRNC capacity targets with BCN-B2 HW in RU50EP1
(mcRNC 4.1):
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mcRNC Architecture and Configurations
Table 4: mcRNC HW Release2 capacity
Configuration ID
S1-B2
S3-B2
S7-B2
NE level performance
Number of subscribers per RNC
coverage area
760000
2140000
4520000
AMR Busy Hour Call Attempts
760000
2140000
4520000
PS BHCA (HSPA)
1400000
3500000
7920000
NAS Busy hour call attempts on top of
maximum call capacity
3050000
7680000
17300000
AMR Erlangs
19000
53500
113000
AMR Erlangs (including soft handover) 26600
74900
158200
NE level capacity
Iub max total UP throughput (CS+PS,
FP, UL+DL)/ Mbps
2640
10000
24000
Iub max total HSDPA UP throughput
(CS+PS, FP, DL)
1850
7050
16910
Iub max total HSDPA UP throughput
(CS+PS, FP, UL)
790
2950
7090
Connectivity
Max number of cells
2600
6600
10000
Max number of BTS sites
520
1320
2000
Max number of RRC connected UE's
352000
1000000
1000000
BCN-B Ethernet Switch Domain
The main processing power of the controller module comes from the cutting-edge
processor technology used. From the HW point of view, processor environments are
identical, so Software (SW) can allocate any kind of processing type to any of these
processors. The processor uses hardware acceleration for various tasks. With these
features, the same hardware can be used for processing of User, Control, Transport
and Management plane functions.
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PCI-E interconnecting:
Communication between the add-in cards, LMP, hard disk controller and
AdvancedMC (AMC) modules takes place through a PCI-E switch.
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Local Management Processor (LMP): A central component on the motherboard.
It is mainly responsible for the following functions:
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HW management of the controller module in conjunction with the Virtual
Carrier Management Controller (VCMC)
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Ethernet switch and interface management
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Offers services for USB mass storage devices
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Performs the function of a console server and provides direct access to the
serial consoles of processors
The following figures illustrates the BCN-B Ethernet switch domain.
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Figure 13: BCN-B Ethernet switch domain
mcRNC SW architecture
All Control plane and Operation and Maintenance (O&M) software runs on Linux in
the mcRNC compared to DMX in the IPA-RNC.
In the mcRNC, the User plane software runs without an actual operating system, on
top of a hardware abstraction layer called Simple Executive (SE). A set of services
provided by the User plane middleware create a pseudo-OS interface to the User
plane applications to ensure that the programming of User plane applications is kept
simple.
Linux distribution is provided by WindRiver and it is provided as part of the
FlexiPlatform in mcRNC.
In the mcRNC, all SW runs on MIPS64-based Cavium Octeon. It replaces the
dedicated processing architectures used in the past such as x86, TI DSP,
PowerQuicc and APP network processors. The Octeon processor is big-endian. It is
different compared to x86 hardware and that has some minor impact on the current
Control plane SW.
Figure 14: mcRNC software architecture overview
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mcRNC Architecture and Configurations
Control plane
The mcRNC has a completely new and different platform compared to IPA-RNC. To
minimize the impact on the currently available Control plane SW an IPA Light layer
is implemented between the Flexi Platform and the Control plane SW. The benefit is
that no changes are needed to the current Control plane SW as the IPA Light layer
provides the API needed by the Control plane SW. The IPA light then uses the Flexi
Platform API. By doing so, it hides the changes from the Control plane SW.
The SW architecture difference in the User plane application is that it is running in
the same processor as the Control plane counterpart.
User plane
The SE does not share memory or cores with the Control plane that is running on
Linux. Therefore, even if the RNC application and the User plane application is
running on the same processor they interact like they are located in different
processors, for example, by using messages.
Some Libgen functionality is implemented in SE to make it possible for SW running
in SE to communicate with the Control plane.
The User plane of mcRNC consists of four significant layers:
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Octeon hardware
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Cavium SE for Octeon
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Middleware for the User plane applications
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User plane applications
Figure 15: mcRNC software architecture Control plane and User plane view
mcRNC functional architecture
mcRNC functionality is comprised of four planes:
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Control Plane
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User Plane
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Transport Plane
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Management Plane
The mcRNC architecture consists of the following high level functions:
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Figure 16: High level functions of mcRNC architecture
The functions are distributed in the entities of mcRNC hardware and software. The
logical functions are freely allocated inside mcRNC physical units. To simplify
mcRNC architecture, the number of different types of physical units as well as the
number of functional units is highly minimized. Four main functional units are utilized
in mcRNC functional architecture design.
The distributed processing architecture of the mcRNC is implemented by a
multiprocessor system, where the data processing capacity is divided among
several processors. Based on the application need, several general purpose
processing units with appropriate redundancy principle can be assigned to different
tasks.
Processing capacity can be increased by:
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Distributing the functionality of the network element to multiple modules
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Upgrading processors with more powerful variants
As the mcRNC has only one type of processing hardware, it allows a large degree of
freedom in the design of functional software architecture.
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mcRNC Architecture and Configurations
mcRNC functional units
Functional units
In a cluster environment, the Functional Unit (FU) is a software entity capable of
accomplishing a specific purpose. A FU usually has a visible operating state. It
belongs to one of Control, User, Transport or Management planes. Most of the FU
are under the control of the Fault Management.
A functional unit can be either a recovery unit or a SE node such as the EITP.
The four main units utilized in mcRNC functional architecture design are as follows:
Figure 17: mcRNC functional units
CFPU
CSPU
USPU
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Consists of Operation and Management Unit (OMU) and
Centralized Functions for Control Plane (CFCP).
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OMU performs the basic system maintenance functions such
as hardware configuration, alarm system, configuration of
signaling transport and centralized recovery functions.
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Contains cellular network related functions such as radio
network configuration management, radio network recovery
and radio network database.
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Implements all cell-specific Control and User plane
processing.
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All Control and User plane resources for a single BTS are
allocated from the same CSPU unit.
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CSPU units are completely independent of each other and
different units might not have mutual communication at all.
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Allocation of BTSs under control of specific CSPUs is
controlled by the OMU.
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Implements all services for UE-specific Control and User
plane processing.
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All dedicated Control and User plane resources for a single
UE are allocated from the same USPU unit.
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USPU units are completely independent of each others and
different USPUs might not have mutual communication at all.
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Implementation of SN+ redundancy features such as moving
UE-specific processing from processor to another is simpler.
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EIPU
Hosts the networking and transport stacks needed for processing
both signaling and User plane data.
The mcRNC provides Ethernet switching functionality for the following:
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Internal communication between the various processing units such as USPUs,
CSPUs and CFPUs.
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Flexible connection between the external network interfaces and the processing
units.
The internal communication and external network switching parts are kept totally
separated.
Transport
Plane
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SITP: Signaling Transport Plane
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EITP: External Interface functions in Transport Plane
Management
Plane
OMU for Management Plane.
Control Plane •
and User
Plane
USUP: UE Specific functions and services in User Plane. This
includes the dedicated and shared channel services relevant
for a UE.
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CSCP: Cell Specific functions and services in Control Plane
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USCP: UE Specific functions and services in Control Plane
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CFCP: Centralized Functions and services in Control Plane
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CSUP: Cell Specific functions and services in User Plane
The following figure shows the physical location of the processing units in the
mcRNC module:
Figure 18: Physical location of processing units
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mcRNC Architecture and Configurations
mcRNC hardware items and interfaces
Hardware items
The following are the various hardware items:
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Add-in cards
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AMC
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Power supply distribution and supply units
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Fan units and air filter
Add-in cards
The following figure shows the processor add-in card (BOC-A) – Octeon+:
Figure 19: Processor add-in card (BOC-A) – Octeon+
The following figure shows the processor add-in card (BMPP2-B) – Octeon II variant
B:
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Figure 20: Processor add-in card (BMPP2-B) – Octeon II variant B
The following figure shows the add-in filler card (BFC-A):
Figure 21: Add-in filler card (BFC-A)
The add-in filler card (BFC-A) is:
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Dummy module with no electrical components
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Placed on empty card slots to ensure proper cooling of BCN module
AMC
The following figure shows the hard disk drive carrier AMC (HDSAM-A):
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mcRNC Architecture and Configurations
Figure 22: Hard disk drive carrier AMC (HDSAM-A)
Following are the features of AMC (HDSAM-A):
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Mid-size (single-width, 4 HP) module
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Provides serial attached SCSI (SAS) storage in the system
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Equipped with a 2.5-inch small form factor serial attached SCSI (SAS) hard disk
drive
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Hard disk drive needs to be acquired separately
BCN AMC filler (BAMF-A)
The following figure shows the BCN AMC filler (BAMF-A):
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Figure 23: BCN AMC filler (BAMF-A)
The following are the features of the BCN AMC filler:
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Dummy module with no electrical components
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Empty AMC bays must always be equipped with AMC fillers to ensure proper
cooling of the BCN module
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AMC filler acts also as an EMC shield
Power distribution and supply units
The following are the different power distribution and supply units:
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AC power distribution unit (BAPDU-A)
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DC power distribution unit (BDPDU-A)
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AC power supply unit, variant B (BAFE-B)
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DC power supply unit, variant B (BDFE-B)
Power distribution unit
The following figure shows the AC power distribution unit (BAPDU-A):
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mcRNC Architecture and Configurations
Figure 24: AC power distribution unit (BAPDU-A)
Following are the features of AC power distribution:
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Used in 19-inch cabinet installation
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Take the input power from the site power supply (180-264V)
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Eight circuit breakers installed in the front panel
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One PDU provides eight outputs
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Can provide power up to eight BCN if the two PSU in each module take
power from two PDUs
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Can provide power up to four BCN if the two PSUs in each module take
power from the same PDUs
The following is the description of the DC power distribution unit (BAPDU-A):
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Used in 19-inch cabinet installation
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Takes the input power from the site power supply
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Eight circuit breakers installed in the front panel
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PDU provides power for the following:
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Up to eight BCN, if the two PSU in each module take power from two PDUs
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Up to four BCN, if the two PSUs in each module take power from the same
PDUs
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A 30A circuit breaker on the negative wire is present at the input to protect the
PDU from overcurrent
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HW Dimensions: 90 mm (2U) x 485 mm x 230 mm
Power supply unit
The following figure shows the AC power supply unit, variant B (BAFE-B):
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Figure 25: AC power supply unit, variant B (BAFE-B)
The following are the features of AC power supply unit, variant B (BAFE-B):
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1200-watt redundant AC power supply units
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Located on the rear of the BCN module
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Hot swappable and has an IEC 320 C20 type input which operates on 230 VAC
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Following are the outputs to the BCN module:
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Main output with 12 V for all BCN electronics including HW management
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Standby output with 3.3 V for BCN HW management
The following figure shows the DC power supply unit, variant B (BDFE-B):
Figure 26: DC power supply unit, variant B (BDFE-B)
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mcRNC Architecture and Configurations
The following are the features of DC power supply unit, variant B (BDFE-B):
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1200-watt redundant DC power supply units
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Located on the rear of the BCN module
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Hot swappable and takes -48/-60 VDC input.
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Following are the outputs to the BCN module:
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Main output with 12 V for all BCN electronics including HW management
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Standby output with 3.3 V for BCN HW management
The following table provides a list of power supply color indicators and their
description:
Table 5: Power supply unit indicators and description
Color
Green
Amber
State
Description
Steady
Supply outputs are on and power
supply operates normally
Blinking
AC power is present, but the supply is
in standby mode and main output is
off
Steady
One of the following events has
occured (PSU is turned off)
Blinking
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fan failure
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over-temperature protection
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standby output overcurrent
protection
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standby output under voltage
protection
One of the following events has
occured (PSU is turned off)
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main output overcurrent
protection
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main output over voltage
protection
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main output under voltage
protection
Fan units and air filter
The BCN module contains two dual-fans (BMFU-A/ BMFU-B) for cooling the BCN.
BMFU-A is used in BCN-A and BMFU-B in BCN-B. The fan speed is controlled by
the HW management system to regulate the temperature within the BCN.
The following figure shows the main fan (BMFU-A/BMFU-B):
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Figure 27: Main fan (BMFU-A/BMFU-B)
Following is the description of the main fan (BMFU-A/BMFU-B):
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Located on the rear of the BCN module.
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BMFU-A is used in BCN-A with max rotation speed 3700 rpm.
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BMFU-B is used in BCN-B with max rotation speed 4000 rpm.
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Dimensions (H x W x D) - 142 mm x 140 mm x 75 mm.
Fan for AMCs (BAFU-A)
The purpose of the fan is for cooling the AMCs that are installed in BCN. Fan speed
is controlled by the HW management system to regulate the temperature within the
BCN. The following figure shows the fan for the AMCs (BAFU-A):
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mcRNC Architecture and Configurations
Figure 28: Fan for AMCs (BAFU-A)
Following is the description of the fan for the AMCs (BAFU-A):
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Located on the rear of the BCN module
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Dimensions (H x W x D) - 95 mm x 75 mm x 105 mm
Air filter (BAFI-A)
The air filter is located at the front of the BCN module in the cooling air inlet. It
prevents dust from accumulating inside the equipment. It meets the NEBS GR 63
CORE and GR 78 CORE requirements.
Figure 29: Air filter (BAFI-A)
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Cabling in BCN
Cabling in BCN is divided into:
•
Internal cables
•
External cables
Figure 30: Overview of cabling in BCN
The following is a list of internal cables and their uses:
Table 6: Internal BCN cabling
Cable Name
Use
CSFPP
Directly attached SFP+ cable between
BCN modules
CMSAS
Mini SAS disk cross-sharing cable
between BCN modules
CSYNC
Synchronization cable between BSAC-A
AMCs, BCN modules, or BCN module
and BSAC-A
CACPB
Power cable between AC PDU and BCN
module
CVKPBA
Power cable between DC PDU and BCN
module, used with 19” cabinets
CVKPB
Power cable between DC PDU and BCN
module, used with CAB216SET-B
cabinet
CGNDE
Grounding cable between PDU (AC or
DC) and cabinet
CGNDC
Grounding cable between BCN module
and cabinet
External BCN cabling
Following are the types of external cables:
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LAN/Ethernet cables for connection to external networks
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External synchronization cables
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External alarm cable
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mcRNC Architecture and Configurations
•
Power cables between site AC/DC power supply and BCN module in standalone
installations (without PDU and cabinet).
•
EU plug model AC power cord between site AC power supply and BCN module
is a part of equipment delivery of mcRNC
•
Power cables between site AC/DC power supply and PDU when cabinet and
PDU are in use
Poll Activity: Power distribution and supply units
Figure 31: Poll
Ask the participants if the following statement is True or False:
One of the features of AC power supply unit, variant B (BAFE-B) is, it is hot
swappable and has an IEC 320 C20 type input which operates on 230 VAC.
External interfaces
The mcRNC module provides the following groups of external interfaces:
Figure 32: Types of external interfaces
External
network
interfaces
•
Used for RNC User plane, Control plane and Management
plane connections.
•
BCN-B hardware supports ten 1 GE interfaces SFP slots and
two 10 GE interfaces (SFP+ slots) for external networking
purposes.
•
The following 10 GE modules are supported:
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•
•
10GBase-SR and 10GBase-LR
•
1000Base-T, 1000Base-SX and 1000Base-LX SFP
modules are supported for 1 GE
External synchronization interfaces and external alarm input
interfaces are not used by the mcRNC.
Network
management
interfaces
mcRNC supports two 1 GE interfaces SFP slots for network
management connectivity per RNC. For redundancy purposes
these are allocated to different mcRNC modules.
Local
hardware
management
and
debugging
interfaces
A 10/100/1000Base-T interface per mcRNC module is provided
for local hardware management and debugging purposes.
An alternative debugging interface, RS-232 interface with an RJ45 connector directly to LMP is available for each mcRNC
module.
These local hardware management interfaces are intended for
service personnel and factory debugging and should not be
connected by the operator.
mcRNC Modules BCN-A and BCN-B
The mcRNC 4.1 supports the second generation mcRNC hardware BCN-B. The
main advantages of a BCN-B module are:
•
Hardware support for mcRNC network elements of up to 8 modules
•
Offers two 10 GE ports for external network connectivity
Table 7: mcRNC modules BCN-A and BCN-B
Number of modules/external
network interfaces
BCN-B
BCN-A
Max. number of modules per
mcRNC network element
8
6
Number of 10 Gigabit external
network interfaces (per module)
2
-
Number of 1 Gigabit external
network interfaces (per module)
10
16
Regardless of the hardware version and capacity step, each mcRNC supports two
dedicated 1 GE connections for network management.
Logical interfaces
The mcRNC provides logical interfaces for the Mobile Services Switching Center
(MSC), the Multimedia Gateway (MGW), other RNCs, NetAct, Base Transceiver
Stations (BTSs), the Serving GPRS Support Node (SGSN) and the Cell Broadcast
Center (CBC).
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mcRNC Architecture and Configurations
Figure 33: Logical interfaces of mcRNC
The following is the description of the logical interfaces:
Iu-CS
Interface between the Radio Network Controller (RNC) and Circuit
Switched (CS) core network.
Iu-PS
Interface between the RNC and the packet core network
Iur
Interface for the interconnection of two neighboring RNCs
Iub
Interface between the RNC and the WBTS
Iu-BC
Interface between the RNC and the Cell Broadcast Center (CBC)
Iu-PC
Interface between the RNC and the Stand-alone SMLC (SAS)
O&M
Proprietary management interface between Network Management
System (NMS) and RNC
Management interfaces
The mcRNC has management interface to Nokia’s management system NetAct
through a standalone Operation & Management Server (OMS). A proprietary BTS
O&M protocol is utilized between the mcRNC and OMS, and Network Interface for
Third Generation Networks (NWI3) is used between OMS and NetAct.
The Data Communications Network (DCN) architecture provides connections for the
implementation of O&M functions from mcRNC to the operation support system
(NetAct). A common transport protocol is provided for the DCN network and IP is
used as a flexible solution for network management.
The following figure shows the management interfaces of mcRNC:
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Figure 34: Management interfaces of mcRNC
Following network internal management interfaces are used:
•
NetAct interconnection: Common Object Request Broker Architecture (CORBA)
and Simple Object Access Protocol (SOAP)/Hypertext Transport Protocol
(HTTP) based NWI3 for OMS
•
BTS interconnection: BTS O&M interface for OMS – RNC, RNC – WBTS, and
OMS
The O&M traffic is secured by:
•
Internet Protocol Security (IPSec) between OMS/RNC and NetAct
•
HTTP between RNC and BTS
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mcRNC Architecture and Configurations
Signaling and data flow in mcRNC
Signaling and data flow overview
For selecting a CSPU for a BTS, a BTS object is added to the RNW DB. The BTS
handler chooses the next available CSCP by round robin method. The eligible list is
maintained based on the existing load. A unit in overload mode can be made
ineligible.
The CSCP uses its own CSUP in same processor for User plane resources. All
resources needed for a BTS are provided from the same processing unit.
In case of CSCP switchover, CSUP may stay in the original CSPU to avoid service
interruption (requires RAN2251 Automatic mcRNC Resource Optimization).
The Transport Resource Manager (TRM) performs the following tasks:
•
Selects an EIPU
•
Configures it with the address and port information for the newly added BTS and
the address of the selected CSCP
The distribution table in EIPU is updated.
Selecting a USPU for a call
For selecting a USPU for a call, A new Radio Resource Control (RRC) Connection
Request comes to the CSPU. The USCP that handles the call is chosen by round
robin with USPU load information to ensure sufficient resource for both CP and UP.
The co-located USUP handles User plane resources. If the co-located USUP
resource is unavailable due to congestion, USUP from other USPU may be used.
Iu-CS User plane data flow
The following figure shows the path of AMR and CS data traffic through the system:
Figure 35: Iu-CS User plane data flow
Downlink data processing
Downlink data processing is performed as follows:
•
When a packet arrives, the EITP in the EIPU terminates the network and
transport layer protocols – IP, IPsec (if configured) and UDP.
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•
Application layer Transport Network Layer (TNL) protocols Real-Time Transport
Protocol (RTP) and Real-Time Transport Control Protocol (RTC) when used are
terminated in USUP. These protocols are used to take care of real time transport
issues and the control of call QoS.
•
Iu-UP is used to decouple the service-related user data characteristics from the
underlying transport protocols and is used in the support mode. It is terminated
in the USUP in case it:
•
Belongs to the Radio Network Layer (RNL)
•
Serves to adapt the transport layers
•
Needs to interact closely with the User Plane.
•
After the processing and adaptation needed for the air interface, the data frames
are sent to the EITP of the EIPU that serves the BTS, where the transport and
network layer functions are located.
•
The centralized scheduling of data is enforced to ensure that the transport
functions can evolve independently and are localized to the Transport plane unit
only. If the UE is in a Soft Handover (SHO) mode, the data is copied to multiple
links by the FP layer.
Uplink data processing
Uplink data processing is performed as follows:
•
When a packet arrives, the EITP in the EIPU terminates the network and
transport layer protocols – IP, IPsec (if configured) and UDP.
•
The frames are forwarded to the respective USPU unit using the internal
transport and MDC is performed in the USUP.
•
The data is forwarded to the Iu interface after required RNL processing through
the EITP.
Iu-PS NRT DCH and HS-DSCh data flow
The following figure shows the path of High-Speed Packet Access (HSPA) traffic
through the RNC:
Figure 36: Iu-PS NRT DCH and HS-DSCh data flow
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mcRNC Architecture and Configurations
The figure illustrates the Iu-PS Non-real time (NRT) Dedicated Channel (DCH) and
High-Speed downlink Shared Channel (HS-DSCh) data flow.
Downlink
The data processing is similar to PS over DCH and the protocols
used are identical. The only difference is that the SHO mode of
the UE is not applicable for High-Speed Downlink Packet Access
(HSDPA) traffic and the data is sent through one carrier only.
Uplink
The Uplink processing is similar to the PS over DCH scenario for
both E-DCH and DCH uplink channels. The Macro Diversity
Combining (MDC) is performed in the USUP.
Iu-PS NRT traffic over CCH data flow
The following figure shows the path for PS data sent over Common Channels
(CCH).
Figure 37: Iu-PS NRT traffic over CCH data flow
Downlink
The data path for the transfer over Forward Access Channel
(FACH) follows the same principles as discussed for PS data. The
only difference is in the Media Access Control (MAC) scheduling.
The MAC-c scheduler and the associated FP are involved after
the MAC-d processing is completed.
Uplink
The data path for the transfer over Random Access Channel
(RACH) involves the MAC-c in CSUP and then the MAC-d in
USUP. The other parts are similar to that of the PS data transfer
over DCH.
Data flow comparison
The following figure illustrates the CS user data flow comparison with the IPA-RNC
involving Asynchronous Transfer Mode (ATM) based Iub and IP-based Iu-CS. DCH
is used and ATM Adaptation Layer Type 2 (AAL2) switching of traffic is done in
NPS1(P).
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Figure 38: CS Data flow comparison with IPA-RNC
The following figure illustrates the Control Plane comparison between the DCH and
the CCH:
Figure 39: Control Plane comparison
The following figure illustrates the Data Plane comparison between the AMR and the
DCH:
Figure 40: Data plane comparison-AMR and NRT (DCH)
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mcRNC Architecture and Configurations
The following figure illustrates the Data Plane comparison in CCH:
Figure 41: Data Plane comparison- NRT (CCH)
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Redundancy system in mcRNC
mcRNC redundancy system
Redundancy is a method of providing the system with redundant equipment to
improve its tolerance against faults. This is achieved by providing backup resources
for functional units.
For redundancy reasons the connectivity towards the site switches is arranged as
shown in the following figure:
Figure 42: Connectivity towards site switches
There are a number of protection schemes in various levels to support redundancy.
The redundancy schemes are as follows:
Table 8: mcRNC redundancy scheme
Unit Type
Redundancy Model
USP
SN+
CSPU
N+M(M>=1)
CFPU
2N
EIPU
1+1
OMS
2N
Ethernet Switching
No redundancy
SN+ (Load
sharing)
Employs resource pool concept. A group of units form a resource
pool. The number of used units in the pool is defined, so that there
is a certain amount of extra capacity left in the pool.
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mcRNC Architecture and Configurations
Faulty units will be disabled in the resource pool. The whole group
of units can still perform its designated functions if a few units in
the pool are disabled because of faults.
A higher level module performs the load distribution. It also
maintains the health status of the hardware units. If one of the
load sharing module fails, the higher level module starts
distributing the load among the rest of the units. There is graceful
degradation of performance with hardware failure.
N+M
Takes M spare units and tries to allocate the M spare units to N
(Replacement) active units.
The spare units are kept in cold standby states.
The synchronization of a spare unit is performed during the
switchover procedure between a spare unit and an active unit. A
higher level Fault Management System monitors the health of the
N active units, and selects one of spare units from the M units to
replace an active unit if it fails.
2N
(Duplication)
Uses a dedicated spare unit designated for one active unit only.
The spare unit is hot standby state, and all of the data in a spare
unit is always synchronized with the active unit.
The spare unit is taken into use immediately if the active unit fails.
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Capacity steps in mcRNC
mcRNC capacity steps
The mcRNC capacity configurations are dynamically optimized for high speech or
data capacity. The configurations are designed especially for simultaneous dynamic
allocation and handling of speech, circuit-switched data, and packet-switched data
using advanced radio resource management algorithms.
Nominal capacity in throughput (Mbit/s) is usually the limiting factor of mcRNC
capacity, but the carrier numbers cannot be exceeded. mcRNC capacity steps are
defined by different number of mcRNC modules in one mcRNC.
To fulfill different RNC capacity requirements, mcRNC4.1 supports the capacity
steps for the following:
mcRNC HW
Rel.1 (BCNA1)
S5-A1 (step 5) – mcRNC with six BCN-A1 modules
mcRNC HW
Rel.2 (BCNB2)
S1-B2 (step 1) – mcRNC with two BCN-B2 modules
S3-B2 (step 3) – mcRNC with four BCN-B2 modules
In addition to capacity steps inherited from previous releases, mcRNC4.1 introduces
the support of the new capacity step for the following:
mcRNC HW
Rel.2 (BCNB2)
S7-B2 (step 7)- mcRNC with eight BCN-B2 modules
The following figure shows the available capacity steps in mcRNC:
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mcRNC Architecture and Configurations
Figure 43: Capacity steps in mcRNC
mcRNC capacity step 1
The mcRNC capacity step 1 (S1-B2) is the basic configuration and it consists of two
BCN-B2d BCN modules.
The following figure shows the mcRNC capacity step 1 configuration:
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Figure 44: mcRNC capacity step 1
The mcRNC capacity step 1 configuration consists of the following items:
•
•
Two module mcRNC NE with DC power includes following items:
•
2 * mcRNC basic module
•
4 * DC power module
•
2 *AMC HDD module
•
2 * SFP+ Direct Attach cable
•
2 * AMCSF-A
•
1 * RJ45 Ethernet batch cable (CNI)
Two module mcRNC NE with AC power includes following items:
•
2 * mcRNC basic module
•
4 * AC power module
•
2 *AMC HDD module
•
2 * SFP+ Direct Attach cable
•
2 * AMCSF-A
•
1 * RJ45 Ethernet batch cable (CNI)
mcRNC capacity step 3
The mcRNC capacity step 3 (S3-B2) consists of the basic NE configuration plus 2
additional type BCN-B2e BCN modules.
The following figure shows the mcRNC capacity step 3 configuration:
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mcRNC Architecture and Configurations
Figure 45: mcRNC capacity step 3
The mcRNC capacity step 3 configuration consists of the following items:
•
•
Four module mcRNC NE with DC power includes following items:
•
4 * mcRNC basic module
•
8 * DC power module
•
2 *AMC HDD module
•
6 * SFP+ Direct Attach cable
•
6 * AMCSF-A
•
2 * RJ45 Ethernet batch cable (CNI)
Four module mcRNC NE with AC power includes following items:
•
4 * mcRNC basic module
•
8 * AC power module
•
2 *AMC HDD module
•
6 * SFP+ Direct Attach cable
•
6 * AMCSF-A
•
2 * RJ45 Ethernet batch cable (CNI)
mcRNC capacity step 5
The following figure shows the mcRNC capacity step 5 configuration:
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Figure 46: mcRNC capacity step 5
mcRNC capacity step 7
The mcRNC4.1 capacity step 7 (S7-B2) consists of the capacity step 3 NE
configuration (S3-B2) plus four BCN-B2e BCN modules.
The following figure shows the mcRNC capacity step 7 configuration:
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mcRNC Architecture and Configurations
Figure 47: mcRNC capacity step 7
The mcRNC Capacity Step 7 configuration consists of the following items:
•
•
Eight module mcRNC NE with DC power includes following items:
•
8 * mcRNC basic module
•
16 * DC power module
•
2 *AMC HDD module
•
28 * SFP+ Direct Attach cable
•
14 * AMCSF-A
•
4 * RJ45 Ethernet batch cable (CNI)
Eight module mcRNC NE with AC power includes following items:
•
8 * mcRNC basic module
•
16 * AC power module
•
2 *AMC HDD module
•
28 * SFP+ Direct Attach cable
•
14 * AMCSF-A
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•
4 * RJ45 Ethernet batch cable (CNI)
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mcRNC Architecture and Configurations
mcRNC site solutions
mcRNC site solutions
A number of IP/Ethernet transport connectivity options and site solutions have been
defined for mcRNC enabling smooth introduction of mcRNC into the existing
IP/Ethernet networks. The solutions are based on a pair of site routers/switches
providing redundant 1 GE and/or 10 GE connectivity for mcRNC.
The mcRNC supports the IP transport option. Network connectivity and transport
layer processing capacity is aligned with the control plane and user plane
processing capacity.
Following are the mcRNC transport features:
Figure 48: mcRNC site solutions
All site solutions have been verified against Juniper (MX and EX series) and Cisco
products (7600 series), thus reducing the need for interoperability testing to a
minimum when selecting one of the described configurations. Router/switch vendors
are supported but interoperability tests have not been performed.
The site solutions for the mcRNC provide support options with main characteristics:
•
L3 static routes
•
Virtual Router Redundancy Protocol/Hot Standby Router Protocol
(VRRP/HSRP)
•
Dynamic routing based configurations
The mcRNC supports 1 GE and 10 GE physical connectivity where both can be also
used at the same time.
Following are the types of mcRNC site solutions:
•
Evolved site solution
•
Open Shortest Path First (OSPF) site solution
•
VRRP/HSRP site solution
mcRNC evolved site solution
The following are the features of the mcRNC evolved site solution:
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•
Based on the Ethernet switchport configuration in the site routers.
•
One Virtual LAN (VLAN) spans over the External Interface Processing Unit
(EIPUs) and a single site router/switch (user plane).
•
Redundancy is based on the static routes configuration (L3 type of a site
solution).
•
Bidirectional Forwarding Detection (BFD) Single-Hop with static routes applied
for next-hop supervision.
•
Available since mcRNC2.0 release.
•
Supports 1 GE interfaces.
•
Cisco 7600 series and Juniper EX4200 series site router/switch are supported.
The following figure shows an example of the mcRNC evolved site solution:
Figure 49: mcRNC evolved site solution example
mcRNC OSPF site solution
The following are the features of the OSPF site solution:
•
Based on dynamic routing for the user plane traffic.
•
OSPF with BFD (Single Hop) is applied for fast reaction to any link failures.
•
Routing domains and VLAN traffic separation are provided by deploying Virtual
Routing and Forwarding (VRF) instances.
•
Supports 1 GE and 10 GE interfaces.
•
For example, with the mixed 1GE and 10GE use case, connectivity to the
following can be handled in these ways:
•
Base stations (Iub): With 1GE interfaces
•
CN and neighbor RNC elements (Iu, Iur): With 10 GE interfaces
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mcRNC Architecture and Configurations
•
Ethernet Link Aggregation can be applied to bundle the 1 GE interfaces
providing one logical interface with higher capacity.
•
Juniper MX420 and Juniper EX4500 site router/switch are supported.
•
The OSPF and VRRP/HSRP site solutions apply similar cabling and Iu/Iur
control plane configuration principles.
The following figure shows an example of the mcRNC OSPF site solution:
Figure 50: mcRNC OSPF site solution
mcRNC VRRP/HSRP site solution
The following are the features of the mcRNC VRRP/HSRP site solution:
•
Site solution based on Ethernet switchport configuration in the site routers.
•
Site router redundancy is managed with VRRP or HSRP protocols (L2 type of a
site solution).
•
One VLAN spans over the EIPUs and site routers/switches (not further to
network). There is no L2 Iub support.
•
Provides planning principles compatibility with the current IPA-RNC
VRRP/HSRP site solution.
•
Supports 1 GE and 10 GE interfaces.
•
Juniper MX420 and Juniper EX4500 site router/switch are supported.
The following figure illustrates an example of the mcRNC VRRP/HSRP site solution:
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Figure 51: mcRNC VRRP/HSRP site solution example
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mcRNC Architecture and Configurations
Summary: mcRNC Architecture and Configurations
Module Summary
This module covered the following learning objectives:
•
Describe mcRNC architecture and configurations.
•
List mcRNC functional units.
•
Describe mcRNC hardware items and interfaces.
•
Explain signaling and data flow in mcRNC.
•
Describe redundancy system in mcRNC.
•
Describe the different capacity steps in the mcRNC.
•
Describe the mcRNC site solutions.
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