Planning aspects: IP layerUser plane IP addressingDCN IP addressing

Configuration overview: user plane

• One IP tunnel between each BTS and PWE3 gateway on RNC site– Multiple pseudo wires inside each tunnel– One pseudo wire label per pseudo wire

• Each tunnel is identified by the IP addresses of the endpoints

IP address space: user plane

• The Mobile Network Operator may or may not have the freedom to select IP addresses:

– In case of a leased layer 2 VPN IP addresses are private, i.e. freely selectable and not visible to other users of the packet network.

– In case of a leased layer 3 service (e.g. wholesale ADSL) the Mobile Network Operator would be assigned an IP address space by the service provider.

• Sub netting may or may not be applied:– /30 subnet: 2 IP addresses, i.e. point-to-point– Or BTSs in different subnets, e.g. split geographically– Or no sub netting at all

• Note that BTS Ethernet interface units do not support routing protocols, thus routes are static

• Network Address Translation (but not Port Translation) can be performed by the DSL router, in order to keep user plane IP addresses identical for all BTSs.

PSN Case 1:Point-to-Multipoint Ethernet

PWE3 GatewayIP/Eth

IP/Eth

Ethernet Network

ATM/SDHGE

Ethernet point-to-multipoint(e.g. Virtual Private LAN Service)

PWE3 Gateway

PWE3 Gateway

Node B site Service Provider RNC site

PSN Case 2:DSL

IP network architecture: Point-to-multipoint Ethernet

• Addresses could be private or public.• Address are assigned statically.• The RNC GW is the default IP gateway for the Node B GWs.• No need for routing protocol.

IP network architecture: DSL (with NAT)

IP/MPLS Core Network

RNC

Node B

Node B

Router

Router

DSL Access NetworkPWE3

Gateway

PWE3Gateway

NAT

Public IPAddress

Public IPAddress

Public IPAddress

PWE3Gateway

DSLAM BRAS

NAT

Private IPAddress

Default gateway

Private IPAddress

Default gateway

• DSL router support NAT. Each modem has two addresses:– Public address (provided by the ISP) for the DSL port. Modem addresses are known by the RNC GW. The RNC GW uses these

addresses as the Node B addresses.– Private static address for the Ethernet port.– Alternatively, NAT can be located in BRAS/core edge.

• Node B GW addresses are private. They are static and all of them can be the same.• RNC GW has been assigned a public static IP address, known by the Node B GWs.• The DSL router is the default gateway for the Node B GW.• RNC GW routing configuration depends on the Core Network architecture (but it will be static)

IP network architecture: DSL (without NAT)

• Node B GW have been assigned public static IP address, known by the RNC GW.• RNC GW has been assigned a public static IP address, known by the Node B GWs.• If the DSL modem is also a router, it will become the default gateway for the Node Bs.• RNC GW routes configuration depend on the Core Network architecture.

IP/MPLS Core Network

RNC

Node B

Node B

Router/Modem

Router/Modem

DSL Access NetworkPWE3

Gateway

PWE3Gateway

Public IPAddress

PWE3Gateway

DSLAM BRAS

Public IPAddress

Public IPAddress

Default gateway

Default gateway

IP addressing on cell site: DCN

The DCN to the BTS remains unchanged.• IP/AAL5 inband over the TDM networkThe DCN is extended to also manage the DSL router through the “backdoor”.• Most secure and reliable connection• The UltraSite-embedded AXC can be configured with IFUG, an 8-port Ethernet hub. Flexi

WCDMA BTS provides additional Local Management Ports on the System Module• “IP address and port-based filtering” (RAS06) might be required to secure the DCN

against unlawful access

PacketPacket PWE3

TDMTDM

DSL

BTS

E1

Eth

RNC

STM1

STM1

Z2

Hub

Z1

ATM

DCNDCN

IP address space: DCN

An additional IP address is required from the existing BTS’s subnet• Not a problem with the frequently

used /28 subnet (4 free addresses)

Planning aspects: Ethernet layerResulting Ethernet bandwidthNetwork PerformanceUse of VLAN

Resulting Ethernet bandwidth

Resulting Ethernet bandwidth• With ADSL being the last mile technology the available Ethernet bandwidth will

vary from cell site to cell site, depending on distance to the DSLAM, crosstalk etc.

• After having determined the available Ethernet bandwidth the ATM VCCs to be emulated across the packet network have to be sized accordingly (PCR, ATM cell concatenation, packetization factor).

• Please refer back the to PWE3 layer planning aspects covered in this slide set.

Network performance

• Delay and delay variation are bound to the performance targets of the ATM transport.• There will be no additional requirement from the fact that the transport is based on PW.• SFS requirement will be linked to the ATM requirement.• Delay target (under consideration, could change)

– As ATM traffic:▪ HSDPA: 750ms (high, TCP applications suffering)▪ AMR: 15ms▪ HSUPA:

• For control frames there is no buffering delays: target is 14ms.• For data frames buffering delay up to 100ms: target is 114ms.

• Packet delay variation target– HSDPA: tbd (for flow control)– HSUPA: tbd (for congestion control)– AMR: 20ms (MDC limited)

• Loss ratio target– 0.05%

VLAN

Use of VLANs in PW:• VLAN ID:

– It is required by some service providers (e.g. BT MegaStream Ethernet Gbe access)– Enables traffic separation, and in case of shared network, security is increased.– Adds flexibility to the solution.

• VLAN priority:– In L2 switched network, it enables QoS.

• VLAN may or may not be used.– Needed for layer 2 differentiation based on VLAN priority bits

• A single VLAN for all BTSs and RNC site nodes is deemed sufficient– ARP requests from BTSs and ARP broadcasts do not create much additional traffic

• VLAN ID=0 not supported