aav performance report readout
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AAV Performance Report ReadoutNational E2E RAN PerformanceTim ZhangAshish Dhital
6/8/2010T-Mobile | stick togetherWednesday, June 09, 2010Confidential and Proprietary Information of T-Mobile USA#
AAV Architecture OverviewT-Mobile | stick togetherWednesday, June 09, 2010Confidential and Proprietary Information of T-Mobile USA#Ethernet backhaul configurationsHybrid Iub architecture involves deploying parallel ATM/T1 and IP/Ethernet backhaul bearers to a given NodeB
In the next two diagrams the traffic paths are illustrated
Notice how the NodeB OAM traffic is routed in the two solutionsThis is critical in understanding the impact of different hybrid alarm constellations
Also notice the different paths the HDSPA/HSUPA traffic takes in the two solutionsConfidential and Proprietary Information of T-Mobile USA3Key fact: IN THIS INITIAL PHASE, ONLY THE HSDPA/HSUPA BEARER IS TO BE MIGRATED TO THE ETHERNET INTERFACE ALL CONTROL PLANE MESSAGES WILL CONTINUE TO BE SENT OVER THE ATM/T1 INTERFACE.What are some of the control messages that will continue to be supported on the ATM/T1?Will ALCAP still be needed to set up HSDPA or HSUPA on the new ETHERNET? State the rationale for your answer.Lets quickly walk-through the ATM-world messaging and traffic flow and introduce the new world.1 | NSN Hybrid Iub - ILT OverviewConfidential and Proprietary Information of T-Mobile USA#ATM Iub
HSDPA/HSUPAR99 + signalingNodeB OAM (carries NodeB alarms)Confidential and Proprietary Information of T-Mobile USA4Notice how the NodeB alarms are routed via the RNC using IPoATM over the T1sThis illustration shows the paths of traffic through the current ATM Iub technology.The HSPA data is carried over T1/ATM to the RNC (ALCAP and bearer best effort).Signaling and R99 voice run over T1/ATM to the RNC (NBAP, ALCAP, bearer).OAM runs over T1s to the RSP and then over Ethernet from the RSP to NMNET (MuB VCI).E/// - Each NodeB has one Iub.The way that the OAM traffic is carried allows the NodeB to still send alarms, even if the Ethernet link is down.NSN OAM traffic to NMNET is via the RNC onto the Ethernet interface.
What will NOT change:NMNET to OSSs will continue to be maintained (a.k.a. E/// OSS-RC and NSN NetAct), as will the interface to NOC NetEx and T-PIM.
1 | NSN Hybrid Iub - ILT OverviewConfidential and Proprietary Information of T-Mobile USA#Hybrid Iub
HSDPA/HSUPAR99 + signalingNodeB OAM (carries NodeB alarms)CellSiteLAN OAM (carries NID alarms/KPIs)Notice how the NodeB and NID alarms take different paths with hybrid Iub.Confidential and Proprietary Information of T-Mobile USA5This illustration shows the paths of traffic through the hybrid Iub technology.The voice traffic path does not change - it stays on T1/ATM.The HSPA rides over Ethernet and can instantly provide 21 Mbps this is the equivalent of about 15 T1s.The NodeBs have Ethernet ports so we can connect any device to the NodeB, thus we can always have OAM connectivity.NodeB alarms go over the T1/ATM link. The NodeB can only detect loss of connectivity and can only report physical problems.If there is a complete loss of Ethernet connectivity to the RNC, the NodeB will raise an alarm (IP Sync), which will cause the OSS to switch the HSPA back to ATM.Only when there is high level of confidence that the hybrid Iub is stable, perhaps after a six-month testing period, will removal of the T1s and going pure-IP be considered.1 | NSN Hybrid Iub - ILT OverviewConfidential and Proprietary Information of T-Mobile USA#Hybrid Iub HW changesConfidential and Proprietary Information of T-Mobile USA6
T-Mobiles UTRAN Iub interface started with an ATM/TDM transport layer. Here is a brief review of the current UTRAN ATM/T1 structure:All traffic between the NodeB and the RNC is transported over ATM/TDM connections. This traffic includes control plane traffic (e.g., NBAP, ALCAP), user plane traffic (e.g., voice, R99 data, HSDPA/HSUPA), and OAM information.Typical physical interfaces include T1s between the NodeB and the CLEC, OC3/OC12/OC48/DS3 between the CLEC TDM Backhaul and the MSO DACS, OC3 from the MSO DACS to the RSP and OC3cs from the RSP to the RNC. OAM traffic, EMS data and all other OSS traffic (i.e., RNC to NMNET) is transported via GigE interfaces off of the ESA cards on the RNC.
All SONET connections are point to point APS links. Multiple T1s are used between the NodeB and the LEC. T1 aggregation is achieved using Inverse Multiplexing over ATM (IMA). The IMA termination is at the RSP.NetEx is used for alarm monitoring. T-PIM is used for KPIs.Vendor EMSs include the NSN NetAct and the Ericsson OSS-RC.
2 | NSN Hybrid Iub - ILT Configuration ManagementConfidential and Proprietary Information of T-Mobile USA#
Hybrid Iub HW changes7
HSDPA traffic flows from RNCs NPGE IP addresses the NodeB UP IP address
HSUPA traffic flows from the NodeB UP IP address to RNCs NPGE IP addresses
NodeBs user plane IP addressRNCs user plane IP addresses(1 per NPGE pair)Recently there has been considerable increase in data traffic which has expedited the transition from an ATM/TDM Iub interface to an all-IP Iub interface. This transition will take place in stages with the first stage being the Hybrid Iub. In this configuration, all HS data will be transported over an IP network. All other traffic from the NodeB will continue to use the existing ATM/TDM transport. To accommodate the new Iub/IP transport, a number of new hardware elements must be added. Key Hybrid Iub Hardware changes:MSO: RNCs require new Ethernet cards (NPGEs). MSO Aggregation Devices (MAD) routers/switches (Cisco 7609 routers) provide routing functions. JDSU QT-600 Ethernet probe for testing and monitoring the Ethernet performanceE-OAM Network Interface Devices (NIDs) to terminate EVCs, monitor SLAs and provide performance reportingCell Site:NodeBs require new Flexi Transport Interface A (FTIA) Ethernet interfaces.E-OAM Network Interface Devices (NIDs) to terminate EVCs, monitor SLAs and provide performance reporting2 | NSN Hybrid Iub - ILT Configuration ManagementConfidential and Proprietary Information of T-Mobile USA#
Ethernet Y.1731 CCM (Continuity Check Message) frames sent every 1 sec between MSO and cell site NIDs on CORENET VLAN monitors live Ethernet performance. E-OAM PM8
KPIsThis chart shows the animated CCM message exchange, UL and DL, between the E-OAM NID and the cell site NID. Statistics (KPI) are reported by these NIDs to JDSU NetOptimize, which then passes them to T-PIM.
4 | NSN Hybrid Iub - ILT Performance ManagementConfidential and Proprietary Information of T-Mobile USA#AAV connectivity issuesTo identify NMNET/CORENET AAV VLAN/layer 1 connectivity issues to a cell site useE-OAM cell site NID and Node B ET-MFX11 HW alarms E-OAM FM and PM alarmsRNC does not see the Ethernet circuit and 7609 AAV VLAN alarms will be disabled
For investigation and fault isolationPing the cell sites IP hostsRun rapid RFC2544 test to cell site NID
Please refer to following links for detail AAV Troubleshooting procedure.Ericsson: Click hereNSN: Click here
Confidential and Proprietary Information of T-Mobile USAThe Alternative Access Vendor (AAV) represents a third-party Carrier Ethernet network connecting the cell site to the Mobile Switching Office (MSO). At the extreme ends of the access network are the Node B in the cell site and the RNC in the MSO. There are two interdependent Virtual Local Area Networks (VLANs) required to provide data services between the cell site and the MSO. The NMNET is used for control and signaling, while CORENET transports the actual user data. It is possible one of these may be working properly while the other is experiencing a fault. Thus, fault management requires each be examined.There are two steps for exploring faults related to the AAV. First, explore the physical (Layer 1) connectivity between the RNC and the Node B. If a fault is detected, the second step is to isolate the fault. Is the issue associated with:Connectivity between E-OAM cell site NID and Node B ET-MFX11 port 7?A BFD generated alarm? The Node B and the RNC establish two-way data-plane BFD sessions between themselves; a failure to receive a response indicates there may be a data plane fault.JDSU E-OAM Ethernet alarms?A degradation alarm from PM stats? VLAN alarms indicating an issue between the MAD 7609 router and AAV? Two primary tools are used for fault isolation when the location of the fault is not apparent from the alarms. We will examine in some detail how the ping tool is used in fault isolation for both the CORENET and the NMNET. We will also examine how Rapid RFC2544 is used to examine service degradation problems. The RNC cant see the last mile Ethernet so use ping first. 3 | Ericsson Hybrid Iub - ILT Fault ManagementConfidential and Proprietary Information of T-Mobile USA#
AAV Performance KPIs(from JDSU)T-Mobile | stick togetherWednesday, June 09, 2010Confidential and Proprietary Information of T-Mobile USA#Intro to JDSU Performance Monitoring CFM Y.1731 Test PacketsTMO has chosen CFM Y.1731 as the standard for real time circuit testing.The E-OAM NIDs send DL frames every second with a time stamp; in the other direction, the cell site NIDs send UL frames with time stamps. When frames are received, the NIDs calculate the delay, evaluate loss, etc. This is on-going all the time. These tests are well defined in the Y.1731 standards and are called Continuity Check Message (CCM) checks. DL and UL frames are sent and monitored on CORENET VLAN (not on NMNET VLAN). We only want to monitor user traffic. NIDs will raise an alarm if there is a high error rate or loss of packets, and gives us KPIs that can be studied later.If it finds problems it will generate an alarm for NetExpert and send data to T-PIM via NetOptimize.