EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsLTE Attach and Default Bearer...
EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsLTE Attach MessageSequence Ch...
EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsS1AP: eNodeB  MMES1AP Initia...
EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsS6A: MME  HSSDiameter Update...
EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsS6A: MME  HSSDiameter Update...
EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsDefault BearerEstablishmentMM...
EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsS11: MME  SGWGTP Create Sess...
EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsS1AP: eNodeB  MMES1AP Initia...
EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsS1AP: eNodeB  MMES1AP Initia...
EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemseNodeB  MMEUE  eNodeBNAS At...
EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemseNodeB  MMEUE  eNodeBActiva...
EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemseNodeB  MMEInitial Context S...
EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsCompleting the Attach andDefa...
EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsThank YouLinks DescriptionEve...
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Lte attach-messaging

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Lte attach-messaging

  1. 1. EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsLTE Attach and Default BearerSetup Messaging© 2012 EventHelix.com Inc.All Rights Reserved
  2. 2. EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsLTE Attach MessageSequence Chart© 2012 EventHelix.com Inc.eNodeB MME HSSInitial UE MessageSGWInitial Context Setup + Attach Accept +Activate Default BearerUpdate Location AnswerCreate Session RequestCreate Session ResponseUpdate Location RequestInitial Context Setup ResponseAttach Complete + Activate Default Bearer AcceptModify Bearer Request2
  3. 3. EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsS1AP: eNodeB  MMES1AP Initial UE MessageS1APInitialUEMessageId: eNB UE S1AP IDTracking Area IdTracking Area CodeCell IdAttach RequestEPS attach typeEPS AttachCombined EPS/IMSIAttachIdentityIMSIOld GUTIEPS EncryptionAlgorithm SupportedEPS IntegrityAlgorithm SupportedConnection RequestPDN Type: IPV4Type: Initial Attach• Initial UE Message is the firstmessage sent to the MME toestablish a connection• The eNode uses the eNB-UE-S1AP-ID to uniquely identify the UE• EPS attach type may be:• EPS Attach: UE is attaching onlyto the 4G LTE network• Combined EPS/IMSI Attach:• The UE identity is specified is:• IMSI: If the UE has is notregistered with the network• Old GUTI: Subsequent attachrequests identify the UE with theOld GUTI© 2012 EventHelix.com Inc. 3
  4. 4. EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsS6A: MME  HSSDiameter Update LocationRequestDiameterUpdateLocationRequestCommand CodeUpdate LocationRequestApplication IdS6a interfaceapplicationOriginHostRealmDestinationHostRealmUser Name IMSIRAT Type EUTRANVisited PLMN IdMCCMNC• MME updates the UE location withthe HSS• Origin and Destination arespecified as Host and Realm(domain)• The user name in the request is setto IMSI• The Radio Access Technology isspecified in the RAT Type• It will be set to EUTRAN for LTEaccess• The Visited PLMN is also includedin the message© 2012 EventHelix.com Inc. 4
  5. 5. EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsS6A: MME  HSSDiameter Update LocationAnswerDiameterUpdateLocationAnswerResult Code: SuccessSubscriber Status:Service GrantedAggregate MaximumBit RateMaximum RequestedBandwidth UplinkMaximum RequestedBandwidth DownlinkAccess RestrictionDataMSISDNAPN ConfigurationProfileCalled Station IdPDN Type IPV4PDN GW AddressPDN GW NameQoS Class IdentifierQCI specifies BER,Priority, GBRServed Party IPAddress3GPP ChargingCharacteristicsAggregate MaximumBit RateMaximum RequestedBandwidth UplinkMaximum RequestedBandwidth Downlink• The HSS accesses the database andresponds with user information to theMME• The Aggregate Maximum Bit Rate (AMBR)occurs twice in the message:• The first occurrence specifies themaximum bit rate for the default PDPcontext• The second occurrence specifies the datamaximum data limit via the APN. Theselimits are specified by the PDN• APN configuration also includes:• IP address of the PDN Gateway. Thisaddress is used to determine the defaultroute for the traffic towards the Internet• IP address assigned to the UE (ServedParty IP Address)© 2012 EventHelix.com Inc. 5
  6. 6. EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsDefault BearerEstablishmentMME  SGW:Create SessionRequestSGW  PGW:Create SessionRequest•The SGW asksthe PGW toestablish thebearerSGW  PGW:Create SessionResponse•The PGWestablishes thebearer andresponds back tothe SGWMME  SGW:Create SessionResponse• The SGWrespondsback to theMME© 2012 EventHelix.com Inc. 6
  7. 7. EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsS11: MME  SGWGTP Create SessionRequestGTPCreateSessionRequestIMSIRAT Type EUTRANSender F-TEID forControl PlaneTEIDMME IP AddressEPS Bearer IdPDN Type IPV4 OR IPV6Bearer ContextARPQCIQCI specifies BER,Priority, GBRMSISDNTAI MCC, MNC, TACECGI Contents MCC, MNC, ECIPGW S5/S9Address for ControlTEIDPGW IP AddressPDN IP AddressAPNPDN AddressAllocationIP AddressAssigned to UEAggregate Max BitRate APN LimitDownlink andUplink• MME initiates the default routeestablishment by asking the SGWto create a GTP tunnel• The source is identified by the fullyqualified endpoint identifier withthe Tunnel Endpoint Identifier(TEID) and the MME IP Address• The IP Address assigned to the UEis also included along with thedownlink and uplink maximumdata rates allowed at the APN level• The TAI and ECGI (E-UTRAN CellGroup Identifier) informationidentify the current location of theuser© 2012 EventHelix.com Inc. 7
  8. 8. EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsS1AP: eNodeB  MMES1AP Initial Context Setup RequestNAS Attach AcceptActivate Default Bearer RequestInitialContextRequest/AttachAccept/DefaultBearerRequestS1AP PDUS1AP Initial ContextSetup RequestEPS mobilitymanagement messagesNAS Attach AcceptEPS sessionmanagement messagesActivate Default BearerRequestThe next message from the MME isreally a three-in-one. The messagecontains:• SIAP Initial Context Setup Request• A request to establish a contextbetween the MME and eNodeB• The message contains SGWtunneling information• NAS Attach Accept• This message acknowledges thesuccessful Attach to the UE.• The eNodeB will pass thismessage to the UE• Activate Default Bearer Request• The message initiates the defaultbearer setup on the UE• The eNodeB will pass thismessage to the UE© 2012 EventHelix.com Inc. 8
  9. 9. EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsS1AP: eNodeB  MMES1AP Initial Context SetupRequestSIAPInitialContextSetupRequestMME UE S1AP IDENB UE S1AP IDAggregate MaxBitrate (AMBR)DownlinkUplinkeRABs to Setup eRAB IDQCIeRAB Max Bit RateDownlinkeRAB Max Bit RateUplinkRAB Guaranteed BitRate DownlinkRAB Guaranteed BitRate UplinkTransport LayerAddressGTP TE IDUE SecurityCapabilityEncryptionAlgorithmIntegrity ProtectionAlgorithmSecurity Key• The MME responds with MME UES1AP ID that was received fromthe eNodeB in the initial UEmessage• The message also contains theMME UE S1AP ID• The message contains themaximum aggregate bit rateinformation.• The message also contains theinformation about the defaulteRAB.• QCI to assign session priority• The maximum bit rate for theeRAB• Guaranteed bit rate for the eRAB• Transport Layer Address assignsthe IP Address for the user planeentity on the S-GW• GTP TE ID identifies the S-GWend of the user plane tunnel• The security capabilities specifythe encryption and integrityprotection algorithm to be usedfor the UE session© 2012 EventHelix.com Inc. 9
  10. 10. EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemseNodeB  MMEUE  eNodeBNAS Attach AcceptNASAttachAcceptEPS Attach Result EPS OnlyT3412TAI ListType One PLMNPartial TAI ListPLMNTAC ListGUTIMCCMNCMME Group IdMME CodeM-TMSIGPRS Ready Timer• The Attach Accept is carried asNAS payload in the Initial ContextSetup Request• The message specifies that theattach has been successful. Theterminal is attached to the EPSonly (i.e. LTE only, no SGSNregistration)• The T3412 timer specifies themaximum time between trackingarea updates from the terminal• The TAI list in the messagespecifies the PLMN and theTracking Area Codes for all theregistered tracking areas• The message contains GUTI. GUTIuniquely identifies the UE withPLMN, MME Group, MMC codeand the M-TMSI• Finally, the GPRS Ready timer isincluded in the message.• The UE will be transitioned toIDLE if no activity is detected forthis period© 2012 EventHelix.com Inc. 10
  11. 11. EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemseNodeB  MMEUE  eNodeBActivate Default BearerRequestActivateDefaultBearerRequestEPS Bearer IdEPS QoSQCIeRAB Max Bit RateDownlinkeRAB Max Bit RateUplinkRAB GuaranteedBit Rate DownlinkRAB GuaranteedBit Rate UplinkAccess Point NamePDN Address• The Attach Accept is carried asNAS payload in the Initial ContextSetup Request• The EPS Bearer id identifies thebearer that needs to be activated• The EPS QoS carries quality ofservice information:• QCI to assign session priority• The maximum bit rate for thebearer• Guaranteed bit rate for thebearer• The Access Point Name (APN) isincluded in the message• The PDN IP address assigned bythe HSS is passed to the UE© 2012 EventHelix.com Inc. 11
  12. 12. EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemseNodeB  MMEInitial Context SetupResponseS1APInitialContextSetupResponseMME UE S1AP IDeNB UE S1AP IDE-RAB Setup List E-RAB Setup ItemE-RAB IDTransport LayerAddressGTP TEID• The eNodeB sends the InitialContext Setup Response messageto the MME.• The message confirms theestablishment of the GTP tunnelon the S1-U interface• The message contains informationabout the RABs that are beingestablished at startup.• The following information ispresent for each RAB• The E-RAB ID• The transport layer IP address onthe eNodeB.• The eNodeB GTP Tunneling ID(TEID) for the eNodeB side.© 2012 EventHelix.com Inc. 12
  13. 13. EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsCompleting the Attach andDefault Bearer ActivationeNodeB  MME:Attach Complete+ Activate DefaultBearer Accept• eNodeB transportsAttach Complete andActivate DefaultBearer Accept• The message wasreceived from the UEMME  SGW:Modify BearerRequest• Inform SGWabout theeNodeB’s userplane IP addressand GTP TEID© 2012 EventHelix.com Inc. 13
  14. 14. EventHelix.com• telecommunication design• systems engineering• real-time and embedded systemsThank YouLinks DescriptionEventStudio System Designer Sequence diagram based systems engineeringtool.VisualEther Protocol Analyzer Wireshark based visual protocol analysis andsystem design reverse engineering tool.Telecom Call Flows GSM, SIP, H.323, ISUP, LTE and IMS call flows.TCP/IP Sequence Diagrams TCP/IP explained with sequence diagrams.Telecom • Networking • Software Real-time and embedded systems, call flows andobject oriented design articles.© 2012 EventHelix.com Inc.Thank you for visiting EventHelix.com. The following links provide more informationabout telecom design tools and techniques:14
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