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    General Flowchart RRC

    Uploaded by

    azka
    1) The document presents a general flowchart of concepts related to RRC, RAB, and other 3G and 4G networking components including the UE, UTRAN, CN, NodeB, RNC, Iu interface, RBs, SRBs, TRBs, and RABs. 2) It uses an analogy of a seller (UTRAN), buyer (UE), and deposit (CN) connected by a road (Iu interface) and rails (RRC) to represent the relationships between these components. 3) Signaling like requests and receipts occur over the RRC, while data shipment occurs over RABs. RBs convey information in the radio path like signaling and

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    General Flowchart RRC

    Uploaded by

    azka
    95 views4 pages
    1) The document presents a general flowchart of concepts related to RRC, RAB, and other 3G and 4G networking components including the UE, UTRAN, CN, NodeB, RNC, Iu interface, RBs, SRBs, TRBs, and RABs. 2) It uses an analogy of a seller (UTRAN), buyer (UE), and deposit (CN) connected by a road (Iu interface) and rails (RRC) to represent the relationships between these components. 3) Signaling like requests and receipts occur over the RRC, while data shipment occurs over RABs. RBs convey information in the radio path like signaling and

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    1) The document presents a general flowchart of concepts related to RRC, RAB, and other 3G and 4G networking components including the UE, UTRAN, CN, NodeB, RNC, Iu interface, RBs, SRBs, TRBs, and RABs. 2) It uses an analogy of a seller (UTRAN), buyer (UE), and deposit (CN) connected by a road (Iu interface) and rails (RRC) to represent the relationships between these components. 3) Signaling like requests and receipts occur over the RRC, while data shipment occurs over RABs. RBs convey information in the radio path like signaling and

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    95 views4 pages

    General Flowchart RRC

    Uploaded by

    azka
    1) The document presents a general flowchart of concepts related to RRC, RAB, and other 3G and 4G networking components including the UE, UTRAN, CN, NodeB, RNC, Iu interface, RBs, SRBs, TRBs, and RABs. 2) It uses an analogy of a seller (UTRAN), buyer (UE), and deposit (CN) connected by a road (Iu interface) and rails (RRC) to represent the relationships between these components. 3) Signaling like requests and receipts occur over the RRC, while data shipment occurs over RABs. RBs convey information in the radio path like signaling and

    Copyright:

    © All Rights Reserved
    Download as DOCX, PDF, TXT or read online from Scribd
    Download as docx, pdf, or txt
    of 4

    General Flowchart - RRC, RAB and Others

    Now that we know what is bearer, let's go back to the analogy presented earlier, but now
    bringing it to the real, more technical side.
    All that we'll talk can be summarized in a single figure, having all the concepts seen today, and
    that will be detailed from now on.
    Note: If you manage to understand the concepts that will be explained in the figure below, you
    will be with a great base for both WCDMA and LTE networks. This is because, in order to
    facilitate we use WCDMA nomenclatures, but the principle is pretty much the same in LTE. Just
    do the equivalent replaces, like NodeB for eNB.

    On that ficticious scenario, the seller is the UTRAN, responsible for creating and maintaining the
    communication between the UE (buyer) and CN (deposit) so that the QoS requirements of each
    are met.

    UTRAN: UMTS Terrestrial Radio Access Network


    o NodeB
    o RNC

    UE: User Equipment

    CN: Core Network


    o MSC: for switched voice services
    o SGSN: for packet-switched services

    The cliff is the Uu Interface between the UE and the UTRAN, and the road through the remote
    control car goes until the deposit is the Iu Interface, between the UTRAN and CN.
    Sending requests and receipts is part of signaling, or the RRC. The shipment of purchases is the
    data part, or the RAB. In our scenario, the RRC are the Rails, and RAB is the full service of
    sending data between the UE and the CN.

    RRC: Radio Resource Control

    RAB: Radio Access Bearer

    Note: the RRC is in Layer 3 - control plane, while the RAB occurs between the UE and CN, in
    the user plane.
    The railcars are the RBs, and convey the information in the radio path. These wagons define
    what type of thing will be transported, and in what quantity. Similarly, the RBs define what type
    of data will in the RRC, which can be Data or Signaling. When the QoS attributes change, then
    the Rbs associated with that RRC connection need to be reconfigured.
    The remote control cars are the Iu bearer, and carry information on Iu Interface (between the
    UTRAN and the CN), either CS or PS.

    RB: Radio Bearer

    Iu bearer: Iu Bearer Interface

    Note: RAB is the combination of RB and Iu bearer.


    As examples of RAB for some services and different rates we have:

    The Conversational RAB and the Interactive RAB can be used together, and in this case we have
    a case of MultiRAB.
    The RB is a layer 2 connection between the UE and the RNC, and can be used for Signalling and
    control User Data. When it is used for Signalling or Control Messages is called SRB. And when
    it is used for user data is called TRB.

    SRB: Signalling Radio Bearer (Control Plane)

    TRB: Traffic Radio Bearer (User Plane)

    Note: in an optimized network, we can find much of the traffic being handled by HSPA bearers,
    even MultiRAB. This option frees resources from CE (Channel Elements), relieving the load on
    R99 (that can only use these resources). However, it should be done with caution, because if
    improperly configured it can degrade the Performance Indicators with Blockage (Congestion)
    and Failures.
    As you've probably noticed, we're talking about several new technical terms, but these terms are
    what you'll find for example when reading UMTS or LTE call flowcharts. But if you can
    understand at least in part the concepts presented today, everything will be much easier.
    Let us then take a look again on our figure, and continue our analogy.

    As we saw, in telecom we work with the concept of layers. And this way of seeing the network
    brings us many advantages, mainly because we were able to 'wrap' physical access. In this way,
    any modification or replacement can be made with less complexity.
    We don't need to tell you how much the radio path is complex, continuously changing, right?
    This structure using beares ensures this simplification: the RNC and CN bother with QoS
    requirements in the path between them (Iu Interface); and only the RNC have to worry about
    meeting the complex radio path QoS.

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