Subject: Re: [NSIS] WG Last Call on draft-ietf-nsis-req-06.txt

From: [email-masked]
Date: Tue, 28 Jan 2003 17:19:50 +0100

Hi,

The proposed text seems fine to me, it has made the text more generic and
well readable.
Only one remark: correct the sentence under bullet 3) of section 10.2

Thanks,
Maarten

Kuntal Chowdhury <[email-masked]>@ietf.org on 27/01/2003 23:47:09

Sent by:    [email-masked]

To:    [email-masked]
cc:
Subject:    Re: [NSIS] WG Last Call on draft-ietf-nsis-req-06.txt

Hi all,
Here is an attempt to generalize the scope of NSIS in 3G wireless networks.
The
following is the suggested update/re-write of section 10.2 and 10.3.

Issue Name: 7
Submitter name: Louis-Nicolas Hamer and Kuntal Chowdhury
Submitter email address: [email-masked]
Date first submitted: 22/01/2003
Reference: none
Document: draft-ietf-nsis-req-06.txt
Comment type: T
Priority:  2
Section: 10.2 & 10.3

Proposed text:

10.2 3G Wireless Networks

    In this scenario, the user is using the packet services of a 3rd
    generation wireless system (e.g. 3GPP/UMTS, 3GPP2/cdma2000). The
    region between the End Host and the Edge Node (Edge Router)
    connecting the wireless network to another QoS domain is considered
    to be a single QoS domain.

    The issues in such an environment regarding QoS include:

    1) 3G wireless networks provide their own QoS technology with
    specialized parameters to co-ordinate the QoS provided by both the
    radio access and wired access networks. Provisioning of QoS
    technologies within a 3G wireless network can be described mainly
    in terms of calling bearer classes, service options and service
    instances. These QoS technologies need to be invoked with suitable
    parameters when higher layers trigger a request for QoS. Therefore
    these involve mapping of the requested higher layer QoS parameters
    onto specific bearer classes or service instances. The request for
    allocation of resources might be triggered by signaling at the IP
    level that passes across the wireless system, and possibly other
    QoS domains. Typically, wireless network specific messages are
    invoked to setup the underlying bearer classes or service instances
    in parallel with the IP layer QoS negotiation, to allocate resources
    within the radio access network.

    2) The IP signaling messages are initiated by the NSIS initiator and
    interpreted by the NSIS Forwarder. The most efficient placement of the
    NSIS Initiator and NSIS Forwarder has not been determined in 3G
    wireless
    networks, but a few potential scenarios can be envisioned. The NSIS
    Initiator could be located at the End Host e.g. UE or MS (triggered by
    applications), the Access Gateway or at a node that is not directly on
    the data path, such as a policy server. The Access Gateway could act as
    a proxy NSIS Initiator on behalf of the UE/MS or an End Host. The
    Policy
    Server that manages per-flow/aggregate resources within its QoS domain
    (e.g. the 3G wireless network) may act as a proxy NSIS Initiator for
    the
    UE/MS or the Access Gateway. Depending on the placement of the NSIS
    Initiator, the NSIS Forwarder may be located at an appropriate
    point in the 3G wireless network.

    3) The need for re-negotation of the resource needs in a new 3G
    wireless
    domain due to UE/MS mobility. In this case the NSIS Initiators and the
    NSIS Forwarders will have to detect mobility events and trigger
    re-negotiation of resources autonomously.

10.3 An example scenario for a 3G wireless network

    The 3G wireless access scenario is shown in Figure 1. The Proxy-Call
    State Control Function (P-CSCF) is the outbound SIP proxy (only used
    in IMS). The Access Gateway is the egress router of the 3G wireless
    domain and it connects the radio access network to the Edge Router
    (ER) of the backbone IP network. The Policy Server is the entity
    responsible for managing the resource allocations/de-allocations in
    the 3G wireless domain. It is also responsible for the policy-based
    control of the end-user service. The Policy Server also controls the
    Access Gateway to open and close the gates and to configure per-flow
    policies, i.e. to authorize or forbid user traffic. The P-CSCF (only
    used in IMS) and the Access Gateway communicate with the Policy Server,
    for network resource allocation/de-allocation decisions. The User
    Equipment (UE) or the Mobile Station (MS) consists of a Mobile Terminal
    (MT) and Terminal Equipment (TE), e.g. a laptop.

                            +--------+
                 +--------->| P-CSCF |-------> SIP signaling
                /           +--------+
               / SIP            |
              |             +--------+
              |             | Policy |         +----------------+
              |             | Server |<------->| NSIS Forwarder |<--->
              |             +--------+         +----------------+
              |                 |                  ^
              |                 |COPS              |
              |                 |                  |
          +------+          +---------+            |
          | UE/MS|----------| Access  |<-----------+         +----+
          +------+          | Gateway |----------------------| ER |
                            +---------+                      +----+

                   Figure 1: 3G wireless access scenario

    The Policy Server has all the required QoS information for per-flow
    or aggregate admission control in 3G wireless networks. It receives
    resource allocation/de-allocation requests from the P-CSCF and/or
    Access Gateway etc. and responds with policy decisions. Hence the
    Policy Server may be a candidate entity to host the functionality
    of the NSIS Initiator, initiating the "NSIS" QoS signaling towards the
    core IP network. On the other hand, the UE/MS may act as the NSIS
    Initiator or the Access Gateway may act as a Proxy NSIS Initiator
    on behalf of the UE/MS. In the former case, the P-CSCF/Policy Server
    has to do the mapping from codec types and media descriptors (derived
    from SIP/SDP signaling) to IP traffic descriptor. In the latter
    case, the UE/MS may use any appropriate QoS signaling mechanism as the
    NSIS Initiator. If the Access Gateway is acting as the Proxy
    NSIS initiator on behalf of the UE/MS, then it may have to do the
    mapping of parameters from radio access specific QoS to IP QoS
    traffic parameters before forwarding the request to the NSIS Forwarder.

    The NSIS Forwarder is currently not part of the standard 3G wireless
    architecture. However, to achieve end-to-end QoS a NSIS Forwarder is
    needed such that the NSIS Initiators can request a QoS connection to
    the IP network. As in the previous example, the NSIS Forwarder
    could manage a set of pre-provisioned resources in the IP network,
    i.e. bandwidth pipes, and the NSIS Forwarder performs per-flow
    admission
    control into these pipes. In this way, a connection can be made between
    two 3G wireless access networks, and hence, end-to-end QoS can be
    achieved. In this case the NSIS Initiator and NSIS Forwarder are
    clearly two separate logical entities. The Access Gateway or/and the
    Edge Router in Fig.1 may contain the NSIS Forwarder functionality,
    depending upon the placement of the NSIS Initiator as discussed in
    scenario 2 in section 10.2. This use case clearly illustrates the need
    for an "NSIS" QoS signaling protocol between NSIS Initiator and NSIS
    Forwarder. An important application of such a protocol may be its use
    in the end-to-end establishment of a connection with specific QoS
    characteristics between a mobile host and another party (e.g. end host
    or content server).

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---

From: Kuntal Chowdhury <[email-masked]>
Date: Tue, 28 Jan 2003 11:42:27 -0600

Hi Maarten,
Thanks for pointing out the inconsistency in bullet 3 in section 10.2.

How about:

     3) The need for re-negotiation of resources in a new 3G wireless
     domain due to UE/MS mobility. In this case the NSIS Initiator and the
     NSIS Forwarder should detect mobility events and autonomously
     trigger re-negotiation of resources.

Regards,
Kuntal