Subject: [AAA-WG]: [Issue] Downstream/upstream confusion

From: Jacques Caron <[email-masked]>
Date: Mon, 11 Jun 2001 01:11:01 +0200

Submitter name: Jacques Caron
Submitter email address: [email-masked]
Date first submitted: 11-Jun-2001
Reference:
Document: Base
Comment type: E
Priority: 1
Section: throughout
Rationale/Explanation of issue:

The terms "upstream" and "downstream" are not used consistently. Even the 
definitions seem contrary to logic: things usually flow from upstream to 
downstream, so upstream should be towards the client, and downstream 
towards the home server.

Requested changes:

In 1.3 Terminology, replace:
    Downstream Server
       Diameter Proxy servers identify a downstream server as one that is
       providing routing services towards the Diameter client.

with:
    Downstream Server
       Diameter Proxy servers identify a downstream server as one that is
       providing routing services towards the home server for a
       particular message.

and replace:
    Upstream Server
       Diameter Proxy servers identify an upstream server as one that is
       providing routing services towards the home server for a
       particular message.

with:
    Upstream Server
       Diameter Proxy servers identify an upstream server as one that is
       providing routing services towards the Diameter client.

In 2.5.2 Proxy Agents, replace:
    Similarly to Relays, Proxy agents route Diameter messages using the
    Diameter Routing Table. However, they differ since they modify
    messages to implement policy enforcement. This requires that proxies
    maintain the state of their downstream peers (e.g. access devices) to
    enforce resource usage, provide admission control, and provisioning.

with:
    Similarly to Relays, Proxy agents route Diameter messages using the
    Diameter Routing Table. However, they differ since they modify
    messages to implement policy enforcement. This requires that proxies
    maintain the state of their upstream peers (e.g. access devices) to
    enforce resource usage, provide admission control, and provisioning.

In 6.0 Capabilities Exchange, replace:
    Since the CER/CEA messages cannot be proxied, it is still possible
    that an upstream proxy receives a message for which it has no
    available peers to handle the application that corresponds to the
    Command-Code. In such instances, the Message-Reject-Answer message is
    used (see Section 9.2.1) to inform the downstream to take action
    (e.g. re-routing request to an alternate peer).

With:
    Since the CER/CEA messages cannot be proxied, it is still possible
    that a downstream proxy receives a message for which it has no
    available peers to handle the application that corresponds to the
    Command-Code. In such instances, the Message-Reject-Answer message is
    used (see Section 9.2.1) to inform the upstream to take action
    (e.g. re-routing request to an alternate peer).

In 9.0, Error Handling, replace:
    Figure 4 provides an example of a message forwarded upstream by a
    Diameter relay. When the message is received by Relay 2, and it
    detects that it cannot forward the request to the home server, an MRA
    message is returned with the Result-Code AVP set to
    DIAMETER_UNABLE_TO_DELIVER. Given that this error falls within the
    protocol error category, Relay 1 would take special action, and given
    the error, attempt to route the message through its alternate Relay
    3.

with:
    Figure 4 provides an example of a message forwarded downstream by a
    Diameter relay. When the message is received by Relay 2, and it
    detects that it cannot forward the request to the home server, an MRA
    message is returned with the Result-Code AVP set to
    DIAMETER_UNABLE_TO_DELIVER. Given that this error falls within the
    protocol error category, Relay 1 would take special action, and given
    the error, attempt to route the message through its alternate Relay
    3.

Alternatively, leave the definitions as they are (though I don't understand 
them?) and fix down/upstream in 6.2 and 10.10.

Jacques.

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---

From: Pat Calhoun <[email-masked]>
Date: Mon, 11 Jun 2001 09:56:59 -0700

All,

The current base protocol spec states that upstream is towards the home server, and
downstream is towards the client.

Do people see a need to invert the two, as Jacques suggests?

PatC