[Docs] [txt|pdf|xml] [Tracker] [WG] [Email] [Diff1] [Diff2] [Nits]
Versions: (draft-donovan-dime-agent-overload)
00 01 02 03 04 05 06 07 08 09 10 11
Diameter Maintenance and Extensions (DIME) S. Donovan
Internet-Draft Oracle
Intended status: Standards Track March 18, 2016
Expires: September 19, 2016
Diameter Agent Overload and the Peer Overload Report
draft-ietf-dime-agent-overload-04.txt
Abstract
This specification documents an extension to the Diameter Overload
Indication Conveyance (DOIC) [RFC7683] base solution. The extension
defines the Peer overload report type. The initial use case for the
Peer report is the handling of occurrences of overload of a Diameter
agent.
Requirements
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on September 19, 2016.
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
Donovan Expires September 19, 2016 [Page 1]
Internet-Draft Diameter Agent Overload and Peer Report March 2016
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology and Abbreviations . . . . . . . . . . . . . . . . 3
3. Peer Report Use Cases . . . . . . . . . . . . . . . . . . . . 4
3.1. Diameter Agent Overload Use Cases . . . . . . . . . . . . 4
3.1.1. Single Agent . . . . . . . . . . . . . . . . . . . . 4
3.1.2. Redundant Agents . . . . . . . . . . . . . . . . . . 5
3.1.3. Agent Chains . . . . . . . . . . . . . . . . . . . . 6
3.2. Diameter Endpoint Use Cases . . . . . . . . . . . . . . . 7
3.2.1. Hop-by-hop Abatement Algorithms . . . . . . . . . . . 7
4. Interaction Between Host/Realm and Peer Overload Reports . . 8
5. Peer Report Behavior . . . . . . . . . . . . . . . . . . . . 8
5.1. Capability Announcement . . . . . . . . . . . . . . . . . 8
5.1.1. Reacting Node Behavior . . . . . . . . . . . . . . . 8
5.1.2. Reporting Node Behavior . . . . . . . . . . . . . . . 9
5.2. Peer Report Overload Report Handling . . . . . . . . . . 10
5.2.1. Overload Control State . . . . . . . . . . . . . . . 10
5.2.2. Reporting Node Maintenance of Peer Report OCS . . . . 11
5.2.3. Reacting Node Maintenance of Peer Report OCS . . . . 11
5.2.4. Peer Report Reporting Node Behavior . . . . . . . . . 13
5.2.5. Peer Report Reacting Node Behavior . . . . . . . . . 13
6. Peer Report AVPs . . . . . . . . . . . . . . . . . . . . . . 14
6.1. OC-Supported-Features AVP . . . . . . . . . . . . . . . . 14
6.1.1. OC-Feature-Vector . . . . . . . . . . . . . . . . . . 14
6.1.2. OC-Peer-Algo . . . . . . . . . . . . . . . . . . . . 15
6.2. OC-OLR AVP . . . . . . . . . . . . . . . . . . . . . . . 15
6.2.1. OC-Report-Type AVP . . . . . . . . . . . . . . . . . 15
6.3. OC-SourceID . . . . . . . . . . . . . . . . . . . . . . . 16
6.4. Attribute Value Pair flag rules . . . . . . . . . . . . . 16
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . 16
7.1. AVP codes . . . . . . . . . . . . . . . . . . . . . . . . 16
7.2. New registries . . . . . . . . . . . . . . . . . . . . . 16
8. Security Considerations . . . . . . . . . . . . . . . . . . . 17
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 17
10. Normative References . . . . . . . . . . . . . . . . . . . . 17
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 18
Donovan Expires September 19, 2016 [Page 2]
Internet-Draft Diameter Agent Overload and Peer Report March 2016
1. Introduction
This document defines the behavior of Diameter nodes when Diameter
agents enter an overload condition and send an overload report
requesting a reduction of traffic. It also defines new overload
report type, the Peer overload report type, that is used for handling
of agent overload conditions. The Peer overload report type is
defined in a generic fashion so that it can also be used for other
Diameter overload scenaios.
The base Diameter overload specification [RFC7683] addresses the
handling of overload when a Diameter endpoint (a Diameter Client or
Diameter Server as defined in [RFC6733]) becomes overloaded.
In the base specification, the goal is to handle abatement of the
overload occurrence as close to the source of the Diameter traffic as
is feasible. When possible this is done at the originator of the
traffic, generally referred to as a Diameter Client. A Diameter
Agent might also handle the overload mitigation. For instance, a
Diameter Agent might handle Diameter overload mitigation when it
knows that a Diameter Client does not support the DOIC extension.
This document extends the base Diameter endpoint overload
specification to address the case when Diameter Agents become
overloaded. Just as is the case with other Diameter nodes --
Diameter Clients and Diameter Servers -- surges in Diameter traffic
can cause a Diameter Agent to be asked to handle more Diameter
traffic than it was configured to handle. For a more detailed
discussion of what can cause the overload of Diameter nodes, refer to
the Diameter Overload Requirements [RFC7068].
This document defines a new overload report type to communicate
occurrences of agent overload. This report type works for the "Loss"
overload mitigation algorithm defined in [RFC7683] and is expected to
work for other overload abatement algorithms defined in extensions to
the DOIC solution.
2. Terminology and Abbreviations
Diameter Node
A RFC6733 Diameter Client, an RFC6733 Diameter Server, and RFC6733
Diameter Agent.
Diameter Endpoint
An RFC6733 Diameter Client and RFC6733 Diameter Server.
Donovan Expires September 19, 2016 [Page 3]
Internet-Draft Diameter Agent Overload and Peer Report March 2016
Reporting Node
A DOIC Node that sends and overload report in a Diameter answer
message.
Reacting Node
A DOIC Node that receives and acts on a Diameter overload report.
DIOC Node
A Diameter Node that supports the DOIC solution defined in
[RFC7683].
3. Peer Report Use Cases
This section outlines representative use cases for the peer report
used to communicate agent overload.
There are two primary classes of use cases currently identified,
those involving the overload of agents and those involving overload
of Diameter endpoints (Diameter Clients and Diameter Servers) that
wish to use an overload algorithm suited controlling traffic sent
from a peer.
3.1. Diameter Agent Overload Use Cases
The peer report needs to support the following use cases.
3.1.1. Single Agent
This use case is illustrated in Figure 1. In this case, the client
sends all traffic through the single agent. If there is a failure in
the agent then the client is unable to send Diameter traffic toward
the server.
+-+ +-+ +-+
|c|----|a|----|s|
+-+ +-+ +-+
Figure 1
A more likely case for the use of agents is illustrated in Figure 2.
In this case, there are multiple servers behind the single agent.
The client sends all traffic through the agent and the agent
determines how to distribute the traffic to the servers based on
local routing and load distribution policy.
Donovan Expires September 19, 2016 [Page 4]
Internet-Draft Diameter Agent Overload and Peer Report March 2016
+-+
--|s|
+-+ +-+ / +-+
|c|----|a|- ...
+-+ +-+ \ +-+
--|s|
+-+
Figure 2
In both of these cases, the occurrence of overload in the single
agent must by handled by the client in a similar fashion as if the
client were handling the overload of a directly connected server.
When the agent becomes overloaded it will insert an overload report
in answer messages flowing to the client. This overload report will
contain a requested reduction in the amount of traffic sent to the
agent. The client will apply overload abatement behavior as defined
in the base Diameter overload specification [RFC7683] or the
extension draft that defines the indicated overload abatement
algorithm. This will result in the throtting of the abated traffic
that would have been sent to the agent, as there is no alternative
route, with the appropriate indication given to the service request
that resulted in the need for the Diameter transaction.
3.1.2. Redundant Agents
Figure 3 and Figure 4 illustrate a second, and more likely, type of
deployment scenario involving agents. In both of these cases, the
client has Diameter connections to two agents.
Figure 3 illustrates a client that has a primary connection to one of
the agents (agent a1) and a secondary connection to the other agent
(agent a2). In this scenario, under normal circumstances, the client
will use the primary connection for all traffic. The secondary
connection is used when there is a failure scenario of some sort.
+--+ +-+
--|a1|---|s|
+-+ / +--+\ /+-+
|c|- x
+-+ . +--+/ \+-+
..|a2|---|s|
+--+ +-+
Figure 3
Donovan Expires September 19, 2016 [Page 5]
Internet-Draft Diameter Agent Overload and Peer Report March 2016
The second case, in Figure 4, illustrates the case where the
connections to the agents are both actively used. In this case, the
client will have local distribution policy to determine the
percentage of the traffic sent through each client.
+--+ +-+
--|a1|---|s|
+-+ / +--+\ /+-+
|c|- x
+-+ \ +--+/ \+-+
--|a2|---|s|
+--+ +-+
Figure 4
In the case where one of the agents in the above scenarios become
overloaded, the client should reduce the amount of traffic sent to
the overloaded agent by the amount requested. This traffic should
instead be routed through the non-overloaded agent. For example,
assume that the overloaded agent requests a reduction of 10 percent.
The client should send 10 percent of the traffic that would have been
routed to the overloaded agent through the non-overloaded agent.
When the client has an active and a standby connection to the two
agents then an alternative strategy for responding to an overload
report from an agent is to change to standby connection to active and
route all traffic through the new active connection.
In the case where both agents are reporting overload, the client may
need to start decreasing the total traffic sent to the agents. This
would be done in a similar fashion as discussed in section 3.1. The
amount of traffic depends on the combined reduction requested by the
two agents.
3.1.3. Agent Chains
There are also deployment scenarios where there can be multiple
Diameter Agents between Diameter Clients and Diameter Servers.
Examples of this type of deployment include when there are edge
agents between Diameter networks. Another example of this type of
deployment is when there are multiple sets of servers, each
supporting a subset of the Diameter traffic.
Figure 5 illustrates one such network deployment case. Note that
while this figure shows a maximum of two agents being involved in a
Diameter transaction, it is possible that more than two agents could
be in the path of a transaction.
Donovan Expires September 19, 2016 [Page 6]
Internet-Draft Diameter Agent Overload and Peer Report March 2016
+---+ +---+ +-+
--|a11|-----|a21|---|s|
+-+ / +---+ \ / +---+\ /+-+
|c|- x x
+-+ \ +---+ / \ +---+/ \+-+
--|a12|-----|a22|---|s|
+---+ +---+ +-+
Figure 5
Handling of overload of one or both of agents a11 or a12 in this case
is equivalent to that discussed in section 2.2.
Overload of agents a21 and a22 must be handled by the previous hop
agents. As such, agents a11 and a12 must handle the overload
mitigation logic when receiving an agent overload report from agents
a21 and a22.
The handling of peer overload reports is similar to that discussed in
section 2.2. If the overload can be addressed using diversion then
this approach should be taken.
If both of the agents have requested a reduction in traffic then the
previous hop agent must start throttling the appropriate number of
transactions. When throttling requests, an agent uses the same error
responses as defined in the base DOIC specification [RFC7683].
3.2. Diameter Endpoint Use Cases
This section outlines use cases for the peer overload report
involving Diameter Clients and Diameter Servers.
3.2.1. Hop-by-hop Abatement Algorithms
It is envisioned that abatement algorithms will be defined that will
support the option for Diameter Endpoints to send peer reports. For
instance, it is envisioned that one usage scenario for the rate
algorithm, [I-D.ietf-dime-doic-rate-control], which is being worked
on by the DIME working group as this document is being written, will
involve abatement being done on a hop-by-hop basis.
This rate deployment scenario would involve Diameter Endpoints
generating peer reports and selecting the rate algorithm for
abatement of overload conditions.
Donovan Expires September 19, 2016 [Page 7]
Internet-Draft Diameter Agent Overload and Peer Report March 2016
4. Interaction Between Host/Realm and Peer Overload Reports
It is possible that both an agent and an end-point in the path of a
transaction are overloaded at the same time. When this occurs,
Diameter entities need to handle both overload reports. In this
scenario the reacting node should first handle the throttling of the
overloaded host or realm. Any messages that survive throttling due
to host or realm reports should then go through abatement for the
peer overload report.
5. Peer Report Behavior
This section defines the normative behavior associated with the Peer
Report extension to the DOIC solution.
5.1. Capability Announcement
5.1.1. Reacting Node Behavior
When sending a Diameter request a DOIC node that supports the
OC_PEER_REPORT feature MUST include an OC-Supported-Features AVP with
an OC-Feature-Vector AVP with the OC_PEER_REPORT bit set.
Note: The sender of a request can be a Diameter Client or Diameter
Server that originates the Diamter request or a Diameter Agent
that relays the request.
Support for the OC_PEER_REPORT feature does not impact the logic for
setting of other feature bits in the OC-Feature-Vector AVP.
When sending a request a DOIC node that supports the OC_PEER_REPORT
feature MUST include an OC-SourceID AVP in the OC-Supported-Features
AVP with its own DiameterIdentity.
Note: This allows the DOIC nodes in the path of the request to
determine if the indication of support came from a Diameter peer
or if the request traversed a node that does not support the
OC_PEER_REPORT feature.
When relaying a request that includes an OC-SourceID AVP in the OC-
Supported-Features AVP, a DOIC node that supuports the OC_PEER_REPORT
feature must remove the received OC-SourceID AVP and replace it with
an OC-SourceID AVP containing its own Diameter identity.
Donovan Expires September 19, 2016 [Page 8]
Internet-Draft Diameter Agent Overload and Peer Report March 2016
5.1.2. Reporting Node Behavior
When receiving a request a DOIC node that supports the OC_PEER_REPORT
feature MUST update transaction state with an indication of whether
or not the peer from which the request was received supports the
OC_PEER_REPORT feature.
Note: The transaction state is used when the DOIC node is acting
as a peer-report reporting node and needs send OC-OLR reports of
type PEER_REPORT in answer messages. The peer overload reports
are only included in answer messages being sent to peers that
support the OC_PEER_REPORT feature.
The following are indications that the peer does not support the
OC_PEER_REPORT feature:
The request does not contain an OC-Supported-Features AVP.
The received request contains an OC-Supported-Features AVP with no
OC-Feature-Vector.
The received request contains an OC-Supported-Features AVP with a
OC-Feature-Vector with the OC_PEER_REPORT feature bit cleared.
The received request contains an OC-Supported-Features AVP with a
OC-Feature-Vector with the OC_PEER_REPORT feature bit set but with
an OC-SourceID AVP with a DiameterIdentity that does not match the
DiameterIdentity of the peer from which the request was received.
The peer supports the OC_PEER_REPORT feature if the received request
contains an OC-Supported-Features AVP with the OC-Feature-Vector with
the OC_PEER_REPORT feature bit set and with an OC-SourceID AVP with a
Diameter ID that matches the DiameterIdentity of the peer from which
the request was received.
When relaying an answer message, a reporting node that supports the
OC_PEER_REPORT feature MUST strip any SourceID AVP from the OC-
Supported-Features AVP.
When sending an answer message, a reporting node that supports the
OC_PEER_REPORT feature MUST determine if the peer to which the answer
is to be sent supports the OC_PEER_REPORT feature.
If the peer supports the OC_PEER_REPORT feature then the reporting
node MUST indicate support for the feature in the Supported-Features
AVP.
Donovan Expires September 19, 2016 [Page 9]
Internet-Draft Diameter Agent Overload and Peer Report March 2016
If the peer supports the OC_PEER_REPORT feature then the reporting
node MUST insert the OC-SourceID AVP in the OC-Supported-Features AVP
in the answer message.
If the peer supports the OC_PEER_REPORT feature then the reporting
node MUST insert the OC-Peer-Algo AVP in the OC-Supported-Features
AVP. The OC-Peer-Algo AVP MUST indicate the overload abatement
algorithm that the reporting node wants the reacting nodes to use
should the reporting node send a peer overload report as a result of
becoming overloaded.
5.2. Peer Report Overload Report Handling
This section defines the behavior for the handling of overload
reports of type peer.
5.2.1. Overload Control State
This section describes the Overload Control State (OCS) that might be
maintained by both the peer report reporting node and the peer report
reacting node.
5.2.1.1. Reporting Node Peer Report OCS
A DOIC Node that supports the OC_PEER_REPORT feature SHOULD maintain
Reporting Node Peer Report OCS. This is used to record overload
events and build overload reports at the reporting node.
If different abatement specific contents are sent to each peer then
the reporting node MUST maintain a separate peer node peer report OCS
entry per peer to which a peer overload report is sent.
Note: The rate overload abatement algorithm allows for different
rates to be sent to each peer.
The Reporting Node Peer Report OCS entry MAY include the following
information (the actual information stored is an implementation
decision):
o Sequence number
o Validity Duration
o Expiration Time
o Abatement Algorithm
Donovan Expires September 19, 2016 [Page 10]
Internet-Draft Diameter Agent Overload and Peer Report March 2016
o Algorithm specific input data (for example, the Reduction
Percentage for the Loss Abatement Algorithm)
5.2.1.2. Reacting Node Peer Report OCS
A DOIC node that supports the OC_PEER_REPORT feature SHOULD maintain
Reacting Node Peer Report OCS for each peer with which it
communicates. This is used to record overload reports received from
peer nodes.
A Reacting Node Peer Report OCS entry is identified by the
DiameterIdentity of the peer as communicated during the RFC6733
defined Capability Exchange procedure.
The Reacting Node Peer Report OCS entry MAY include the following
information (the actual information stored is an implementation
decision):
o Sequence number
o Expiration Time
o Abatement Algorithm
o Algorithm specific input data (for example, the Reduction
Percentage for the Loss Abatement Algorithm)
5.2.2. Reporting Node Maintenance of Peer Report OCS
A reporting node SHOULD create a new Reporting Node Peer Report OCS
entry Section 5.2.1.1 in an overload condition and sending a peer
overload report to a peer for the first time.
If the reporting node knows that there are no reacting nodes
supporting the OC_PEER_REPORT feature then the reporting node can
choose to not create OCS entries.
All rules for managing the reporting node OCS entries defined in
[RFC7683] apply to the peer report.
5.2.3. Reacting Node Maintenance of Peer Report OCS
When a reacting node receives an OC-OLR AVP with a report type of
peer it MUST determine if the report was generated by the Diameter
peer from which the report was received.
Donovan Expires September 19, 2016 [Page 11]
Internet-Draft Diameter Agent Overload and Peer Report March 2016
If the DiameterID in the SourceID contained in the OLR matches the
DiameterIdentity of the peer from which the request was received then
the report was received from a Diameter peer.
If a reacting node receives an OC-OLR AVP of type peer and the OC-
SourceID does not match the ID of the Diameter peer from which the
request was received then the reacting node MUST ignore the overload
report.
In all cases, if the reacting node is a relay then it MUST strip the
OC-OLR AVP from the message.
If the Peer Report OLR was received from a Diameter peer then the
reacting node MUST determine if it is for an existing or new overload
condition.
The OLR is for an existing overload condition if the reacting node
has an OCS that matches the received OLR. For a peer report-type
this means the DiameterIdentity received in the SourceID AVP matches
the DiameterIdentity of an existing peer report OLR.
If the OLR is for an existing overload condition then it MUST
determine if the OLR is a retransmission or an update to the existing
OLR.
If the sequence number for the received OLR is greater than the
sequence number stored in the matching OCS entry then the reacting
node MUST update the matching OCS entry.
If the sequence number for the received OLR is less than or equal to
the sequence number in the matching OCS entry then the reacting node
MUST silently ignore the received OLR. The matching OCS MUST NOT be
updated in this case.
If the received OLR is for a new overload condition then the reacting
node MUST generate a new OCS entry for the overload condition.
For a peer report this means it creates an OCS entry with an
DiameterID from the SourceID AVP in the received OC-OLR AVP.
If the received OLR contains a validity duration of zero ("0") then
the reacting node MUST update the OCS entry as being expired.
The reacting node does not delete an OCS when receiving an answer
message that does not contain an OC-OLR AVP (i.e. absence of OLR
means "no change").
Donovan Expires September 19, 2016 [Page 12]
Internet-Draft Diameter Agent Overload and Peer Report March 2016
The reacting node sets the abatement algorithm based on the OC-Peer-
Algo AVP in the received OC-Supported-Features AVP.
5.2.4. Peer Report Reporting Node Behavior
When there is an existing reporting node peer report OCS entry, the
reporting node MUST include an OC-OLR AVP with a report type of peer
using the contents of the reporting node peer report OCS entry in all
answer messages sent by the reporting node to peers that support the
OC_PEER_REPORT feature.
The reporting node determines if a peer supports the
OC_PEER_REPORT feature based on the indication recorded in the
reporting nodes transaction state.
The reporting node MUST include its DiameterIdentity in the OC-
SourceID AVP in the OC-OLR AVP. This is used by DOIC nodes that
support the OC_PEER_REPORT feature to determine if the report was
received from a Diameter peer.
The reporting agent must follow all other overload reporting node
behaviors outlined in the DOIC specification.
5.2.5. Peer Report Reacting Node Behavior
A reacting node supporting this extension MUST support the receipt of
multiple overload reports in a single message. The message might
include a host overload report, a realm overload report and/or a peer
overload report.
When a reacting node sends a request it MUST determine if that
request matches an active OCS.
If the request matches and active OCS then the reacting node MUST
apply abatement treatment on the request. The abatement treatment
applied depends on the abatement algorithm indicated in the OCS.
For peer overload reports, the preferred abatement treatment is
diversion. As such, the reacting node SHOULD attempt to divert
requests identified as needing abatement to other peers.
If there is not sufficient capacity to divert abated traffic then the
reacting node MUST throttle the necessary requests to fit within the
available capacity of the peers able to handle the requests.
If the abatement treatment results in throttling of the request and
if the reacting node is an agent then the agent MUST send an
appropriate error as defined in [RFC7683].
Donovan Expires September 19, 2016 [Page 13]
Internet-Draft Diameter Agent Overload and Peer Report March 2016
In the case that the OCS entry validity duration expires or has a
validity duration of zero ("0"), meaning that it the reporting node
has explicitly signaled the end of the overload condition then
abatement associated with the overload abatement MUST be ended in a
controlled fashion.
6. Peer Report AVPs
6.1. OC-Supported-Features AVP
This extension adds a new feature to the OC-Feature-Vector AVP. This
feature indication shows support for handling of peer overload
reports. Peer overload reports are used by agents to indicate the
need for overload abatement handling by the agents peer.
A supporting node must also include the OC-SourceID AVP in the OC-
Supported-Features capability AVP.
This AVP contains the Diameter Identity of the node that supports the
OC_PEER_REPORT feature. This AVP is used to determine if support for
the peer overload report is in an adjacent node. The value of this
AVP should be the same Diameter identity used as part of the CER/CEA
base Diameter capabilities exchange.
This extension also adds the OC-Peer-Algo AVP to the OC-Supported-
Features AVP. This AVP is used by a reporting node to indicate the
abatement algorithm it will use for peer overload reports.
OC-Supported-Features ::= < AVP Header: TBD1 >
[ OC-Feature-Vector ]
[ OC-SourceID ]
[ OC-Peer-Algo]
* [ AVP ]
6.1.1. OC-Feature-Vector
The peer report feature defines a new feature bit is added for the
OC-Feature-Vector AVP.
OC_PEER_REPORT (0x0000000000000010)
When this flag is set by a DOIC node it indicates that the DOIC
node supports the peer overload report type.
Donovan Expires September 19, 2016 [Page 14]
Internet-Draft Diameter Agent Overload and Peer Report March 2016
6.1.2. OC-Peer-Algo
The OC-Peer-Algo AVP (AVP code TBD1) is of type Unsigned64 and
contains a 64 bit flags field of announced capabilities of a DOIC
node. The value of zero (0) is reserved.
Feature bits defined for the OC-Feature-Vector AVP and associated
with overload abatement algorithms are reused in for this AVP.
6.2. OC-OLR AVP
This extension makes no changes to the SequenceNumber or
ValidityDuration AVPs in the OC-OLR AVP. These AVPs are also be used
in peer overload reports.
The OC_PEER_REPORT feature extends the base Diameter overload
specification by defining a new overload report type of "peer". See
section [7.6] in [RFC7683] for a description of the OC-Report-Type
AVP.
The overload report must also include the Diameter identity of the
agent that generated the report. This is necessary to handle the
case where there is a non supporting agent between the reporting node
and the reacting node. Without the indication of the agent that
generated the overload request, the reacting node could erroneously
assume that the report applied to the non supporting node. This
could, in turn, result in unnecessary traffic being either
redistributed or throttled.
The OC-SourceID AVP is used in the OC-OLR AVP to carry this
DiameterIdentity.
OC-OLR ::= < AVP Header: TBD2 >
< OC-Sequence-Number >
< OC-Report-Type >
[ OC-Reduction-Percentage ]
[ OC-Validity-Duration ]
[ OC-Source-ID ]
* [ AVP ]
6.2.1. OC-Report-Type AVP
The following new report type is defined for the OC-Report-Type AVP.
PEER_REPORT 2 The overload treatment should apply to all requests
bound for the peer identified in the overload report. If the peer
identified in the overload report is not a peer to the reacting
Donovan Expires September 19, 2016 [Page 15]
Internet-Draft Diameter Agent Overload and Peer Report March 2016
endpoint then the overload report should be stripped and not acted
upon.
6.3. OC-SourceID
The SourceID AVP (AVP code TBD2) is of type DiameterIdentity and is
inserted by the DOIC node that either indicates support for this
feature (in the OC-Supported-Features AVP) or that generates an OC-
OLR AVP with a report type of peer.
It contains the Diameter Identity of the inserting node. This is
used by other DOIC nodes to determine if the a peer indicated support
this feature or inserted the peer report.
6.4. Attribute Value Pair flag rules
+---------+
|AVP flag |
|rules |
+----+----+
AVP Section | |MUST|
Attribute Name Code Defined Value Type |MUST| NOT|
+--------------------------------------------------------+----+----+
|OC-SourceID TBD1 x.x DiameterIdentity | | V |
|OC-Peer-Algo TBD2 x.x Unsigned64 | | V |
+--------------------------------------------------------+----+----+
7. IANA Considerations
7.1. AVP codes
New AVPs defined by this specification are listed in Section 6. All
AVP codes are allocated from the 'Authentication, Authorization, and
Accounting (AAA) Parameters' AVP Codes registry.
7.2. New registries
There are no new IANA registries introduced by this document.
The values used for the OC-Peer-Algo AVP are the subset of the "OC-
Feature-Vector AVP Values (code 622)" registry. Only the values in
that registry that apply to overload abatement algorithms apply to
the OC-Peer-Algo AVP.
Donovan Expires September 19, 2016 [Page 16]
Internet-Draft Diameter Agent Overload and Peer Report March 2016
8. Security Considerations
Agent overload is an extension to the base Diameter overload
mechanism. As such, all of the security considerations outlined in
[RFC7683] apply to the agent overload scenarios.
It is possible that the malicious insertion of an agent overload
report could have a bigger impact on a Diameter network as agents can
be concentration points in a Diameter network. Where an end-point
report would impact the traffic sent to a single Diameter server, for
example, a peer report could throttle all traffic to the Diameter
network.
This impact is amplified in an agent that sits at the edge of a
Diameter network that serves as the entry point from all other
Diameter networks.
9. Acknowledgements
Adam Roach and Eric McMurry for the work done in defining a
comprehensive Diameter overload solution in draft-roach-dime-
overload-ctrl-03.txt.
Ben Campbell for his insights and review of early versions of this
document.
10. Normative References
[I-D.ietf-dime-doic-rate-control]
Donovan, S. and E. Noel, "Diameter Overload Rate Control",
draft-ietf-dime-doic-rate-control-01 (work in progress),
March 2015.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 5226,
DOI 10.17487/RFC5226, May 2008,
<http://www.rfc-editor.org/info/rfc5226>.
[RFC6733] Fajardo, V., Ed., Arkko, J., Loughney, J., and G. Zorn,
Ed., "Diameter Base Protocol", RFC 6733,
DOI 10.17487/RFC6733, October 2012,
<http://www.rfc-editor.org/info/rfc6733>.
Donovan Expires September 19, 2016 [Page 17]
Internet-Draft Diameter Agent Overload and Peer Report March 2016
[RFC7068] McMurry, E. and B. Campbell, "Diameter Overload Control
Requirements", RFC 7068, DOI 10.17487/RFC7068, November
2013, <http://www.rfc-editor.org/info/rfc7068>.
[RFC7683] Korhonen, J., Ed., Donovan, S., Ed., Campbell, B., and L.
Morand, "Diameter Overload Indication Conveyance",
RFC 7683, DOI 10.17487/RFC7683, October 2015,
<http://www.rfc-editor.org/info/rfc7683>.
Author's Address
Steve Donovan
Oracle
7460 Warren Parkway, Suite 300
Frisco, Texas 75034
United States
Email: srdonovan@usdonovans.com
Donovan Expires September 19, 2016 [Page 18]
Html markup produced by rfcmarkup 1.129d, available from
https://tools.ietf.org/tools/rfcmarkup/