draft-ietf-sipping-presence-scaling-requirements-02.txt   draft-ietf-sipping-presence-scaling-requirements-03.txt 
SIPPING WG A. Houri SIPPING WG A. Houri
Internet-Draft IBM Internet-Draft IBM
Intended status: Informational S. Parameswar Intended status: Informational S. Parameswar
Expires: May 6, 2009 Microsoft Corporation Expires: July 31, 2009 Microsoft Corporation
E. Aoki E. Aoki
AOL LLC AOL LLC
V. Singh V. Singh
H. Schulzrinne H. Schulzrinne
Columbia U. Columbia U.
November 2, 2008 January 27, 2009
Scaling Requirements for Presence in SIP/SIMPLE Scaling Requirements for Presence in SIP/SIMPLE
draft-ietf-sipping-presence-scaling-requirements-02.txt draft-ietf-sipping-presence-scaling-requirements-03.txt
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any This Internet-Draft is submitted to IETF in full conformance with the
applicable patent or other IPR claims of which he or she is aware provisions of BCP 78 and BCP 79.
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on May 6, 2009. This Internet-Draft will expire on July 31, 2009.
Copyright Notice
Copyright (c) 2009 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
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document.
Abstract Abstract
The document provides a set of requirements for enabling interdomain The document provides a set of requirements for enabling interdomain
scaling in presence for SIP/SIMPLE. scaling in presence for SIP/SIMPLE.
Table of Contents Table of Contents
1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3 1. Requirements notation . . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2.1. Very large network peering . . . . . . . . . . . . . . . . 3 3. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.2. State Management . . . . . . . . . . . . . . . . . . . . . 8 3.1. Backward Compatibility Requirements . . . . . . . . . . . . 4
2.2.1. State Size Calculations . . . . . . . . . . . . . . . 8 3.2. Policy, Privacy, Permissions Requirements . . . . . . . . . 4
3. Requirements . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.3. Scalability Requirements . . . . . . . . . . . . . . . . . 4
3.1. Backward Compatibility Requirements . . . . . . . . . . . 10 3.4. Topology Requirements . . . . . . . . . . . . . . . . . . . 5
3.2. Policy, Privacy, Permissions Requirements . . . . . . . . 11 4. Considerations for Possible Optimizations . . . . . . . . . . . 5
3.3. Scalability Requirements . . . . . . . . . . . . . . . . . 11 5. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
3.4. Topology Requirements . . . . . . . . . . . . . . . . . . 12 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
4. Considerations for Possible Optimizations . . . . . . . . . . 12 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . 7
4.1. Very Optimized SIP . . . . . . . . . . . . . . . . . . . . 13 8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
5. Security Considerations . . . . . . . . . . . . . . . . . . . 18 8.1. Normative References . . . . . . . . . . . . . . . . . . . 7
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 8.2. Informational References . . . . . . . . . . . . . . . . . 7
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 18 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 19
8.1. Normative References . . . . . . . . . . . . . . . . . . . 19
8.2. Informational References . . . . . . . . . . . . . . . . . 19
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 20
Intellectual Property and Copyright Statements . . . . . . . . . . 22
1. Requirements notation 1. Requirements notation
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
2. Introduction 2. Introduction
The document lists requirements for optimizations of the SIP/SIMPLE The document lists requirements for optimizations of the SIP/SIMPLE
protocol. See [I-D.ietf-simple-simple] for the list of RFCs and protocol. See [I-D.ietf-simple-simple] for the list of RFCs and
drafts that are considered as part of the SIP/SIMPLE protocol. These drafts that are considered as part of the SIP/SIMPLE protocol. These
optimizations should reduce the load on the network and the presence optimizations should reduce the load on the network and the presence
servers in interdomain presence subscriptions. The requirements are servers in interdomain presence subscriptions. The need for the
based on a separate scaling analysis document requirements is based on a separate scaling analysis document
[I-D.ietf-simple-interdomain-scaling-analysis]. [I-D.ietf-simple-interdomain-scaling-analysis].
The scaling analysis document have shown that there is much room for The scaling analysis document have shown that there is much room for
optimizations in the SIP/SIMPLE protocol. The need for optimizations optimizations in the SIP/SIMPLE protocol. The need for optimizations
is in the number of by teds that are sent between two federating is in the number of bytes that are sent between two federating
domains, the number of messages that need to be processed and the domains, the number of messages that need to be processed and the
amount of state that needs to be managed by the presence servers. amount of state that needs to be managed by the presence servers.
The following is a snaphot of various numbers from the scaling
analysis document. This snapshot is in clouded here for
completeness, please refer to the scaling analysis document for the
full details including the description of the calculations and the
various SIP optimizations investigated.
2.1. Very large network peering
In this environment, two or more very large networks create a peering
relationship allowing their users to subscribe to presence in the
other domains. Where as the number of users in other deployment
types ranges from hundreds to several hundred thousand, these large
networks host up to hundreds of millions of users. Examples of these
networks are large wireless carriers and consumer IM networks.
Common characteristics of this deployment are:
o As users become accustomed to network boundaries disappearing,
federated subscriptions become as common as subscriptions within
the same domain
o Individual users are highly likely to want to see presence of
multiple presentities in the peer network
o The intersection of users in the deployment watching the same
presentities is very high (i.e., two or more users in network A
are extremely likely to be watching a same user in network B)
o Status changes increase greatly due to typical observed consumer
behavior
The first table below provides the calculations without optimizations
the second table provides the calculations with optimizations. Even
though the optimizations help a lot (almost cut the number of
messages by half), the numbers are still very high. Note also that
the bandwidth required is very high.
** Constants
(C01) Subscription lifetime (hours)...........................8
(C02) Presence state changes / hour...........................6
(C03) Subscription refresh interval / hour....................1
(C04) Total federated presentities per watcher...............10
(C05) Number of dialogs to maintain per watcher..............10
(C06) Total number of watchers in domains............20,000,000
(C07) SUBSCRIBE message size in bytes.......................450
(C08) 200 OK for SUBSCRIBE message size in bytes............370
(C09) NOTIFY message size not including presence doc........500
(C10) 200 OK for NOTIFY message size in bytes...............370
(C11) Size of an average presence document..................350
** Initial Messages
(I01) Initial SUBSCRIBE msgs per watcher.....................10
(I02) Initial 200 OK msgs (SUBSCRIBE) per watcher............10
(I03) Initial NOTIFY msgs per watcher........................10
(I04) Initial 200 OK msgs (NOTIFY) per watcher...............10
(I05) Total number & bytes of initial SUBSCRIBE msgs
Number of msgs for all watchers...........200,000,000
Bytes for all watchers.................90,000,000,000
(I06) Total number & bytes of initial 200 OK (SUBSCRIBE) msgs
Number of msgs for all watchers...........200,000,000
Bytes for all watchers.................74,000,000,000
(I07) Total number & bytes of initial NOTIFY msgs
Number of msgs for all watchers...........200,000,000
Bytes for all watchers................170,000,000,000
(I08) Total number & bytes of initial 200 OK (NOTIFY) msgs
Number of msgs for all watchers...........200,000,000
Bytes for all watchers.................74,000,000,000
(I09) Total number & bytes of initial messages per day
Number of msgs for all watchers...........800,000,000
Bytes for all watchers................408,000,000,000
** Steady State Messages
(S01) NOTIFY msgs due to state change
per watched presentity per day.....................46
(S02) 200 (for NOTIFY due to state change) msgs
per watched presentity per day.....................46
(S03) Total number and size of msgs due to state change per day
Number of msgs for all watchers........18,400,000,000
Bytes for all watchers.............11,224,000,000,000
(S04) Number of SUBSCRIBE msgs for refreshes
per watcher per day................................70
(S05) Number of 200 OK msgs for SUBSCRIBE msgs for refreshes
per watcher per day................................70
(S06) Number of NOTIFY msgs for refreshes
per watcher per day................................70
(S07) Number of 200 OK msgs for NOTIFY msgs for refreshes
per watcher per day................................70
(S08) Total number and size of msgs due to SUBSCRIBE refreshes
Number of msgs for all watchers per day.5,600,000,000
Bytes for all watchers per day......2,856,000,000,000
(S09) Total number & bytes of steady messages per day
Number of msgs for all watchers........24,000,000,000
Bytes for all watchers.............14,080,000,000,000
** Termination Messages
(T01) Terminating SUBSCRIBE msgs per watcher.................10
(T02) Terminating 200 OK msgs (SUBSCRIBE) per watcher........10
(T03) Terminating NOTIFY msgs per watcher....................10
(T04) Terminating 200 OK msgs (NOTIFY) per watcher...........10
(T05) Total number & bytes of Terminating SUBSCRIBE msgs
Number of msgs for all watchers...........200,000,000
Bytes for all watchers.................90,000,000,000
(T06) Total number & bytes of terminating 200 OK (SUBSCRIBE) msgs
Number of msgs for all watchers...........200,000,000
Bytes for all watchers.................74,000,000,000
(T07) Total number & bytes of terminating NOTIFY msgs
Number of msgs for all watchers...........200,000,000
Bytes for all watchers................170,000,000,000
(T08) Total number & bytes of terminating 200 OK (NOTIFY) msgs
Number of msgs for all watchers...........200,000,000
Bytes for all watchers.................74,000,000,000
(T09) Total number & bytes of terminating messages per day
Number of msgs for all watchers...........800,000,000
Bytes for all watchers................408,000,000,000
** Bottom Line
(B01) Total of messages between domains..........25,600,000,000
Total of bytes bet. domains (PD=350)...14,896,000,000,000
Total of bytes bet. domains (PD=3000)..44,046,000,000,000
(B02) Total number of messages / second.................888,889
Total of bytes per second (PD=350)............517,222,222
Total of bytes per second (PD=3000).........1,529,375,000
(B03) Total number of by msgs per user/day................1,280
Total number of bytes per user/day (PD=350).......744,800
Total number of bytes per user/day (PD=3000)....2,202,300
Figure 1: Very large network peering with no optimizations
** Constants
(C01) Subscription lifetime (hours)...........................8
(C02) Presence state changes / hour...........................6
(C03) Subscription refresh interval / hour....................1
(C04) Total federated presentities per watcher...............10
(C05) Number of dialogs to maintain per watcher...............1
(C06) Total number of watchers in domains............20,000,000
(C07) SUBSCRIBE message size in bytes.......................450
(C08) 200 OK for SUBSCRIBE message size in bytes............370
(C09) NOTIFY message size not including presence doc........500
(C10) 200 OK for NOTIFY message size in bytes...............370
(C11) Size of an average presence document..................350
(C13) Additional data per document in RLMI..................160
(C14) Multiparty boundary in RLMI document..................144
(C15) XML root node in RLMI document........................144
** Initial Messages
(I01) Initial SUBSCRIBE msgs per watcher......................1
(I02) Initial 200 OK msgs (SUBSCRIBE) per watcher.............1
(I03) Initial NOTIFY msgs per watcher.........................1
(I04) Initial 200 OK msgs (NOTIFY) per watcher................1
(I05) Total number & bytes of initial SUBSCRIBE msgs
Number of msgs for all watchers............20,000,000
Bytes for all watchers..................9,000,000,000
(I06) Total number & bytes of initial 200 OK (SUBSCRIBE) msgs
Number of msgs for all watchers............20,000,000
Bytes for all watchers..................7,400,000,000
(I07) Total number & bytes of initial NOTIFY msgs
Number of msgs for all watchers............20,000,000
Bytes for all watchers................146,560,000,000
(I08) Total number & bytes of initial 200 OK (NOTIFY) msgs
Number of msgs for all watchers............20,000,000
Bytes for all watchers..................7,400,000,000
(I09) Total number & bytes of initial messages per day
Number of msgs for all watchers............80,000,000
Bytes for all watchers................170,360,000,000
** Steady State Messages
(S01) NOTIFY msgs due to state change
per watched presentity per day.....................46
(S02) 200 (for NOTIFY due to state change) msgs
per watched presentity per day.....................46
(S03) Total number and size of msgs due to state change per day
Number of msgs for all watchers........18,400,000,000
Bytes for all watchers.............16,670,400,000,000
(S04) Number of SUBSCRIBE msgs for refreshes
per watcher per day.................................7
(S05) Number of 200 OK msgs for SUBSCRIBE msgs for refreshes
per watcher per day.................................7
(S06) Number of NOTIFY msgs for refreshes
per watcher per day.................................0
(S07) Number of 200 OK msgs for NOTIFY msgs for refreshes
per watcher per day.................................0
(S08) Total number and size of msgs due to SUBSCRIBE refreshes
Number of msgs for all watchers per day...280,000,000
Bytes for all watchers per day........114,800,000,000
(S09) Total number & bytes of steady messages per day
Number of msgs for all watchers........18,680,000,000
Bytes for all watchers.............16,785,200,000,000
** Termination Messages
(T01) Terminating SUBSCRIBE msgs per watcher..................1
(T02) Terminating 200 OK msgs (SUBSCRIBE) per watcher.........1
(T03) Terminating NOTIFY msgs per watcher.....................0
(T04) Terminating 200 OK msgs (NOTIFY) per watcher............0
(T05) Total number & bytes of Terminating SUBSCRIBE msgs
Number of msgs for all watchers............20,000,000
Bytes for all watchers..................9,000,000,000
(T06) Total number & bytes of terminating 200 OK (SUBSCRIBE) msgs
Number of msgs for all watchers............20,000,000
Bytes for all watchers..................7,400,000,000
(T07) Total number & bytes of terminating NOTIFY msgs
Number of msgs for all watchers.....................0
Bytes for all watchers..............................0
(T08) Total number & bytes of terminating 200 OK (NOTIFY) msgs
Number of msgs for all watchers.....................0
Bytes for all watchers..............................0
(T09) Total number & bytes of terminating messages per day
Number of msgs for all watchers............40,000,000
Bytes for all watchers.................16,400,000,000
** Bottom Line
(B01) Total of messages between domains..........18,800,000,000
Total of bytes bet. domains (PD=350)...16,971,960,000,000
Total of bytes bet. domains (PD=3000)..41,881,960,000,000
(B02) Total number of messages / second.................652,778
Total of bytes per second (PD=350)............589,304,167
Total of bytes per second (PD=3000).........1,454,234,722
(B03) Total number of by msgs per user/day..................940
Total number of bytes per user/day (PD=350).......848,598
Total number of bytes per user/day (PD=3000)....2,094,098
Figure 2: Very large network peering with optimizations
2.2. State Management
In previous sections we have demonstrated the large amount of
messages that need to be sent to/from a presence server In this
section the state that needs to be maintained by a presence server
will be analyzed and shown to be far from trivial.
The presence server has two parallel tasks.
1. Maintain the state of the presentities to which watchers For example, for two peering networks that have total of 20 million
subscribe. users, we got around 19 billion messages per 8 hours work day that
2. Maintain the state of the subscriptions of watchers and provide needs to be exchanged between the networks only for supporting the
timely updates to the watchers. presence service.
For a single subscription from a single watcher on a presentity, the
presence server has to maintain the following state:
o Subscription state including all the parameters that are needed in
order to maintain the subscription as timers.
o Optional filtering information that was requested by the watcher.
This includes enough information that is needed for doing the
filtering. In addition additional information has to be
maintained if partial notification is being supported for the
subscription
o Optional rate management information as throttling
o Watcher information [RFC3857], [RFC3858] that is the result of the
subscription in order to enable watched presentities to see who is
watching them.
For each presentity that has been subscribed to in the presence
server, the presence server has to maintain the following state:
o A list of the subscriptions for the presentity. Note that this is
already taken care of from the size calculation point of view by
the subscription state above.
o Authorization information for the presentity.
For each presentity for which there was any publication and the
presentity has a state other then a default value, the presence
server has to maintain the current value of the presentity.
2.2.1. State Size Calculations
Assuming the following sizes, the state size is calculated for
various systems:
o Subscription size - 2K bytes. This includes watcher information
that need to be created by the presence server for each
subscription. This is for each subscription that is done by each
watcher to each presentity that the watcher is watching. So if we
have 10K watchers we should have 10K of these.
o Subscribed to resource - 1K bytes (for privacy information and
other management info). This is for each presentity that is being
watched. No matter how many watchers are watching it. The
subscriptions themselves are already calculated in the previous
bullet.
o Resource with a state - 6K bytes. This is a moderate assumption
if we take into account the amount of data that is being put in a
presence document as multiple devices, calendar and geographical
information. This is for each presentity that has state other
then the default empty state. It does not matter if it is being
watched or not.
Tiny System:
o 10K subscriptions = 19M bytes.
o 5K subscribed to presentities = 5M bytes.
o 10K presentities with state = 58M bytes.
The total for tiny system is 82M bytes.
Medium System:
o 100K subscriptions = 195M bytes.
o 50K subscribed to presentities = 49M bytes.
o 100K presentities with state = 586M bytes.
The total for medium system is 830M bytes.
Large System:
o 6M subscriptions = 11,718M bytes.
o 3M subscribed to presentities = 2,929M bytes.
o 4M presentities with state = 23437M bytes.
The total for large system is 38G bytes.
Very Large System:
o 150M subscriptions = 292,969M bytes.
o 75M subscribed to presentities = 73,242M bytes.
o 100M presentities with state = 585,937M bytes.
The total for very large system is 952G bytes which is a very big For very large session peering (150 million subscriptions) we got a
number for a very dynamic storage as needed by the presence server. state close to a tera byte that needs to be managed by the server in
order to manage presence.
Although the numbers above may seem moderate enough for the sizes It may be that when deploying a very large systems big resources need
that the presence server is handling we should consider the to be allocated but we should take into the considration the
following: following:
o Dynamic state - Although the state may seem not so big for o The assumptions that have been used in the scaling analysis
databases even for the very large system, we need to remember that document are very moderate from the aspect of number of presence
this state is a very dynamic state. Subscriptions come and go all status changes per hour and the the size of the presence document
the time, the status of presentities is being updated and so that was assumed.
forth. This means that the presence server has to manage its
state in a medium that is very dynamic and for such large sizes
this task is not trivial.
o Interlinked state - The subscriptions and the subscribed to
presentities are dependent on each other. There needs to be a
link from the presentity to the subscriptions and vice versa.
There is a need to be a linkage between the Resource List Server
(RLS [RFC4662]) and the various presence servers that hold the
presence data. See section 4.5 in the presence scaling document
for more details.
o Moderate assumptions - The size assumptions that were made above
are quite moderate. As presence is becoming more a core
middleware functionality that holds a lot of data on the user. In
real-life the numbers above may be even higher and the presence
server can have additional overhead as managing the SIP sessions,
networking and more.
Although the calculations above do not show that there is a real o Even when applying all current drafted and/or RFCd optimizations
issue with state management of presence in medium systems or even in for presence we still got around 10 billion messages per 8 hours
big systems since it should be possible to divide the state between work day for a total of 20 million fedearting users. This is good
different machines, the state size is still very big. A bigger issue but not enough given the moderate assumptions that we have used
with the state is more when resource lists are involved and create an and given that when presence will be deployed to a mass market the
interlinked state between many servers. In that case the division of number of federating users will be much more then 20 million
very big state to multiple servers becomes less trivial... federating users.
3. Requirements 3. Requirements
This section lists requirements for a solution that will optimize the This section lists requirements for a solution that will optimize the
interdomain presence loads. The requirements are based on the interdomain presence loads. The requirements are based on the
presence scaling draft presence scaling draft
[I-D.ietf-simple-interdomain-scaling-analysis]. [I-D.ietf-simple-interdomain-scaling-analysis].
3.1. Backward Compatibility Requirements 3.1. Backward Compatibility Requirements
o REQ-001: The solution SHOULD NOT deprecate existing protocol o REQ-001: The solution SHOULD NOT deprecate existing protocol
mechanisms defined in SIP/SIMPLE. The ability of existing SIP/ mechanisms defined in SIP/SIMPLE.
SIMPLE clients and/or servers from peering with a domain or a
client implementing the solution SHOULD be retained with no
changes required of existing servers to interoperate.
o REQ-002-A: The solution SHOULD NOT constrain any existing RFC o REQ-002: Existing SIP/SIMPLE clients SHOULD be able to communicate
with clients and servers that implement new presence scaling
features.
o REQ-003: The solution SHOULD NOT constrain any existing RFC
functional requirements for presence. functional requirements for presence.
o REQ-002-B: The solution MUST NOT constrain any existing RFC o REQ-004: The solution MUST NOT constrain any existing RFC security
security requirements for presence. requirements for presence.
o REQ-003: Systems that are not using the new additions to the o REQ-005: Systems that are not using the new additions to the
protocol SHOULD operate at the same level as they do today. protocol SHOULD operate at the same level as they do today.
3.2. Policy, Privacy, Permissions Requirements 3.2. Policy, Privacy, Permissions Requirements
o REQ-004: The solution SHOULD NOT limit the ability for o REQ-006: The solution SHOULD NOT limit the ability for
presentities to present different views of presence to different presentities to present different views of presence to different
watchers. watchers.
o REQ-005: The solution SHOULD NOT restrict the ability of a o REQ-007: The solution SHOULD NOT restrict the ability of a
presentity to obtain its list of watchers. presentity to obtain its list of watchers.
o REQ-006: The solution MUST NOT create any new or make worse any o REQ-008: The solution MUST NOT create any new or make worse any
existing privacy holes. existing privacy holes.
3.3. Scalability Requirements 3.3. Scalability Requirements
o REQ-007: Presence systems (intra or inter-domain) SHOULD scale in o REQ-009: Presence systems (intra or inter-domain) SHOULD scale in
linear proportion to the number of watchers and presentities in linear proportion to the number of watchers and presentities in
the system. the system.
o REQ-008: The solution SHOULD NOT require significantly more state o REQ-010: The solution SHOULD NOT require a significant increase in
then solutions based on current protocol in order to implement the the size of state to maintain, compared to the current state size
optimizations. required by SIP/SIMPLE.
o REQ-009: The solution MUST allow presence systems to scale. Note: o REQ-011: The solution MUST allow presence systems to scale. Note:
we view scalability on the order of tens of millions of users in we view scalability on the order of tens of millions of users in
each peer domain. each peer domain.
o REQ-010: There may be various usage patterns when users of one o REQ-012: There may be various usage patterns when users of one
domain subscribe to users from another domain. It may be that domain subscribe to users from another domain. It may be that
only small percentage of users from each domain will subscribe to only small percentage of users from each domain will subscribe to
users from the other domain, it may be that most watchers will be users from the other domain, it may be that most watchers will be
from the other domain while there will be few watchers from the from the other domain while there will be few watchers from the
same domain. The solution MUST support high percentage of same domain. The solution MUST support high percentage of
watcher/presentity intersections between the domains and it MUST watcher/presentity intersections between the domains and it MUST
support various intersection models. support various intersection models.
o REQ-011: Protocol changes MUST NOT prohibit optimizations in o REQ-013: Protocol changes MUST NOT prohibit optimizations in
different deployment models especially where there is a high level deployment models where there is a high level of cross
of cross subscriptions between the domains. subscriptions between the domains.
o REQ-012: New functionalities and extensions to the presence o REQ-014: New functionalities and extensions to the presence
protocol SHOULD take into account scalability with respect to the protocol SHOULD take into account scalability with respect to the
number of messages, state size and management and processing load. number of messages, state size and management and processing load.
3.4. Topology Requirements 3.4. Topology Requirements
o REQ-013: The solution SHOULD allow for arbitrary federation o REQ-015: The solution SHOULD allow for arbitrary federation
topologies including direct and indirect peering. topologies including direct and indirect peering.
4. Considerations for Possible Optimizations 4. Considerations for Possible Optimizations
The document provides an initial list of requirements for a solution The document provides an initial list of requirements for a solution
of scalability of interdomain presence systems using the SIP/SIMPLE of scalability of interdomain presence systems using the SIP/SIMPLE
protocol. The issue of scalability was shown in a separate document protocol. The issue of scalability was shown in a separate document
[I-D.ietf-simple-interdomain-scaling-analysis]. [I-D.ietf-simple-interdomain-scaling-analysis].
The following is a discussion of the various possible paths for The following is a discussion of the various possible paths for
skipping to change at page 13, line 36 skipping to change at page 7, line 5
video and even text messaging. The SUBSCRIBE method may be extended video and even text messaging. The SUBSCRIBE method may be extended
to negotiate the route and other parameters of the NOTIFY messages, to negotiate the route and other parameters of the NOTIFY messages,
in a similar way that the INVITE method negotiates media parameters. in a similar way that the INVITE method negotiates media parameters.
This way the load can be offloaded to a specialized NOTIFY "relays" This way the load can be offloaded to a specialized NOTIFY "relays"
thus not loading the control path of SIP. One of the possible ideas thus not loading the control path of SIP. One of the possible ideas
(Marc Willekens) is to use the SIP protocol for client/server NOTIFY (Marc Willekens) is to use the SIP protocol for client/server NOTIFY
but make use of a more optimized and controllable protocol for the but make use of a more optimized and controllable protocol for the
server-to-server interface. Another possibility is to use the MSRP server-to-server interface. Another possibility is to use the MSRP
[RFC4975], [RFC4976] protocol for the notifications. [RFC4975], [RFC4976] protocol for the notifications.
4.1. Very Optimized SIP
SIP is network agnostic protocol, therefore, the protocol carries
additional messages like 200 OK that would have been redundant in a
protocol that is TCP based only.
The following calculation assumes an imaginary TCP only based version
of SIP that optimizes the following:
o There is no 200 OK for each message. Since only TCP has to be
supported, there is not need to compensate for network issues.
o There is no refresh for subscriptions.
o There is no NOTIFY upon termination of SUBSCRIPTION
o The size of each message is smaller since there is no need for the
various headers that SIP uses for routing etc. So we need to
assume smaller message sizes while we will keep the size of the
presence document the same.
As notes above the calculations in this document do not assume
offline means of getting parts of the presence information.
Therefore, in addition to the above optimizations, the other
optimizations that were assumed in the document will be assumed here
also. These includes partial notifications and the dialog
optimizations. The NOTIFY optimization is not relevant here since
there are no refreshes of subscriptions.
The following is a calculation for the very large networks peering
scenario assuming the imaginary TCP only SIP. It is very interesting
to note that the dialog optimization does not reduce the number of
bytes when partial notification optimization is applied (on the
contrary) due to the RLMI overhead.
** Constants
(C01) Subscription lifetime (hours)...........................8
(C02) Presence state changes / hour...........................6
(C03) Subscription refresh interval / hour....................0
(C04) Total federated presentities per watcher...............10
(C05) Number of dialogs to maintain per watcher...............1
(C06) Total number of watchers in domains............20,000,000
(C07) SUBSCRIBE message size in bytes.......................150
(C08) 200 OK for SUBSCRIBE message size in bytes..............0
(C09) NOTIFY message size not including presence doc........150
(C10) 200 OK for NOTIFY message size in bytes.................0
(C11) Size of an average presence document..................350
(C12) Size of an average partial presence document..........200
** Initial Messages
(I01) Initial SUBSCRIBE msgs per watcher......................1
(I02) Initial 200 OK msgs (SUBSCRIBE) per watcher.............0
(I03) Initial NOTIFY msgs per watcher.........................1
(I04) Initial 200 OK msgs (NOTIFY) per watcher................0
(I05) Total number & bytes of initial SUBSCRIBE msgs
Number of msgs for all watchers............20,000,000
Bytes for all watchers..................3,000,000,000
(I06) Total number & bytes of initial 200 OK (SUBSCRIBE) msgs
Number of msgs for all watchers.....................0
Bytes for all watchers..............................0
(I07) Total number & bytes of initial NOTIFY msgs
Number of msgs for all watchers............20,000,000
Bytes for all watchers................136,680,000,000
(I08) Total number & bytes of initial 200 OK (NOTIFY) msgs
Number of msgs for all watchers.....................0
Bytes for all watchers..............................0
(I09) Total number & bytes of initial messages per day
Number of msgs for all watchers............40,000,000
Bytes for all watchers................139,680,000,000
** Steady State Messages
(S01) NOTIFY msgs due to state change
per watched presentity per day.....................46
(S02) 200 (for NOTIFY due to state change) msgs
per watched presentity per day......................0
(S03) Total number and size of msgs due to state change per day
Number of msgs for all watchers.........9,200,000,000
Bytes for all watchers..............8,666,400,000,000
(S04) Number of SUBSCRIBE msgs for refreshes
per watcher per day.................................0
(S05) Number of 200 OK msgs for SUBSCRIBE msgs for refreshes
per watcher per day.................................0
(S06) Number of NOTIFY msgs for refreshes
per watcher per day.................................0
(S07) Number of 200 OK msgs for NOTIFY msgs for refreshes
per watcher per day.................................0
(S08) Total number and size of msgs due to SUBSCRIBE refreshes
Number of msgs for all watchers per day.............0
Bytes for all watchers per day......................0
(S09) Total number & bytes of steady messages per day
Number of msgs for all watchers.........9,200,000,000
Bytes for all watchers..............8,666,400,000,000
** Termination Messages
(T01) Terminating SUBSCRIBE msgs per watcher..................1
(T02) Terminating 200 OK msgs (SUBSCRIBE) per watcher.........0
(T03) Terminating NOTIFY msgs per watcher.....................0
(T04) Terminating 200 OK msgs (NOTIFY) per watcher............0
(T05) Total number & bytes of Terminating SUBSCRIBE msgs
Number of msgs for all watchers............20,000,000
Bytes for all watchers..................3,000,000,000
(T06) Total number & bytes of terminating 200 OK (SUBSCRIBE) msgs
Number of msgs for all watchers.....................0
Bytes for all watchers..............................0
(T07) Total number & bytes of terminating NOTIFY msgs
Number of msgs for all watchers.....................0
Bytes for all watchers..............................0
(T08) Total number & bytes of terminating 200 OK (NOTIFY) msgs
Number of msgs for all watchers.....................0
Bytes for all watchers..............................0
(T09) Total number & bytes of terminating messages per day
Number of msgs for all watchers............20,000,000
Bytes for all watchers..................3,000,000,000
** Bottom Line
(B01) Total of messages between domains...........9,260,000,000
Total of bytes between domains (PD=350).8,809,080,000,000
Total of bytes bet. domains (PD=3000)...9,339,080,000,000
(B02) Total number of messages / second.................321,528
Total of bytes per second (PD=350)............305,870,833
Total of bytes per second (PD=3000)...........324,273,611
(B03) Total number of by msgs per user/day..................463
Total number of bytes per user/day (PD=350).......440,454
Total number of bytes per user/day (PD=3000)......466,954
<artwork><![CDATA[
Figure 3: Very large networks peering, TCP only SIP+Partial+Dialog
optimizations
** Constants
(C01) Subscription lifetime (hours)...........................8
(C02) Presence state changes / hour...........................6
(C03) Subscription refresh interval / hour....................0
(C04) Total federated presentities per watcher...............10
(C05) Number of dialogs to maintain per watcher..............10
(C06) Total number of watchers in domains............20,000,000
(C07) SUBSCRIBE message size in bytes.......................150
(C08) 200 OK for SUBSCRIBE message size in bytes..............0
(C09) NOTIFY message size not including presence doc........150
(C10) 200 OK for NOTIFY message size in bytes.................0
(C11) Size of an average presence document..................350
(C12) Size of an average partial presence document..........200
** Initial Messages
(I01) Initial SUBSCRIBE msgs per watcher.....................10
(I02) Initial 200 OK msgs (SUBSCRIBE) per watcher.............0
(I03) Initial NOTIFY msgs per watcher........................10
(I04) Initial 200 OK msgs (NOTIFY) per watcher................0
(I05) Total number & bytes of initial SUBSCRIBE msgs
Number of msgs for all watchers...........200,000,000
Bytes for all watchers.................30,000,000,000
(I06) Total number & bytes of initial 200 OK (SUBSCRIBE) msgs
Number of msgs for all watchers.....................0
Bytes for all watchers..............................0
(I07) Total number & bytes of initial NOTIFY msgs
Number of msgs for all watchers...........200,000,000
Bytes for all watchers................100,000,000,000
(I08) Total number & bytes of initial 200 OK (NOTIFY) msgs
Number of msgs for all watchers.....................0
Bytes for all watchers..............................0
(I09) Total number & bytes of initial messages per day
Number of msgs for all watchers...........400,000,000
Bytes for all watchers................130,000,000,000
** Steady State Messages
(S01) NOTIFY msgs due to state change
per watched presentity per day.....................46
(S02) 200 (for NOTIFY due to state change) msgs
per watched presentity per day......................0
(S03) Total number and size of msgs due to state change per day
Number of msgs for all watchers.........9,200,000,000
Bytes for all watchers..............3,220,000,000,000
(S04) Number of SUBSCRIBE msgs for refreshes
per watcher per day.................................0
(S05) Number of 200 OK msgs for SUBSCRIBE msgs for refreshes
per watcher per day.................................0
(S06) Number of NOTIFY msgs for refreshes
per watcher per day.................................0
(S07) Number of 200 OK msgs for NOTIFY msgs for refreshes
per watcher per day.................................0
(S08) Total number and size of msgs due to SUBSCRIBE refreshes
Number of msgs for all watchers per day.............0
Bytes for all watchers per day......................0
(S09) Total number & bytes of steady messages per day
Number of msgs for all watchers.........9,200,000,000
Bytes for all watchers..............3,220,000,000,000
** Termination Messages
(T01) Terminating SUBSCRIBE msgs per watcher.................10
(T02) Terminating 200 OK msgs (SUBSCRIBE) per watcher.........0
(T03) Terminating NOTIFY msgs per watcher.....................0
(T04) Terminating 200 OK msgs (NOTIFY) per watcher............0
(T05) Total number & bytes of Terminating SUBSCRIBE msgs
Number of msgs for all watchers...........200,000,000
Bytes for all watchers.................30,000,000,000
(T06) Total number & bytes of terminating 200 OK (SUBSCRIBE) msgs
Number of msgs for all watchers.....................0
Bytes for all watchers..............................0
(T07) Total number & bytes of terminating NOTIFY msgs
Number of msgs for all watchers.....................0
Bytes for all watchers..............................0
(T08) Total number & bytes of terminating 200 OK (NOTIFY) msgs
Number of msgs for all watchers.....................0
Bytes for all watchers..............................0
(T09) Total number & bytes of terminating messages per day
Number of msgs for all watchers...........200,000,000
Bytes for all watchers.................30,000,000,000
** Bottom Line
(B01) Total of messages between domains...........9,800,000,000
Total of bytes between domains (PD=350).3,380,000,000,000
Total of bytes bet. domains (PD=3000)...3,910,280,000,000
(B02) Total number of messages / second.................340,278
Total of bytes per second (PD=350)............117,361,111
Total of bytes per second (PD=3000)...........135,763,889
(B03) Total number of by msgs per user/day..................490
Total number of bytes per user/day (PD=350).......169,000
Total number of bytes per user/day (PD=3000)......195,500
Figure 4: Very large networks peering, TCP only SIP+Partial
optimizations
5. Security Considerations 5. Security Considerations
This document discusses scalability requirements for the existing This document discusses scalability requirements for the existing
SIP/SIMPLE protocol and model. Many of the changes to the protocol SIP/SIMPLE protocol and model. Many of the changes to the protocol
will have security implications as mentioned in some of the will have security implications as mentioned in some of the
requirements above. requirements above.
One example of possible protocol changes that may have security One example of possible protocol changes that may have security
implications is sending a presence document only once between domains implications is sending a presence document only once between domains
in order to optimize the number of messages and network load. This in order to optimize the number of messages and network load. This
skipping to change at page 19, line 20 skipping to change at page 8, line 6
8.2. Informational References 8.2. Informational References
[I-D.ietf-simple-interdomain-scaling-analysis] [I-D.ietf-simple-interdomain-scaling-analysis]
Houri, A., Aoki, E., Parameswar, S., Rang, T., Singh, V., Houri, A., Aoki, E., Parameswar, S., Rang, T., Singh, V.,
and H. Schulzrinne, "Presence Interdomain Scaling Analysis and H. Schulzrinne, "Presence Interdomain Scaling Analysis
for SIP/SIMPLE", for SIP/SIMPLE",
draft-ietf-simple-interdomain-scaling-analysis-05 (work in draft-ietf-simple-interdomain-scaling-analysis-05 (work in
progress), October 2008. progress), October 2008.
[I-D.ietf-simple-intradomain-federation] [I-D.ietf-simple-intradomain-federation]
Rosenberg, J., Houri, A., and C. Smyth, "Models for Intra- Rosenberg, J., Houri, A., Smyth, C., and F. Audet, "Models
Domain Presence and Instant Messaging (IM) Federation", for Intra-Domain Presence and Instant Messaging (IM)
draft-ietf-simple-intradomain-federation-01 (work in Bridging", draft-ietf-simple-intradomain-federation-02
progress), July 2008. (work in progress), November 2008.
[I-D.ietf-simple-simple] [I-D.ietf-simple-simple]
Rosenberg, J., "SIMPLE made Simple: An Overview of the Rosenberg, J., "SIMPLE made Simple: An Overview of the
IETF Specifications for Instant Messaging and Presence IETF Specifications for Instant Messaging and Presence
using the Session Initiation Protocol (SIP)", using the Session Initiation Protocol (SIP)",
draft-ietf-simple-simple-04 (work in progress), draft-ietf-simple-simple-04 (work in progress),
October 2008. October 2008.
[I-D.ietf-simple-view-sharing] [I-D.ietf-simple-view-sharing]
Rosenberg, J., Donovan, S., and K. McMurry, "Optimizing Rosenberg, J., Donovan, S., and K. McMurry, "Optimizing
Federated Presence with View Sharing", Federated Presence with View Sharing",
draft-ietf-simple-view-sharing-01 (work in progress), draft-ietf-simple-view-sharing-02 (work in progress),
July 2008. November 2008.
[RFC3857] Rosenberg, J., "A Watcher Information Event Template- [RFC3857] Rosenberg, J., "A Watcher Information Event Template-
Package for the Session Initiation Protocol (SIP)", Package for the Session Initiation Protocol (SIP)",
RFC 3857, August 2004. RFC 3857, August 2004.
[RFC3858] Rosenberg, J., "An Extensible Markup Language (XML) Based [RFC3858] Rosenberg, J., "An Extensible Markup Language (XML) Based
Format for Watcher Information", RFC 3858, August 2004. Format for Watcher Information", RFC 3858, August 2004.
[RFC4662] Roach, A., Campbell, B., and J. Rosenberg, "A Session [RFC4662] Roach, A., Campbell, B., and J. Rosenberg, "A Session
Initiation Protocol (SIP) Event Notification Extension for Initiation Protocol (SIP) Event Notification Extension for
skipping to change at page 22, line 4 skipping to change at line 386
Henning Schulzrinne Henning Schulzrinne
Columbia University Columbia University
Department of Computer Science Department of Computer Science
450 Computer Science Building 450 Computer Science Building
New York, NY 10027 New York, NY 10027
US US
Phone: +1 212 939 7004 Phone: +1 212 939 7004
Email: hgs+ecrit@cs.columbia.edu Email: hgs+ecrit@cs.columbia.edu
URI: http://www.cs.columbia.edu/~hgs URI: http://www.cs.columbia.edu/~hgs
Full Copyright Statement
Copyright (C) The IETF Trust (2008).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Intellectual Property
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
 End of changes. 33 change blocks. 
617 lines changed or deleted 84 lines changed or added

This html diff was produced by rfcdiff 1.35. The latest version is available from http://tools.ietf.org/tools/rfcdiff/