One document matched: draft-deng-ippm-wireless-00.txt
IPPM L. Deng
Internet-Draft Z. Cao
Intended status: Informational China Mobile
Expires: April 21, 2014 October 18, 2013
Problem Statement for IP measurement in mobile networks
draft-deng-ippm-wireless-00.txt
Abstract
This document analyzes the potential problems of applying existing
IP-based performance measurement methods to wireless accessing
environments. It suggests that more robust passive measuring methods
and performance metrics are needed.
Status of This Memo
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This Internet-Draft will expire on April 21, 2014.
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Internet-DrafProblem Statement for IP measurement in mobile October 2013
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . 2
2.1. Dynamic Load Balancing . . . . . . . . . . . . . . . . . 3
2.2. Radio Congestion Detection . . . . . . . . . . . . . . . 4
3. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4. Security Considerations . . . . . . . . . . . . . . . . . . . 5
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 5
6. References . . . . . . . . . . . . . . . . . . . . . . . . . 5
6.1. Normative References . . . . . . . . . . . . . . . . . . 5
6.2. Informative References . . . . . . . . . . . . . . . . . 5
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6
1. Introduction
It is well-accepted that mobile Internet usage is going to increase
fast in the coming years and replace the traditional voice service to
be the dominant revenue source for mobile operators. In the
meantime, fast evolving network and terminal technologyies and
changing service trend (e.g. social networking, video on demand,
online reading, etc.) results in higher user service requirement.
Therefore, as the basic infrastruture service provider, operators are
deemed responsible for mobile Internet end-to-end performance, for
subscribers want to get what they want, which gives rise to a basic
yet important question: how does network service provider manage end-
to-end service quality? In particular, there are two goals for
operator's quality management intiative:
o to make sure and validate the QoS metrics of specific IP flows
agains the values pre-defined by the service SLA(Service Level
Agreement) from the user/service provider's point of view; and
o to make sure and validate the sanity of network devices/links.
In this draft, we analyze two usecases the potential problems of
applying existing IP-based performance measurement methods to
wireless accessing environments, which are tending to utilize resouce
pooling and dynamic load balancing techques to accommodate
explosively increasing data traffic, and conclude that more robust
passive measuring methods and performance metrics are needed.
2. Motivation
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2.1. Dynamic Load Balancing
Pooling technology has been introduced to the user plane in the
packet switched domain of operator's core network for cellular
subscribers since 3GPP Release 5 (3GPP TS23.236). With pooling, the
traffic path from user equipements to the Internet via core network
is not static, but rather dynamically assigned to a proper instantce
of an device pool, according to load balancing policies. The
assignment is dynamically made at the time of user equipment's
attachment establishement with the celluar core network, and would
remain unchanged unless the mobile terminal detaches from the network
or moves outside the base-stations' coverage subordinating to the
specific core network's device pool.
As shown by Figure 1, potential device pools along the path all the
way from the user terminal via the packet switching domain of the
mobile network core to a third party service provider over the
Internet. Examples of network devices that can be poolized
includeSGSN(Serving GPRS Support Node) and GGSN(Gateway GPRS
Supporting Node). Moreover, the service provider could also
implement load balancing on the server's side either via server-
pooling within a data certer or via (third party) CDN nodes.
Radio |Packet |Internet
Access |Switching |
Network |Core Network |
| +--------+ +----+---+ +--------+
| |+------+| |+------+| |+------+|
| +-->|SGSN_1|+------->|GGSN_1|+--+ ||SERV_1||
| | |+------+| |+------+| | |+------+|
+--+ +--+--+ +-----+ | | | | | | | |
| |---->| +--->| +--+ |+------+| |+------+| | |+------+|
|UE| |NodeB| | RNC | ||SGSN_2|| ||GGSN_2|| +---->|SERV_2||
| |....>| |...>| |... |+------+| |+------+| |+------+|
+--+ +--+--+ +-----+ . | | | | | |
| . | ... | | ... | | ... |
| . |+------+| |+------+| |+------+|
+--------------------+ ...>|SGSN_N|........>|GGSN_M|........>|SERV_K||
| Injected Traffic | |+------+| |+------+| |+------+|
| ---------------> | +--------+ +----+---+ +--------+
| Actual Traffic | |
| ...............> | |
+--------------------+
Figure 1: Active Measuring Traffic versus Actual Traffic in case of
Device Pooling
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Hence, under such environments, if active performance measurement
methods[RFC4656][RFC5357] are employed, the injected bogus data
traffic may traverse along a different path to the one used by the
targeted traffic or even interfere with them due to the subtle nature
of wireless-involved links (as explained in the next subsection).
2.2. Radio Congestion Detection
Mobile Internet usage is going to increase fast in the coming years
due to the following facts: on one hand, as a result of pervasively
deployed and fast maturing 3G/4G cellular technologies combined with
smartphone's dominance in mobile handset's market, Internet data
traffic via mobile operator's packet switched core network manifests
to be an increasingly important contributor to the operator's
revenue. On the other hand, wireless technologies (such as WiFi
through APs or celluar networks through small cells) are more and
more accepted by the end users, either at home, in the office or in a
pulic place, to be carring the "last mile" to various portable
personal computing devices.
There are two common features of the above two scenarios:
o the combination of both wireless and wired links along the end-to-
end traffic path, and
o almost all the time, the wireless "last mile" would be the
bottleneck of end-to-end service quality.
To make more efficient use of relatively more scarce radio resouces,
it is important for the core network to understand the congestion
status of both wireless and wired links along the traffic path, and
make proper management of data traffic through cell reselection or
load balancing via pooling.
However, the wireless link's thoughput is consistently subject to
other interfereing factors (e.g. distance to the nearest base
station, terminal's radio signal strength, random interferece,
shadowing of buildings, multipath fading, etc.), which should be
properly filtered out before handing over to the network management,
as they are rooted in terminal mobility and outside the realm of
mobile accessing network.
In other words, there is considerable gap between IP measurement
results to the performance evaluation and fault detection
requirements in mobile-involved environment, if we directly employ
active performance measurement
methods[I-D.draft-chen-ippm-coloring-based-ipfpm-framework].
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3. Summary
In summary, for mobile-ended data paths, we believe there is need for
o viable passive measurement methodology for Active measurements
inject extra traffic, which may traverse along a different path to
the one used by the targeted traffic or even interfere with them.
o robust metric against transient wireless conditions, as there is
considerable gap between existing IP measurement metrics (e.g.
delay, jitter, throughput etc.), which are subject to change
caused by external environmental factors and of little use to
operator's traffic management from the network side.
4. Security Considerations
TBA
5. IANA Considerations
None.
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2234] Crocker, D., Ed. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", RFC 2234, November 1997.
6.2. Informative References
[I-D.draft-chen-ippm-coloring-based-ipfpm-framework]
Chen, M., Liu, H., Yin, Y., Papneja, R., Abhyankar, S.,
and G. Deng, "Coloring based IP Flow Performance
Measurement Framework", draft-chen-ippm-coloring-based-
ipfpm-framework-00 (work in progress), July 2013.
[RFC4656] Shalunov, S., Teitelbaum, B., Karp, A., Boote, J., and M.
Zekauskas, "A One-way Active Measurement Protocol
(OWAMP)", RFC 4656, September 2006.
[RFC5357] Hedayat, K., Krzanowski, R., Morton, A., Yum, K., and J.
Babiarz, "A Two-Way Active Measurement Protocol (TWAMP)",
RFC 5357, October 2008.
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Authors' Addresses
Lingli Deng
China Mobile
Email: denglingli@chinamobile.com
Zhen Cao
China Mobile
Email: caozhen@chinamobile.com
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