Network Management Research Group M. Behringer
Internet-Draft Cisco Systems
Intended status: Informational B. Carpenter
Expires: August 18, 2014 Univ. of Auckland
S. Jiang
Huawei Technologies Co., Ltd
February 14, 2014
Gap Analysis for Autonomic Networking
draft-jiang-nmrg-an-gap-analysis-00
Abstract
This document summarises a problem statement for an IP-based
autonomic network that is mainly based on distributed network
devices. The document reviews the history and current status of
autonomic aspects of IP networks. It then reviews the current
network management style, which is still heavily depending on human
administrators. Finally the document describes the general gaps
between the ideal autonomic network concept and the current network
abilities.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
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This Internet-Draft will expire on August 18, 2014.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Current Status of Autonomic Aspects of IP Networks . . . . . 3
3.1. IP Address Management and DNS . . . . . . . . . . . . . . 3
3.2. Routing . . . . . . . . . . . . . . . . . . . . . . . . . 4
3.3. Configuration of Default Router . . . . . . . . . . . . . 4
3.4. Hostname Lookup . . . . . . . . . . . . . . . . . . . . . 5
3.5. User Authentication and Accounting . . . . . . . . . . . 5
3.6. Security . . . . . . . . . . . . . . . . . . . . . . . . 5
3.7. Miscellaneous . . . . . . . . . . . . . . . . . . . . . . 6
4. Current Non-Autonomic Behaviors . . . . . . . . . . . . . . . 6
4.1. Network Establishment . . . . . . . . . . . . . . . . . . 7
4.2. Network Maintenance & Management . . . . . . . . . . . . 7
4.3. Troubleshooting and Recovery . . . . . . . . . . . . . . 8
5. Approach toward Autonomy . . . . . . . . . . . . . . . . . . 9
5.1. More Coordination among Devices or Network Partitions . . 9
5.2. Benefit from Knowledge . . . . . . . . . . . . . . . . . 9
6. Security Considerations . . . . . . . . . . . . . . . . . . . 10
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10
9. Informative References . . . . . . . . . . . . . . . . . . . 10
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction
The general goals and relevant definitions for autonomic networking
are discussed in [I-D.irtf-nmrg-autonomic-network-definitions]. In
summary, the fundamental goal of an autonomic network is self-
management, including self-configuration, self-optimization, self-
healing and self-protection. Whereas interior gateway routing
protocols such as OSPF and IS-IS largely exhibit these properties,
most other aspects of networking require top-down configuration often
involving human administrators and a considerable degree of
centralisation. In essence Autonomous Networking is putting all
network configuration onto the same footing as routing, limiting
manual or database-driven configuration to an essential minimum. It
should be noted that this is highly unlikely to eliminate the need
for human administrators, because many of their essential tasks will
remain. The idea is to eliminate tedious and error-prone tasks, for
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example manual calculations, cross-checking between two different
configuration files, or tedious data entry. Higher level operational
tasks, and trouble-shooting, will remain to be done in any case.
Note in draft: This is a preliminary version. It certainly lacks
information about current status, and it lacks many external
references. Especially the final section (Section 5) is very
preliminary. Comments and suggestions are very welcome.
2. Terminology
The terminology defined in
[I-D.irtf-nmrg-autonomic-network-definitions] is used in this
document. Additional terms include:
o Automatic: A process that occurs without human intervention, with
step-by-step execution of rules. However it relies on humans
defining the sequence of rules, so is not Autonomic in the full
sense. For example, a start-up script is automatic but not
autonomic.
3. Current Status of Autonomic Aspects of IP Networks
This section discusses the history and current status of autonomy in
various aspects of network configuration, in order to establish a
baseline for the gap analysis. In one particular area, routing
protocols, autonomic information exchange and decision is a well
established mechanism. The question is how to extend autonomy to
cover all kinds of network management objectives.
3.1. IP Address Management and DNS
Originally there was no alternative to completely manual and static
management of IP addresses. Once a site had received an IPv4 address
assignment (usually a Class C /24 or Class B /16, and rarely a Class
A /8) it was a matter of paper-and-pencil design of the subnet plan
(if relevant) and the addressing plan itself. Subnet prefixes were
manually configured into routers, and /32 addresses were assigned
administratively to individual host computers, and configured
manually by system administrators. Records were typically kept in a
plain text file or a simple spreadsheet.
Clearly this method was clumsy and error-prone as soon as a site had
more than a few tens of hosts, but it had to be used until DHCP
[RFC2131] became a viable solution during the second half of the
1990s. DHCP made it possible to avoid manual configuration of
individual hosts (except, in many deployments, for a small number of
servers configured with static addresses).
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In terms of management, it is difficult to separate IP address
management from DNS management. At roughly the same time as DHCP
came into widespread use, it became very laborious to manually
maintain DNS source files in step with IP address assignments.
Because of reverse DNS lookup, it also became necessary to synthesise
DNS names even for hosts that only played the role of clients.
Therefore, it became necessary to synchronise DHCP server tables with
forward and reverse DNS. For this reason, Internet Protocol address
management tools emerged. These are, however, a centralised and far
from autonomic type of solution.
A related issue is prefix delegation, especially in IPv6 when more
than one prefix may be delegated to the same physical subnet. DHCPv6
Prefix Delegation [RFC3633] is a useful solution, but how this topic
is to be handled in home networks is still an open question. Still
further away is automated assignment and delegation of IPv4 subnet
prefixes.
Another complication is the possibility of Dynamic DNS Update
[RFC2136]. With appropriate security, this is an autonomic approach,
where no human intervention is required to create the DNS records for
a host. Also, there are coexistence issues with a traditional DNS
setup.
3.2. Routing
Since a very early stage, it has been a goal that Internet routing
should be self-healing when there is a failure of some kind in the
routing system (i.e. a link or a router goes wrong). Also, the
problem of finding optimal routes through a network was identified
many years ago as a problem in mathematical graph theory, for which
well known algorithms were discovered (the Dijkstra and Bellman-Ford
algorithms). Thus routing protocols became largely autonomic in the
1980s, as soon as the network was big enough for manual configuration
of routing tables to become difficult.
IGP routers do need some initial configuration data to start up the
autonomic routing protocol. Also, BGP-4 routers need static
configuration of routing policy data. So far, this policy
configuration has not been made autonomic at all.
3.3. Configuration of Default Router
Originally this was a manual operation. Since the deployment of
DHCP, this has been automatic as far as most IPv4 end systems are
concerned, but the DHCP server must be appropriately configured. In
simple environments such as a home network, the DHCP server resides
in the same box as the default router, so this configuration is also
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automatic. In more complex environments, where an independent DHCP
server or a local DHCP relay is used, configuration is more complex
and not automatic.
In IPv6 networks, the default router is provided by Router
Advertisement messages [RFC4861] from the router itself, and all IPv6
hosts make use of it. The router may also provide more complex Route
Information Options. The process is automatic as far as all IPv6 end
systems are concerned, and DHCPv6 is not involved. Howwever there
are still open issues when more than one prefix is in use on a subnet
and more than one first-hop router may be available as a result.
3.4. Hostname Lookup
Originally host names were looked up in a static table, often
referred to as /etc/hosts from its traditional file path in Unix
systems. When the DNS was deployed during the 1980s, all hosts
needed DNS resolver code, and needed to be configured with the IP
addresses (not the names) of suitable DNS servers. Like the default
router, these were originally manually configured. Today, they are
provided automatically via DHCP or DHCPv6 [RFC3315]. For IPv6 end
systems, there is also a way for them to be provided automatically
via a Router Advertisement option. However, the DHCP or DHCPv6
server, or the IPv6 router, need to be configured with the
appropriate DNS server addresses.
3.5. User Authentication and Accounting
Originally, user authentication and accounting are mainly based on
the physical connectivities. Network operators charged based on the
set up of dedicated physical links with users. Autonomic user
authentication are introduced by Point-to-Point Protocol [RFC1661],
[RFC1994] and RADIUS protocol [RFC2865], [RFC2866] in early 1990s. As
long as a user complete online authentication through RADIUS
protocol, the accounting for that user starts on AAA server
autonomically. This mechanism enables charging business model based
on the usage of users, either traffic based or time based. However,
the management for user authentication information remains manual by
network administrators.
3.6. Security
Security has many aspects that need configuration and are therefore
candidates to become autonomic. On the other hand, it is essential
that a network's central policy should be applied strictly for all
security configuration. As a result security has largely been based
on centrally imposed configurations.
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Many aspects of security depend on policy, for example firewall
policies. Policies are by definition human made and will therefore
also persist in an autonomic environment. However, policies are
becoming more high-level, abstracting for example addressing, and
focusing on the user or application. The methods to manage,
distribute and apply policy, and to monitor compliance and violations
could be autonomic.
Today, many security mechanisms show some autonomic properties. For
example user authentication via 802.1x allows automatic mapping of
users after authentication into logical contexts (typically VLANs).
While today configuration is still very important, the overall
mechanism displays signs of self-adaption to changing situations.
BGP Flowspec [RFC5575] allows a partially autonomic threat defense
mechanism, where threats are identified, the flow information is
automatically distributed, and counter-actions can be applied. Today
typically a human operator is still in the loop to check correctness,
but over time such mechanisms can become more autonomic.
Negotiation capabilities, present in many security protocols, also
display simple autonomic behaviours. In this case a security policy
about algorithm strength can be configured into servers but will
propagate automatically to clients. A proposal has been made
recently for automatic bootstrapping of trust in a network
[I-D.behringer-default-secure]. Solutions for opportunistic
encryption have been defined [RFC4322],
[I-D.farrelll-mpls-opportunistic-encrypt], but these do not adhere to
a central policy.
3.7. Miscellaneous
There are innumerable other properties of network devices and end
systems that today need to be configured either manually or using a
management protocol such as SNMP [RFC1157] or NETCONF [RFC6241]. In
a truly autonomic network, all of these would need to either have
satisfactory default values or be configured automatically. Some
examples are parameters for tunnels of various kinds, flows (in an
SDN context), quality of service, service function chaining, energy
management, system identification, NTP configuration etc. Even one
undefined parameter would be sufficient to prevent fully autonomic
operation.
4. Current Non-Autonomic Behaviors
In the current networks, many operations are still heavily depending
on human intelligence and decision, or on centralised top-down
network management systems. These operations are the targets of
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Autonomic Network technologies. The ultimate goal of Autonomic
Network is to replace tedious human operations by autonomic
functions, so that the networks can independently run without having
to ask human support for routine details, while it remains possible
to restore human intervention when unavoidable. Of course, there
would still be the absolute minimum of human input required,
particularly during the network establishment stage, and during
difficult trouble-shooting.
This section analyzes the existing human and central dependencies in
the current networks.
4.1. Network Establishment
Network establishment requires network operators to analyze the
requirements of the new network, design a network archetecture and
topology, decide device locations and capacities, set up hardware,
design network services, choose and enable required protocols,
configure each device and each protocol, set up user authentication
and accounting policies and databases, design and deploy security
mechanisms, etc.
Overall, these jobs are quite complex work that cannot become fully
autonomic in the forseeable future. However, part of these jobs may
be able to become autonomic, such as device and protocol
configurations and database population. The initial network
management policies/behaviors may also be transplanted from other
networks and automatically localized.
4.2. Network Maintenance & Management
The network maintenance and management are very different for ISP
networks and enterprise networks. ISP networks have to change much
more frequently than enterprise networks, given the fact that ISP
networks have to serve a large number of customers who have very
diversified requirements. The current rigid model is that network
administrators design a limited number of services for customers to
order. New requirements of network services may not be able to be
met quickly by human management. Given a real-time request, the
response must be autonomic, in order to be flexible and quickly
deployed. However, behind the interface, describing abstracted
network information and user authorization management may have to
depend on human intelligence from network administrators in the
forseeable future. User identification integration/consolidation
among networks or network services are another challenge for
autonomic network access. Currently, the end users have to manually
manage their user accounts and authentication information when they
switch among networks or network services.
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Classical network maintenance and management mainly manages the
configuration of network devices. Tools have developed to enable
remote management and make the management easier. However, the
decision of each configuration depends either on human intelligence
or rigid templates. This is the source of most network configuration
errors. It is also the barrier to increase the utility of network
resources because the human management cannot respond quickly enough
to network events, such as traffic bursts, etc. For example,
currently, a light load is normally assumed in network design because
there is no mechanism to properly handle a sudden traffic flood. It
is actually normal to avoid network crashes caused by traffic
overload by wasting a huge amount of resources.
Autonomic decision processes of configuration would enable dynamic
management of network resources (by managing resource relevant
configuration). Self-adapting network configuration would adjust the
network into the best possible situation, which also prevents
configuration errors from having lasting impact.
4.3. Troubleshooting and Recovery
The current networks are suffering difficulties in locating the cause
of network failures. Although the network devices may issue many
warnings during running, most of them are not sufficiently precise to
be identified as errors. Some of them are early warnings that would
not develop into real errors. Others are in effect random noise.
For many scenarios, human experience is vital to identify real issues
and locate them. This situation may be improved by associating
warnings from multiple network devices together. Also, introducing
automated learning techniques (comparing current warnings with
historical relationships between warnings and actual faults) could
increase the possibility and success rate of autonomic network
diagnoses and troubleshooting.
Depending on the network errors, some of them may require human
interventions, particularly for hardware failures. Meanwhile, some
network management behavior may help to reduce the impact from
errors, such as switching traffic flows around. Today this is
usually manual. Software failures and configuration errors
(including to roll back software versions and to reboot hardware)
currently depend on humans. Such problems could be autonomically
corrected if there were diagnostics and recovery functions defined in
advance for them. This would fulfill the concept of self-healing.
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5. Approach toward Autonomy
The task of autonomic networking is to build up individual autonomic
decision processes that could properly combine to respond to every
type of network event. This section (when complete) will outline
what needs to be developed.
5.1. More Coordination among Devices or Network Partitions
Events in networks are normally not independent. They are associated
with each other. But most of current response functions are based on
independent processes. The network events that may naturally happen
distributed should be associated in the autonomic processes.
In order to make right or good decisions autonomically, the network
devices need to know more information than just reachability
(routing) information from the relevant or neighbor devices. There
are dependencies between such information and configurations.
Currently, most of these configurations currently require manual
coordination by network administrators.
There are therefore increased requirements for horizontal information
exchanging in the networks. Particularly, negotiation among network
devices are needed for autonomic decision.
[I-D.jiang-config-negotiation-ps] analyzes such requirements.
Although there are many existing protocols with negotiation ability,
each of them are only serve a specifc and narrow purpose.
[I-D.jiang-config-negotiation-protocol] is one of the attempts to
create a generic negotiation platform, which would support different
negotiation objectives.
5.2. Benefit from Knowledge
The more knowledge we have, the more intelligent we are. It is the
same for networks and network management. It is when one component
in the network lacks knowledge that affects what it should do, and
another component has that knowledge, that we usually rely on a human
operator or a centralised management tool to convey the knowledge.
Up to now, most available network knowledge is only the current
network status, either inside a device or relevant data from other
devices.
However, historic knowledge is very helpful to make correct
decisions, in particular to reducing network oscillation or to manage
network resources over time. Transplantable knowledge from other
networks can be helpful to initially set up a new network or new
network devices. Knowledge of relationship between network events
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and network configuration may help network to decide the best
parameters according to real performance feedback.
6. Security Considerations
This document is focussed on what is missing to allow autonomic
network configuration, including of course security settings.
Therefore, it does not itself create any new security issues. It is
worth underlining that autonomic technology must be designed with
strong security properties from the start, since a network with
vulnerable autonomic functions would be at great risk.
7. IANA Considerations
This memo includes no request to IANA.
8. Acknowledgements
This document was produced using the xml2rfc tool [RFC2629].
9. Informative References
[I-D.behringer-default-secure]
Behringer, M., Pritikin, M., and S. Bjarnason, "Making The
Internet Secure By Default", draft-behringer-default-
secure-00 (work in progress), January 2014.
[I-D.farrelll-mpls-opportunistic-encrypt]
Farrel, A. and S. Farrell, "Opportunistic Encryption in
MPLS Networks", draft-farrelll-mpls-opportunistic-
encrypt-02 (work in progress), February 2014.
[I-D.irtf-nmrg-autonomic-network-definitions]
Behringer, M., Pritikin, M., Bjarnason, S., Clemm, A.,
Carpenter, B., Jiang, S., and L. Ciavaglia, "Autonomic
Networking - Definitions and Design Goals", draft-irtf-
nmrg-autonomic-network-definitions-00 (work in progress),
December 2013.
[I-D.jiang-config-negotiation-protocol]
Jiang, S., Carpenter, B., Liu, B., and Y. Yin,
"Configuration Negotiation Protocol for Network Devices",
draft-jiang-config-negotiation-protocol-00 (work in
progress), October 2013.
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[I-D.jiang-config-negotiation-ps]
Jiang, S., Yin, Y., and B. Carpenter, "Network
Configuration Negotiation Problem Statement and
Requirements", draft-jiang-config-negotiation-ps-02 (work
in progress), January 2014.
[RFC1157] Case, J., Fedor, M., Schoffstall, M., and J. Davin,
"Simple Network Management Protocol (SNMP)", STD 15, RFC
1157, May 1990.
[RFC1661] Simpson, W., "The Point-to-Point Protocol (PPP)", STD 51,
RFC 1661, July 1994.
[RFC1994] Simpson, W., "PPP Challenge Handshake Authentication
Protocol (CHAP)", RFC 1994, August 1996.
[RFC2131] Droms, R., "Dynamic Host Configuration Protocol", RFC
2131, March 1997.
[RFC2136] Vixie, P., Thomson, S., Rekhter, Y., and J. Bound,
"Dynamic Updates in the Domain Name System (DNS UPDATE)",
RFC 2136, April 1997.
[RFC2629] Rose, M., "Writing I-Ds and RFCs using XML", RFC 2629,
June 1999.
[RFC2865] Rigney, C., Willens, S., Rubens, A., and W. Simpson,
"Remote Authentication Dial In User Service (RADIUS)", RFC
2865, June 2000.
[RFC2866] Rigney, C., "RADIUS Accounting", RFC 2866, June 2000.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
and M. Carney, "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003.
[RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
Host Configuration Protocol (DHCP) version 6", RFC 3633,
December 2003.
[RFC4322] Richardson, M. and D. Redelmeier, "Opportunistic
Encryption using the Internet Key Exchange (IKE)", RFC
4322, December 2005.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007.
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[RFC5575] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
and D. McPherson, "Dissemination of Flow Specification
Rules", RFC 5575, August 2009.
[RFC6241] Enns, R., Bjorklund, M., Schoenwaelder, J., and A.
Bierman, "Network Configuration Protocol (NETCONF)", RFC
6241, June 2011.
Authors' Addresses
Michael H. Behringer
Cisco Systems
Email: mbehring@cisco.com
Brian Carpenter
Department of Computer Science
University of Auckland
PB 92019
Auckland 1142
New Zealand
Email: brian.e.carpenter@gmail.com
Sheng Jiang
Huawei Technologies Co., Ltd
Q14, Huawei Campus, No.156 Beiqing Road
Hai-Dian District, Beijing, 100095
P.R. China
Email: jiangsheng@huawei.com
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