Dynamic Host Configuration (DHC) T. Mrugalski
Internet-Draft ISC
Intended status: Informational K. Kinnear
Expires: January 04, 2014 Cisco
July 03, 2013
DHCPv6 Failover Requirements
draft-ietf-dhc-dhcpv6-failover-requirements-06
Abstract
The DHCPv6 protocol, defined in [RFC3315] allows for multiple servers
to operate on a single network, however it does not define any way
the servers could share information about currently active clients
and their leases. Some sites are interested in running multiple
servers in such a way as to provide increased availability in case of
server failure. In order for this to work reliably, the cooperating
primary and secondary servers must maintain a consistent database of
the lease information. [RFC3315] allows for but does not define any
redundancy or failover mechanisms. This document outlines
requirements for DHCPv6 failover, enumerates related problems, and
discusses the proposed scope of work to be conducted. This document
does not define a DHCPv6 failover protocol.
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
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This Internet-Draft will expire on January 04, 2014.
Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the
document authors. All rights reserved.
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This document is subject to BCP 78 and the IETF Trust's Legal
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Definitions . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Scope of work . . . . . . . . . . . . . . . . . . . . . . . . 4
3.1. Alternatives to Failover . . . . . . . . . . . . . . . . 5
3.1.1. Short-lived addresses . . . . . . . . . . . . . . . . 5
3.1.2. Redundant servers . . . . . . . . . . . . . . . . . . 5
3.1.3. Distributed databases . . . . . . . . . . . . . . . . 5
3.1.4. Load Balancing . . . . . . . . . . . . . . . . . . . 6
4. Failover Scenarios . . . . . . . . . . . . . . . . . . . . . 6
4.1. Hot Standby Model . . . . . . . . . . . . . . . . . . . . 6
4.2. Geographically Distributed Failover . . . . . . . . . . . 6
4.3. Load balancing . . . . . . . . . . . . . . . . . . . . . 6
4.4. 1-to-1, m-to-1 and m-to-m models . . . . . . . . . . . . 7
4.5. Split prefixes . . . . . . . . . . . . . . . . . . . . . 7
4.6. Long lived connections . . . . . . . . . . . . . . . . . 7
4.7. Partial server communication loss . . . . . . . . . . . . 8
5. Principles of DHCPv6 Failover . . . . . . . . . . . . . . . . 8
5.1. Failure modes . . . . . . . . . . . . . . . . . . . . . . 8
5.1.1. Server Failure . . . . . . . . . . . . . . . . . . . 9
5.1.2. Network partition . . . . . . . . . . . . . . . . . . 9
5.2. Synchronization mechanisms . . . . . . . . . . . . . . . 10
5.2.1. Lockstep . . . . . . . . . . . . . . . . . . . . . . 10
5.2.2. Lazy updates . . . . . . . . . . . . . . . . . . . . 11
6. DHCPv4 and DHCPv6 Failover Comparison . . . . . . . . . . . . 11
7. DHCPv6 Failover Requirements . . . . . . . . . . . . . . . . 12
7.1. Features out of scope . . . . . . . . . . . . . . . . . . 13
8. Security Considerations . . . . . . . . . . . . . . . . . . . 14
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 14
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 14
11. References . . . . . . . . . . . . . . . . . . . . . . . . . 14
11.1. Normative References . . . . . . . . . . . . . . . . . . 14
11.2. Informative References . . . . . . . . . . . . . . . . . 15
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 15
1. Introduction
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The DHCPv6 protocol, defined in [RFC3315] allows for multiple servers
to be operating on a single network, however it does not define how
the servers can share the same address and prefix delegation pools
and allow a client to seamlessly extend its existing leases when the
original server is down. [RFC3315] provides for these capabilities,
but does not document how the servers cooperate and communicate to
provide this capability. Some sites are interested in running
multiple servers in such a way as to provide redundancy in case of
server failure. In order for this to work reliably, the cooperating
primary and secondary servers must maintain a consistent database of
the lease information.
This document discusses failover implementations scenarios, failure
modes, and synchronization approaches to provide background to the
list of requirements for a DHCPv6 failover protocol. It then defines
a minimum set of requirements that failover must provide to be
useful, while acknowledging that additional features may be specified
as extensions. This document does not define a DHCPv6 failover
protocol.
2. Definitions
This section defines terms that are relevant to DHCPv6 failover.
Definitions from [RFC3315] are included by reference. In particular,
client means any device (e.g., end user host, CPE or other router)
that implements client functionality of the DHCPv6 protocol. A
server means a DHCPv6 server, unless explicitly noted otherwise. A
relay is a DHCPv6 relay.
A binding (or client binding) is a group of server data records
containing the information the server has about the addresses in
an IA or configuration information explicitly assigned to the
client. Configuration information that has been returned to a
client through a policy - for example, the information returned to
all clients on the same link - does not require a binding.
DDNS - an abbreviation for "Dynamic DNS", which refers to the
capability to update a DNS server's name database using the on-
the-wire protocol defined in [RFC2136]. Clients and servers can
negotiate the scope of such updates as defined in [RFC4704].
Failover - an ability of one partner to continue offering services
provided by another partner, with minimal or no impact on clients.
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FQDN - a fully qualified domain name. A fully qualified domain
name generally is a host name with at least one domain label under
the top-level domain. For example "dhcp.example.org" is a fully
qualified domain name.
High Availability - a desired property of DHCPv6 servers to
continue providing services despite experiencing unwanted events
such as server crashes, link failures, or network partitions.
Load Balancing - the ability for two or more servers to each
process some portion of the client request traffic in a conflict-
free fashion.
Lease - an IPv6 address, an IPv6 prefix or other resource that was
assigned ("leased") by a server to a specific client. A lease may
include additional information, like associated fully qualified
domain name (FQDN) and/or information about associated DNS
updates.
Partner - A "partner", for the purpose of this document, refers to
a failover server, typically the other failover server in a
failover relationship.
Stable Storage - each DHCP server is required to keep its lease
database in some form of storage (known as "stable storage") that
will be consistent throughout reboots, crashes and power failures.
Partner Failure - A power outage, unexpected shutdown, crash or
other type of failure that renders a partner unable to continue
its operation.
3. Scope of work
In order to fit within the IETF process effectively and efficiently,
the standardization effort for DHCPv6 failover is expected to proceed
with the creation of documents of increasing specificity. It begins
with this document specifying the requirements for DHCPv6 failover
("requirements document"). Later documents are expected to address
the design of the DHCPv6 failover protocol ("design document"), and
if sufficient interest exists, the protocol details required to
implement the DHCPv6 failover protocol itself ("protocol document").
The goal of this partitioning is, in part, to ease the validation,
review, and approval of the DHCPv6 failover protocol by presenting it
in comprehensible parts to the larger community.
Additional documents describing extensions may also be defined.
DHCPv6 Failover requirements are presented in Section 7.
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3.1. Alternatives to Failover
There are many scenarios when it seems that a failover capability
would be useful. However, there are often much simpler approaches
that will meet the required goals. This section documents examples
where failover is not really needed.
3.1.1. Short-lived addresses
There are cases when IPv6 addresses are used only for a short time,
but there is a need to have high degree of confidence that those
addresses will be served. A notable example is a PXE scenario where
hosts require an address during boot. Address and possibly other
configuration parameters are used during boot process and are
discarded afterwards. Any lack of available DHCPv6 service at this
time may render the devices unbootable.
Instead of deploying failover, it is better to use the much simpler
preference mechanism, defined in [RFC3315]. For example, consider
two or more servers with each having distinct preference set (e.g. 10
and 20). Both will answer to a client's request. The client should
choose the one with larger preference value. In case of failure of
the most preferred server, the next server will keep responding to
clients' queries. This approach is simple to deploy, but does not
offer lease stability, i.e. in case of server failure, clients'
addresses and prefixes will change.
3.1.2. Redundant servers
In some cases the desire to deploy failover is motivated by high
availability, i.e. to continue providing services despite server
failure. If there are no additional requirements, that goal may be
fulfilled with simply deploying two or more independent servers on
the same link.
There are several well documented approaches how such deployment
works. They are discussed in detail in [RFC6853]. Each of those
approaches is simpler to deploy and maintain than full failover.
3.1.3. Distributed databases
Some servers may allow their lease database to be stored in external
databases. Another possible alternative to failover is to configure
two servers to connect to the same distributed database.
Care should be taken to understand how inconsistencies are solved in
such database backends and how such conflict resolutions affect
DHCPv6 server operation.
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It is also essential to use only databases that are really
distributed and do not have single point of failure themselves.
Otherwise the single point of failure is only moved to a different
location (database rather than DHCPv6 server). Such a configuration
does not improve redundancy, but significantly complicates
deployment.
3.1.4. Load Balancing
Sometimes the desire to deploy more than one server is based on the
assumption that they will share the client traffic. Administrators
that are interested in such a capability are advised to deploy a load
balancing mechanism, defined in [I-D.ietf-dhc-dhcpv6-load-balancing].
4. Failover Scenarios
The following section provides several examples of deployment
scenarios and use cases that may be associated with capabilities
commonly referred to as failover. These scenarios may be inside or
outside of scope for DHCPv6 failover protocol as defined by this
document. They are enumerated here to provide a common basis for
discussion.
4.1. Hot Standby Model
In the simplest case, there are two partners that are connected to
the same network. Only one of partners ("primary") provides services
to clients. In case of its failure, the second partner ("secondary")
continues handling services previously handled by first partner. As
both servers are connected to the same network, a partner that fails
to communicate with its partner while also receiving requests from
clients may assume with high probability that its partner is down and
the network is functional. This assumption may affect its operation.
4.2. Geographically Distributed Failover
Servers may be physically located in separate locations. A common
example of such a topology is where a service provider has at least a
regional high performance network between geographically distributed
datacenters. In such a scenario, one server is located in one
datacenter and its failover partner is located in another remote
datacenter. In this scenario, when one partner finds that it cannot
communicate with the other partner, it does not necessarily mean that
the other partner is down.
4.3. Load balancing
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A desire to have more than one server in a network may also be
created by the desire to have incoming traffic be handled by several
servers. This decreases the load each server must endure when all
servers are operational. Although such a capability does not,
strictly, require failover - it is clear that failover makes such an
architecture more straightforward.
Note that in a load balancing situation which includes failover, each
individual server must be able to handle the full load normally
handled by both servers working together, or there is not a true
increase in availability.
4.4. 1-to-1, m-to-1 and m-to-m models
A failover relationship for a specific network is provided by two
failover partners. Those partners communicate with each other and
back up all pools. This scenario is sometimes referred to as the
1-to-1 model and is considered relatively simple. In larger networks
one server may be participating in several failover relationships,
i.e. it provides failover for several address or prefix pools, each
served by separate partners. Such a scenario can be referred to as
m-to-1. The most complex scenario - m-to-m - assumes that each
partner participates in multiple failover relationships.
4.5. Split prefixes
Due to the extensive IPv6 address space, it is possible to provide
semi-redundant service by splitting the available pool of addressees
into two or more non-overlapping pools, with each server handling its
own smaller pool. Several versions of such a scenario are discussed
in [RFC6853].
4.6. Long lived connections
Certain nodes may maintain long lived connections. Since the IPv6
address space is large, techniques exist (e.g. [RFC6853]) that use
the easy availability of IPv6 addresses in order to provide increased
DHCPv6 availability. However, these approaches do not generally
provide for stable IPv6 addresses for DHCPv6 clients should the
server with which the client is interacting become unavailable.
The obvious benefit of stable addresses is the ability to update DNS
infrequently. While the DNS can be updated every time IPv6 address
changes, it introduces delays and (depending on DNS configuration)
old entries may be cached for prolonged periods of time.
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The other benefit of having stable address is that many monitoring
solutions provide statistics on a per IP basis, so IP changes make
measuring characteristics of a given box more difficult.
It should be noted that lease stability is an explicit non-goal in
some deployments. One notable example is an ISP who wants to provide
addresses that change frequently to prevent his customers from
running servers (without paying extra for more enterprise oriented
service).
4.7. Partial server communication loss
There is a scenario where the DHCPv6 server may be configured to
serve clients on one network adapter and communicate with a partner
server (server to server traffic) on a different network adapter. In
this scenario, if the server loses connectivity on the network
adapter used to communicate with the clients because of network
adapter (hardware) failure, there is no intimation of the loss of
service to the partner in the DHCPv6 failover protocol. Since the
servers are able to communicate with each other, the partner remains
ignorant of the loss of service to clients.
5. Principles of DHCPv6 Failover
This section describes important issues that will affect any DHCPv6
failover protocol. This section is not intended to define
implementation details, but rather high level concepts and issues
that are important to DHCPv6 failover. These issues form a basis for
later documents which deal with the solutions to these issues.
General failover concept assumes that there are backup servers that
can provide service in case of the primary server failure. In theory
there could be more than one backup server that could take up the
role if such a need arise. However, having more than two servers
introduces a very difficult issue of synchronizing between partners.
In case of just a pair of cooperating servers, the notification and
processes can result in only one of two states: fully successful (got
response from a partner) and total failure (no response, failure
event occurred). Had there be more than two partners participating
in a relationship, there would be a third states in between (some
partners updated their state, but some didn't). This would greatly
complicate protocol design, and would give little advantage in
return. Therefore an approach that assumes a pair of cooperating
servers was chosen.
5.1. Failure modes
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This section documents failure modes. Each failure mode is listed as
either an in-scope or out-of-scope requirement for the failover
protocol.
5.1.1. Server Failure
Servers may become unresponsive due to a software crash, hardware
failure, power outage or any number of other reasons. The failover
partner will detect such event due to lack of responses from the down
partner. In this failure mode, the assumption is that the server is
the only equipment that is off-line and all other network equipment
is operating normally. In particular, communication between other
nodes is not interrupted.
When working under the assumption that this is the only type of
failure that can happen, the server may safely assume that its
partner unreachability means that it is down, so other nodes (clients
in particular) are not able to reach it either and no services are
provided.
It should be noted that recovery after the failed server is brought
back on-line is straightforward, due to the fact that it just needs
to download current information from the lease database of the
healthy partner and there is no conflict resolution required.
This is by far the most common failure mode between two failover
partners.
When the two servers are located physically close to each other,
possibly in the same room, the probability that a failure to
communicate between failover partners is due to server failure is
increased.
5.1.2. Network partition
Another possible cause of partner unreachability is a failure in the
network that connects the two servers. This may be caused by failure
of any kind of network equipment: router, switch, physical cables, or
optic fibers. As a result of such a failure the network is split
into two or more disjoint sections (partitions) that are not able to
communicate with each other. Such an event is called network
partition. If failover partners are located in different partitions,
they won't be able to communicate with each other. Nevertheless,
each partner may still be able to serve clients that happen to be
part of the same partition.
If this failure mode is taken into consideration, a server can't
assume that partner unreachability automatically means that its
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partner is down. They must consider the fact that the partner may
continue operating and interacting with a subset of the clients. The
only valid assumption is that partner also detected the network
partition event and follows procedures specified for such a
situation.
It should be noted that recovery after a partitioned network is
rejoined is significantly more complicated than recovery from a
server failure event. As both servers may have kept serving clients,
they have two separate lease databases, and they need to agree on the
state of each lease (or follow any other algorithm to bring their
lease databases into agreement).
This failure mode is more likely (though still rare) in the situation
where two servers are in physically distant locations with multiple
network elements between them. This is the case in geographically
distributed failover (see Section 4.2).
5.2. Synchronization mechanisms
Partners must exchange information about changes made to the lease
database. There are at least two types of synchronization methods
that may be used. These concepts are related to distributed
databases, so some familiarity with distributed database is useful to
better understand this topic.
5.2.1. Lockstep
When a server receives a REQUEST message from a client it consults
its lease database and assigns requested addresses and/or prefixes.
To make sure that its partner maintains a consistent database, it
then sends information about a new or just updated lease to the
partner and waits for the partner's response. After the response
from partner is received the REPLY message is transmitted to the
client.
This approach has the benefit of having a completely consistent lease
database between partners at all times. Unfortunately, there is a
large performance penalty for this approach as each response sent to
a client is delayed by the total sum of the delays caused by two
transmissions between partners and the processing by the second
partner. The second partner is expected to update its own copy of
the lease database in permanent storage, so this delay is not
negligible, even in fast networks.
Due to advent of SSD disks or battery backed ram disks technology,
this write performance penalty can be limited to some degree.
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5.2.2. Lazy updates
Another approach to synchronizing the lease databases is to transmit
the REPLY message to the client before completing the update to the
partner. The server sends the REPLY to the client immediately after
assigning appropriate addresses and/or prefixes and initiates the
partner update at a later time, depending on the algorithm chosen.
Another variation of this approach is to initiate transmission to the
partner, but not wait for its response before sending the REPLY to
the client.
This approach has benefit of a minimal impact on server response
times, thus it is much better from a performance perspective.
However, it makes the lease databases loosely synchronized between
partners. This makes the synchronization more complex (and
particularly the re-integration after a network partition event), as
there may be cases where one client has been given a lease on an
address or prefix of which the partner is not aware (e.g. if server
crashes after sending REPLY to the client, but before sending update
information to its partner).
6. DHCPv4 and DHCPv6 Failover Comparison
There are significant similarities between existing DHCPv4 and
envisaged DHCPv6 failovers. In particular both serve IP addresses to
clients, require maintaining consistent databases among partners,
need to perform consistent DNS Updates, must be able take over
bindings offered by failed partner, must be able to resume operation
after partner is recovered. DNS conflict resolution works on the
same principles in both DHCPv4 and DHCPv6.
Nevertheless, there are significant differences. IPv6 introduced
prefix delegation [RFC3633] that is a crucial element of the DHCPv6
protocol. IPv6 also introduced the concept of deprecated addresses
with separate preferred and valid lifetimes, both being configured
via DHCPv6. Negative response (NACK) in DHCPv4 has been replaced
with the ability in DHCPv6 to provide corrected response in a REPLY
message that differs from a REQUEST.
Also, the typical large address space (close to 2^64 addresses on /64
prefixes expected to be available on most networks) may make managing
address assignment significantly different from DHCPv4 failover. In
DHCPv4 it was not possible to use a hash or calculated technique to
divide the significantly more limited address space and therefore
much of the protocol that deals with pool balancing and rebalancing
might not be necessary and can be done mathematically. Also, because
of the much lower degree of contention for IP addresses, the DHCPv6
failover protocol does not need to be tuned to support rapid
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reclamation of IPv6 addresses following the loss of a failover peer's
database.
However, DHCPv6 Prefix Delegation is similar to IPv4 addressing in
terms of the number of available leases and therefore techniques for
pool balancing and rebalancing and more rapid reclamation of prefixes
allocated by a failed peer will be needed.
7. DHCPv6 Failover Requirements
This section summarizes the requirements for DHCPv6 failover.
Certain capabilities may be useful in some, but not all scenarios.
Such additional features will be considered optional parts of
failover, and will be split and defined in separate documents. As
such, this document can be considered an attempt to define
requirements for the DHCPv6 failover "core" protocol.
The core of the DHCPv6 failover protocol is expected to provide the
following properties:
1. The number of supported partners must be exactly two, i.e. there
are at most two servers that are aware of a specific lease.
2. For each prefix or address pool, a server must not participate
in more than one failover relationship.
3. The defined protocol must support the m-to-1 model (i.e. one
server may form more than one relationship), but an
implementation may choose to implement only the 1-to-1 model
(i.e. everything from one server is backed on another).
4. One partner must be able to continue serving leases offered by
the other partner. This property is also sometimes called
"lease stability". The failure of either failover partner
should pose minimal or no impact on client connectivity. In
particular, it must not force the client to change addresses and
/or change prefixes delegated to it. Long-lived connections
must not be disturbed.
5. Prefix delegation must be supported.
6. Use of the failover protocol must not introduce significant
performance impact on server response times. Therefore
synchronization between partners must be done using some form of
lazy updates (see Section 5.2.2).
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7. The pair of failover servers must be able to recover from a
server down failure (see Section 5.1.1).
8. The pair of failover servers must be able to recover from a
network partition event (see Section 5.1.2).
9. The design must allow secure communication between the failover
partners.
10. The definition of extensions to this core protocol should be
allowed, when possible.
Depending on the specific nature of the failure, the recovery
procedures mentioned in points 7 and 8 may require manual
intervention.
High Availability is a property of the protocol that allows clients
to receive DHCPv6 services despite the failure of individual DHCPv6
servers. In particular, it means the server that takes over
providing service to clients from its failed partner, will continue
serving the same addresses and/or prefixes. This property is also
called "lease stability".
Despite the lack of standardization of DHCPv4 failover, the
coexistence of DHCPv4 and DHCPv6 failover may be taken into
consideration. In particular, certain features that are common for
both IPv4 and IPv6, like DNS Update mechanism should be taken into
consideration.
7.1. Features out of scope
The following features are explicitly out of scope.
1. Load Balancing - a capability is considered an extension and may
be defined in a separate document. It must not be part of the
core protocol, but rather defined as an extension. The primary
reason for this the desire to limit core protocol complexity.
Load Balancing is likely to be defined as an extension. See
[I-D.ietf-dhc-dhcpv6-load-balancing].
2. Configuration synchronization - two failover partners are
expected to maintain the same configuration. Mismatched
configuration between partners is a frequent problem in failover
solutions. Unfortunately, that is an open-ended problem, since
different servers have very different configuration data models.
3. m-to-m model (see Section 4.4)
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4. Servers participating in multiple failover relationships for any
given pool.
8. Security Considerations
The design must allow secure communication between the failover
partners. This requirement applies to the specification only, i.e.
the design must include a way to secure communication. It does not
mandate such security be employed, just that it be available.
The protocol specification, when it is written, should provide
operational guidelines in the case of authentication mechanisms that
require access to network servers that have the potential to be
unreachable (e.g. what to do if a partner is reachable, but remote
Certificate Authority is unreachable due to network partition event).
The security considerations for the design itself will be discussed
in the design document.
9. IANA Considerations
IANA is not requested to perform any actions at this time.
10. Acknowledgements
This document extensively uses concepts, definitions and other parts
of [dhcpv4-failover] document. Thanks to Bernie Volz and Shawn
Routhier for their frequent reviews and substantial contributions.
Authors would also like to thank Qin Wu, Jean-Francois Tremblay,
Frank Sweetser, Jiang Sheng, Yu Fu, Greg Rabil, Vithalprasad
Gaitonde, Krzysztof Nowicki and Steinar Haug for their comments and
feedback.
This work has been partially supported by Gdansk University of
Technology and the Polish Ministry of Science and Higher Education
under the European Regional Development Fund, Grant No.
POIG.01.01.02-00-045/09-00 (Future Internet Engineering Project).
11. References
11.1. Normative References
[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.
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[RFC3633] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic
Host Configuration Protocol (DHCP) version 6", RFC 3633,
December 2003.
[RFC4704] Volz, B., "The Dynamic Host Configuration Protocol for
IPv6 (DHCPv6) Client Fully Qualified Domain Name (FQDN)
Option", RFC 4704, October 2006.
11.2. Informative References
[I-D.ietf-dhc-dhcpv6-load-balancing]
Kostur, A., "DHC Load Balancing Algorithm for DHCPv6",
draft-ietf-dhc-dhcpv6-load-balancing-00 (work in
progress), December 2012.
[RFC2136] Vixie, P., Thomson, S., Rekhter, Y., and J. Bound,
"Dynamic Updates in the Domain Name System (DNS UPDATE)",
RFC 2136, April 1997.
[RFC6853] Brzozowski, J., Tremblay, J., Chen, J., and T. Mrugalski,
"DHCPv6 Redundancy Deployment Considerations", BCP 180,
RFC 6853, February 2013.
[dhcpv4-failover]
Droms, R., Kinnear, K., Stapp, M., Volz, B., Gonczi, S.,
Rabil, G., Dooley, M., and A. Kapur, "DHCP Failover
Protocol", draft-ietf-dhc-failover-12 (work in progress),
March 2003.
Authors' Addresses
Tomek Mrugalski
Internet Systems Consortium, Inc.
950 Charter Street
Redwood City, CA 94063
USA
Phone: +1 650 423 1345
Email: tomasz.mrugalski@gmail.com
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Kim Kinnear
Cisco Systems, Inc.
1414 Massachusetts Ave.
Boxborough, Massachusetts 01719
USA
Phone: +1 (978) 936-0000
Email: kkinnear@cisco.com
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