Transport diversity is a general terminology used for selecting or preferring a network exit-point for
end-user application traffic across network topologies that have a variety of characteristics. These
characteristics include things like monetary cost, reliability or availability, availability of bandwidth, and
One example of transport diversity is a branch office environment that has a primary path using Frame
Relay and a backup or alternate path using basic rate ISDN.
Upon completing this lesson, you will be able to:
Describe the features and operation of static routing
Describe the features and operation of dynamic routing protocols, including RIP, IGRP, EIGRP, and OSPF
Build a functional router configuration to support the specified network operational requirements, given a network design
Use show commands to identify anomalies in routing operation, given an operational router
Use debug commands to identify events and anomalies in routing operation, given an operational router...
You have two routers connected to your network. As you will see, having two default gateways
does not provide a very reliable path in the event of an outage. Configure your two routers to
provide hot standby access to networks. This will allow the web server and workstation to have
access to a reliable router in the event of a failure.
The event notiﬁcation service can carry out a selection process to determine
which of the published notiﬁcations are of interest to which of its clients, rout-
ing and delivering notiﬁcations only to those clients that are interested. In
addition to serving clients’ interests, the selection process also can be used by
the event notiﬁcation service to optimize communication within the network.
The information that drives the selection process originates with clients.
Messaging systems based on queuing include products such as Microsoft’s MSMQ and
IBM’s MQSeries . The queuing model with their store-and-forward mechanisms come into
play where the sender of the message expects someone to handle the message while imposing
asynchronous communication and guaranteed delivery constraints. A widely used standard
in messaging is the Message Passing Interface Standard (MPI) . MPI is designed for
high performance on both massively parallel machines and workstation clusters.
This paper presents SIENA, an event notiﬁcation service that we have de-
signed and implemented to maximize both expressiveness and scalability. In
Section 3we describe the service’s formally deﬁned application programming in-
terface,which is an extension of the familiar publish/subscribe protocol [Birman
1993]. Several candidate server topologies and protocols are presented in Sec-
The justiﬁcation for choosing this typing scheme is scalability. In other sys-
tems, such as one ﬁnds for example in the Java Distributed Event Speciﬁca-
tion [SunMicrosystems 1998] andCORBANotiﬁcation Service [ObjectManage-
ment Group 1998b], a notiﬁcation is a value of some named, explicit notiﬁcation
type. This implies a global authority formanaging and verifying the type space,
something which is clearly not feasible at an Internet scale. On the other hand,
we deﬁne a restricted set of attribute types from which to construct (arbitrary)
Our desire for the event notiﬁcation service to be general purpose also compli-
cates the routing problem for the service. In particular, we assume that objects
of interest have no knowledge of interested parties. Therefore, event notiﬁca-
tions cannot be addressed and routed in the same, relatively simple manner
as, for example, an electronic mail message. Moreover, we cannot assume any
particular locality of objects of interest and interested parties, which is a fact
that bears a strong relationship to the server topology issue.
Given these considerations, solving the routing problem can be seen as a
choice among three alternatives. Common to the three alternatives is the need
to broadcast some piece of information to all the servers in the network, where
the broadcast is required by the lack of a priori knowledge of locality. The ﬁrst
alternative broadcasts notiﬁcations, which implies that notiﬁcation matching
is performed at each local server based on the subscriptions received at that
The components of a loosely coupled system are typically designed to operate by generating and
responding to asynchronous events. An event notiﬁcation service is an application-independent in-
frastructure that supports the construction of event-based systems, whereby generators of events
publish event notiﬁcations to the infrastructure and consumers of events subscribe with the infras-
tructure to receive relevant notiﬁcations. The two primary services that should be provided to com-
ponents by the infrastructure are notiﬁcation selection (i.e.
If your route can be organised as a predominantly self-guided walk this means you don’t need so many
marshals or signs. This reduces the cost, time and effort spent putting up signs. However, large, mass-
participation events do need highly visible marshals and may well need signs placed at strategic points
to keep people on the right route. If you want to put up signs you’ll need to get approval from the local
If the route is mostly self-guided everyone should be given a clear map.
This module provides students with the ability to use the Microsoft® Exchange
Server Event Service within collaborative applications. The module also
provides an introduction to Exchange Server Routing. At the end of this
module, you will be able to create, edit, and debug an event script on an
Exchange Server public folder.
Abstract—Efficient event delivery in a content-based
publish/subscribe system has been a challenging problem.
Existing group communication solutions, such as IP multicast or
application-level multicast techniques, are not readily applicable
due to the highly heterogeneous communication pattern in such
systems. We first explore the design space of event routing
strategies for content-based publish/subscribe systems.
The entire format, name, route and length of your event depends solely on what you want to achieve.
You’re in charge of how complex or simple you want to make it. There are masses of different types of
walking event, ranging from fun walks and sponsored charity walks, to courses with measured
distances and long distance challenges.
A promoted walking event can be very attractive to people who are unused to walking or to exploring
the countryside, since they know they can’t get lost, they can go at their own pace, they may meet new
friends, learn more...
Some beautiful and famous countryside sites are at risk of being over-used for large-scale walks. This
kind of activity brings hundreds of tramping feet and a hubbub of noise and bustle which can destroy
the very beauty and atmosphere for which the place is famous. Other sites and routes are much more
robust and lend themselves happily to throngs of people all enjoying themselves at the same place at
the same time. Choose your event site wisely.
Obviously you will need to tailor your walk event to the interests and abilities of the people you plan to
attract. This will affect your choice of route, its length and difficulty and the way you publicise and
It is often a good idea to offer a shorter route option for people who do not want to walk the whole
way. This can help widen the appeal of your event to young families and older people.
Think about what you need your walkers to know and when they need to know it. The following list...
Silverlight is a framework for building rich, browser-hosted applications that run on a variety of
operating systems. Silverlight works its magic through a browser plug-in. When you surf to a web page
that includes Silverlight content, this browser plug-in runs, executes the code, and renders that content
in a specifically designated region of the page. The important part is that the Silverlight plug-in provides
Building upon the FeedTree distribution system, we
foresee a potential for entirely new services based on
RSS which cannot be accomplished today. By using
single-writer logs  in combination with a distributed
storage mechanism such as a DHT [22, 15, 9], we can
record permanently every RSS item published, allowing
a distributed archival store of micronews across the In-
ternet. Clients of such a system would easily be able to
ﬁnd out what they “missed” if they had been ofﬂine for
so long that old RSS items are no longer available in any
conventional, static RSS feed.
To accomplish this, a reliable transportmechanismis required
in addition to robust modulation and media access, link error
control and fault tolerant routing. The functionalities and design
of a suitable transport solution for WSN are the main issues
addressed in this paper.
The need for a transport layer for data delivery in WSN was
questioned in a recent work  under the premise that data
ﬂows from source to sink are generally loss tolerant.