There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

The Transmission Control Protocol.

At some point in the future, how far out we do not exactly know, wireless access to the Internet will outstrip all other forms of access bringing the freedom of mobility to the way we access the we...

ACM SIGCOMM computer communication review

In general, techniques are described for configuring and managing virtual networks. For example, a distributed virtual network controller is described that configures and manages an overlay network within a physical network formed by plurality of switches. A plurality of servers are interconnected by the switch fabric, each of the servers comprising an operating environment executing one or more virtual machines in communication via the overlay networks. The servers comprises a set of virtual switches that extends the overlay network as a virtual network to the operating environment of the virtual machines. The controller may instruct the servers and the virtual switches to perform various operations, such as determining a physical network path taken by packets of a network packet flow, determining latency through the network, re-routing traffic in the virtual network due to network events, replicating traffic for multicasting, providing multi-tenant services to support multiple virtual networks, monitoring and logging traffic characteristics within the virtual networks and other operations.

Physical path determination for virtual network packet flows

The Internet Protocol.

Segment Routing (SR) leverages the source routing paradigm. A node
steers a packet through an ordered list of instructions, called
segments. A segment can represent any instruction, topological or
service-based. A segment can have a semantic local to an SR node or
global within an SR domain. SR allows to enforce a flow through any
topological path while maintaining per-flow state only at the ingress
nodes to the SR domain. Segment Routing can be directly applied to the
MPLS architecture with no change on the forwarding plane. A segment is
encoded as an MPLS label. An ordered list of segments is encoded as a
stack of labels. The segment to process is on the top of the stack.
Upon completion of a segment, the related label is popped from the
stack. Segment Routing can be applied to the IPv6 architecture, with a
new type of routing header. A segment is encoded as an IPv6 address.
An ordered list of segments is encoded as an ordered list of IPv6
addresses in the routing header. The active segment is indicated by
the Destination Address of the packet. The next active segment is
indicated by a pointer in the new routing header.

Segment Routing Architecture

We describe and analyse in details the various factors that influence the convergence time of intradomain link state routing protocols. This convergence time reflects the time required by a network to react to the failure of a link or a router. To characterise the convergence process, we first use detailed measurements to determine the time required to perform the various operations of a link state protocol on currently deployed routers. We then build a simulation model based on those measurements and use it to study the convergence time in large networks. Our measurements and simulations indicate that sub-second link-state IGP convergence can be easily met on an ISP network without any compromise on stability.

/pdf/achieving-sub-second-igp-convergence-in-large-ip-networks-4uxrt3x1ki.pdf

Achieving sub-second IGP convergence in large IP networks

A path verification protocol (PVP), which enumerates a series of messages sent to a set of nodes, or routers, along a suspected path, identifies forwarding plane problems for effecting changes at the control plane level. The messages includes a command requesting interrogation of a further remote node for obtaining information about the path between the node receiving the PVP message and the further remote node (202). The node receiving the PVP message replies with a command response indicative of the outcome of attempts to tech the further remote node (206). The series of message collectively covers a set of important routing points along a path from the originator to the recipient. The aggregate command responses to the series of PVP messages is analyzed to identify not only whether the entire path is operational, but also the location and nature of the problem (308).

System and methods for detecting network failure

Network operators anticipate the offering of an increasing variety of cloud-based services with stringent Service Level Agreements. Technologies currently supporting IP networks however lack the flexibility and scalability properties to realize such evolution. In this article, we present Segment Routing (SR), a new network architecture aimed at filling this gap, driven by use-cases defined by network operators. SR implements the source routing and tunneling paradigms, letting nodes steer packets over paths using a sequence of instructions (segments) placed in the packet header. As such, SR allows the implementation of routing policies without per-flow entries at intermediate routers. This paper introduces the SR architecture, describes its related ongoing standardization efforts, and reviews the main use-cases envisioned by network operators.

The Segment Routing Architecture

QoS, short for "quality of service," is one of the most important goals a network designer or administrator will have. Ensuring that the network runs at optimal precision with data remaining accurate, traveling fast, and to the correct user are the main objectives of QoS. The various media that fly across the network including voice, video, and data have different idiosyncrasies that try the dimensions of the network. This malleable network architecture poses an always moving potential problem for the network professional.

The authors have provided a comprehensive treatise on this subject. They have included topics such as traffic engineering, capacity planning, and admission control. This book provides real world case studies of QoS in multiservice networks. These case studies remove the mystery behind QoS by illustrating the how, what, and why of implementing QoS within networks. Readers will be able to learn from the successes and failures of these actual working designs and configurations.

*Helps readers understand concepts of IP QoS by presenting clear descriptions of QoS components, architectures, and protocols
*Directs readers in the design and deployment of IP QoS networks through fully explained examples of actual working designs
*Contains real life case studies which focus on implementation

Clarence Filsfils

Papers

Segment Routing Architecture

Achieving sub-second IGP convergence in large IP networks

System and methods for detecting network failure

The Segment Routing Architecture

Deploying IP and MPLS QoS for Multiservice Networks: Theory & Practice