- Information
- AI Chat
Was this document helpful?
Deployment of MPLs
Course: Systems Programming (01:198:214)
23 Documents
Students shared 23 documents in this course
University: Rutgers University
Was this document helpful?
Deployment of MPLs
Originally conceived as a technology that would operate within the network of individual service
providers, MPLS remains hidden from most consumer and academic users of the Internet today.
However, it is now sufficiently popular among service providers that it has become almost
mandatory for high-end router manufacturers to include MPLS capabilities in their products. The
widespread success of MPLS is a relatively well-kept secret, at least to students and researchers
focused on the public Internet. Two main applications of MPLS account for most of its
deployment. The layer 3 VPN application described in this section is the killer application for
MPLS. Almost every service provider in the world now offers an MPLS-based layer 3 VPN
service.
This is often run on routers that are essentially separate from the Internet, since the main use of
layer 3 VPNs is to provide private IP service to corporations, not to provide global Internet
connectivity. Some providers do run their Internet service and VPN service over a common
backbone, however. The second popular usage of MPLS is explicit routing, either for traffic
engineering or fast reroute, or both. Unlike the layer 3 VPN service, which is explicitly marketed
to end customers, explicit routing is an internal capability that providers use to improve the
reliability of their networks or reduce the cost. Providers do not usually publicize details of their
internal network designs, making it more difficult to determine how many providers actually use
this technology.
It is clear that the explicit routing features of MPLS are used by fewer providers than the VPN
features, but nevertheless there is evidence of significant usage, especially when bandwidth is
expensive or when there is a strong desire to maintain low levels of congestion (e.g., to support
real-time services). It probably should not be a great surprise to learn that mobile devices LAB
09: Mobile WLAN present some challenges for the Internet architecture. The Internet was
designed in an era when computers were large, immobile devices, and, while the Internet’s
designers probably had some notion that mobile devices might appear in the future, it’s fair to
assume it was not a top priority to accommodate them.
Today, of course, mobile computers are everywhere, notably in the forms of laptops and IP-
enabled mobile phones, and increasingly in other forms such as sensors. In this section, we will
look at some of the challenges posed by the appearance of mobile devices and some of the
current approaches to accommodating them. Most readers of this book have probably used a
networked mobile device at some point, and for many of us mobile devices have become the
norm. So one might reasonably think that mobile networking is a solved problem. Certainly, it is
easy enough today to turn up in a wireless hotspot, connect to the Internet using 802.11 or some
other wireless networking protocol, and obtain pretty good Internet service. One key enabling
technology that made the hotspot feasible is DHCP.
If we look a little more closely, however, it’s clear that for some application scenarios, just
getting a new IP address every time you move—which is what DHCP does for you—isn’t always
enough. Suppose you are using your laptop or smartphone for a Voice over IP telephone call, and
while talking on the phone you move from one hotspot to another, or even switch from 802.11 to
