Case Study: Virtual Private Networks in SuperCom Service Provider Network
As with all complex topics, the MPLS/VPN concepts are best explained through use of a case study. Imagine a service provider (let’s call it SuperCom) that is offering VPN services based on MPLS/VPN technologies. The service provider has two points of presence (POP), a U.S. POP in the San Jose area and a French POP in the Paris area. The POPs are linked through a core router located in Washington, D.C. The service provider has two customers: FastFood, with headquarters in Sa..
For very large networks, it is quite common to have a large number of areas. It also is not uncommon to have low-end routers in these areas. Therefore, receiving a large amount of summary LSA data is a cause for concern. As a solution, OSPF created the totally stubby area. As with a stub area, external LSAs are not advertised in a totally stubby area; unlike a stub area, however, a totally stubby area does not pass interarea traffic. Now, even summary link state..
A wealth of security concepts have been covered in the previous chapters; now, you are ready to look at some of the techniques that are used to secure areas of your network that are vulnerable to attacks, in particular the demilitarized zone (DMZ). The DMZ is defined as an isolated part of the network that is easily accessible to hosts outside of the network, such as the Internet. Figure 6-1 displays a typical network design where a DMZ is defined with a number of bastion h..
Technical Overview of Cisco IOS Frame Relay Compression Schemes
This section introduces the different compression schemes for Frame Relay that are supported by the Cisco IOS software. In general, users select a compression scheme that falls under either the payload compression scheme or packet header compression scheme. Data Payload Compression Schemes The Cisco IOS software supports a packet-by-packet payload compression scheme using Stacker compression. The Cisco packet-by-packet payload compression for Frame Relay feature..
Suppose that a switch port is receiving BPDUs and the switch port is in the Blocking state. The port makes up a redundant path; it is blocking because it is neither a root port nor a designated port. It will remain in the Blocking state as long as a steady flow of BPDUs is received. If BPDUs are being sent over a link but the flow of BPDUs stops for some reason, the lastknown BPDU is kept until the Max Age timer expires. Then that BPDU is flushed, and the switch thinks..
