Overloading NAT with Port Address Translation
As mentioned earlier, NAT is one of the key features that helped to reduce the speed at which the IPv4 address space was being depleted. NAT overloading, also known as Port Address Translation (PAT), is the NAT feature that actually provides the significant savings of IP addresses. The key to understanding how PAT works is to consider the following: From a server’s perspective, there is no significant difference between 100 different TCP connections, each from a different h..
STP Configuration and Analysis
Example 3-1, based on Figure 3-6, shows some of the basic STP configuration and show commands. Take care to note that many of the upcoming commands allow the parameters to be set for all VLANs by omitting the VLAN parameter, or set per VLAN by including a VLAN parameter. Example 3-1 begins with SW1 coincidentally becoming the Root switch. After that, SW2 is configured to become root, and SW3 changes its Root Port as a result of a configured port cost in VLAN 1. figure..
The 802.11i working group has improved the security of 802.11 wireless LANs with an update to the 802.11 standard in 2004. The Temporal Key Integrity Protocol, for example, fixes the keyreuse problem of WEP. The TKIP process begins with a 128-bit “temporal key” shared among clients and access points. TKIP combines the temporal key with the client’s MAC address and then adds a relatively large 16-octet initialization vector to produce the key used to encrypt data. This..
Wide-Area Networks and Technologies
Wide-area network (WAN) technologies are characterized as networks covering a broad geographical area. These technologies use common carrier facilities. On a seven-layer model, they operate on the physical, data link layer. WANs are divided into three types of links: Point-to-point(leased line)— There are several common protocols used in these links—the most common are Point -to Point Protocol (PPP), Synchronous Data Link Control (SDLC), and High-Level Data Link Control..
The access layer is present where the end users are connected to the network. Access switches usually provide Layer 2 (VLAN) connectivity between users. Devices in this layer, sometimes called building access switches, should have the following capabilities: ■ Low cost per switch port ■ High port density ■ Scalable uplinks to higher layers ■ User access functions such as VLAN membership, traffic and protocol filtering, and quality of service (QoS) ■ Resiliency throu..
