My Netwok Dictionary

Route summarization or aggregation,  is a mechanism used to design networks that are more flexible and perform better. With route summarization  or aggregation, in a hierarchical routing infrastructure, one route in a routing table represents many routes.

Although some routing protocols summarize only at the boundaries of major network numbers, others support route summarization (aggregation) at any bit boundary. Variable-length subnet masks enable routing protocols to summarize on bit boundaries.

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It is important to note that the ip helper-address command does not just forward DHCP requests. In fact, although you can configure it to forward any UDP broadcast you want, by default it will forward UDP broadcast packets for several different UDP ports to the specified address. In some cases, this unwanted traffic can cause problems on the network or DHCP server. Read the rest of this entry »

The traditional role of routers in DHCP has been simply to act as a proxy device.DHCP proxy function is still the most common for routers.

Initial DHCP request comes from a client that typically doesn’t have an IP address, it must find the server using a Layer 2 broadcast. So, if the router was not able to function as a proxy for these broadcasts, it would be necessary to put a DHCP server on every network segment. Read the rest of this entry »

A broadcast is a data packet that is destined for multiple hosts. Broadcasts can occur at the data link layer and the network layer. Data-link broadcasts are sent to all hosts attached to a particular physical network. Network layer broadcasts are sent to all hosts attached to a particular logical network. The Transmission Control Protocol/Internet Protocol (TCP/IP) supports the following types of broadcast packets:
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This case study addresses the issue of integrating Routing Information Protocol (RIP) networks with Open Shortest Path First (OSPF) networks. Most OSPF networks also use RIP to communicate with hosts or to communicate with portions of the internetwork that do not use OSPF. Cisco supports both the RIP and OSPF protocols and provides a way to exchange routing information between RIP and OSPF networks. This case study provides examples of how to complete the following phases in redistributing Read the rest of this entry »

The Routing Information Protocol (RIP) is a dynamic routing protocol used in local and wide area networks. As such it is classified as an interior gateway protocol (IGP) using the distance-vector routing algorithm. It was first defined in RFC 1058 (1988). The protocol has since been extended several times, resulting in RIP Version 2 (RFC 2453). The original version is now known as RIP. Both versions are still in use today, however, they are considered technically obsoleted by more advanced techniques, such as Read the rest of this entry »

To configure Site-to-Site VPN the routers used must support IPSec. Most of Cisco routers do. Another need is that both sides use a static public IP address to connect to the Internet.

We will go through the steps to be done on one side and the same steps must be repeated on the other side too. The encryption of data will depend on a shared-key. This way, we will not need specialized CAs or RSA methodologies. Read the rest of this entry »